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  • 1.
    A. Manneh, Ilana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Hamza, Karim M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Rundgren, Carl-Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Progression in action for developing chemical knowledgeManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In this paper, we discuss the well-known teaching challenge of how to provide undergraduate students with basic chemistry knowledge without making them experience these basics as meaningless and unintelligible. First, we situate the challenge in a classic dilemma: should we teach the necessary basic facts before the chemical explanations or should the explanations be taught before or in parallel to these facts? Here we draw on examples from interviews with graduate students reflecting on their experiences regarding their studies at the undergraduate level. Second, we suggest a way out of the dilemma, through a shift in perspective from the typical progression of facts and explanations towards a purpose and activity-based progression. We conclude with a discussion of implications of such a shift for university chemistry education together with suggestions for future research.

  • 2.
    A. Manneh, Ilana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Hamza, Karim
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Rundgren, Carl-Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    The role of anthropomorphisms in students’ reasoning about chemical structure and bonding2018Ingår i: Asia-Pacific Forum on Science Learning and Teaching, ISSN 1609-4913, E-ISSN 1609-4913, Vol. 19, nr 2, artikel-id 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anthropomorphisms are widespread at all levels of the educational system even among science experts. This has led to a shift in how anthropomorphisms are viewed in science education, from a discussion of whether they should be allowed or avoided towards an interest in their role in supporting students’ understanding of science. In this study we examine the role of anthropomorphisms in supporting students’ understanding of chemistry. We analyze examples from undergraduate students’ discussions during problem-solving classes through the use of practical epistemology analysis (PEA). Findings suggest that students invoked anthropomorphisms alongside technical relations which together produced more or less chemically appropriate explanations. Also, anthropomorphisms constitute potentially productive points of departure for rendering students’ explanations more chemically appropriate. The implications of this study refer to the need to deal with anthropomorphisms explicitly and repeatedly as well as to encourage explicit connections between different parts of the explanation - teleological as well as causal.

  • 3.
    A. Manneh, Ilana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Rundgren, Carl-Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Hamza, Karim M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Tutor-student interaction in undergraduate chemistry: a case of learning to make relevant distinctions of molecular structures for determining oxidation states of atoms2018Ingår i: International Journal of Science Education, ISSN 0950-0693, E-ISSN 1464-5289, Vol. 40, nr 16, s. 2023-2043Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we explore the issues and challenges involved in supporting students’ learning to discern relevant and critical aspects of determining oxidation states of atoms in complex molecules. We present a detailed case of an interaction between three students and a tutor during a problem-solving class, using the analytical tool of practical epistemology analysis (PEA). The results show that the ability to make relevant distinctions between the different parts of a molecule for solving the problem, even with the guidance of the tutor, seemed to be challenging for students. These shifts were connected to both purposes that were specific for solving the problem at hand, and additional purposes for general learning of the subject matter, in this case how to assign oxidation states in molecules. The students sometimes could not follow the additional purposes introduced by the tutor, which made the related distinctions more confusing. Our results indicate that in order to provide adequate support and guidance for students the tutor needs to consider how to sequence, move between, and productively connect the different purposes introduced in a tutor-student interaction. One way of doing that is by first pursuing the purposes for solving the problem and then successively introduce additional, more general purposes for developing students’ learning of the subject matter studied. Further recommendations drawn from this study are discussed as well.

  • 4. Abbasi, Alireza
    et al.
    Badiei, Alireza
    Khaniani, Yeganeh
    Golchoubian, Hamid
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    N,N '-bis(2,6-dichlorobenzyl)ethylene-diimine2007Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 63, s. o3773-U2712Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the centrosymmetric title compound, C16H12Cl4N2, the asymmetric unit is one half-molecule. Weak van der Waals interactions between the molecules are effective in the molecular packing. This is the first reported structure of a chloro-substituted benzaldehyde derivative that can potentially form a tetradentate ligand.

  • 5. Abbasi, Alireza
    et al.
    Damian Risberg, Emiliana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Mink, Janos
    Persson, Ingmar
    Sandström, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Sidorov, Yurii V.
    Skripkin, Mikhail Yu.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Ullström, Ann-Sofi
    Crystallographic and Vibrational Spectroscopic Studies of Octakis(dimethyl sulfoxide)lanthanoid(III) Iodides2007Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 46, nr 19, s. 7731-7741Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z = 8. In all [Ln(OS(Me2)8]I3 compounds the lanthanoid(III) ions coordinate eight DMSO oxygen atoms in a distorted square antiprism. Up to three of the DMSO ligands were found to be disordered and were described by two alternative configurations related by a twist around the metal−oxygen (Ln−O) bond. To resolve the atomic positions and achieve reliable Ln−O bond distances, complete semirigid DMSO molecules with restrained geometry and partial occupancy were refined for the alternative sites. This disorder model was also applied on previously collected data for the monoclinic octakis(DMSO)yttrium(III) iodide. At ambient temperature, the eight Ln−O bond distances are distributed over a range of about 0.1 Å. The average value increases from Ln−O 2.30, 2.34, 2.34, 2.36, 2.38, 2.40 to 2.43 Å (Ln = Lu, Er, Y, Dy, Gd, Sm, and Nd) for the monoclinic [Ln(OSMe2)8]I3 structures, and from 2.44, 2.47 to 2.49 Å (Ln = Pr, Ce, and La) for the orthorhombic structures, respectively. The average of the La−O and Nd−O bond distances remained unchanged at 100 K, 2.49 and 2.43 Å, respectively. Despite longer bond distances and larger Ln−O−S angles, the cell volumes are smaller for the orthorhombic structures (Ln = Pr, Ce, and La) than for the monoclinic structure with Ln = Nd, showing a more efficient packing arrangement. Raman and IR absorption spectra for the [Ln(OS(CH3)2)8]I3 (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Lu, and Y) compounds, also deuterated for La and Y, have been recorded and analyzed by means of normal coordinate methods. The force constants for the Ln−O and S−O stretching modes in the complexes increase with decreasing Ln−O bond distance and show increasing polarization of the bonds for the smaller and heavier lanthanoid(III) ions.

  • 6. Abbasi, Alireza
    et al.
    Geranmayeh, Shokoofeh
    Skripkin, Mikhail Y.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Potassium ion-mediated non-covalent bonded coordination polymers2012Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, nr 3, s. 850-859Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Crystal structures and vibrational spectra of three related network-forming coordination complexes have been studied. Two novel thermodynamically stable pseudo-polymorphic solvated rhodium chloro compounds, [cis-RhCl4(DMSO-kappa S)(2)K](n), 1, and [cis-RhCl4(DMSO-kappa S)(2)K center dot 3H(2)O](n), 2, and one metastable compound [trans-RhCl4(DMSO-kappa S)(2)K center dot 0.25H(2)O](n), 3, crystallize at ambient temperature in the orthorhombic space group P2(1)2(1)2(1) for 1, and the monoclinic space groups P2(1)/n and P2(1)/c for 2 and 3, respectively. All three structures contain [RhCl4(DMSO-kappa S)(2)]-complexes in which the rhodium(III) ions bind to two dimethyl sulfoxide (DMSO) sulfur atoms and four chloride ions in distorted octahedral coordination geometries. The complexes are connected in networks via potassium ions interacting with the Cl- and the DMSO oxygen atoms. As the sum of Shannon ionic radii of K+ and Cl- exceeds the K-Cl distances in compounds under study, these compounds can be described as Rh-Cl-K coordination polymers with non-covalent bonding, which is not common in these systems, forming 1- and 2-D networks for 1/2 and 3, respectively. The 2-D network with nano-layered sheets for compound 3 was also confirmed by TEM images. Further evaluation of the bonding in the cis- and trans-[RhCl4(DMSO-kappa S)(2)](-) entities was obtained by recording Raman and FT-IR absorption spectra and assigning the vibrational frequencies with the support of force-field calculations. The force field study of complexes reveals the strong domination of trans-effect (DMSO-kappa S > Cl) over the effect of non-covalent bonding in coordination polymeric structures. The comparison of calculated RhCl, RhS and SO stretching force constants showed evidence of K+-ligand interactions whereas direct experimental evidences of K+-Cl- interaction were not obtained because of strong overlap of the corresponding spectral region with that where lattice modes and Rh-ligand bendings appear.

  • 7.
    Abbasi, Alireza
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Lindqvist-Reis, Patric
    Eriksson, Lars
    Sandström, Dick
    Lidin, Sven
    Persson, Ingmar
    Sandström, Magnus
    Highly hydrated cations: Deficiency, mobility and coordination of water in crystalline nonahydrated scandium(III), yttrium(III) and lanthanoid(III) trifluoromethanesulfonate2005Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 11, nr 14, s. 4065-4077Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Trivalent lanthanide-like metal ions coordinate nine water oxygen atoms, which form a tricapped trigonal prism in a large number of crystalline hydrates. Water deficiency, randomly distributed over the capping positions, was found for the smallest metal ions in the isomorphous nonahydrated trifluoromethanesulfonates, [M(H2O)(n)]CF3SO3)(3), in which M=Sc-III, Lu-III, Yb-III, Tm-III or Er-III. The hydration number n increases (n=8.0(1), 8.4(1), 8.7(1), 8.8(1) and 8.96(5), respectively) with increasing ionic size. Deuterium (H-2) solid-state NMR spectroscopy revealed fast positional exchange between the coordinated capping and prism water molecules; this exchange started at temperatures higher than about 280 K for lutetium(m) and below 268 K for scandium(m). Similar positional exchange for the fully nonahydrated yttrium(m) and lanthanum(m) compounds started at higher temperatures, over about 330 and 360 K, respectively. An exchange mechanism is proposed that can exchange equatorial and capping water molecules within the restrictions of the crystal lattice, even for fully hydrated lanthanoid(III) ions. Phase transitions occurred for all the water-deficient compounds at; 185 K. The hydrated scandium(III) trifluoromethanesulfonate transforms reversibly (Delta H degrees= -0.80(1) kJ mol(-1) on cooling) to a trigonal unit cell that is almost nine times larger, with the scandium ion surrounded by seven fully occupied and two partly occupied oxygen atom positions in a distorted capped trigonal prism. The hydrogen bonding to the trifluoromethanesulfonate anions stabilises the trigonal prism of water ligands, even for the crowded hydration sphere of the smallest metal ions in the series. Implications for the Lewis acid catalytic activity of the hydrated scandium(III) and lanthanoid(III) trifluoromethanesulfonates for organic syntheses performed in aqueous media are discussed.

  • 8. Abbasi, Alireza
    et al.
    Skripkin, Mikhail Yu.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Torapava, Natallia
    Ambidentate coordination of dimethyl sulfoxide in rhodium(III) complexes2011Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 40, nr 5, s. 1111-1118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The two dimethyl sulfoxide solvated rhodium(III) compounds, [Rh(dmso-kappa O)(5)(dmso-kappa S)](CF(3)SO(3))(3) (1 & 1* at 298 K and 100 K, respectively) and [Rh(dmso-kappa O)(3)(dmso-kappa S)(2)Cl](CF(3)SO(3))(2) (2), crystallize with orthorhombic unit cells in the space group Pna2(1) (No. 33), Z = 4. In the [Rh(dmso)(6)](3+) complex with slightly distorted octahedral coordination geometry, the Rh-O bond distance is significantly longer with O trans to S, 2.143(6) angstrom (1) and 2.100(6) angstrom (1*), than the mean Rh-O bond distance with O trans to O, 2.019 angstrom (1) and 2.043 angstrom (1*). In the [RhCl(dmso)(5)](3+) complex, the mean Rh-O bond distance with O trans to S, 2.083 angstrom, is slightly longer than that for O trans to Cl, 2.067(4) angstrom, which is consistent with the trans influence DMSO-kappa S > Cl > DMSO-kappa O of the opposite ligands. Raman and IR absorption spectra were recorded and analyzed and a complete assignment of the vibrational bands was achieved with support by force field calculations. An increase in the Rh-O stretching vibrational frequency corresponded to a decreasing trans-influence from the opposite ligand. The Rh-O force constants obtained were correlated with the Rh-O bond lengths, also including previously obtained values for other M(dmso)(6)(3+) complexes with trivalent metal ions. An almost linear correlation was obtained for the MO stretching force constants vs. the reciprocal square of the MO bond lengths. The results show that the metal ion-oxygen bonding of dimethyl sulfoxide ligands is electrostatically dominated in those complexes and that the stretching force constants provide a useful measure of the relative trans-influence of the opposite ligands in hexa-coordinated Rh(III)-complexes.

  • 9. Abrahamsson, Maria
    et al.
    Lundqvist, Maria J.
    Wolpher, Henriette
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johansson, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Bergquist, Jonas
    Rasmussen, Torben
    Becker, Hans-Christian
    Hammarström, Leif
    Norrby, Per-Ola
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Persson, Petter
    Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands2008Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 47, nr 9, s. 3540-3548Artikel i tidskrift (Refereegranskat)
  • 10. Abrahamsson, Maria
    et al.
    Wolpher, Henriette
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johansson, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Larsson, Jan
    Kritikos, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Norrby, Per-Ola
    Bergquist, Jonas
    Sun, Licheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hammarström, Leif
    A New Strategy for Improvement of Photophysical Properties in Ruthenium(II) Polypyridyl Complexes. Synthesis, Photophysical and Electrochemical characterisation of Six Mononuclear Ruthenium(II) Bisterpyridine Type Complexes2005Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, nr 9, s. 3215-3225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis and characterization of six ruthenium(II) bistridentate polypyridyl complexes is described. These were designed on the basis of a new approach to increase the excited-state lifetime of ruthenium(II) bisterpyridine-type complexes. By the use of a bipyridylpyridyl methane ligand in place of terpyridine, the coordination environment of the metal ion becomes nearly octahedral and the rate of deactivation via ligand-field (i.e., metal-centered) states was reduced as shown by temperature-dependent emission lifetime studies. Still, the possibility to make quasi-linear donor−ruthenium−acceptor triads is maintained in the complexes. The most promising complex shows an excited-state lifetime of τ = 15 ns in alcohol solutions at room temperature, which should be compared to a lifetime of τ = 0.25 ns for [Ru(tpy)2]2+. The X-ray structure of the new complex indeed shows a more octahedral geometry than that of [Ru(tpy)2]2+. Most importantly, the high excited-state energy was retained, and thus, so was the potential high reactivity of the excited complex, which has not been the case with previously published strategies based on bistridentate complexes.

  • 11.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Amino Acid Derived Rhodium Complexes: On the Origin of Enantioselectivity and Enantioswitchability2009Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, nr 42, s. 11197-11209Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amino acid based thioamides, hydroxamic acids, and hydrazides have been evaluated as ligands in the rhodium-catalyzed asymmetric transfer hydrogenation of ketones in 2-propanol. Catalysts containing thioamide ligands derived from L-valine were found to selectively generate the product with an R configuration (95 % ee), whereas the corresponding L-valine-based hydroxamic acids or hydrazides facilitated the formation of the (S)-alcohols (97 and 91 % ee, respectively). The catalytic reduction was examined by performing a structure–activity correlation investigation with differently functionalized or substituted ligands and the results obtained indicate that the major difference between the thioamide and hydroxamic acid based catalysts is the coordination mode of the ligands. Kinetic experiments were performed and the rate constants for the reduction reactions were determined by using rhodium–arene catalysts derived from amino acid thioamide and hydroxamic acid ligands. The data obtained show that the thioamide-based catalyst systems demonstrate a pseudo-first-order dependence on the substrate, whereas pseudo-zero-order dependence was observed for the hydroxamic acid containing catalysts. Furthermore, the kinetic experiments revealed that the rate-limiting steps of the two catalytic systems differ. From the data obtained in the structure–activity correlation investigation and along with the kinetic investigation it was concluded that the enantioswitchable nature of the catalysts studied originates from different ligand coordination, which affects the rate-limiting step of the catalytic reduction reaction.

  • 12.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric transfer hydrogenation of ketones catalyzed by amino acid derived rhodium complexes: on the origin of enantioselectivity and enantioswitchability: Corrigendum to vol 15(2009) 42, pp. 11197-2010Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, nr 35, s. 10610-10610Artikel i tidskrift (Refereegranskat)
  • 13.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nordin, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mechanistic investigation of enantioswitchable catalysts for asymmetric transfer hydrogenation2010Ingår i: Abstracts of Papers, 239th ACS National Meeting, San Francisco , CA, United States, March 21-25, 2010, Washington: American Chemical Society , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 14.
    Akhtar, Tashfeen
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Unusual synthesis of carbohydrate sec-sec ether-linked pseudodisaccharides2008Ingår i: Carbohydrate Research, ISSN 0008-6215, Vol. 343, nr 12, s. 2094-2100Artikel i tidskrift (Refereegranskat)
  • 15.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Das, Arindam
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Huang, Genping
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereoselective allylboration of imines and indoles under mild conditions. An in situ E/Z isomerization of imines by allylboroxines2014Ingår i: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 5, nr 7, s. 2732-2738Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct allylboration of various acyclic and cyclic aldimine, ketimine and indole substrates was performed using allylboronic acids. The reaction proceeds with very high anti-stereoselectivity for both E and Z imines. The allylboroxines formed by dehydration of allylboronic acids have a dual effect: promoting E/Z isomerization of aldimines and triggering the allylation by efficient electron withdrawal from the imine substrate.

  • 16.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diner, Colin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jonker, Sybrand
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters2016Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 55, nr 46, s. 14417-14421Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The catalytic asymmetric allylboration of cyclic imines with gamma,gamma-disubstituted allylboronic acids provides products with adjacent stereocenters in high yield and stereoselectivity. Various electrophiles, including 3,4-dihydroisoquinolines and indoles, were prenylated in a fully stereodivergent fashion by switching the E/Z geometry of the allylboronate and/or the enantiomer of the BINOL catalyst. 3-Methylindole provided products with three adjacent stereocenters with high stereoselectivity in one synthetic operation.

  • 17.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mihai, Raducan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabo, Kalman J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selective Formation of Adjacent Stereocenters by Allylboration of Ketones under Mild Neutral Conditions2013Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 15, nr 10, s. 2546-2549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboronic acids readily react with a broad variety of ketones, affording homoallylic alcohols with adjacent quaternary and tertiary stereocenters. The reaction proceeds with very high anti stereoselectivity even if the substituents of the keto group have a similar size. a-Keto acids react with syn stereoselectivity probably due to the formation of acyl boronate intermediates. The allylation reactions proceed without added acids/bases under mild conditions. Because of this, many functionalities are tolerated even with in situ generated allylboronic acids.

  • 18.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Raducan, Mihai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diastereoselective allylboration of wide variety of carbonyl compounds using allylboronic acids: Construction of adjacent tertiary and quaternary centers2013Ingår i: Abstracts of papers of The American Chemical Society, American Chemical Society (ACS), 2013, Vol. 246, s. 364-ORGN-Konferensbidrag (Refereegranskat)
  • 19.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vollgraff, Tobias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration2015Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, nr 35, s. 11262-11265Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboration of ketones with gamma-disubstituted allylboronic acids is performed in the presence of chiral BINOL derivatives. The reaction is suitable for single-step creation of adjacent quaternary stereocenters with high selectivity. We show that, with an appropriate choice of the chiral catalyst and the stereoisomeric prenyl substrate, full control of the stereo- and enantioselectivity is possible in the reaction.

  • 20. Altomare, Angela
    et al.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Werner, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Advances in powder pattern indexing: N-TREOR092009Ingår i: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767, Vol. 42, s. 768-775Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Powder pattern indexing can still be a challenge, despite the great recent advances in theoretical approaches, computer speed and experimental devices. More plausible unit cells, belonging to different crystal systems, are frequently found by the indexing programs, and recognition of the correct one may not be trivial. The task is, however, of extreme importance: in case of failure a lot of effort and computing time may be wasted. The classical figures of merit for estimating the unit-cell reliability {i.e.M20 [de Wolff (1968). J. Appl. Cryst.1, 108–113] and FN [Smith & Snyder (1979). J. Appl. Cryst.12, 60–65]} sometimes fail. For this reason, a new figure of merit has been introduced in N-TREOR09, the updated version of the indexing package N-TREOR [Altomare, Giacovazzo, Guagliardi, Moliterni, Rizzi & Werner (2000). J. Appl. Cryst. 33, 1180–1186], combining the information supplied by M20 with additional parameters such as the number of unindexed lines, the degree of overlap in the pattern (the so-called number of statistically independent observations), the symmetry deriving from the automatic evaluation of the extinction group, and the agreement between the calculated and observed profiles. The use of the new parameters requires a dramatic modification of the procedures used worldwide: in the approach presented here, extinction symbol and unit-cell determination are simultaneously estimated. N-TREOR09 benefits also from an improved indexing procedure in the triclinic system and has been integrated into EXPO2009, the updated version of EXPO2004 [Altomare, Caliandro, Camalli, Cuocci, Giacovazzo, Moliterni & Rizzi (2004). J. Appl. Cryst. 37, 1025–1028]. The application of the new procedure to a large set of test structures is described.

  • 21.
    Aydin, Juhanes
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kumar, K. Senthil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium pincer complex-catalyzed condensation of sulfonimines and isocyanoacetate to imidazoline derivatives. Dependence of the stereoselectivity on the ligand effects2007Ingår i: Advanced Synthesis & Catalysis, ISSN 1615-4150, Vol. 349, nr 17-18, s. 2585-2594Artikel i tidskrift (Refereegranskat)
  • 22. Berggren, Gustav
    et al.
    Huang, Ping
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Anderlund, Magnus F.
    Synthesis, Characterization and Reactivity Study of a New Penta-Coordinated Mn(II) Complex2009Ingår i: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 36, nr 1, s. 9-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A penta-coordinated Mn(II) compound [dqpMnCl2] (1) (dqp = 2,6-di-(8-quinoline-yl)-pyridine) has been synthesized and its X-ray crystallographic structure is reported here. Magnetic susceptibility measurements confirmed a high-spin Mn(II) (S = 5/2) center in 1. The X-band EPR spectrum of 1 in dimethylformamide solution exhibits widely distributed transitions in the spectral range from 0 to 700 mT with particularly well-resolved hyperfine lines due to the 55Mn (I = 5/2) nucleus. The abundance of highly resolved transition lines in the spectrum facilitated the electron paramagnetic resonance spectral simulation which revealed large zero-field splitting and g-anisotropies. When dissolved, 1 exists in equilibrium with a hexa-coordinated species, the latter probably resulting from disassociation of one chlorido-ligand allowing ligation of two solvent molecules. The redox behavior of 1 was studied and was compared to that of a structural analog for which water oxidation in the presence of a chemical oxidant has been shown. The results from water oxidation trials of 1 are discussed

  • 23. Berggren, Gustav
    et al.
    Huang, Ping
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Styring, Stenbjorn
    Anderlund, Magnus F.
    Thapper, Anders
    Synthesis and characterisation of low valent Mn-complexes as models for Mn-catalases2010Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 39, nr 45, s. 11035-11044Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work we report the synthesis of two novel manganese complexes, [L1(3)Mn(6)(II)](ClO4)(6) (1 center dot(ClO4)(6)) and [L2Mn(2)(II)(mu-OAc)(mu-Cl)](ClO4)(2) (2 center dot(ClO4)(2)), where L1(2-) is the 2,2'-(1,3-phenylenebis(methylene))bis-((2-(bis(pyridin-2-ylmethyl)amino)ethyl)azanediyl)diacetic acid anion and L2 is N1,N1'-(1,3-phenylenebis(methylene))bis(N2,N2'-bis(pyridin-2-ylmethyl)ethane-1,2-diamine). The ligands Na(2)L1 and L2 are built on the same backbone, L2 only contains nitrogen donors, while two carboxylate arms have been introduced in Na(2)L1. The two complexes have been characterized by single-crystal X-ray diffraction, magnetic susceptibility, EPR spectroscopy, and electrochemistry. X-Ray crystallography revealed that 1 is a manganese(II) hexamer and 2 is a manganese(II) dimer featuring an unprecedented mono-mu-acetato, mono-mu-chlorido bridging motif. The ability of the complexes to catalyse H2O2 disproportionation, thereby acting as models for manganese catalases, has been investigated and compared to the activity of two other related manganese complexes. The introduction of carboxylate donors in the ligands, leading to increased denticity, resulted in a drop in H2O2 disproportionation activity.

  • 24. Berggren, Gustav
    et al.
    Kaynak, Filiz Betul
    Anderlund, Magnus F.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Åkermark, Björn
    Institutionen för organisk kemi.
    Tetraethylammonium [12,12-diethyl-2,2,9,9-tetramethyl-1,4,7,10-tetraza-5,6-benzotridecane-3,8,11,13-tetra-one(4-)]oxidomanganate(V)2007Ingår i: Acta Crystallographica Section E, ISSN 1600-5368, Vol. E63, s. m2672-m2673Artikel i tidskrift (Refereegranskat)
  • 25. Berggren, Gustav
    et al.
    Thapper, Anders
    Anderlund, Magnus
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Two tetranuclear Mn-complexes as biomimetic models of the oxygen evolving complex in Photosystem II - A synthesis, characterisation and reactivity study2009Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, s. 10044-10054Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work we report the preparation of two metallamacrocyclic tetranuclear manganese(II) complexes, [L1(4)Mn(4)](ClO4)(4) and [L2(4)Mn(4)](ClO4)(4) where L1 and L2 are the anions of the heptadentate ligands 2-((2-(bis(pyridin-2-ylmethyl) amino) ethyl)(methyl) amino) acetic acid and 2-(benzyl(2-(bis(pyridin-2-ylmethyl) amino) ethyl) amino) acetic acid), respectively. The complexes have been fully characterized by ESI-MS, elemental analysis, single-crystal X-ray diffraction, magnetic susceptibility, and EPR spectroscopy. Electrochemical reactions as well as reactions with different chemical redox reagents have been performed and a reversible two electron oxidation per manganese ion has been identified. The reaction of [L1(4)Mn(4)](ClO4)(4) with oxone or cerium(IV) results in the evolution of oxygen which makes this system interesting for future studies in the search for a functional mimic of the oxygen evolving complex in Photosystem II.

  • 26. Berggren, Gustav
    et al.
    Thapper, Anders
    Huang, Ping
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Styring, Stenbjörn
    Ander, Magnus F.
    Mechanistic Studies on the Water-Oxidizing Reaction of Homogeneous Manganese-Based Catalysts: Isolation and Characterization of a Suggested Catalytic Intermediate2011Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 50, nr 8, s. 3425-3430Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis, isolation, and characterization of two high-valent manganese dimers with isomeric ligands are reported. The complexes are synthesized and crystallized from solutions of low-valent precursors exposed to tert-butyl hydroperoxide. The crystal structures display centrosymmetric complexes consisting of Mn(2)(IV,IV)(mu-O)(2) cores, with one ligand coordinating to each manganese. The ligands coordinate with the diaminoethane backbone, the carboxylate, and one of the two pyridines, while the second pyridine is noncoordinating. The activity of these complexes, under water oxidation conditions, is discussed in light of a proposed mechanism for water oxidation, in which this type of complexes have been suggested as a key intermediate.

  • 27.
    Burkhardt, Anja
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    (Z)-1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose O-benzyloxime2009Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. E65, nr Part 3, s. o633-o633Artikel i tidskrift (Refereegranskat)
  • 28.
    Cantillana, T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
    Lindström, V.
    Eriksson, L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Brandt, I.
    Bergman, Å.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
    Interindividual differences in o,p '-DDD enantiomer kinetics examined in Göttingen minipigs2009Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Chemosphere, Vol. 76, nr 2, s. 167-172Artikel i tidskrift (Refereegranskat)
  • 29.
    Cantillana, Tatiana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    (2S)-1,1-Dichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane2009Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 65, s. OO297-U1934Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The title compound, C14H10Cl4, is easily crystallized while the other enantiomorph only forms an oil upon crystallization attempts. The title compound has a considerably higher density, rho similar or equal to 1.562 Mg m(-3) compared to the racemic substance, rho similar or equal to 1.514 Mg m(-3). This is supported by the fact there are two intermolecular halogen-halogen contacts in the title compound compared with only one the racemic compound. The dihedral angle between the two phenyl rings is 76.83 (5)degrees

  • 30.
    Cui, Daqing
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för miljökemi.
    Rondinella, V. V.
    Fortner, J. A.
    Kropf, A. J.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wronkiewicz, D. J.
    Spahiu, K.
    Characterization of alloy particles extracted from spent nuclear fuel2012Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 420, nr 1-3, s. 328-333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We characterized, for the first time, submicro- and nanosized fission product-alloy particles that were extracted nondestructively from spent nuclear fuel, in terms of noble metal (Mo-Ru-Tc-Rh-Pd-Te) composition, atomic level homogeneity and lattice parameters. The evidences obtained in this work contribute to an improved understanding of the redox chemistry of radionuclides in nuclear waste repository environments and, in particular, of the catalytic properties of these unique metal alloy particles.

  • 31.
    Cumpstey, Ian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Bis(methyl 2,4,6-tri-O-acetyl-beta-D-allofuranosid-3-yl)sulfane2007Ingår i: Acta Crystallographica Section E, ISSN 1600-5368, Vol. E63, s. o4197-Artikel i tidskrift (Refereegranskat)
  • 32.
    Damian, E
    et al.
    Stockholms universitet.
    Eriksson, L
    Stockholms universitet.
    Sandström, M
    Stockholms universitet.
    Sodium trichloromethanesulfonate monohydrate2006Ingår i: Acta Crystallographica Section C-Crystal Structure Communications, Vol. 62, s. M419-M420Artikel i tidskrift (Refereegranskat)
  • 33.
    Das, Arindam
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereocontrol in Synthesis of Homoallylic Amines. Syn Selective Direct Allylation of Hydrazones with Allylboronic Acids2014Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, nr 14, s. 3808-3811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboronic acids directly react with acyl hydrazones, affording homoallylic amine derivatives. The reaction proceeds with very high syn selectivity, which is the opposite of the stereochemistry observed for allylboration of imines. The reaction can be carried out with both aromatic and aliphatic acyl hydrazones. Based on our studies the excellent syn stereochemistry can be explained by chelation control of the acyl hydrazone and the B(OH)(2) moiety.

  • 34. Dekov, Vesselin M.
    et al.
    Hålenius, Ulf
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologi och geokemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Native Sn–Pb droplets in a zeolitic amygdale (Isle of Mull, Inner Hebrides)2009Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, nr 10, s. 2907-2919Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the particular scientific interest in the elements with high affinity to S and O2, but found in zero-valence state in nature, the origin of these native minerals has been little explored and remains obscure. Here we describe unique Sn–Pb droplets found in a closed analcime–calcite amygdale collected from a basaltic unit cropping out at Carsaig Bay (Isle of Mull, Inner Hebrides). The droplets consist of intimate intergrowths of nearly pure Sn0 and Pb0 domains in proportion 88:12 and are enveloped in a thin, brownish film of organic composition. The occurrence of the Sn–Pb droplets in a closed amygdale, their relationship with the host analcime + calcite and their Pb isotope composition (which does not match any known anthropogenic Pb source) rule out the possibility of anthropogenic contamination and support the natural origin of the Sn–Pb alloy.

    The variable isotope (Pb, Sr, Nd) compositions in different members of the host basaltic sequence suggest that a parent basaltic magma was modified by crustal assimilation and post-emplacement alteration processes. Considering all possible explanations, it appears that the most likely source of Pb for the Sn–Pb alloy is a discrete basaltic unit with an isotopic composition comparable to the Antrim basalts (Northern Ireland). The amygdale phases, on the other hand, show isotopic evidence for incorporation of elements from both local basaltic and sedimentary units. The apparent isotopic disequilibrium between Sn–Pb droplets and amygdale phases indicates a complex, multi-stage fluid evolution. The occurrence of Sn–Pb droplets in organic capsules suggests that the droplets and the enveloping organic substances are co-precipitates. This implies that the transportation and deposition of Sn and Pb might have occurred through organometallic compounds. We assume interaction of seawater fluids carrying metals leached from basaltic rocks with hydrocarbons from sedimentary units as a prerequisite for the formation of the organometallic complexes. The zeolites lining the basaltic vesicles might have destabilized the migrating organo-Sn and Pb compounds causing their breakdown and precipitation of Sn–Pb alloy.

  • 35.
    Deng, Hong-Ping
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Allylic sp (3) C-H borylation of alkenes via allyl-Pd intermediates: an efficient route to allylboronates2014Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 50, nr 65, s. 9207-9210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Palladium catalyzed allylic C-H functionalization was performed using exocyclic alkene substrates. Multi-component synthesis of stereodefined homoallylic alcohols could be performed using a reaction sequence involving allylic C-H borylation and allylation of aldehydes.

  • 36.
    Eriksson, Johan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Jakobsson, Eva
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Decabromodiphenyl ether1999Ingår i: Acta crystallographica Section C, ISSN 0108-2701, Vol. 55, nr 12, s. 2169-2171Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bis(pentabromophenyl) ether, C12Br100, shows strangedifferences in the endocyclic angles between the twodifferent rings, although they are both substituted inthe same manner. Several short van der Waals contact distances give clues to the anomalous endocyclic anglesand some hints to the formation of decompositionproducts. We suggest that the intermolecular Br...Brcontacts contribute to the distortions of the ring systems.Usually distortions of this kind would be explained fromhighly anisotropic TLS behaviour, but the data from thetitle compound do not show any conclusive TLS effects.

  • 37.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Melcher, Charles L.
    Eriksson, Marita
    Rothfuss, Harold
    Grazioso, Ron
    Aykac, Mehmet
    Design Considerations of Phoswich Detectors for High Resolution Positron Emission Tomography2009Ingår i: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 56, nr 1, s. 182-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A way to improve the spatial resolution in positron emission tomography (PET) is to determine the depth-of-interaction (DOI) in the detector. A way to achieve this is to use the phoswich approach, a detector with two or more layers of different scintitlators. The layer identification is done by using differences in scintillation decay time and pulse shape discrimination techniques. The advantages of the concept have been demonstrated in the HRRT high resolution PET system using a LSO/LYSO combination giving a high spatial resolution uniformity of around 2.5 mm within a larger part of the imaged volume. A phoswich combination that lately has received attention is LuAP/LSO or LuYAP/LSO. The suggestions come from the Crystal Clear Collaboration and there is a patent application for its use in PET. This particular combination of phoswich may, however, have a complication since both LuAP and LuYAP emit in the excitation band of LSO, thus making the functionality more complex. In the present paper we have looked into this and suggested different ways to overcome potential drawbacks.

  • 38.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Crystal structure of methyl alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-rhamnopyranoside monohydrate2019Ingår i: Acta Crystallographica Section E: Crystallographic Communications, ISSN 2056-9890, Vol. 75, s. 854-857Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The title compound, C13H24O9 center dot H2O, a structural model for part of bacterial O-antigen polysaccharides from Shigella flexneri and Escherichia coli, crystallizes with four independent disaccharide molecules and four water molecules in the asymmetric unit. The conformation at the glycosidic linkage joining the two rhamnosyl residues is described by the torsion angles phi(H) of 39, 30, 37 and 37 degrees, and psi(H) of -32, -35, -31 and -32 degrees, which are the major conformation region known to be populated in an aqueous solution. The hexopyranose rings have the C-1(4) chair conformation. In the crystal, the disaccharide and water molecules are associated through O-H center dot center dot center dot O hydrogen bonds, forming a layer parallel to the bc plane. The layers stack along the a axis via hydrophobic interactions between the methyl groups.

  • 39.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Widmalm, Göran
    Institutionen för organisk kemi.
    Methyl 3-O-alpha-D-mannopyranosyl beta-D-glucopyranoside tetrahydrate2008Ingår i: Acta Crystallographica Section E, ISSN 1600-5368, Vol. E64, nr 8, s. o1639-o1640Artikel i tidskrift (Refereegranskat)
  • 40.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Methyl 3-O-alpha-L-fucopyranosyl alpha-D-galactopyranoside: a synchrotron study2012Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 68, s. o528-U1770Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The title compound, C13H24O10 is the methyl glycoside of a structural element alpha-L-Fucp-(1 -> 3)-alpha-D-Galp making up two thirds of the repeating unit in the capsular polysaccharide of Klebsiella K63. The conformation of the title compound is described by the glycosidic torsion angles phi(H) = 55 (1)degrees and psi H = -24 (1)degrees. The hydroxymethyl group in the galactose residue is present in the gauche-trans conformation. In the crystal, O-H center dot center dot center dot O hydrogen bonds connect the disaccharide units into chains along the a-axis direction and further hydrogen bonds cross-link the chains.

  • 41.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Methyl 3-O-α-l-fucopyranosyl β-d-glucopyranoside tetrahydrate2012Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 68, s. o3180-o3181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The title compound, C13H24O10·4H2O, is the methyl glycoside of a disaccharide structural element present in the backbone of the capsular polysaccharide from Klebsiella K1, which contains only three sugars and a substituent in the polysaccharide repeating unit. The conformation of the title disaccharide is described by the glycosidic torsion angles ϕH = 51.1 (1)° and ψH = 25.8 (1)°. In the crystal, a number of O—HO hydrogen bonds link the methyl glycoside and water mol­ecules, forming a three-dimensional network. One water mol­ecule is disordered over two positions with occupancies of 0.748 (4) and 0.252 (4).

  • 42. Eriksson, Lars
    et al.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Methyl α-l-rhamnosyl-(1→2)[α-l-rhamnosyl-(1→3)]-α-l-rhamnoside penta­hydrate: synchrotron study2012Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 68, nr 7, s. o2221-o2222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The title hydrate, C19H34O13·5H2O, contains a vicinally disubstituted tris­accharide in which the two terminal rhamnosyl sugar groups are positioned adjacent to each other. The conformation of the tris­accharide is described by the glycosidic torsion angles ϕ2 = 48 (1)°, ψ2 = −29 (1)°, ϕ3 = 44 (1)° and ψ3 = 4 (1)°, whereas the ψ2 torsion angle represents a conformation from the major state in solution, the ψ3 torsion angle conformation may have been caught near a potential energy saddle-point when compared to its solution structure, in which at least two but probably three conformational states are populated. Extensive inter­molecular O—HO hydrogen bonding is present in the crystal and a water-containing channel is formed along the b-axis direction.

  • 43.
    Frigell, Jens
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Cumpstey, Ian
    Carbasugar analogues of galactofuranosides: β-O-linked derivativesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    A selectively protected carbasugar analogue of β-galactofuranose was synthesised from glucose using ring-closing metathesis as the key step. The carbasugar was converted into an α-galacto configured 1,2-epoxide, which was an effective electrophile in Lewis acid catalysed coupling reactions with alcohols. The epoxide was opened with regioselective attack at C-1 to give β-galacto configured C-1 ethers. Using carbohydrates as nucleophiles, we synthesised a number of pseudodisaccharides.

  • 44.
    Färnbäck, Magnus
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Methyl 2-O-beta-L-fucopyranosyl alpha-D-glucopyranoside monohydrate: a synchrotron study2008Ingår i: Acta Crystallographica Section C, ISSN 0108-2701, Vol. 64, nr 2, s. o31-o32Artikel i tidskrift (Refereegranskat)
  • 45.
    Färnbäck, Magnus
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Söderman, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Methyl 3,4,6-tri-O-acetyl-2-deoxy-2-azido-alpha-D-galactopyranosyl-(1-2)-: [3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl-(1-3)]-4-O-benzoyl-alpha-L-rhamnopyranoside n-hexane 0.1-solvate2007Ingår i: Acta Crystallographica: Section E, Vol. E63, s. o1581-o1583Artikel i tidskrift (Refereegranskat)
  • 46. Gao, Weiming
    et al.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianhui
    Chen, Changneng
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Weng, Linhong
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Binuclear iron-sulfur complexes with bidentate phosphine ligands as active site models of Fe-hydrogenase and their catalytic proton reduction2007Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 46, nr 6, s. 1981-1991Artikel i tidskrift (Refereegranskat)
  • 47.
    Gao, Weiming
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Åkermark, Torbjörn
    Li, Mingrun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Sun, Licheng
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Attachment of a hydrogen-bonding carboxylate side chain to an [FeFe]-hydrogenase model complex: Influence on the catalytic mechanism2010Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, nr 8, s. 2537-2546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Azapropanedithiolate (adt)-bridged model complexes of [FeFe]-hydrogenase bearing a carboxylic acid functionality have been designed with the aim of decreasing the potential for reduction of protons to hydrogen. Protonation of the bisphosphine complexes 46 has been studied by in situ IR and NMR spectroscopy, which revealed that protonation with triflic acid most likely takes place first at the N-bridge for complex 4 but at the FeFe bond for complexes 5 and 6. Using an excess of acid, the diprotonated species could also be observed, but none of the protonated species was sufficiently stable to be isolated in a pure state. Electrochemical studies have provided an insight into the catalytic mechanisms under strongly acidic conditions, and have also shown that complexes 3 and 6 are electro-active in aqueous solution even in the absence of acid, presumably due to hydrogen bonding. Hydrogen evolution, driven by visible light, has been observed for three-component systems consisting of [Ru(bpy)3]2+, complex 1, 2, or 3, and ascorbic acid in CH3CN/D2O solution by on-line mass spectrometry.

  • 48.
    Hamark, Christoffer
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Landström, Jens
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ethyl 3,6-di-O-benzyl-2-deoxy-N-phthalimido-1-thio-β-D-glucopyranoside2010Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. E66, s. o3250-o3251Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the title compound, C30H31NO6S, the plane of the N-phthalimido group is nearly orthogonal to the least-squares plane of the sugar ring (defined by atoms C2, C3, C5 and O5 using standard glucose nomenclature), making a dihedral angle of 72.8 (1)°. The thioethyl group has the exo-anomeric conformation. The hydroxy group forms an intermolecular hydrogen bond to the O atom in the sugar ring, generating [100] chains. There are four close - contacts with centroid-centroid distances less than 4.0 Å, all with dihedral angles between the interacting systems of only 8°, supporting energetically favourable stacking interactions

  • 49.
    Hamark, Christoffer
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Landström, Jens
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ethyl 4,6-O-benzylidene-2-deoxy-N-phthalimido-1-thio-β-D-glucopyranoside2010Ingår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. E66, s. o3249-Artikel i tidskrift (Refereegranskat)
  • 50. He, Xibing
    et al.
    Hatcher, Elizabeth
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    MacKerell, Alexander D., Jr.
    Bifurcated Hydrogen Bonding and Asymmetric Fluctuations in a Carbohydrate Crystal Studied via X-ray Crystallography and Computational Analysis2013Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, nr 25, s. 7546-7553Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The structure of the O-methyl glycoside of the naturally occurring 6-O-[(R)-1-carboxyethyl]-alpha-D-galactopyranose, C10H18O8, has been determined by X-ray crystallography at 100 K, supplementing the previously determined structure obtained at 293 K (Acta Crystallogr. 1996, C52, 2285-2287). Molecular dynamics simulations of this glycoside were Performed in the crystal environment with different numbers of units cells included in the primary simulation system at both 100 and 293 K. The Calculated unit cell Parameters and the intramolecular geometries (bonds, angles, and dihedrals) agree well with experimental results. Atomic fluctuations, including B-factors and anisotropies, are in good agreement with respect to the relative values on an atom-by-atom basis. In addition, the fluctuations increase with increasing simulation system size, with the simulated values converging to values lower than those observed experimentally indicating that the simulation model is not accounting for all possible contributions to the experimentally observed B-factors, which may be related to either the simulation time scale or size. In the simulation's, the hydroxyl group of O7 is found to from bifurcated hydrogen bonds with O6 and O8 of an adjacent molecule, with the interactions dominated by the interaction HO7-O6 interaction. Quantum mechanical calculations support this observation.

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