Browsing Artikler, rapporter og annet (kjemi) by Title

Now showing items 522-527 of 527

    • X-ray absorption resonances near L2,3-edges from real-time propagation of the Dirac–Kohn–Sham density matrix 

      Kadek, Marius; Konecny, Lukas; Gao, Bin; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-07)
      The solution of the Liouville–von Neumann equation in the relativistic Dirac–Kohn–Sham density matrix formalism is presented and used to calculate X-ray absorption cross sections. Both dynamical relaxation effects and spin–orbit corrections are included, as demonstrated by calculations of the X-ray absorption of SF6 near the sulfur L2,3-edges. We also propose an analysis facilitating the interpretation ...

    • X-ray Absorption Spectroscopy as a Probe of Ligand Noninnocence in Metallocorroles: The Case of Copper Corroles 

      Lim, Hyeongtaek; Kolle, Ekaney Thomas; Hedman, Britt; Hodgson, Keith O; Ghosh, Abhik; Solomon, Edward I. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-02)
      The question of ligand noninnocence in Cu corroles has long been a topic of discussion. Presented herein is a Cu K-edge X-ray absorption spectroscopy (XAS) study, which provides a direct probe of the metal oxidation state, of three Cu corroles, Cu[TPC], Cu[Br8TPC], and Cu[(CF3)8TPC] (TPC = meso-triphenylcorrole), and the analogous Cu(II) porphyrins, Cu[TPP], Cu[Br8TPP], and Cu[(CF3)8TPP] (TPP = ...

    • X-ray absorption spectroscopy of archetypal chromium porphyrin and corrole derivatives 

      Cao, Rui; Thomas, Kolle E.; Ghosh, Abhik; Sarangi, Ritimukta (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-29)
      A combination of Cr K-edge XAS and DFT calculations have been performed on archetypal chromium porphyrinoid complexes Cr<sup>IV</sup>[TMP]O (<b>2</b>) and Cr<sup>V</sup>[TPC]O (<b>3</b>), and the results have been compared to the reference compound Cr<sup>III</sup>[TPP]Cl (<b>1</b>), where TPP<sup>2−</sup>, TMP<sup>2−</sup>, and TPC<sup>3−</sup> are the anions of <i>meso</i>-tetraphenylporphyrin, ...

    • X-ray absorption spectroscopy of exemplary platinum porphyrin and corrole derivatives: metal- versus ligand-centered oxidation 

      Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-30)
      A combination of Pt L<sub>3</sub>-edge X-ray absorption spectroscopy (EXAFS and XANES) and DFT (TPSS) calculations have been performed on powder samples of the archetypal platinum porphyrinoid complexes Pt<sup>II</sup>[TpCF<sub>3</sub>PP], Pt<sup>IV</sup>[TpCF<sub>3</sub>PP]Cl<sub>2</sub>, and Pt<sup>IV</sup>[TpCF<sub>3</sub>PC](Ar)(py), where TpCF<sub>3</sub>PP<sup>2-</sup> = meso-tetrakis(p-tr ...

    • X-ray crystal structure of Vibrio alkaline phosphatase with the non-competitive inhibitor cyclohexylamine 

      Ásgeirsson, Bjarni; Markússon, Sigurbjörn; Hlynsdóttir, Sigríður S.; Helland, Ronny; Hjörleifsson, Jens G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-15)
      <i>Background</i> - <i>Para</i>-nitrophenyl phosphate, the common substrate for alkaline phosphatase (AP), is available as a cyclohexylamine salt. Here, we report that cyclohexylamine is a non-competitive inhibitor of APs.<br><br> <i>Methods</i> - Cyclohexylamine inhibited four different APs. Co-crystallization with the cold-active <i>Vibrio</i> AP (VAP) was performed and the structure solved.<br><br> ...

    • β-Octabromo- and β-Octakis(trifluoromethyl)isocorroles: New Sterically Constrained Macrocyclic Ligands 

      Kolle, Ekaney Thomas; Beavers, Christine M.; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-26)
      Presented herein is a study of the acid-induced demetalation of two sterically hindered copper corroles, Cu b-octabromomeso-triphenylcorrole (Cu[Br8TPC]) and b-octakis(trifluoromethyl)-meso-tris(p-methoxyphenyl)corrole (Cu[(CF3 )8TpOMePC]). Unlike reductive demetalation, which affords the free-base boctabromocorrole, demetalation of Cu[Br8TPC] under nonreductive conditions (CHCl3 /H2SO4 ) ...