Neumann, Tristan and Jess, Inke and Pielnhofer, Florian and Naether, Christian (2018) Selective Synthesis and Thermodynamic Relations of Polymorphic Co(NCS)(2)-4-Dimethylaminopyridine Coordination Compounds. EUROPEAN JOURNAL OF INORGANIC CHEMISTRY (46). pp. 4972-4981. ISSN 1434-1948, 1099-0682
Full text not available from this repository. (Request a copy)Abstract
Reaction of Co(NCS)(2) with 4-dimethylaminopyridine (DMAP) leads to the formation of four new compounds. The crystal structures of Co(NCS)(2)(DMAP)(2)(H2O)(2)center dot 2H(2)O (1), Co(NCS)(2)(DMAP)(2)(MeOH)(2) (2) and Co(NCS)(2)(DMAP)(2)(MeCN)(2) (3) consist of discrete simple solvato complexes in which the Co cations are octahedrally coordinated by two terminally N-bonded thiocyanate anions, two DMAP ligands as well as two solvato ligands. Co(NCS)(2)(DMAP)(2) (4/II) also forms discrete complexes, but the Co cations are tetrahedral coordinated by two anionic ligands and two DMAP ligands. Upon heating, the hydrate 1 transforms into 4/II, whereas the methanol solvate 2 transforms into a new polymorphic modification of Co(NCS)(2)(DMAP)(2) (4/I). For structure determination the corresponding Zn(NCS)(2) compound was prepared that is isotypic to 4/I. Solvent mediated conversion experiments prove that 4/II represents the thermodynamic stable form at room-temperature and density functional theory (DFT) calculations indicate that this form is also stable at 0 K. Upon heating both modifications show melting with the higher melting polymorph 4/I having the lower melting enthalpy. Temperature dependent X-ray powder diffraction shows that 4/II transforms into 4/I upon heating. All experimental results indicate, that both modifications are related by enantiotropism.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SLOW MAGNETIC RELAXATIONS; SUPRAMOLECULAR ISOMERISM; MOLECULAR-CRYSTALS; THIOCYANATE COMPLEXES; KINETIC ASPECTS; HARTREE-FOCK; CO-LIGAND; POLYMER; NETWORK; CO(II); Coordination compounds; Crystal structures; Thermal properties; Enantiotropism; Polymorphism |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Arno Pfitzner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 04 Oct 2019 06:38 |
| Last Modified: | 04 Oct 2019 06:38 |
| URI: | https://pred.uni-regensburg.de/id/eprint/13357 |
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