Synthesis, crystal structure and thermal properties of a new polymorphic modification of diiso-thio-cyanato-tetra-kis-(4-methyl-pyridine)cobalt(II).
Acta Crystallogr E Crystallogr Commun
; 80(Pt 6): 677-681, 2024 May 01.
Article
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| ID: mdl-38845725
ABSTRACT
The title compound, [Co(NCS)2(C6H7N)4] or Co(NCS)2(4-methyl-pyridine)4, was prepared by the reaction of Co(NCS)2 with 4-methyl-pyridine in water and is isotypic to one of the polymorphs of Ni(NCS)2(4-methyl-pyridine)4 [Kerr & Williams (1977 â¸). Acta Cryst. B33, 3589-3592 and Soldatov et al. (2004 â¸). Cryst. Growth Des. 4, 1185-1194]. Comparison of the experimental X-ray powder pattern with that calculated from the single-crystal data proves that a pure phase has been obtained. The asymmetric unit consists of one CoII cation, two crystallographically independent thio-cyanate anions and four independent 4-meth-yl-pyridine ligands, all located in general positions. The CoII cations are sixfold coordinated to two terminally N-bonded thio-cyanate anions and four 4-methyl-pyridine coligands within slightly distorted octa-hedra. Between the complexes, a number of weak C-Hâ¯N and C-Hâ¯S contacts are found. This structure represent a polymorphic modification of Co(NCS)2(4-methyl-pyridine)4 already reported in the CCD [Harris et al. (2003 â¸). NASA Technical Reports, 211890]. In contrast to this form, the crystal structure of the new polymorph shows a denser packing, indicating that it is thermodynamically stable at least at low temperatures. Thermogravimetric and differential thermoanalysis reveal that the title compound starts to decomposes at about 100°C and that the coligands are removed in separate steps without any sign of a polymorphic transition before decomposition.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
Acta Crystallogr E Crystallogr Commun
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Alemanha