Crystal structure of tris(pyridine)(salicylaldehyde semicarbazonato(2-))cobalt(Ⅲ)-trichloropyridinecobaltate(Ⅱ) at 293 and 120 K

摘要

The crystal structure of [Co~Ⅲ(L)(py)_3][Co~ⅡCl_3(py)] (H_2L = salicylaldehyde semicarbazone) was determined by X-ray analysis based on two single crystal X-ray experiments performed at 120 K and 293 K, respectively. It was found that the pyridine ligand of the complex anion is disordered over two positions. The preferential position of this pyridine found at 120 K was explained in terms of the C-H...Cl intermolecular interaction between the tetrahedral [Co~Ⅱ(py)Cl_3]~- anions. The mer-octahedral geometry of the cation in the presented crystal structure was compared with previously published structures of similar composition, [Co~Ⅲ(L~Ⅰ)(py)_3]~+[Co~ⅡCl_3(py)]~-·EtOH and [Co~Ⅲ(L~Ⅰ)(py)_3]~+Ⅰ_3~- (H_2L~Ⅰ = salicylaldehyde S-methylisothiosemicarbazone). Although the tetrahedral [Co~ⅡCl_3(py)]~- anions possess the same charge, they mutually form different intermolecular interactions which can be realized either by C-H...Cl hydrogen bonds or by π—π interactions between the pyridine rings.