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

Abstract

The crystal structure of [CoIII(L)(py)3][CoIICl3(py)[ (H2L = 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 at120Kwas explained in terms of the C–H...Cl intermolecular interaction between the tetrahedral [CoII(py)Cl3]- anions. The mer-octahedral geometry of the cation in the presented crystal structure was compared with previously published structures of similar composition, [CoIII(L1)(py)3]+[CoIICl3(py)]-·EtOH and [CoIII(LI)(py)3]+I3- (H2LI = salicylaldehyde S-methylisothiosemicarbazone). Although the tetrahedral [CoIICl3(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 p-p interactions between the pyridine rings.

Keywords

• Co(III) complexes
• salicylaldehyde semicarbazone
• crystal structure
• low temperature X-ray experiment
• disordered crystal structure