Conformational polymorphism in a cobalt(II) dithiocarbamate complex.

Two conformational polymorphs of (N,N-dibutyldithiocarbamato-κS,S')[tris(3,5-diphenylpyrazol-1-yl-κN)hydroborato]cobalt(II), [Co(CHBN)(CHNS)] or [TpCo(SCNBu)], 1, are accessible by recrystallization from dichloromethane-methanol to give orthorhombic polymorph 1a, while slow evaporation from acetonitrile produces triclinic polymorph 1b. The two polymorphs have been characterized by IR spectroscopy and single-crystal X-ray crystallography at 150 K. Polymorphs 1a and 1b crystallize in the orthorhombic space group Pbca and the triclinic space group P-1, respectively. The polymorphs have a trans (1a) and cis (1b) orientation of the butyl groups with respect to the SCN plane of the dithiocarbamate ligand, which results in an intermediate five-coordinate geometry for 1a and a square-pyramidal geometry for 1b. Hirshfeld surface analysis reveals minor differences between the two polymorphs, with 1a exhibiting stronger C-H...S interactions and 1b favouring C-H...π interactions.