Structures and electronic properties of cobalt(II) selone coordination complexes.

The structural chemistry of selenourea ligands is quite diverse, though examples of their coordination to cobalt are rare. In this study, the solid-state structures of the selenourea 1,3-diethylimidazole-2-selone, C7H12N2Se, and the cobalt complexes dichloridobis(1,3-diethylimidazole-2-selone-κSe)cobalt(II), [CoCl2(C7H12N2Se)2] (1), and dichloridobis(1,3-diisopropylimidazole-2-selone-κSe)cobalt(II), [CoCl2(C9H16N2Se)2] (2), are presented. Two crystallization methods for the coordination complexes are utilized. The structures of complexes 1 and 2 are compared with the few existing examples in the literature, revealing a similar trend for terminal binding modes, rather than bridging modes which are often seen for late d-block metal complexes. Density functional theory calculations reveal a trend in cobalt-selenium bond strengths for 1,3-dialkyl-substituted imidazole-2-selones of Me ≃ Et < iPr.