Intramolecular hydrogen bonding in dichloridobis(3,5-di-tert-butyl-1H-pyrazole-κN2)cobalt(II) as a consequence of ligand steric bulk

Acta Crystallogr C. 2010 Nov;66(Pt 11):m336-8. doi: 10.1107/S0108270110040412. Epub 2010 Oct 21.

Abstract

The title compound, [CoCl(2)(C(11)H(20)ClN(2))(2)], forms two intramolecular hydrogen bonds [graph set S(5)] between the N atoms of the pyrazole ligands and the chloride ligands. This hydrogen-bonding motif is uncommon among related compounds but occurs here because of the bulk of tert-butyl substituents on the pyrazole ligands which shield the central metal atom to a significantly larger extent than pyrazole ligands with smaller 3,5-substituents.