Effect of N–H⋯S amide–thiolate hydrogen bonding on bond lengths in rubredoxin models [(CH3)3NCH2CONH2]2[M(S2-o-xyl)2]

The complexes [(CH3)3NCH2CONH2]2[M(S2-o-xyl)2], M=Fe (1), Co (2), and [(CH3)4N]2[Co(S2-o-xyl)2]·1/2C2H5OH (3) have been characterized by X-ray crystallography and vibrational spectroscopy. Complexes 1 and 2 exhibit linear one-dimensional concatenated hydrogen bonded structures. In complex 2 there is an increase in the average metal–ligand bond length in the hydrogen-bonded form relative to 3, which contains a non-hydrogen bonded congener.