Structural diversity within transition metal–sulfimide complexes

S,S'-diphenylsulfimide, Ph2SNH, 1, is an excellent ligand that readily forms N-bound complexes with a range of transition metals. Its importance as a ligand is enhanced by two significant features of the resulting complexes: (1) the strong hydrogen bonding interactions between the NH unit and the counterions; and (2) the ligand's ability to stabilise unusual structural combinations. By varying the counterions, the hydrogen bonding pattern can be changed and this affects the geometry at the metal centre. The anion also plays an important role in determining the coordination number of the metal. The hydrogen bonding interactions have been utilised to prepare extended arrays by the inclusion of appropriate outer sphere, bridging ligands, such as terephthalate and fumarate into the system. The fixation of atmospheric CO2 has been observed in a number of systems leading to the formation of both a bicarbonate dimer and a metal-bound carbonate ligand. These act as hydrogen bonding acceptors to give extended 2-D networks. [Continues.]