The reaction of Ru(
6-cot)(dmfm)
2 (
1; cot = 1,3,5-cyclooctatriene, dmfm = dimethyl fumarate) withwater and dppe derivatives (dppe = 1,2-bis(diphenylphosphino)ethane) having two or four methoxy groupsat the ortho positions of the phenyl rings, (
S,
S)-DIPAMP or
o-MeO-dppe, afforded the unique binuclearRu(II) aqua complexes
4a,
b, where two oxaruthenacycles are combined and hold a water molecule bycoordination and hydrogen bonding, as revealed by X-ray crystallography. Although complex
4b has abinuclear form in the solid state, disintegration occurred in solution to give the mononuclear aqua complex
4b'. Complex
4b was further treated with ammonia, resulting in the formation of the mononuclear Ru(II)ammonia complex
5 via ligand displacement with water. The water oxygen atom and ammonia nitrogenatom in these complexes can be regarded as chiral centers in the solid state, since they have four differentgroups, distinguished by coordination to ruthenium and nonequivalent hydrogen bondings.