Insertion of COS into Group 2 metal–ethoxide bonds; crystal structures of [Mg(OCSOEt)2(EtOH)4] and [Sr3(OCSOEt)6(EtOH)8]

Some compounds of the alkaline-earth metals, which result from the insertion of COS into metal–ethoxide bonds, have been synthesized and characterised. The crystal structure of the first linear trinuclear metal strontium complex [Sr 3 (OCSOEt) 6 (EtOH) 8 ] 2, which resulted from the reaction of [{Sr(OEt) 2 (EtOH) 4 } n ] with COS gas, has been determined. The octahedral monomer [Mg(OCSOEt) 2 (EtOH) 4 ] 1 resulted from the insertion of a molecule of COS into the ethoxide bonds of [{Mg(OEt) 2 (EtOH) 4 } n ]. The structures demonstrate three alternative co-ordination modes of the OCS(OR) - ligand.