Rhenium and osmium thionitrosyl complexes

The rhenium(V) and osmium(VI) nitrido-complexes [ReNX2(PR3)2](X = Cl, L2= 2PMe2-Ph, 2AsPh3, or bipy; X = Br, L2= 2AsPh3 or bipy), react with disulphur dichloride to give the thionitrosyl complexes [ReClX(NS)(PR3)3] and [OsClX2(NS)L2] respectively, whereas an excess of disulphur dichloride with the nitrides [ReNCl2(PR3)3] gives the rhenium(III) derivatives [ReCl3(NS)(PR3)2].