Co-ordination of hydrazine and substituted hydrazines on reaction with [Rh2(CO)4Cl2] and disproportionation of 1,2-N2H2Ph2

The progressive addition of hydrazine and the following increasingly substituted hydrazines L (N2H4 Ia, H2NNHMe Ib, H2NNHPh Ie, H2NNMe2 Id, or MeHNNHMe Ic) to [Rh-2(CO)(4)Cl-2] resulted in the initial formation of [{Rh(CO)(2)Cl}(2)(mu-L)] 1 followed by the formation of cis-[Rh(CO)(2)L(Cl)] 2; analogous mononuclear complexes were formed directly on addition of the more heavily substituted hydrazines Me2NNMe, IIf and H2NNPh2 IIg, but addition of 1,2-N2H2Ph2 IIIh to [Rh-2(CO)(4)Cl-2] resulted in disproportionation of the hydrazine and formation of cis-[Rh(CO)(2)(NH2Ph)Cl] 3 and cis-[Rh(CO)(2)(PhN=NPh)Cl] 4. The above complexes have been spectroscopically characterised by IR and C-13/N-15 NMR measurements. X-Ray structural analysis on [{Rh(CO)(2)Cl}(2)(mu-L)] (L = H2NNHMe or MeHNNHMe) confirmed that L adopts mu-eta(1):eta(1)-mode of bonding with a cisoid arrangement of the Rh(CO)(2)Cl groups about the N-N bond.