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

Abstract

The progressive addition of hydrazine and the following increasingly substituted hydrazines L (N2H4 Ia, H2NNHMe Ib, H2NNHPh Ie, H2NNMe2 Id, or MeHNNHMe Ic) to [Rh2(CO)4Cl2] resulted in the initial formation of [{Rh(CO)2Cl}2(μ-L)] 1 followed by the formation of cis-[Rh(CO)2L(Cl)] 2; analogous mononuclear complexes were formed directly on addition of the more heavily substituted hydrazines Me2NNMe2 IIf and H2NNPh2 IIg, but addition of 1,2-N2H2Ph2 IIIh to [Rh2(CO)4Cl] resulted in disproportionate 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 13C/15N NMR measurements. X-Ray structural analysis on [{Rh(CO)2Cl}2(μ-L)] (L = H2NNHMe or MeHNNHMe) confirmed that L adopts a μ-η1:η1-mode of bonding with a cisoid arrangement of the Rh(CO)2Cl groups about the N-N bond.