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)₄Cl₂] resulted in disproportionation of the hydrazine and formation of cis-[Rh(CO)₂(NH₂Ph)Cl] 3 and cis-[Rh(CO)₂(PhNNPh)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.