The synthesis and reactivity of some 2-ethyltetraphenoxydiphosphazane derivatives of rhodium

Abstract

Treatment of [{Rh(diene)Cl}₂](diene = C₈H₁₂ or C₇H₈) with the ditertiary phosphite (PhO)₂PN(Et)P(OPh)₂(etdp) in benzene leads to successive replacement of the diene ligands and the formation of [Rh₂(diene)(etdp)Cl₂] and [{Rh(etdp)Cl}₂]. The corresponding bromo- and iodo- derivatives [{Rh(etdp)X}₂](X = Br or I) are produced analogously. Reactions of [{Rh(C₈H₁₂)Cl}₂] with excess of etdp in ethanol or methanol in the presence of a suitable counter ion effects not only the displacement of the diene ligands but also the halogens as halide ions to afford [Rh(etdp)₂][A](A = BPh₄ or SbF₆). Carbon monoxide reacts reversibly with [Rh(etdp)₂]⁺ and [Rh(C₈H₁₂)(etdp)]⁺ obtained by treatment of [Rh(C₈H₁₂)(solvent)x]⁺ with etdp, to yield [Rh(etdp)₂(CO)]⁺ and [Rh(C₈H₁₂)(etdp)(CO)]⁺ respectively. Reaction of [Rh(etdp)₂]⁺ with HBr and Br₂ gives trans-[Rh(etdp)₂H(Br)]⁺ and [Rh(etdp)₂Br₂]⁺ respectively, although the former degrades to [Rh(etdp)₂]⁺ in solution.