Cyclopentadienyl- and pentamethylcyclopentadienyl-rhodium(III) complexes containing isocyanide ligands

The complexes (η⁵-C₅H₅)RhCl₂]₂ and (η⁵-C₅Me₅)RhCl₂]₂ react with stoichiometric amounts of isocyanide ligands L to give (η⁵-C₅H₅)RhLCl₂ and (η⁵-C₅Me₅)RhLCl₂ (L = CNC₆H₁₁, CNC₆H₄CH₃-p); an excess of ligand L reacts further with (η⁵-C₅Me₅)RhLCl₂ to give the cationic complex (η⁵-C₅Me₅)RhL₂Cl]⁺ which was isolated as tetraphenylborate salt. The cationic complexes (η⁵-C₅Me₅)RhL(PPh₃)Cl]⁺ and (η⁵-C₅Me₅)Rh(Ph₂PC₂H₄PPh₂)Cl]⁺ were obtained in the reaction of (η⁵-C₅Me₅)RhLCl₂ with PPh₃ and Ph₂PC₂H₄PPh₂ respectively. Unidentified solids which do not contain the cyclopentadienyl moiety were obtained in the analogous reactions of (η⁵-C₅H₅)RhLCl₂ with an excess of isocyanide or of tertiary phosphine.The complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ react with SCN^? or SeCN^? giving the corresponding dithiocyanate or diselenocyanate derivatives in which the pseudohalogen groups are S- or Se-bonded to the metal atom. The analogous reactions with C₆Cl₅MgCl gave the chiral complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl.The potentially chelating anion Ph₂PSS^? reacts with (η⁵-C₅H₅)Rh(CNC₆H_n11)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ to give (η⁵-C₅H₅)Rh(CNC₆H¹¹)(SSPPh₃)Cl and (η⁵-C₅Me₅)Rh(CNC₆H¹¹)(SSPPh₂)Cl in which the dithio ligand acts as monodentate; these compounds react with MeI or EtI to give the dihalide derivatives and the esters Ph₂PSSMe and PSSEt. The complex (η⁵-C₅Me₅)Rh(CNC₆H₁₁)(SSPPh₂)]Cl was obtained by refluxing a benzene solution of the corresponding neutral complex; the cyclopentadienyl derivative failed to give the analogous chelate complex.The complexes (η⁵-C₅H₅)RhLCl₂, (η⁵-C₅Me₅)RhLCl₂ and (η⁵-C₅Me₅)RhL₂Cl]⁺ (L = CNC₆H₁₁) were found to be unreactive towards amines.