Cationic ruthenium(II) systems. Part 1. The preparation and reactivity of diene(hydrazine)ruthenium(II) cations, and the formation of aminobonded hydrazone complexes

Abstract

The polymeric species [{RuCl₂(diene)}_n](1; n > 2) and the appropriate hydrazine have been used to prepare the salts [Ru(diene)(N₂H₄)₄][BPh₄]₂{2; diene = bicyclo[2.2.1]hepta-2,5-diene(nbd) or cyclo-octa-1,5-diene(cod)}[Ru(cod)(NH₂NHMe)₄][PF₆]₂, and [RuH(cod)(NH₂NRR′)₃]X [R = R′= Me, X = BPh₄(3) or X = PF₆(4); R = H, R′= H or Me, X = BPh₄(5)]. Solutions of (2; diene = cod) in refluxing acetone–ethanol mixtures give a complex of stoicheiometry [Ru(BPh₄)(cod)](6) and, in the presence of ligands L, [Ru(cod)L₄][BPh₄]₂[L = pyridine (py), Me₂SO (dmso), or MeCN], [RuL₆][BPh₄]₂(L = 4Me-py or dmso), and the hydrazone-containinig salts [Ru(NH₂NCMe₂)₂L₄]₂{7; L = P(OMe)₃, P(OEt)₃, P[(OCH₂)₃CR](R = Me or Et), and PPh(OMe)₂}. Treatment of [Ru(cod)(NH₂NHMe)₄][PF₆]₂ with PPh(OMe)₂ in acetone produces [Ru(NH₂NHMe)₂{PPh(OMe)₂}₄]-[PF₆]₂. Substitution reactions of (3) give [RuH(cod)L₃]⁺[L = py, 4Me-py, or MeCN] and [RuHL₅]⁺[L = PPh(OMe)₂, P(OEt)₃, or PPh(OEt)₂], while the neutral complexes [{RuXH(cod)}₂NH₂NMe₂](8) have been prepared from (3) and LiX (X = Cl or Br) in methanol or acetone solutions. Complex (8) may be converted into [RuXH(PPh₃)₃] and [RuXH(cod)(PMePh₂)₂](X = Cl or Br) with PPh₃ and PMePh₂ respectively.