Synthesis and reactivity of the tetrakis(acetonitrile)nitrosylrhodium dication

Abstract

The salts [NO][X](X = BF₄ or PF₆) react with [Rh(1,5-C₈H₁₂)(NCMe)₂][X] or [Rh(1,5-C₈H₁₂)₂][X] in acetonitrile to give [Rh(NCMe)₄(NO)][X]₂(1), and with [{Rh(1,5-C₈H₁₂)Cl}₂] or [{Rh(CO)₂Cl}₂] to give [RhCl(NCMe)₃(NO)][X](2). Complexes (1), with L, Ph₂PCH₂CH₂PPh₂(dppe), Na[S₂CNMe₂]·2H₂O, and CO afford [Rh(NCMe)₂(NO)L₂][X]₂[L = PPh₃(3) or AsPh₃(4)][RH(NO)(dppe)₂][X]₂, (5). [Rh(NO)(S₂CNMe₂)₃][X](6), and [Rh(CO)₂(NCMe)₂][X](7) respectively. Complexes (2) react with PPh₃,to give [RhCl(NCMe)(NO)(PPh₃)₂][X](8) which may also be prepared from (3) and Cl^–. Excess of halide ion with (3). however, yields [RhY₂(NO)(PPh₃)₂](Y = Cl or I), whereas Na[S₂CNR₂]·nH₂O give [Rh(PPh₃)₂(S₂CNR₂)₂][X](R = Me or Et) with loss of the co-ordinated nitrosyl ligand. In the presence of PPh₃, (3) reacts with N₂H₄ to give [Rh(NO)(PPh₃)₃](9). The analogous ¹⁵NO species have also been prepared and attempts have been made to assign the ‘bent’ or ‘linear’ modes of bonding to the metal-nitrosyl groups on the basis of i.r. and ¹⁵N n.m.r. spectroscopy.