Reactions of phosphine, arsine, and stibine with carbonylbis(triethylphosphine)iridium(I) halides. Part 2. Reactions in dichloromethane

Abstract

In CD₂Cl₂, as in toluene, AsH₃ and SbH₃ react with trans-[Ir(CO)X(PEt₃)₂][X = Cl (1) or Br (2)], by oxidative addition. With PH₃, the product of the initial reaction at 180 K gives [Ir(CO)(PEt₃)₂(P′H₃)₂]⁺, (3). In the presence of excess of PH₃, (3) is converted into [Ir(CO)H(PEt₃)₂(P′_tH₃)(P′_cH₂)]⁺, (4)(c and t imply cis and trans respectively to hydride). All these species were identified by ¹H and ³¹P n.m.r. spectroscopy. The spectra show that P′_t is much more basic than P′_c′ P′_tH₃ in (4) can be deprotonated by NMe₃, to give [Ir(CO)H(PEt₃)₂(P′_tH₂)(P′_cH₂)], (5), and P′_cH₂ in (4) can be protonated with excess of HCl to give [Ir(CO)H(PEt₃)₂(P′_tH₃)(P′_cH₃)]²⁺, (6). Compound (5) reacts with B₂H₆ to give [Ir(CO)H(PEt₃)₂(P′_tH₂BH₃)(P′_cH₂BH₃)], (9); compound (4) reacts with a half-molar proportion of B₂H₆ to give (6) and (9). Reaction of [{RuCl₂(η⁶-MeC₆H₄CHMe₂-p)}₂], (10), with (5) in a 1 : 1 molar ratio gives [Ir(CO)H(PEt₃)₂{µ-P′H₂RuCl₂(η⁶-MeC₆H₄CHMe₂-p)}₂], (11); with a 2 : 1 [(5) : (10)] molar ratio, the initial product appears to be [Ir(CO)H(PEt₃)₂{µ-P′_tH₂RuCl₂(η⁶-MeC₆H₄CHMe₂-p)}(P′_cH₂)], but on standing at room temperature for several hours this gives [Ir(CO)H(PEt₃)₂(µ-P′_tH₂)(µ-P′_cH₂)RuCl(η⁶-MeC₆H₄CHMe₂-p)]. [Ir(CO)H(PEt₃)₂(P′_tH₃)(µ-P′_cH₂)RuCl₂(η⁶-MeC₆H₄CHMe₂-p)] was formed from (4) and (10), and this could be deprotonated with NMe₃. Reactions of (5) with [Mo(CO)₄(nbd)](nbd = bicyclo[2.2.1]hepta-2,5-diene) and with [PtCl₂(cod)](cod = cyclo-octa-1,5-diene) are also described.