Synthesis, crystal structure and some reactions of trans-[Ir(CO)Cl2(PEt3)2(PCl2)]

Abstract

Reaction between trans-[Ir(CO)Cl(PEt₃)₂](1) and PCl₃ gives trans-[Ir(CO)Cl₂(PEt₃)₂(P′Cl₂)](2), which has been characterised by partial elemental analysis, X-ray crystal-structure analysis, and mass and n.m.r. spectra. Reaction with HCl leads to slow cleavage of the Ir–P′ bond at room temperature, but HCl–BCl₃(1 : 1) protonates the P′Cl₂ group. A BH₃ adduct is formed with B₂H₆ at low temperature, but with an excess of B₂H₆ at room temperature a mixture of adducts is produced containing both Ir–H and P′–H bonds. An equimolar adduct is formed by (2) with BCl₃ but not with BF₃. Reaction with O₂, S₈, or Se₈ gives trans-[Ir(CO)Cl₂(PEt₃)₂{P′Cl₂(Y)}](Y = O, S, or Se): the reaction with O₂ is very slow, but trans-[Ir(CO)Cl₂(PEt₃)₂{P′Cl₂(O)}](3) is also formed from (2) and N₂O₄. The crystal structure of (3) was also determined and has been shown to form adducts with both BCl₃ and AlCl₃. Complex (2) reacts with H₂Se to give first trans-[Ir(CO)Cl₂(PEt₃)₂{P′HCl(Se)}], then trans-[Ir(CO)Cl₂(PEt₃)₂{P′H(Se)(Se′H)}], and finally trans-[Ir(CO)Cl₂(PEt₃)₂{P′H₂(Se)}], the last of which was isolated. Reaction with H₂S is much slower, and gives only trans-[Ir(CO)Cl₂(PEt₃)₂{P′HCl(S)}]. With water, the phosphinate complex trans-[Ir(CO)Cl₂(PEt₃)₂{P′H(O)(OH)}] is formed, which crystallizes with H₃O⁺Cl^–. The Ir–P′ bond is broken by methanol. There is no reaction with either [{RuCl₂(η⁶-MeC₆H₄CHMe₂-p)}₂] or [PtCl₂(cod)](cod = cyclo-octa-1,5-diene).