Synthesis of trimethylphosphine complexes of rhodium and ruthenium. X-Ray crystal structures of tetrakis(trimethylphosphine)rhodium(I) chloride and chlorotris(trimethylphosphine)rhodium(I)

Abstract

The synthesis and characterization of the following trimethylphosphine complexes of rhodium and ruthenium are reported; [Rh(PMe₃)₄]Cl, (A), RhCl(PMe₃)₃, (B), [Rh(PMe₃)₃]X, (X = PF₆, BPh₄), [RhH₂(PMe₃)₄]Cl, RhCl(CO)(PMe₃)₂, [Rh(PMe₃)₃(CH₂Cl₂)]Cl, [RuCl(PMe₃)₂]₂, [RuCl(PMe₃)₄]BF₄, trans-RuCl₂(PMe₃)₄, [RuCl(PMe₃)₄]₂Cl₂ and RuHCl(PMe₃)₄.

The crystal structures of (A) and (B) have been determined by single-crystal X-ray diffraction. Compound (A) is orthorhombic, space group Ccmm with a= 12.366, b= 13.584, c= 12.554 Å, and Z= 4; (B) is triclinic, space group P1 with a= 8.842, b= 8.982, c= 11.825 Å, α= 98.74, β= 92.38, γ= 116.09°, Z= 2. The structures were determined using 1 476 and 2 695 observed intesities measured on an automatic diffractometer and refined to R values of 0.030 and 0.023 for (A) and (B) respectively. The geometries of both the RhP₄⁺ cation and RhP₃Cl molecule can be described as square planar, with considerable tetrahedral distortion as a result of steric crowding. Rh–P distances in (A) are 2.295 and 2.299(1)Å, whilst in (B) Rh–P bonds trans to each other are 2.295 and 2.296(1)Å, but trans to Cl 2.203 Å; Rh–Cl is 2.410 Å.