The preparation and characterisation of cationic formyl complexes of ruthenium(II); crystal and molecular structure of the complex trans-bis[1,2-bis(diphenylphosphino)ethane-PP′]carbonyl(deuterioformyl)ruthenium(II) hexafluoroantimonate–dichloromethane(1/1)

Abstract

Reactions of the complexes trans-[Ru(CO)₂(dppe)₂][SbF₆]₂(dppe = Ph₂PCH₂CH₂PPh₂) or cis-[Ru(CO)₂(dppm)₂][SbF₆]₂(dppm = Ph₂PCH₂PPh₂) with [Na{HB(OEt)₃}] or [K{HB(OPrⁱ)₃}] afford [Ru(CHO)(CO)(P–P)₂][SbF₆](P–P = dppe or dppm), without change of stereochemistry, in high yield. [Li(HBEt₃)] gives [Ru(CHO)(CO)(P–P)₂][BEt₄], the counter ion being introduced as an impurity in [Li(HBEt₃)]. [Li(DBEt₃)] gives [Ru(CDO)(CO)(P–P)₂][SbF₆] and a ¹³C labelled analogue is prepared from trans-[Ru(¹³CO)₂(dppe)₂][SbFe₆]₂. The complexes are sufficiently stable in the solid state and in solution at –30 °C for full characterisation by spectroscopic means, one notable feature being the appearance of two peaks in the ν_C-H region of the i.r. spectrum of cis-[Ru(CHO)(CO)(dppm)₂]Y(Y =[SbF₆] or [BEt₄]) attributable to Fermi resonance between pure ν_C-H and 2δ_C-H. trans-[Ru(CDO)(CO)(dppe)₂][SbF₆]·CH₂Cl₂ is orthorhombic, space group Pn2₁a(Pna2₁, no. 33), with a= 22.364(1), b= 20.244(2), c= 11.944(1)Å, and Z= 4. The structure was obtained from 1 752 observed intensities measured on an automatic diffractometer and refined to an R value of 0.084. The main features of interest are a long Ru–C (2.09 Å) bond and a Ru–C–O angle of 133°.