Carbonyl Stretching Frequencies and Electronic Spectra of Rhodium(I) Monocarbonyl Complexes

Department of Chemistry, Dibrugarh University, Dibrugarh-786 004, Assam, India

Manuscript received 1 November 1978, accepted 12 March 1979

Substituted monocarbonyl trans-Rh(CO)XL₂ complexes, where L is triphenylarsine (AsPh₂) and triphenylstibine (SbPh₃) ; X =F, Cl, Br, I, CN, SCN, SeCN, NO_2' NO₃ and ClO₄, and their adducts with sulphur-dioxide and tetracyanoethylene (TCNE) have been prepared and characterised. The infrared and electronic spectra of these com­pounds have been reported. The carbonyl stretching frequencies (v_co) in Rh(CO)XL₂, and in their SO₂, adducts follow the increasing sequence X=F<CL<Br<ClO₄<I<NO₃(?)<SCN~NO₂<SeCN<CN and the influence of anionic ligands X on (v_co) values has been explained. The nature of TCNE adducts has also been discussed.