Diminished electron density in the Vaska-type rhodium(I) complex trans-[Rh(NCBH₃)(CO)(PPh₃)₂].

Galding, M. R.; Virovets, A. V.; Kazakov, I. V.; Scheer, M.; Smirnov, S. N.; Timoshkin, A. Y.

Vaska-type complexes, i.e. trans-[RhX(CO)(PPh3)2] (X is a halogen or pseudohalogen), undergo a range of reactions and exhibit considerable catalytic activity. The electron density on the RhI atom in these complexes plays an important role in their reactivity. Many cyanotrihydridoborate (BH3CN-) complexes of Group 6-8 transition metals have been synthesized and structurally characterized, an exception being the rhodium(I) complex. Carbonyl(cyanotrihydridoborato-κN)bis(triphenylphosphine-κP)rhodium(I), [Rh(NCBH3)(CO)-(C18H15P)2], was prepared by the metathesis reaction of sodium cyanotrihydridoborate with trans-[RhCl(CO)(PPh3)2], and was characterized by singlecrystal X-ray diffraction analysis and IR, 1H, 13C and 11B NMR spectroscopy. The X-ray diffraction data indicate that the cyanotrihydridoborate ligand coordinates to the RhI atom through the N atom in a trans position with respect to the carbonyl ligand; this was also confirmed by the IR and NMR data. The carbonyl stretching frequency υ(CO) and the carbonyl carbon 1JC-Rh and 1JC-P coupling constants of the Cipso atoms of the triphenylphosphine groups reflect the diminished electron density on the central RhI atom compared to the parent trans-[RhCl(CO)(PPh3)2] complex.

ELECTRON density; RHODIUM catalysts; CHEMICAL synthesis; CARBONYL compounds

Acta Crystallographica Section C: Structural Chemistry, 2016, Vol 72, Issue 7, p514

2053-2296

Academic Journal

10.1107/S2053229616008536