title: Diminished electron density in the Vaska-type rhodium(I) complex trans-[Rh(NCBH3)(CO)(PPh3)2].
abstract: 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 Rh(I) 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 single-crystal X-ray diffraction analysis and IR, (1)H, (13)C and (11)B NMR spectroscopy. The X-ray diffraction data indicate that the cyanotrihydridoborate ligand coordinates to the Rh(I) 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 ν(CO) and the carbonyl carbon (1)JC-Rh and (1)JC-P coupling constants of the Cipso atoms of the triphenylphosphine groups reflect the diminished electron density on the central Rh(I) atom compared to the parent trans-[RhCl(CO)(PPh3)2] complex.
authors.affiliation: SPbSU, Universitetskaya nab. 7/9, St Petersburg 199034, Russian Federation.
authors.forename: M R
authors.initials: MR
authors.lastname: Galding
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Division of RAS, Acad. Lavrentyev str. 3, Novosibirsk 630090, Russian Federation.
authors.forename: A V
authors.initials: AV
authors.lastname: Virovets
authors.affiliation: SPbSU, Universitetskaya nab. 7/9, St Petersburg 199034, Russian Federation.
authors.forename: I V
authors.initials: IV
authors.lastname: Kazakov
authors.affiliation: Institut für Anorganische Chemie, Universität Regensburg, Universitätsstrasse 31, Regensburg 93053, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Scheer
authors.affiliation: SPbSU, Universitetskaya nab. 7/9, St Petersburg 199034, Russian Federation.
authors.forename: S N
authors.initials: SN
authors.lastname: Smirnov
authors.affiliation: SPbSU, Universitetskaya nab. 7/9, St Petersburg 199034, Russian Federation.
authors.forename: A Y
authors.initials: AY
authors.lastname: Timoshkin
keywords: IR analysis; NMR analysis; Vaska-type complex; crystal structure; cyanotrihydridoborate ligand; diminished electron density; rhodium(I) complex