Tris(pentafluorophenyl) neutral and anionic five-co-ordinate complexes of rhodium(III). Crystal structures of [Rh(C6F5)3(PEt3)2] and [Rh(C6F5)3(AsPh3)2]
Abstract
The binuclear compound [P(CH2Ph)Ph3]2[{Rh(µ-Cl)(C6F5)3}2](1) has been prepared by reaction of HCl with [P(CH2Ph)Ph3]2[Rh(C6F5)5](2) in methanol. Treatment of (1) with thallium(I) acetylacetonate has given the anionic complex [P(CH2Ph)Ph3][Rh(acac)(C6F5)3](acac = acetylacetonate). Addition of neutral ligands L to (1) yields anionic derivatives of the type [P(CH2Ph)Ph3][RhCl(C6F5)3L][L = pyrazole (Hpz), pyridine (py), PPh3, AsPh3, or CO](3)–(7) and the reaction of (1) with AgClO4 in the presence of 2 mol of neutral ligands gives rise to neutral compounds [Rh(C6F5)3L2][L = P(OMe)3, PPh3, PEt3, AsPh3, py, Hpz, 4-methylpyrazole, or 3,5-dimethylpyrazole](8)–(15). The crystal structures of the complexes [Rh(C6F5)3(PEt3)2](10) and [Rh(C6F5)3(AsPh3)2](11) have been determined by X-ray diffraction methods. Both structures consist of very flattened square-pyramidal complexes in which two C atoms from C6F5 groups and two P from PEt3 ligands [(10)], or two As from AsPh3 ligands [(11)], occupy the basal positions, whereas the third C atom from a C6F5 ligand lies at the apex.