Synthesis and Reactivity of Trifluoromethyl Isocyanide Rhodium(I) Complexes

Abstract

The complex trans-[Rh(CF3)(CNXy)2(PPh3)] (1) reacts with SO2, tetracyanoethylene (TCNE), or maleic anhydride (MA) to give the complexes [Rh(CF3)(CNXy)2(PPh3)L] (L = SO2 (2), TCNE (3), MA (4)) and with CO or CF3CO2H to give, respectively, mixtures containing mainly [Rh(CF3)(CNXy)2(CO)(PPh3)] or trans-[Rh(CNXy)2(PPh3)2]CF3CO2, which is prepared in better yield by reaction of trans-[RhCl(PPh3)2(CO)] with XyNC and NaCF3CO2. [Rh(CF3)(CNXy)3] (6) is prepared by reaction of [Rh(CF3)(CNXy)3(PPh3)] (7) with 35% H2O2 or, better, by reaction of [Rh(μ-OH)(COD)]2 with XyNC and Me3SiCF3. The reaction of 6 with tetracyanoethylene (TCNE) or maleic anhydride (MA) gives the complexes [Rh(CF3)(CNXy)3L] (L = TCNE (8), MA (9)). The oxidative addition reaction of MeI or n-C4F9I with complex 6 gives the octahedral Rh(III) complexes [Rh(CF3)(R)I(CNXy)3] (R = Me (10), n-C4F9 (11)). In an attempt to obtain single crystals of complex 11, a few crystals of [{Rh(CF3)(n-C4F9)(CNXy)2}2(μ-I)2] (12) were obtained. The crystal structures of complexes 2−4 and 12 have been determined by X-ray diffraction studies.