Synthesis and reactivity of trifluoromethyl isocyanide rhodium(I) complexes

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(mu-OH)(COD)](2) with XyNC and Me3SiCF3. The reaction of 6 with tetracyanoethylene (TCNE) or maleic anhydride (MA) gives the complexes [Rh(CF3)(CNXy)(3)L] (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)](CNXy)(3)] (R = Me (10), n-C4F9 (11)). In an attempt to obtain single crystals of complex 11, a few crystals of [{Rh(CF3)(nC(4)F(9))(CNXy)(2)](2)(mu-I)(2)] (12) were obtained. The crystal structures of complexes 2-4 and 12 have been determined by X-ray diffraction studies.