Synthesis and Reactivity of Trifluoromethyl Isocyanide Rhodium(I) Complexes

Abstract

The complex trans -[Rh(CF 3 )(CNXy) 2 (PPh 3 )] ( 1 ) reacts with SO 2, tetracyanoethylene (TCNE), or maleic anhydride (MA) to give the complexes [Rh(CF 3 )(CNXy) 2 (PPh 3 )L] (L = SO 2 ( 2 ), TCNE ( 3 ), MA ( 4 )) and with CO or CF 3 CO 2 H to give, respectively, mixtures containing mainly [Rh(CF 3 )(CNXy) 2 (CO)(PPh 3 )] or trans -[Rh(CNXy) 2 (PPh 3 ) 2 ]CF 3 CO 2, which is prepared in better yield by reaction of trans -[RhCl(PPh 3 ) 2 (CO)] with XyNC and NaCF 3 CO 2 . [Rh(CF 3 )(CNXy) 3 ] ( 6 ) is prepared by reaction of [Rh(CF 3 )(CNXy) 3 (PPh 3 )] ( 7 ) with 35% H 2 O 2 or, better, by reaction of [Rh(μ-OH)(COD)] 2 with XyNC and Me 3 SiCF 3 . The reaction of 6 with tetracyanoethylene (TCNE) or maleic anhydride (MA) gives the complexes [Rh(CF 3 )(CNXy) 3 L] (L = TCNE ( 8 ), MA ( 9 )). The oxidative addition reaction of MeI or n -C 4 F 9 I with complex 6 gives the octahedral Rh(III) complexes [Rh(CF 3 )(R)I(CNXy) 3 ] (R = Me ( 10 ), n -C 4 F 9 ( 11 )). In an attempt to obtain single crystals of complex 11, a few crystals of [{Rh(CF 3 )( n -C 4 F 9 )(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.