Synthesis and chemistry of secondary alkyl iodide complexes of the formula[(η5-C5H5)Re(NO)(PPh3)(ICHRR′)]+BF4−

Abstract Reactions of deuterodichloromethane complex [(η 5 -C 5 H 5 )Re(NO)(PPh 3 ) (ClCD 2 Cl)] + BF 4 − with ( a ) isopropyl iodide, ( b ) sec -butyl iodide, ( c ) cyclopentyl iodide, and ( d ) cyclohexyl iodide give secondary alkyl iodide complexes [(η 5 -C 5 H 5 )Re(NO) (PPh 3 )(ICHRR′)] + BF 4 − ( 3a–d ) in good to high NMR yields, depending upon the quantity of alkyl iodide employed. These compounds are much less stable than analogous primary alkyl iodide complexes, but analytically pure 3d can be isolated from the reaction of (η 5 -C 5 H 5 )Re(NO)(PPh 3 )(CH 3 ) and HBF 4 ·OEt 2 in neat cyclohexyl iodide (73%). Complex 3d decomposes in CD 2 Cl 2 to give cyclohexyl fluoride, cyclohexene (74% total) and bridging halide complexes [(η 5 -C 5 H 5 )Re(NO)(PPh 3 )] 2 X + BF 4 − (X = I, 33%; Cl, 36%). The formation of cyclohexyl fluoride suggests BF 4 − participation in carbon-iodine bond cleavage. Reaction of 3d and PPh 3 gives the substitution product [Ph 3 PC 6 H 11 ] + BF 4 − (24%), cyclohexyl fluoride (24%), cyclohexene (30%) and (η 5 -C 5 H 5 )Re(NO)(PPh 3 )(I) (7, 95%). An analogous reaction of 3d and PPN + Br − gives cyclohexene (57%) and 7 (99%).