Synthesis, structure, and reactivity of rhenium N-isocyanide complexes ReBr(CO) 3(CNR)(CNNPPh 3)

Abstract

The rhenium isocyanide complex ReBr(CO) 3(CNR)(NCMe) ( 1) reacted with CNNPPh 3 in CH 2Cl 2 to give ReBr(CO) 3(CNR)(CNNPPh 3) ( 2a, R=Ph; 2b, R=Pr) in good yields. Treatment of 2 with ketones in the presence of a catalytic amount of HBF 4 yielded the derivatives ReBr(CO) 3(CNR)(CNNCR′R″) ( 3). The complex ReBr(CO) 3(CNR)(CNNCMe 2) on reaction with isopropylamine gave the amino(hydrazono)carbene complex ReBr(CO) 3(CNR){C(NHPr i )(NHNCMe 2)} ( 4). Prolonging the reaction of 3a (R=Ph, R′=R″=Me) with isopropylamine in CDCl 3, it was converted first into ReBr(CO) 3(CNPh){C(NHPr i )(NHNCMe 2)}, followed by the formation of the biscarbene product ReBr(CO) 3{C(NHPr i )(NHPh)}{C(NHPr i )(NHNCMe 2)} ( 5). The complexes ReBr(CO) 3(CNPr)(CNNPPh 3) ( 2b) and ReBr(CO) 3(CNPh)(CNNCMe 2) ( 3a) have been characterized by single-crystal X-ray diffraction analyses.