Reaction of the half-sandwich cationic aminorhenium complex with amines. Preparation of rhenium bis(amine) hydride and rhenium isocyanate complexes

The aminorhenium ester complex {[eta(5):eta(1)-C5H4CH2CH2NH(CH3)]Re(CO)(2)( CH2CO2CH3)}(+)-Br- (2a) reacts with n-butylamine in refluxing CH2Cl2 soluti on, giving the n-butylamine coordinated complex {[eta(5):eta(1)-C5H4CH2CH2N H(CH3)n-BuNH2)}Br-+(-) (6a), which was derived via rhenium-carbamoyl bond c leavage of the intermediate. In contrast, the slightly electron-rich methyl complex {[eta(5):eta(1)-C5H4CH2CH2NH(CH3)]Re(CO)(2)(CH3)}+CF3SO3- (3) reac ts with n-butylamine, giving the n-butylamine hydride complex {[eta(5):eta( 1)-C5H4CH2CH2NH(CH3)]ReH(CO)(n-BuNH2)}+CF3SO3- (7a), which was derived via the coupling of the carbamoyl and the methyl groups followed by an amine co ordination, Methyl complex 3 also reacts with tert-butylamine, diethylamine , and ammonia to give the corresponding amine hydride complexes. The presen ce of an Re-H bond is evidenced by the characteristic hydride resonance in the H-1 NMR spectra. The tert-butylamine hydride complex 7b has been charac terized by an X-ray analysis. The reaction of both 2 and 3 with hydrazine p roceeds via a net loss of 1 mol of ammonia to give isocyanate complexes 12a and 12b, respectively. The structure of 12a is supported by single-crystal X-ray analysis.