Insertions of Isocyanides in Diamidoamine Rhenium(III) Complexes

Rhenium(III) complexes of the form (CO)Re(DAAm) (R) 1_, (DAAm = N¹-mesityl-N²-(2-(mesitylamino)-ethyl)-N²-methylethane-1,2-diamine) (R = benzyl, 1a; methyl, 1b; 4-OMe-benzyl, 1c) react with isocyanides R′NC, (R′ = 2,6-dimethylphenyl, tert-butyl) to give η¹ and η² iminoacyl complexes. When 2,6-dimethylphenylisocyanide reacts with 1a, the resulting iminoacyl complex was η² while the reaction with 1c leads to an η¹ iminoacyl complex. However, the less bulky isocyanide tert-butyl isocyanide produced only η² iminoacyl complexes with 1b and 1c. Carbene complexes were obtained by the reaction with methyl triflate. The mechanism for the formation of the iminoacyl complexes in this study was also investigated by DFT (APFD).