Insertions\nof Isocyanides in Diamidoamine Rhenium(III)\nComplexes

Rhenium(III) complexes of the form (CO)Re(DAAm) (R) <b>1</b><sub>,</sub> (DAAm = <i>N</i><sup>1</sup>-mesityl-<i>N</i><sup>2</sup>-(2-(mesitylamino)-ethyl)-<i>N</i><sup>2</sup>-methylethane-1,2-diamine) (<i>R</i> = benzyl, <b>1a</b>; methyl, <b>1b</b>; 4-OMe-benzyl, <b>1c</b>) react with isocyanides R′NC, (R′ = 2,6-dimethylphenyl, <i>tert</i>-butyl) to give η<sup>1</sup> and η<sup>2</sup> iminoacyl complexes. When 2,6-dimethylphenylisocyanide reacts\nwith <b>1a</b>, the resulting iminoacyl complex was η<sup>2</sup> while the reaction with <b>1c</b> leads to an η<sup>1</sup> iminoacyl complex. However, the less bulky isocyanide <i>tert</i>-butyl isocyanide produced only η<sup>2</sup> iminoacyl\ncomplexes with <b>1b</b> and <b>1c</b>. Carbene complexes\nwere obtained by the reaction with methyl triflate. The mechanism\nfor the formation of the iminoacyl complexes in this study was also\ninvestigated by DFT (APFD).