Reaction of Fischer Alkynyl Carbene Complexes with Fluorenone I mines: Mechanistic Studies

The reaction of Fischer carbene complexes with imines to yield fluorenylidene-pyrroline molecular switches has been explored. A combined experimental and theoretical study was carried out to understand the reaction mechanism. Experimental and theoretical data are in good agreement, which allows delimiting the reaction outcome. Nucleophilic attack of the imine to alkyne is the first step in the reaction path and the one with a higher energy harrier. The most stable intermediate was isolated from the reaction mixture, thus supporting the proposed mechanism. The different reaction outcome when using fluorenone or benzophenone imines was investigated with diverse imine moieties. The effect of substitution in both imine and carbene complexes was also explored in order to increase the reaction's scope.