Pseudo-Jahn-Teller effect in deprotonated dimethyl amino phenyl substituted phthalocyanine

Geometries of dimethyl amino phenyl substituted phtalocyanine deprotonated at two nitrogen atoms [dmaphPc](q), q = -2, -1 and 0, were optimized within the D-4h symmetry group and its subgroups. Their excited states were evaluated using the TD-DFT treatment. Using an epikernel principle method based on the symmetries of the imaginary vibrations of the optimized geometries and the symmetries of the corresponding excited states, the symmetry descent paths D-4h -> D-4 for [dmaphPc](2-), D-4h -> D-2 for [dmaphPc]-, and D-4h -> C-2 for [dmaphPc](0) were explained as a consequence of the pseudo-Jahn-Teller effect.