Resonance Raman spectra of N-deprotonated σ-type dianion of porphycenes

Resonance Raman spectra of N-deprotonated σ-type dianion of porphycenes were measured in an effort to characterize the structural changes concomitant with N-deprotonation. The observed resonance Raman behavior was consistent with the results of vibrational analysis by quantum chemical calculations based on density functional theory methods. Resonance Raman behavior predicted an expanded porphycene core for N-deprotonated σ-type dianion with elongation of peripheral bond lengths. This σ-type dianion is distinctive from π-type dianion which has an expanded core with alternating changes in peripheral bond lengths.