Photophysical investigations and binding strength in supramolecular interaction of a newly designed diporphyrin tweezer with fullerenes C60 and C70 in solution

The present Letter reports the synthesis of a designed diporphyrin (1), and its supramolecular complexes with C60 and C70 in toluene and benzonitrile medium. While UV–Vis studies reveal ground state interaction between fullerenes and 1, steady-state fluorescence measurements establish quenching of fluorescence of 1 by fullerenes. Binding constants data evoke that 1 may be employed as an efficient tweezer for C70 in benzonitrile medium. Time resolved emission studies establish relatively long-lived charge separated state for the C70/1 complex in both the solvents. Molecular mechanics force field calculations in vacuo establish the stereoscopic structures of the fullerene/1 complexes and interpret the stability difference between C60 and C70 complexes of 1.