Spectroscopic and Theoretical Investigations on Supramolecular Interaction of a Newly Designed Monoporphyrin with Fullerenes and Functionalized Fullerenes in Solution

The present paper reports the results of a photophysical investigation of a designed monoporphyrin (1) and its supramolecular complexes with C₆₀, C₇₀ and derivatized fullerenes, namely tert-butyl-(1,2-methanofullerene)-61-carboxylate (2) and [6,6]-phenyl C₇₁ butyric acid methyl ester (3) in toluene. UV–vis studies reveal appreciable ground state interaction between the fullerenes and compound 1. Steady state fluorescence studies show quenching of fluorescence of 1 in the presence of fullerenes. The binding constants of the C₆₀/1, C₇₀/1, 2/1 and 3/1 complexes are estimated to be 300, 20770, 1150 and 13170 dm³⋅mol⁻¹, respectively. Molecular mechanics calculations in vacuo evoke the stereoscopic structures of the fullerene/1 complexes and allow interpretation of the stability difference among various fullerene complexes of 1 in terms of their enthalpies of formation.