Spectroscopic and theoretical investigations on fullerene complexation by free-base and metalated “bisarylmonoporphyrin” hosts in toluene medium

The present article reports the non-covalent interaction of a designed free-base bisarylporphyrin, viz., H2-1 and its metalated form, Zn-1, with C60 and C70, in toluene medium. Ground state complex formation between these tailored macrocyclic porphyrins and fullerenes was evidenced from the decrease in intensity of the Soret band of the monoporphyrins in presence of fullerene. The decrease of fluorescence intensity and the shift of the emission maxima of both H2- and Zn-1 in presence of fullerenes C60 and C70 suggest a static quenching event inside a well defined supramolecular C60/H2-1, C60/Zn-1, C70/H2-1 and C70/Zn-1 complexes. Quantum chemical calculations offer insight into the geometric and electronic structure of the supramolecules.