Study of non-covalent interaction between a designed monoporphyrin and fullerenes (C60 and C70) in absence and presence of silver nanoparticles

The present article reports on supramolecular interaction between fullerenes (C60 and C70) and a designed monoporphyrin, e.g., 5,15-di(para-methoxyphenyl)zincporphyrin (1), in absence and presence of silver nanoparticles (AgNp) having diameter of ∼3–7 nm in toluene. While UV–Vis studies establish the ground state electronic interaction between fullerenes and 1 in absence and presence of AgNp, steady state fluorescence experiment enables us to determine the value of binding constant (K) for the fullerene-1 complexes in solution. Steady state fluorescence measurement reveals that reduction in the K value takes place for both C60−1 (K = 1560 dm3 mol−1) and C70−1 systems (K = 14,970 dm3 mol−1) in presence of AgNp, i.e., K C60−1 = 1445 dm3 mol−1 and Kc60−1 = 14,550 dm3 mol−1. SEM measurements establish formation of surface holes in fullerene-1-AgNp structure. Both SEM and dynamic light scattering measurement demonstrates that the electrostatic attraction between porphyrin-based supramolecules and AgNp is very much responsible behind the formation of larger aggregates. Quantum chemical calculations evoke the single projection geometric structures of the fullerene-1 complexes in vacuo and well interpret the alignment of the C60 and C70 molecule with the flat -belt region of 1.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Fullerene-porphyrin complexation is examined in presence of silver nanoparticles. ► Silver nanoparticles (AgNp) inhibit binding between fullerene and porphyrin (1). ► DLS study reveals larger size particles of AgNp in presence of fullerene-1 complex. ► SEM measurements establish formation of surface holes in fullerene-1-AgNp structure. ► Electrostatic attraction between porphyrin-based supramolecule and AgNp is observed.