REACTIVITY OF FULLERENES - QUANTUM-CHEMICAL DESCRIPTORS VERSUS CURVATURE

The relation between the reactivity of a fullerene towards a nucleophi le and the curvature of the fullerene surface, reflecting the hybridis ation of the carbon atoms, is investigated. Model 3-21G calculations o n distorted ethenes show that the electronic part of the molecular ele ctrostatic potential, V-el, might be a good measure for the reactivity of a double bond towards a nucleophile when only the influence of geo metrical changes is considered (increasing reactivity upon increasing curvature). STO-3G calculations on the fullerenes C-60, C-70 and C-76 again indicate the quality of V-el as a reactivity descriptor. Both th e regioselectivity in C-60, C-70 and C-76 (in line with local curvatur e), and the relative reactivity of C-60 and C-70 calculated by V-el ar e in agreement with experimental data. The local hardness for these sy stems shows a fair correlation with the global hardness calculated in a finite difference approximation.