Water Entrapped inside Fullerene Cages: A Potential Probe for Evaluation of Bond Polarization.

Abstract

The concept of the bond polarization is a useful tool to understand chemical reactions and fundamental properties of compounds. However, experimental considerations are limited owing to its difficulty of reliable description. We demonstrated that geometrically isolated H2 O inside the cage of fullerene C60 is a possible probe to evaluate the polarization degree of covalent bonds C(C60 )-X (X=heteroatom) on the C60 cage. The 1 H NMR relaxation times of entrapped H2 O have been systematically measured at variable temperatures for H2 O@C60 X (X=CR2 , NR, O, and O2 ). The results followed in the order of electronegativities of C (2.55), N (3.04), and O (3.44), indicating that entrapped H2 O can sensitively respond to the degree of the bond polarization.