“…NQR spectroscopy is one of the very sensitive of these techniques to characterize the electronic environment and reveal the details of charge distribution around the nuclei with spin angular momentum of over one half (I > 1/2). [17][18][19] Another powerful, high potential tool for the exploration of the local electronic structure of framework atoms in the solid catalysts is based on solid state NMR spectroscopy, which offers invaluable evidence about the electrostatic interactions. 20,21 Hydrogen bondings, at the other extreme, can be described as far as delocalization (or charge transferring) effects are concerned.…”