DEUTERON QUADRUPOLE COUPLING IN HYDROGEN-BONDED SYSTEMS .3. PYRIDINIUM SALTS

Deuterium quadrupole coupling parameters have been measured for the Perchlorate, iodide, bromide, chloride, and nitrate salts of pyridinium ion at 77 K. Coupling constants range from 187.2 kHz (η=0.129) for the ClO 4- salt to 128.9 kHz (η=0.185) for the NO 3- salt, and correlate well with what is known about the crystal structure and hydrogen bonding tendencies for the series. A theoretical discussion of the data is given in terms of approximate Hartree-Fock calculations at the STO-3G level, in terms of which a major component of the alteration in field gradient arises from changes in the orbital population on N and D. © 1979 American Institute of Physics.