Deuterium and nitrogen quadrupole coupling in derivatives of imidazole: an ab initio SCF study

Quadrupole coupling constants at deuterium nitrogen in compounds that contain the imidazole group are discussed in the light of ab initio SCF calculations of field gradients in imidazole. In particular, estimates of the effect of hydrogen bonding to imino nitrogen on the field gradients at /sup 14/N and /sup 2/H are made by use of a point charge polarizing field. The calculations are intended to be relevant to experimental data on nucleosides and other biological species in which a significant feature of the structure is hydrogen bonding to imino nitrogen (-N:). The polarization density of imidazole in the point charge field is also discussed. The SCF calculations are at the level of Dunning-Hay + d,p polarization bases.