AB INITIO CALCULATIONS OF 14N NQR PARAMETERS AND 13C, 1H, AND 15N CHEMICAL SHIFTS INCLUDING A COMPARISON WITH EXPERIMENTAL NMR DATA FOR CYCLOTRISAZOBENZENE

Abstract

Nuclear quadrupole coupling constant, χ, and asymmetry parameter, η, of 14 N nucleus and 13 C , 1 H , and 15 N chemical shifts for cyclotrisazobenzene at the level of B3LYP and MP2 methods have been studied using the Gaussian 98 suite of programs. Also, nuclear quadrupole resonance (NQR) frequencies (ν0, ν+, ν-) for 14 N have been calculated, thoroughly. The optimized structure of the compound was very similar to that given by the X-ray crystallographic data. The electric field gradient (EFG) calculation verified that the N = N bonds are highly localized in this molecule; therefore, electron-pairs of the nitrogen atoms remain nonbonding. The comparison of the calculated chemical shifts with the experimental values for cyclotrisazobenzene shows no significant structural changes in solution.