LAUSR

In this study, quantum chemical calculations using MPW1PW91 method were applied to analyze substituent effect on the 14N NQR and NMR parameters in trans-(NHC) PtI2 (para-NC5H4X); (X = H, F, CHO, COOH, CN, NO2, Me, OH, NH2) complex. The substituent effect was examined in the presence of electron withdrawing groups (EWG) and electron donor groups (EDG). The chemical shifts (δ) and spin-spin coupling constants (J and K) were evaluated with the gauge including atomic orbital (GIAO) approach. Significant factors contributing to the magnitude of coupling constants (Fermi contact (FC), spin-dipolar (SD) terms, the diamagnetic spin orbital (DSO), and the paramagnetic spin orbital (PSO) terms) were elucidated. 14N NQR frequencies, quadrupole coupling constants, and the asymmetry parameters were calculated. The linear correlations between 14N NQR and NMR parameters with Hammett constants of substituents were studied. Also, NBO analysis was used for calculation of the p character value of lone pair electrons of nitrogen of para-NC5H4X ligand and the related occupancies. These parameters were effective on nuclear quadrupole coupling constant.