Combined theoretical and experimental study on the molecular structure, FT-IR, and NMR spectra of cyadox and 1,4-bisdesoxycyadox

Abstract

1,4-Bisdesoxycyadox, a deoxidized metabolite of cyadox, was synthesised and characterized. Structural and conformational analyses were performed using theoretical calculations employing density functional theory (DFT). The molecular geometry was optimized using B3LYP method with 6-311+G(d,p) basis set and then it was compared with X-ray diffraction data of similar molecular compounds. From the optimized geometry of the molecule, vibrational frequencies of the title compounds were calculated via B3LYP/6-311+G(d,p) approach. The 1H and 13C NMR chemical shift were calculated by gauge-including atomic orbital method with B3LYP/6-311++G(2df,2pd) approach. Comparison of the experimental and calculated 1H and 13C chemical shifts resulted in the reliable assignment of cyadox and 1,4-bisdesoxycyadox. The first, second, total, and mean NO bond dissociation enthalpies were also obtained theoretically.