Polarized continuum model study of bond dissociation energies of the O-NO2 bond - A density functional theory study and natural bond order analysis

摘要

Density functional methods (B3LYP, B3PW91, B3P86, and MPWB95) with 6-31G~(**) basis sets and complete basis methods are employed to investigate the bond dissociation energies (BDEs) of the O-NO2 bond for seven 0-nitroalco-hol compounds in acetonitrile solution. B3LYP/6-31+G~(**), (RO)B3LYP/6-311++G(2df,2p), and B3LYP/6-311G(d,p) methods are also used. By comparing the calculated results with the experimental values, B3LYP/6-31+G~(**) is the most accurate method to compute the reliable BDEs for the studied compounds. The substituent effects on the O-NO2 BDEs are analyzed. It is found that electron-withdrawing groups increase the BDE of the parent compound, whereas electron-donating groups decrease the BDE of the parent compound. Further, the natural bond orbital analysis shows that there exist good linear correlations between E~((2)) and Hammett constants, the BDE, and the difference of the second-order stabilization energies E~((2))> of lpO3 → BD~*(O1-N1) and lpO3 → BD~*(O2-N1).