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In this paper, quantum chemical calculations are used to estimate C–NO2 bond dissociation energies (BDE) for 16 chain nitro compounds. These compounds are studied by employing four hybrid density functional theory (B3LYP, B3PW91, B3P86 and PBE1PBE) methods in conjunction with the 6-31G∗, 6-311G∗ and 6-311++G∗∗ basis sets, and at the same time, the complete basis set CBS-QB3 method is also performed. The obtained results are compared with the available experimental values. It is demonstrated that the B3LYP and B3PW91 methods are not suitable for our nitro compounds system, while B3P86 method is able to give reliable BDE data. The results show that P3P86 together with 6-31G∗ is also better than CBS-QB3 method for most of molecules. So we can see that the B3P86 method may be more suitable to produce reasonable BDE of C–NO2 bond for chain nitro compounds. In order to know if the rule is fit to the ring nitro compounds, two molecules have been calculated. The result is not consistent with the former. |
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