C-I键均裂解离焓的密度泛函理论研究

在高级别理论(包含使用外推基组的MP2和CCSD(T))方法及大量密度泛函方法的理论基础上， 研究了不同种类有机碘化物的C-I键均裂解离能. 密度泛函方法的系统性评估计算结果表明，MPWLYP1M方法的计算精度最高. 运用该方法系统地考查了C(sp³)-I和C(sp²)-I键的取代基效应. 以及取代碘苯及取代苄基碘化物的远程取代基效应. 此外，在MPWLYP1M方法的基础上研究了典型五元及六元芳香杂环碘化物的C-I键解离焓值.

DFT Study on Homolytic Dissociation Enthalpies of C-I Bonds

The C-I bond dissociation enthalpies (BDE) of various organic iodides were calculated using high-level theoretical methods including MP2 and CCSD(T) with extrapolated basis set as well as a number of density functional theory methods. After systematic evaluation of the theoretical results against available experimental C-I BDEs, it was found that the MPW-LYP1M method gave the lowest root mean square error. We, therefore, used this method to examine the substituent effects on different categories of C(sp³)-I and C(sp²)-I bonds. Fur-thermore, the remote substituent effects on the C-I BDEs of substituted iodobenzenes and substituted (iodomethyl)benzenes were also investigated at the same level. The C-I BDEs of typical heteroaromatic iodides including five-membered and six-membered heterocyclic iodides were also examined.