杂氮硅三环类化合物的紫外光电子能谱及化学键的理论研究

报道了10种杂氮硅三环类化合物的紫外光电子能谱(UPS).采用RHF/3-21G^*对各化合物进行了构型优化.根据各化合物UPS的谱带特征结合RHF/6-31G^*的计算结果对谱图进行了合理的解析和指认.利用6-31G^*基组进行的电子密度拓扑分析表明,各化合物的N和Si原子间均存在键鞍点,从理论上证实了N和Si原子间存在成键作用.各化合物的UPS和SCFMO计算和电子密度拓扑分析都表明,在该类体系中σ_N→Si配键是比杂氮硼三环类化合物中σ_N→B配键弱得多的成键作用;文中同时讨论了不同取代基对Si和N间成键作用的影响.

Ultraviolet Photoelectron Spectrum and Bonding Studies on the Silatranes: Experimental and Theoretical Studies

The Ultraviolet Photoelectron Spectra(UPS) of 10 silatranes are recorded in this paper. The configurations of ten molecules are optimized at RHF/3-21Glevel. The assignment of the UPSbands has also been done with the aid of the bands shape and RHF/6-31G^* calculation. The electronic charge density topological analysis of the compounds shows that there is a bond critical point between Si and Nof each compound, which suggests the existence of a Si-N bond in these compounds. The σ_N→Si in the silatranes is weaker than σ_N→B in the boratranes, and the bond strength of σ_N→Si is affected with the addition of the substituents at Si atoms. Aspecial substituent effect is also found as the substituents are F, Cl, Br and I. The above substitution effect is confirmed by UPS, SCF MO calculation and electronic charge density topological analysis.