1,2-二硒方酸气相酸性和芳香性的理论研究  

Theoretical Studies of the Aromaticity and Gas-phase Acidity of 1,2-Diselenosquaric Acid

作　　者：周立新[1] 吴立明[1] 李奕[1] 李俊■ 

机构地区：[1]福州大学化学系,福州350002

出　　处：《化学学报》1999年第10期1107-1113,共7页Acta Chimica Sinica

摘　　要：在RHF/6-311G~* *水平优化得到1,2-二硒方酸(3,4-二羟基-3-环丁烯-1,2-二硒酮)三种平面构象异构体的平衡几何构型.进一步用MP2(full)/6-311G^(?)∥RHF/6-311G^(?)方法计算三种异构体的单点能量,发现ZZ型异构体是能量最低构象,且ZZ和ZE型能量非常接近.用优化的最稳定构象ZZ型异构体在RHF/6-311G^(?)∥RHF/6-311G^(?),RHF/6-311+G^(?)∥RHF/6-311+G^(?),MP2(full)/6-311+G^(?)∥⌒RHF/6-311+G^(?)和B3LYP/6-311+G^(?)∥B3LYP/6-311+G^(?)水平计算其气相酸性[ΔG°(298k)]和同键反应芳香性稳定化能(HASE).用基团加和法(group increment approach)在RHF/6-311+G^(?)∥RHF/6-311+G^(?)和B3LYP/6-311+G^(?)∥B3LYP/6-311+G^(?)水平计算其磁化率增量(A).计算结果指出标题化合物的键长发生了平均化,同键反应芳香性稳定化能和磁化率增量均为负值,表明它具有芳香性,实现了标题化合物芳香性的几何、能量和磁性的判定.The conformation, aromaticity and gas-phase acidity (free energy of deprotonation, △G°) of 1,2-diselenosquaric acid (3,4-dihydroxy-3-cyclubutene-1,2-diselenone) were calculated at the SCF and MP2 and B3LYP levels using 6-311G(d,p) and 6-311 + G(d,p) basis sets. The global minimum found on the potential energy surface of 1, 2-diselenosquaric acid presents a planar conformation. The ZZ isomer was found to be the most stable of the three planar conformers. The homodesmotic reaction aromatic stabilization energy (HASE) and magnetic susceptibility exaltation ( ∧ ) were also computed by using the SCF-CSGT (Continues Set of Gauge Transformations) (IGAIM, a slight variation on CSGT) and B3LYP-CSGT (IGIAM) methods at the 6-311 + G(d,p) level. The calculated HASE and @ were more negative values, indicating that 1,2- diselenosqaric acid is aromatic. Thus the titled compound fulfills the geometrical, energetic and magnetic criteria of aromaticity. The most reliable theoretical gas-phase acidity are △G°1 (298K) - 1271.5kJ/mol and △G°2 (298K) = 1619.6 kJ/mol.

关 键 词：1 2-二硒方酸 从头算 密度泛函理论 芳香性 气相酸性 

分 类 号：O627.61[理学—有机化学]