2-Butyl-tetrahydrothiophene-1-oxide (BTHTO) and its three isomeric Pd(II) complexes models have been calculated by various quantum chemistry methods. Geometry optimization results show BHandH method can give adequate accuracy for both free sulfoxide and its Pd(II) complexes. Molecular energy of complex A with O coordination is the highest in three isomeric complexes models, while that of model B with S coordination is the lowest, and molecular energy of model C with mixed S and O coordination is slight higher than model B. The O atom is advantageously in coordination, but S atom do not in S=O group for geometries structure. So in the SX process the extracted Pd(II)- BTHTO extraction complex forms the model C with mixed S and O coordination quickly, and then became the model B with S coordination in steady thermodynamic state in period of time.%采用多种理论研究方法对2-丁基-四氢噻吩亚砜(BTHTO)及其钯配合物进行几何优化,发现BHandH/6-31G*法所得构型最优,从理论上研究BTHTO与钯(II)的配合模式及其分子稳定性的关系.结果表明Pd-O配位的A模式能量最高,Pd-S配位的B模式能量最低最稳定,而混合配位的C模式能量稍高于B.环状亚砜中的氧原子处于分子的外侧,所受位阻较小,配位速度较快;硫原子受环状结构和侧链影响,位阻较大,配位速度较慢.在萃取过程中,萃合物以硫氧混合配位的C模式形成,随时间的增加,氧配位转化为硫配位即B模式,能量达到最低值,为热力学的稳定状态.
展开▼
