Cu+离子作用的量子化学计算和FTIR光谱
(中南大学 化学化工学院， 长沙 410083)
摘 要: 乙氧羰基硫代氨基甲酸酯（EECTC）最高占据分子轨道（HOMO）主要由硫代羰基中硫原子的px和py轨道组成； 最低未占据分子轨道（LUMO）由官能团—O—C(—O)—N—C(—S)—O—中各原子的pz轨道组成， 为共轭π键，具有接受和分散电子对的能力。 Cu+离子的电子结构为t6e4，具有反馈d电子对的能力。 因此， 当EECTC与Cu+离子反应时， EECTC可向Cu+离子提供其硫代羰基中硫原子的电子对， 形成σ键， 而得到电子的Cu+离子也可向EECTC的LUMO提供d轨道电子， 形成反馈π键。 EECTC及其与Cu+离子的反应产物Cu(EECTC′)在HF/3-21G(D)和B3PW91/6-31G(D)水平的量子化学计算和FTIR光谱数据结果表明， EECTC通过其C—S硫原子和C—O氧原子与Cu+离子结合，生成六员环螯合物， 同时N—H键断裂， 释放出H+离子。
关键字: 乙氧羰基硫代氨基甲酸酯; Cu+离子; 量子化学计算
（ School of Chemistry and Chemical Engineering，
Central South University， Changsha 410083, China）
Abstract: The highest occupied molecular orbit（HOMO）of ethoxylcarbonyl thionocarbamate（EECTC） is composed by px and py orbits of thiol sulfur atom. And its lowest unoccupied molecular orbit（LUMO）which can easily accept and delocalize electrons is constituted by pz orbits of every atoms in the conjugate of —O—C(—O)—N—C(—S)—O— group. The t6e4 configuration of Cu+ ion can easily donate d-orbital electrons(feedback electrons). As a result, the interaction between EECTC and Cu+ ion is potentially involved in forming σ bond(EECTC offers electrons of thiol sulfur atom to Cu+ ion ) and feedback π bond(Cu+ ion donates d-orbital electrons to the LUMO of EECTC). The results of FTIR analysis and quantum chemistry calculation at the HF/3-21G(D) and B3PW91/6-31G(D) levels for EECTC and Cu(EECTC′) which is the reactive product for EECTC and Cu+ ion in aqueous solution show that EECTC acts as a bidentate ligand, bonding with the Cu+ ion through the thiol sulfur and carbonyl oxygen atoms to form a six membered ring structure as in which the N—H bond is shown to dissociate.
Key words: ethoxylcarbonyl thionocarbamate; cuprous ion; quantum chemistry calculation
