钴卟啉对有机小分子的手性识别  

Chiral Recognitions of Organic Small Molecules by Cobalt(Ⅲ)- Porphyrin

作　　者：莽朝永[1] 赵霞[1] 刘彩萍[2] 吴克琛[2] 

机构地区：[1]大理学院生命科学与化学学院,大理671000 [2]中国科学院福建物质结构研究所 结构化学国家重点实验室,福州350002

出　　处：《化学学报》2008年第2期195-199,共5页Acta Chimica Sinica

基　　金：大理学院引进人才科研启动基金(No．KY421040);福建省青年创新基金(No．2003J043);云南省教育厅基金(Nos．07Z10786，07Z11621)资助项目

摘　　要：采用含时密度泛函理论方法研究了手性钻卟啉识别手性生物小分子，解释了分子结构与光学活性的关系．通过基组叠加误差（BSSE）校正，Co（Ⅲ）-卟啉衍生物与（S）-脯氨醇和（S）-2-丁氨之间的作用能分别为310．5和241．6kJ／mol．这种较强的分子识别作用起源于主体与客体之间的配位和氢键作用．具有较大负比旋度的金属卟啉分子对具有较小的正比旋度的生物分子的分子识别作用，极大地抵消了金属卟啉分子的负比旋度数值．电子吸收光谱和电子圆二色谱表明，最低能带起源于主体卟啉环-客体小分子的HOMO-LUMO电荷转移跃迁，具有负或正的康登效应．较高能带由配体内部的π→π^＊电子跃迁所致，具有一个负的和一个正的康登效应．最高能带由取代基到卟啉环的p→π^＊电子跃迁所致，具有两个负的康登效应．Theoretical calculations on chiral discrimination of organic molecules by a chiral Co（Ⅲ） α,α,β,β-tetramethylchiroporphyrin （TMCP） have been performed at the time-dependent density functional theory level. Upon taking the correction of the basis set superposition errors into consideration, molecular recognition leads to a large interaction energy, 310.5 kJ/mol for discrimination of S-prolinol by Co（Ⅲ）-TMCP and 241.6 kJ/mol for discrimination of （S）-2-butylamine by Co（Ⅲ）-TMCP. In addition to the coordinated bond between the host Co（Ⅲ）-TMCP and the guest （S）-prolinol or （S）-2-butylamine, the hydrogen bond interactions are also an important factor in enhancing the molecular recognitions. Chiral discrimination induces remarkable differences in both electronic circular dichroism and optical rotatory power. The lowest-energy band of electronic absorption spectra originates from the host-guest charge-transfer transition （π→p^＊） between the HOMO and the LUMO, which causes a negative/positive Cotton effect. The higher-energy band is induced by the localized π→π^＊ transition in the porphyrin ring, and is composed of a negative Cotton effect and a positive Cotton effect. The highest-energy band stems from the p→π^＊ transition from the substituents to the porphyrin ring, which leads to two negative Cotton effects.

关 键 词：分子识别 手性识别 卟啉 电子圆二色谱 密度泛函理论 

分 类 号：O641.3[理学—物理化学]