手性Salen-Ni(Ⅱ)络合物的ECD光谱及其绝对构型关联：可见区第一ECD吸收带的指纹作用  

Correlation between ECD Spectra and the Absolute Configurations of Chiral Salen-Ni(Ⅱ) Complexes:a Fingerprint Role of the First ECD Band in the Visible Region

作　　者：章慧[1] 曾丽丽[1] 王越奎[2] 曹石[1] 郭栋[1] 李丹[1] 方雪明[1] 林丽榕[1] 

机构地区：[1]厦门大学化学化工学院化学系,福建厦门361005 [2]山西大学分子科学研究所,化学生物学与分子工程教育部重点实验室,太原030006

出　　处：《物理化学学报》2015年第12期2229-2250,共22页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21273175,21273139,21271150)资助项目~~

摘　　要：对系列手性salen-Ni（Ⅱ）络合物的电子圆二色（ECD）光谱及其绝对构型关联进行了概述.根据晶体结构和对固、液ECD光谱的表征,结合理论计算,着重探讨了准平面型手性[Ni（salen）]的固态结构及其在溶液中的绝对构型和优势构象.在此基础上通过若干实例说明了平面四方形[M（Salen）]络合物两种绝对构型命名法,并给出了我们的建议.对[Ni（sal-R,R-chxn）][sal-R,R-chxn=（R,R）-N,N＇-双（亚水杨基）-1,2-二亚氨基环己烷]的二氯甲烷溶液ECD光谱的计算结果表明,可见区第一个ECD吸收带主要是π→d荷移跃迁（LMCT）所致,而不是通常认为的d-d跃迁：[Ni（sal-R,R-chxn）]的绝对构型为∧,其在可见区第一个ECD吸收带为正.将此ECD指纹应用于具有“闭壳层”电子结构的其它平面型手性[Ni（Salen）]和六配位trans-[CoⅢ（salen）L_2]络合物的绝对构型指认,具有一定的普适性.本文的研究结果对于深入理解手性[M（Salen）]络合物的配位立体化学、手征光学性质及其手性识别和不对称催化机理具有重要科学意义。A correlation between the electronic circular dichroism （ECD） spectra and the absolute configurations of a serials＇ chiral salen-Ni（ll） complexes was investigated. The solid-state structures, absolute configurations, and preferential conformations in solution of quasi-planar chiral [Ni（salen）] complexes were studied using their crystal structures, solid-state and solution ECD spectra in combination with theoretical ECD calculations. Furthermore, two different nomenclatures for the absolute configurations of square-planar [M（salen）] complexes were inspected carefully, and suggestions for proper use of them are discussed. The calculated ECD spectra of [Ni（saI-R,R-chxn）] [saI-R,R-chxn = （R,R）-1,2-cyclohexylene bis（salicylicdeneiminate）] in dichloromethane solution revealed that the first ECD band in the visible region was dominated by the ligand- to-metal charge transfer transition （LMCT）, which was incorrectly assigned to a d-d transition in the literature. When the absolute configuration of [Ni（saI-R,R-chxn）] was/k, the first ECD absorption band in the visible region was positive. This ECD fingerprint is universally applicable for assigning the absolute configurations of other square-planar chiral [Ni（salen）] and six-coordinate trans-[CoⅢ（salen）L2] complexes with a ＂closed-shell＂ electronic structure. This work provides some insight into the coordination stereochemistry and chiroptical properties of chiral [M（salen）] complexes. Additionally, this work is significant for the understanding of chira~ recognition and asymmetric catalytic mechanisms.

关 键 词：Salen-Ni(Ⅱ)络合物 电子圆二色 固体手性光谱 绝对构型关联 指纹技术 

分 类 号：O641.4[理学—物理化学]