Stereochemistry of optically active nickel(ii) and cobalt(ii) coordination compounds derived from N-acetyl aminoalcohols
作者:Gabriela Vargas-Díaz、Horacio López-Sandoval、Adriana B. Vázquez-Palma、Marcos Flores-Alamo、Adrián Peña-Hueso、Sonia A. Sánchez-Ruíz、Angelina Flores-Parra、Rosalinda Contreras、Norah Barba-Behrens
DOI:10.1039/b705195f
日期:——
through the nitrogen atom, the OH group and the deprotonated carboxylic group, forming two five-membered rings. The coordination compounds are characterized in the solid state by UV-Vis-NIR reflectance spectra, IR, X-ray crystallography and magnetic susceptibility measurements. The metal becomes a stereogeniccenter and, for each ligand, coordination to the metal ion produces two newstereogenic nitrogen
effects. The experimental circular dichroism (CD) for the studied diasteromers [Ni(S,S(+)Hcpse)2] 6 and [Ni(R,S(−) Hceph)2]∙7 compounds, with two chiral C atoms, presented CD spectra with mirror images and opposite Cotton effects. This was confirmed by the theoretical calculations, TD-DFT (Time-Dependent DFT), which allowed to assign the observed electronic transitions. The influence of the spatial orientation
摘要 本文研究了手性乙酰氨基醇及其与镍(II) 的八面体配位化合物的实验和理论性质。确定基态 (GS) 的结构弛豫基于它们的 X 射线晶体结构。DFT(密度泛函理论)用于电子交换和相关,PCM(极化连续谱法)用于模拟水溶剂效应。所研究的非对映异构体 [Ni(S,S(+)Hcpse)2] 6 和 [Ni(R,S(−) Hceph)2]∙7 化合物的实验圆二色性 (CD),具有两个手性 C 原子,呈现具有镜像和相反 Cotton 效应的 CD 光谱。理论计算 TD-DFT(时间相关 DFT)证实了这一点,它允许分配观察到的电子跃迁。通过这两种方法分析了手性碳原子上取代基空间取向的影响,这可能对电子性质产生显着影响。对 [Ni(R(-) Hcphen)2] 8 化合物进行了类似的研究,只有一个手性 C 原子,因为 C-甲基被 C-H 取代,以研究在6 和 7 的电子性质。6、7 和 8 的差异反映在偶极矩、立体化学和参与