配合物Co(SDDA) (en)+的绝对构型与N-邻位效应的理论研究

摘要

For the 8 isomers of the complex [Co (SDDA) (en)] + (SDDA =l-stilbenediamine-N,N'-diacetate,en=ethylenediamine),their geometries have been optimized at the B3LYP/6-311++G(2d,p) level.Based on the optimized geometries,their 13C-NMR spectra were also computed by using the GIAO method with the same functional and basis set.The twist form of E-ring in SDDA has been determined as δ by comparing the calculated and observed 13C-NMR spectra.Then,the transition wavelengths,oscillator and rotational strengths of the chelate has been calculated employing the TDDFT method with the same functional and basis set.The assignments of the first 30 low-lying transitions have been made carefully.A comparison of the calculated and observed ECD spectra showed that the metal-centered chirality of [Co (SDDA)(en)]+is A,not A as reported in the reference.It belongs to the normal N-vicinal effects.%应用密度泛函理论(DFT),在B3LYP/6-311++G(2d,p)水平上,对配合物[Co (SDDA) (en)]+(SDDA=二苄基乙二胺N,N'-二乙酸,en=乙二胺)可能的8种非对映异构体进行了几何优化.在优化结构基础上,采用相同的泛函和基组结合GIAO方法计算了13C-NMR谱,并与实验谱对比,证明主配体SDDA中E环的折叠方式为δ.此外,用含时密度泛函理论(TDDFT)方法进一步计算了配合物的激发波长、振子强度和旋转强度,分析了其前30个低能激发态的跃迁性质.通过比较计算与实验ECD谱,确认配合物[Co(SDDA) (en)]+的金属中心手性为A型而不是文献中推断的△型,且该配合物的N-邻位效应是正常的,也不是文献中认为的反常邻位效应.