Co (2,6-diaminomethylpyridine) (2-methylethylenediamine) ClCo (2,6-diaminomethylpyridine) (2-methylethylenediamine) ClZnCl4体系中几何经式异构体的合成、ZnCl4体系中几何经式异构体的合成、结构解析和稳定性研究

摘要

合成了[Co(bamp)(cmen)Cl]2+(bamp=2，6-二甲胺基吡啶；cmen=1，2-二胺基丙烷)体系的两个经式异构体。利用一维及二维核磁共振(2D NMR)技术，结合三元胺中吡啶环的磁屏蔽效应，对两个异构体在溶液中的结构进行了解析，对应于Dowex 50Wx 2柱色层分离的第一包带的H离子为n2(cmen的2位胺基与Cl处于邻位)：第二色带的阳离子为ml。由第一色带配合物制备的单晶晶体结构解析也表明其为m2[ZnCl4]。用量子化学从头计算方法，在赝势基组RHF/LANL2DZ的水平上研究了该体系两个经式几何异构体的稳定性，结果表明后者较前者稳定，但差别不大，与在合成条件下异构体平衡分布一致。由计算得到的几何优化键参数与晶体结构分析结果能较好地吻合。%Two geometric meridional isomers in a new [ Co (bamp) (cmen) Cl ]2+ (bamp = 2, 6- (Aminomethyl) pyridine; cmen = 1, 2-diaminopropane) system were synthesised and isolated. The structures of the isomers were assigned by using 2D NMR techniques such as gCOSY. Comparing to the eluates from the chromatographic column, the first band contains the m2, the second band contains the ml. Also the crystal structure of the m2[ZnCl4] also were determized by X-ray diffraction determination. The stability of the isomers was studied by using ab initio method of quantum chemistry at RHF/ LANL2DZ level. The calculation results shows that the difference of the ground energies of the two geometric isomers is 10. 6kJ·mol-1 in water ( E0m1 > E0m2), and the distribution of the two isomers is m1: m2 =2: 3. A comparison the structural parameters of the [Co(bamp) (cmen)Cl]2+ isomer shows that the errors between the calculated results and those from the X-ray diffraction determination are less than + 3% generally.