【作者】 郭瑞云； 赵永德； 常俊标； 陈荣峰； 林素风；

【Author】 Guo Ruiyun Zhao Yongde Chang JunBiao Chen Rongfeng Lin Sufeng (HeNan Institute of Chemistry,Zheng Zhou 450003)

【机构】 河南化学研究所；

【摘要】 本文报道了中性水溶液中Cu（L-氨基酸）（1:2）体系的圆二色谱,根据d-d区域跃迁带的CD符号给出了Cu（L-氨基酸）₂络合物的构型。更多还原

【Abstract】 In this paper,we report the CD（Circular Dichroisms） spectra of the Cu（L-amino acid）（1:2） systems in neutral aqueous solution and devote the CD bands to the d-d transition O_N→Cu3d CT transition andσ_o→Cu3d transition band.According to the sign model in d-d region,the coordination configuration of the Cu（L-amino acid）（1:2） complexes are given. According to the research of Luigi Casella and Michele Gullotti,the most species is CuL₂ in the neutral aqueous solution（HL=L-amino acid）.We think the configuration we give of the Cu（L-lysine）2 and Cu（L-glu）2 are only possible configuration because their 615nm d-d band are not intense.This imply that the coordination is not fixed because it is the eight-membered ring.The stabilitry of the rine is high.If the ring is released the ligand L will appear as bidentate ligand not tridentate ligand.Thus the mode will change to square structure. The spectrum of the Cu（L-cysteine）₂ system shows that an intense positive CD at 710nm an intense positive CD at 310nm and an intense positive CD at 220nm.The intense positive CD of 710nm is apparently associated with the X configuration of the chelate ring with the side chain S atom binding Cu（Ⅱ） in an apical position and stabilizing the X configuration.The coordination of S and Cu（Ⅰ） is associated with the charge-transfer transition fromσ_S→Cu3d at 310nm. The spectrum of the Cu（L-tryptophane）₂ shows that an intense negative CD band at 585nm an intense positive CD at 280nm and weak positive CD at 220nm. The intense negative CD at 585nm is associated with the 6 configuration and the intense positive CD at 280nm is associated with theπ（indolyl）→Cu（Ⅱ） transition. This LMCT transition stabilize the 6 configuration and make the d-d transition intense. And a considerable advantage of the cis structure for Cu（L-trtyptophane）₂ is that it allows both L-tryptophane molecules coordinated to bind as tridentate ligands while only one can be tri dentate and one bidentated in the trans structure.更多还原