Cd(II) enantiomers embedding helices from 3D frameworks to 2D layers controlled by shapes of ancillary ligands

• Published in: Journal of coordination chemistry 2021-04, Vol.74 (7), p.1124-1133
• Main Authors: Xu, Zhong-Xuan, Bai, Xu-Ling, Li, Li-Feng, XU, Shi-Fei
• Format: Article
• Language: English
• Subjects: 2D layer; 3D framework; Benzene; Benzoic acid; Chiral coordination polymer; Coordination polymers; effect of ancillary ligand; Enantiomers; helical structure; Helices; Hydrocarbons; Imidazole; Ligands; Photoluminescence; Shape
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2021.1898602

Two pairs of chiral coordination polymers, [Cd 2 ((R)-CBA) 2 (1,4-BMIB)] n (1-R ), [Cd 2 ((R)-CBA) 2 (1,4-BMIB)] n (1-S ), {[Cd((R)-CBA)(1,3-BMIB)]·H 2 O} n (2-R ), and {[Cd((R)-CBA)(1,3-BMIB)]·H 2 O} n (2-S ) (H 2 CBA = 4-(1-carboxyethoxy) benzoic acid, 1,4-BMIB = 1,4-bis(2-methyl-1H-imidazol-1-yl)benzene, 1,3-BMIB = 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene), were constructed from lactate derivatives H 2 CBA and imidazole ancillary ligands under hydrothermal conditions. These complexes show different structures depending on shapes of ancillary ligands. For the linear 1,4-BMIB, complexes 1-R and 1-S are three dimensional (3D) frameworks with dinuclear clusters of Cd(II). For the V-shaped 1,3-BMIB, complexes 2-R and 2-S are two dimensional (2D) layers, where 4-connected Cd(II) centers were isolated by imidazole groups and carboxylic groups from 1,3-BMIB and H 2 CBA, respectively. The resulting complexes were characterized by PXRD, TGA, UV-visible absorptions and CD measurements. Additionally, 1 and 2 exhibit different photoluminescence behavior in the solid state compared to free H 2 CBA.