Cadmium-1,4-cyclohexanedicarboxylato coordination polymers bearing different di-alkyl-2,2′-bipyridines: syntheses, crystal structures and photoluminescence studiesElectronic supplementary information (ESI) available: FTIR spectra, TGA, fluorescence spectra, bond lengths and bond angle tables for 1 to 4. CCDC 1555262, 1555263, 1555264 and 1555265 for 1 to 4, respectively. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt02376f

• Main Authors: Rosales-Vázquez, Luis D, Sánchez-Mendieta, Víctor, Dorazco-González, Alejandro, Martínez-Otero, Diego, García-Orozco, Iván, Morales-Luckie, Raúl A, Jaramillo-Garcia, Jonathan, Téllez-López, Antonio
• Format: Journal Article
• Language: English
• Published: 26.09.2017
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt02376f

Four coordination polymers have been synthesized using self-assembly solution reactions under ambient conditions, reacting Cd( ii ) ions with 1,4-cyclohexanedicarboxylic acid in the presence of different 2,2′-bipyridine co-ligands: {[Cd(H 2 O)( e , a-cis -1,4-chdc)(2,2′-bpy)]·H 2 O} n ( 1 ); [Cd 2 (H 2 O) 2 ( e , a-cis -1,4-chdc) 2 (4,4′-dmb) 2 ] n ( 2 ); {[Cd( e , a-cis -1,4-chdc)(5,5′-dmb)]·H 2 O·CH 3 OH} n ( 3 ) and {[Cd( e , e-trans -1,4-chdc)(4,4′-dtbb)]·CH 3 OH} n ( 4 ), where 1,4-chdc = 1,4-cyclohexanedicarboxylato, 2,2′-bpy = 2,2′-bipyridine, 4,4′-dmb = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-dmb = 5,5′-dimethyl-2,2′-bipyridine and 4,4′-dtbb = 4,4′-di- tert -butyl-2,2′-bipyridine. Crystallographic studies show that compound 1 has a 1D structure propagating along the crystallographic b -axis; the Cd ion in 1 is six-coordinated with a distorted-octahedral coordination sphere. Compound 2 has two crystallographic different Cd ions and both are six-coordinated with a distorted-octahedral coordination sphere. Compound 3 exhibits a seven-coordinated Cd ion having a distinctive distorted-monocapped trigonal prismatic geometry. In compound 4 , the Cd ion is also seven-coordinated in a distorted monocapped octahedral geometry. Compounds 2 , 3 and 4 possess rhombic-shaped dinuclear units (Cd 2 O 2 ) as nodes to generate larger cycles made up of four dinuclear units, a Cd 4 motif, bridged by four 1,4-chdc ligands, accomplishing, thus, 2D structures. Remarkably, in compound 4 the 1,4-chdc ligand conformation changes to the equatorial , equatorial trans , unlike the other compounds where the bridging ligand conformation is the more typical equatorial , axial cis . The solid state luminescence properties of 1-4 were investigated; polymers 3 and 4 exhibited a strong blue emission ( λ em = 410-414 nm) compared to 1 and 2 ; structure-related photoluminescence is attributed to the degree of hydration of the compounds. Furthermore, Cd-polymer 3 suspended in acetone allows the fluorescence selective sensing of acetonitrile over common organic solvents such as alcohols and DMF, based on turn-on fluorescence intensity with a limit of 53 μmol L −1 . Cd( ii ) polymers, in acetone, can be used as luminescent materials for detection of CH 3 CN.