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Design and understanding of solid-state and crystalline materials



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CrystEngComm, 2009, 11, 817 - 826, DOI: 10.1039/b816721d

From copper(II) carboxylate to copper(II) 4-pyridylsulfonate coordination polymers as a consequence of the copper(II)-assisted oxidative cleavage of the 4,4-dipyridyldisulfide ligand

Rosa Carballo, Berta Covelo, Nuria Fernández-Hermida, Ana B. Lago and Ezequiel M. Vázquez-López

Five coordination polymers 1 {[Cu4(HCO2)6(OH)2(4dpds)2]·2CH2Cl2}n, 2 {[Cu4(CH3CO2)6(OH)2(4dpds)2]}n, 3 {[Cu(4dpds)2(H2O)2](4pySO3)2·2H2O}n, 4 {[Cu(4pySO3)2(4dpds)2]·2H2O}n and 5 {[Cu(4pySO3)2(dmso)2]·2H2O}n (where 4dpds = 4,4-dipyridyldisulfide, 4pySO3 = 4-pyridylsulfonate) have been obtained during a study into the reactivity of basic copper(II) salts (formate and acetate) with 4,4-dipyridyldisulfide (4dpds). The coordination polymers 1 and 2 consist of a repeated rhomboid structure in which analogous Cu4(RCO2)6(OH)2 cores are joined by two 4,4-dipyridyldisulfide bridging ligands to generate two different chain topologies: planar ribbon in 1 and ruffled ribbon in 2. 4-Pyridylsulfonate ions appear as ligands or counterions in the coordination polymers 3, 4 and 5 due to oxidative cleavage of the 4,4-dipyridyldisulfide under mild conditions. The coordination polymer 3 has been isolated repeatedly in several direct reactions of the copper(II) carboxylates with 4,4-dipyridyldisulfide. However, the coordination polymers 4 and 5 have been obtained from 1 and 2, respectively, by recrystallization from DMF and DMSO. In compound 4, as in 3, the 4,4-dipyridyldisulfide has only been partially oxidized to 4-pyridylsulfonate and a proportion of these units remain in the structure as disulfide. However, in 5 the oxidation is complete. The structural analysis of these coordination polymers reveals that, in all cases, weak interactions such as classical and non-classical hydrogen bonds, as well as CH, S and SO interactions, join the polymeric chains to generate three-dimensional networks.

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