| Abstrakt: |
Four new cobalt coordination polymers based on cyclohexane-1e,2a,4a,5e-tetracarboxylic acid (2e+2a, H4LI), [Co4(μ4-LI)2(4,4′-bpy)3(H2O)6]·2H2O (1), [Co4(μ5-LI)2(4,4′-bpy)3(H2O)4]·3H2O (2), [Co2(μ4-LIV)(2,2′-bpy)2(H2O)2] (3) and [Co2(μ4-LIV)(1,10-phen)2(H2O)2]·4H2O (4), were synthesized in hydrothermal reactions with some auxiliary ligands to study the conformations and coordination chemistry of H4L. The structural analysis revealed a new conformation, cyclohexane-1e,2e,4e,5e-tetracarboxylic acid (4e, H4LIV), for the flexible ligand H4Ltrapped in compounds 3and 4, which were synthesized in the presence of different chelating ligands whereas in the compounds of 1and 2, the ligands adapt the same conformation (2e+2a, H4LI) as found in the solid state when the linear bridging 4,4′-bpy was added as auxiliary ligand. The conformational transformation originated from the removal of α-protons of H4L, which has been confirmed viathe production of [CuI(4,4′-bpy)(H2O)]2(ip)·2H2O (5) (H2ip = isophthalic acid) from the reaction of Cu2+ions, H4LIligand and 4,4′-bpy under hydrothermal conditions. The magnetic properties of 2and 3were investigated [ABSTRACT FROM AUTHOR] |
