Transition Metal Coordination Polymers with Trans-1,4-Cyclohexanedicarboxylate: Acidity-Controlled Synthesis, Structures and Properties

Five trans-1,4-cyclohexanedicarboxylate (chdc(2−)) metal–organic frameworks of transition metals were synthesized in aqueous systems. A careful control of pH, reaction temperature and solvent composition were shown to direct the crystallization of a particular compound. Isostructural [Co(H(2)O)(4)(chdc)](n) (1) and [Fe(H(2)O)(4)(chdc)](n) (2) consist of one-dimensional hydrogen-bonded chains. Compounds [Cd(H(2)O)(chdc)](n)∙0.5nCH(3)CN (3), [Mn(4)(H(2)O)(3)(chdc)(4)](n) (4) and [Mn(2)(Hchdc)(2)(chdc)](n) (5) possess three-dimensional framework structures. The compounds 1, 4 and 5 were further characterized by magnetochemical analysis, which reveals paramagnetic nature of these compounds. A presence of antiferromagnetic exchange at low temperatures is observed for 5 while the antiferromagnetic coupling in 4 is rather strong, even at ambient conditions. The thermal decompositions of 1, 4 and 5 were investigated and the obtained metal oxide (cubic Co(3)O(4) and MnO) samples were analyzed by X-ray diffraction and scanning electron microscopy.