resumo
One novel coordination polymer [Mn-2(mu-2,6-DCBA)(3)(mu(2)-CH3CO2)(2)(2H(2)O)]center dot 2H(2)O (2,6-DCBA = 2,6-dichlorobenzoato) (compound 1) has been synthesized by self-assembly of bridging ligand 2,6-dichlorobenzoic acid and manganese acetate tetrahydrate. Single crystal X-ray diffraction analysis reveals that this compound crystallizes in space group P2(1)/c with a = 10.1547(7), b = 24.5829(2), c = 12.6606(2) angstrom, beta = 93.707(3), V = 3153.9(3) angstrom(3) and Z = 4. The Mn(II) ions are connected by 2,6-DCBA and acetate group in mu-bridging mode to form 1D chains. Two water molecules are in the inter-layer space forming strong hydrogen bonds originating 2D layer structure. The preparation of this compound is very sensitive to the synthesis conditions, mainly to the solution pH and solvent yielding other two compounds 2 and 3. In compound 1 Mn(II) atoms in octahedral coordination are arranged in a zig -zag chain, with a trimeric structure repeated periodically along the chain, giving two exchange parameters: J(1) related to a syn-syn bond; and J(2) related to a bond of type anti-anti. A theoretical model was developed and then fitted to the magnetic susceptibility data, revealing an antiferromagnetic arrangement along the chain. (C) 2014 Elsevier B.V. All rights reserved.
palavras-chave
METAL-ORGANIC FRAMEWORKS; 1D CHAIN; CARBOXYLATE; MN
categoria
Materials Science
autores
Esteves, D; Tedesco, JCD; Pedro, SS; Cruz, C; Reis, MS; Brandao, P
nossos autores
Diogo António da Costa e Veiga Esteves
Bolseiro de investigação
Paula Cristina Ferreira da Silva Brandão
Investigador Auxiliaragradecimentos
The authors acknowledge European Union, QREN, Fundo Europeu para o desenvolvimento regional (FEDER), COMPETE, FCT, Collaboration Project FCT/CAPES and CICECO (pEstc/CTM/LA001/2011 for financial support) and to Dr. J.P. de Araujo from University of Porto for magnetic measurements. C. C, J. C. G. T., S. S. P. and M. S. R. also thanks FAPERJ, CNPq, CAPES and PROPPI-UFF for financial support.