Cobalt(II) Coordination Polymers Containing trans-1,2-Bis(4-pyridyl)ethene and Their Magnetic Properties

• Published in: European Journal of Inorganic Chemistry Vol. 2010; no. 24; pp. 3856 - 3865
• Main Authors: Peedikakkal, Abdul Malik Puthan, Song, Yu-Mei, Xiong, Ren-Gen, Gao, Song, Vittal, Jagadese J.
• Format: Book Review Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.08.2010; WILEY‐VCH Verlag
• Subjects: Anions; Bridging ligands; Cobalt; Magnetic properties; Metal-organic frameworks
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201000375

Reaction of the CoII ion and the bpe [trans‐1,2‐bis(4‐pyridyl)ethene] ligand in the presence of the CH3CO2–, CF3CO2–, C6H5CO2– and NO3– anions affords six coordinationpolymers, namely [Co2(μ‐bpe)2(μ‐O2CCH3)2(O2CCH3)2]·H2O (1), [Co2(μ‐bpe)2(μ‐O2CCF3)2(O2CCH3)2] (2), [Co(μ‐bpe)2(O2CCF3)2] (3), [Co(μ‐bpe)(O2CC6H5)2(HO{O}CC6H5)2] (4), [Co(μ‐bpe)(O2CC6H5)2(CH3OH)2] (5) and [Co2(μ‐bpe)3(NO3)3(CH3OH)](NO3) (6). All the compounds have been characterized by X‐ray crystallography, IR spectroscopy and thermogravimetry. Variable‐temperature magnetic measurements were also performed on 3 and 6. Compounds 1 and 2 form 1D molecular ladder coordination polymers bridged by acetate ligands. Replacing the acetate ligands completely by trifluoroacetate ligands produced interpenetrated square‐grid sheets in 3. Replacing acetate and trifluoroacetate ligands by benzoate ligands resulted in two 1D coordination polymers, 4 and 5, having zigzag and linear structures, respectively. When the nitrate anion was used, a 3D network, 6, was afforded with inclined interpenetration of a 1D molecular ladder structure with threefold polycatenation. The variation of anions, reaction conditions and the ratio of reactants profoundly affect the final topological structure of the coordination polymers synthesized. The trifluoroacetate and nitrate anions influence the topology and the degree of interpenetration in the coordination polymers 3 and 6, respectively. Six coordination polymers were synthesized from the CoII ion and bpe [bpe = 1,2‐bis(4‐pyridyl)ethene] ligand in the presence of the CH3CO2–, CF3CO2–, C6H5CO2– and NO3– anions. The topology of the coordination polymers were varied by using different anions and reaction conditions. Two interpenetrated diagonal (4,4) and (4,3) nets exhibit interesting magnetic properties.