Polypyridyl-based Cu(II) coordination polymers: Synthesis, structural and magnetic characterizations
作者:Karine Déniel、Kahina Nebbali、Nathalie Cosquer、Françoise Conan、Carlos J. Gómez-García、Said Yefsah、Smail Triki
DOI:10.1016/j.poly.2015.05.032
日期:2015.9
New Cu(II) coordination polymeric neutral Chains of formula [Cu-2(1,4-tpbd)Cl2L2] (1,4-tpbd = N,N,N'N' -te-trakis(2-pyridylmethyl)benzene-1,4-diamine, L = 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet) (1) or 1,1,3,3-tetracyano-2-propoxypropenide (tcnopr)(-) (2)) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. The crystal structure determinations of 1 and 2 reveal in both cases a one-dimensional structure in which the 1,4-tpbd acts as a bis-chelating ligand and the two chloride anions as asymmetrical bridging ligands. The Cu center dot center dot center dot Cu distances through the bis-chelating 1,4-tpbd ligand (8.194(1) and 8.245(3) angstrom for 1 and 2 respectively) are in the range of the corresponding distances observed for parent complexes involving similar bridges; and as expected, the Cu center dot center dot center dot Cu distances through the asymmetrical (mu(2)-Cl)(2) bridges are significantly shorter (4.021(2) and 4.125(2) angstrom for 1 and 2, respectively). For both compounds, magnetic measurements exhibit a maximum in the chi(m). versus T plot (at 50 K for 1, and at 48 K for 2), characteristic of antiferromagnetic exchange interactions occurring mainly through the tbpd organic ligand that can be very well reproduced with a S = 1/2 dimer model with g = 2.114, J = -41.2 cm(-1) for 1 and g = 2.105 and J = -39.3 cm(-1) for 2. (C) 2015 Elsevier Ltd. All rights reserved.