6533b7dafe1ef96bd126f466

RESEARCH PRODUCT

Coordinating and hydrogen bonding ability of a bifunctional 2D paddle-wheel copper(II) coordination polymer

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abstract A new copper(II) complex of formula {[Cu 2 (H 2 btc) 2 (dmf) 2 ] 4dmf} n (1)[H 4 btc = 1,2,4,5-benzenetetracarb-oxylic acid, dmf = dimethylformamide] has been synthesised and its structure determined by X-raydiffraction. The structure displays a new square grid of ‘‘paddle-wheel’’ tetracarboxylate-bridgeddicopper(II) units with an intradimer copper–copper separation of 2.619(2) A. The dmf molecules areretained through weak axial coordinative bonds and hydrogen bonding interactions with the carboxylicgroups of the porous neutral network of 4 4 net topology. The magnetic behaviour of 1 corresponds to astrong antiferromagnetic coupling within each dicopper(II) unit (J = 343 cm 1 with the Hamiltonianbeing defined by H = J S 1 S 2 ). Complex 1 does not adsorb N but it exhibits certain absorption of COwith a hysteretic desorption behaviour typical of flexible MOFs. 2014 Elsevier Ltd. All rights reserved. 1. IntroductionThe rational design and synthesis of porous coordination poly-mers, known as metal–organic frameworks (MOFs), is a very inter-esting subject of current research in the field of crystal engineering[1,2]. Due to their diverse structural architectures and net topolo-gies, this new class of multifunctional materials has potentialapplications in different areas, like catalysis, gas storage, ionexchange, molecular electronics and spintronics [3–9]. The selec-tion of an appropriate ligand is one of the most important stepsin order to obtain the desired compound in the reticular synthesisof porous coordination polymers. Aromatic carboxylate ligandshave been widely used for the construction of new coordinationpolymers of variable dimensionality. Among them, 1,2,4,5-benzenetetracarboxylic acid (hereafter noted H