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RESEARCH PRODUCT

Phenylmalonate‐Containing Copper( II ) Complexes: Synthesis, Crystal Structure and Magnetic Properties

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Three new copper(II) complexes of formula [Cu(2,2′-bpy)(Phmal)(H2O)]·2H2O (1), [{Cu(2,2′-bpym)(Phmal)}]n (2) and [{Cu(phen)(Phmal)}]n·3nH2O (3) (Phmal = phenylmalonate; 2,2′-bpy = 2,2′-bipyridine; 2,2′-bpym = 2,2′-bipyrimidine; phen = 1,10-phenanthroline) have been prepared and their structures determined by X-ray diffraction techniques. Complex 1 is mononuclear whereas 2 and 3 are uniform chain compounds. The copper atoms in 1−3 are distorted square-pyramidal: two nitrogen atoms from the bidentate nitrogen heterocycle and two carboxylate oxygen atoms from the phenylmalonate ligand build the equatorial plane; the axial position is filled either by a water molecule (1) or a carboxylate oxygen atom from another phenylmalonate group (2 and 3). The values of the intrachain copper−copper separation through the phenylmalonate-carboxylate bridge in the anti-syn conformation are 4.6853(7) (2) and 5.014(3) A (3). The phenyl ring of the Phmal ligand in 1 produces an unusual intramolecular π−π stacking interaction with the CuII−(aromatic 2,2′-bpy) chelate ring. Intrachain edge-to-face phenyl−pyridyl and offset phen−phen-type interactions occur in 2 and 3, respectively. Magnetic susceptibility measurements of 2 and 3 in the temperature range 1.9−290 K show the occurrence of weak intrachain ferromagnetic interactions between the copper(II) ions through the phenylmalonate-carboxylate bridge [J = +0.10(1) (2) and +0.31(1) cm−1 (3)]. These values are compared with those reported for malonate-containing copper(II) complexes with the same exchange pathway through the anti-syn carboxylate bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)