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

Abstract

AbstractThree 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) Å (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)