869103-18-4Relevant articles and documents
Polymeric networks of copper(II) phenylmalonate with heteroaromatic N-donor ligands: Synthesis, crystal structure, and magnetic properties
Pasan, Jorge,Sanchiz, Joaquin,Ruiz-Perez, Catalina,Lloret, Francesc,Julve, Miguel
, p. 7794 - 7801 (2005)
Two new phenylmalonate-bridged copper(II) complexes with the formulas [Cu(4,4′-bpy)(Phmal)]n·2nH2O (1) and [Cu(2,4′-bpy)(Phmal)(H2O)]n (2) (Phmal = phenylmalonate dianion, 4,4′-bpy = 4,4′-bipyridine, 2,4′-bpy = 2,4′-bipyridine) have been synthesized and characterized by X-ray diffraction. Complex 1 crystallizes in monoclinic space group P21, Z = 4, with unit cell parameters of a = 9.0837(6) A, b = 9.3514(4) A, c = 11.0831(8) A, and β = 107.807(6)°, whereas complex 2 crystallizes in orthorhombic space group C2cb, Z = 8, with unit cell parameters of a = 10.1579(7) A, b = 10.3640(8) A, and c = 33.313(4) A. The structures of 1 and 2 consist of layers of copper(II) ions with bridging bis-monodentate phenylmalonate (1 and 2) and 4,4′-bpy (1) ligands and terminal monodentate 2,4′-bpy (2) groups. Each layer in 1 contains rectangles with dimensions of 11.08 x 4.99 A2, the edges being defined by the Phmal and 4,4′-bpy ligands. The intralayer copper-copper separations in 1 through the anti-syn equatorial-apical carboxylate-bridge and the 4,4′-bpy molecule are 4.9922(4) and 11.083(1) A, respectively. The anti-syn equatorial-equatorial carboxylate bridge links the copper(II) atoms in complex 2 within each layer with a mean copper-copper separation of 5.3709(8) A. The presence of 2,4′-bpy as a terminal ligand accounts for the large interlayer separation of 15.22 A. The copper(II) environment presents a static pseudo-Jahn-Teller disorder which has been studied by EPR and low-temperature X-ray diffraction. Magnetic susceptibility measurements of both compounds in the temperature range 2-290 K show the occurrence of weak antiferromagnetic [J = -0.59(1) cm-1 (1)] and ferromagnetic [J = +0.77(1) cm-1 (2)] interactions between the copper(II) ions. The conformation of the phenylmalonate-carboxylate bridge and other structural factors, such as the planarity of the exchange pathway in 1, account for the different nature of the magnetic interaction.
