Structural and magnetic properties of three copper(II) pyridine-2,3-dicarboxylate coordination polymers incorporating the same chain motif

• Published in: Polyhedron Vol. 22; no. 22; pp. 3025 - 3035
• Main Authors: Patrick, Brian O., Stevens, Cecilia L., Storr, Alan, Thompson, Robert C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2003
• Subjects: Bridging ligands; Chain polymers; Structural and magnetic properties; X-ray diffraction; X-ray diffraction; Chain polymers; Bridging ligands; Structural and magnetic properties
• ISSN: 0277-5387
• DOI: 10.1016/S0277-5387(03)00433-9

The same chain motif that appears in the chain polymer, [Cu(2,3-pydcH)
2] appears also in the two heterometallic polymeric materials [Cu(2,3-pydc)
2] [Na
2(H
2O)
6 (μ-H
2O)
2] and [Cu(2,3-pydc)
2] [Mn(H
2O)
6]
·
2H
2O. Magnetic studies reveal weak antiferromagnetic exchange mediated by teh bridging pyridinedicarboxylate ligands in all three compounds.
The complex [Cu(2,3-pydcH)
2], (
1), (2,3-pydcH
2=2,3-pyridinedicarboxylic acid) is a chain polymer. Two ligands occupy the equatorial plane of each tetragonally elongated octahedral Cu
2+ coordination sphere, chelating through the pyridine nitrogen and one oxygen of the deprotonated 2-carboxylic acid group; the axial positions are occupied by long bonds to a 3-carboxylic acid oxygen of adjacent Cu(2,3-pydcH)
2 repeat units. This polymeric chain motif also appears in two heterometallic complexes incorporating the doubly deprotonated dicarboxylate ligand species 2,3-pydc; namely [Cu(2,3-pydc)
2][Na
2(H
2O)
6(μ-H
2O)
2], (
2), and [Cu(2,3-pydc)
2][Mn(H
2O)
6]
·
2H
2O, (
3). In
2, the chains are cross-linked via a novel disodium cation [Na
2(H
2O)
6(μ-H
2O)
2]
2+ to form a 2D sheet structure. In
3, the chains carry a formal 2− charge per copper centre, with charge neutrality achieved by the presence of isolated [Mn(H
2O)
6]
2+ complex cations in the lattice. The structural and magnetic properties of these three species are compared.