Nickel(II)-, cobalt(II)-, copper(II)-, and zinc(II)-phthalate and 1-methylimidazole coordination compounds: synthesis, crystal structures and magnetic properties

• Published in: Inorganica Chimica Acta Vol. 357; no. 12; pp. 3419 - 3429
• Main Authors: Baca, Svetlana G., Filippova, Irina G., Gherco, Olesea A., Gdaniec, Maria, Simonov, Yurii A., Gerbeleu, Nicolae V., Franz, Patrick, Basler, Reto, Decurtins, Silvio
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10-09-2004
• Subjects: Carboxylates; Coordination polymers; Crystal structures; Magnetic properties; Phthalate complexes; Coordination polymers; Crystal structures; Phthalate complexes; Carboxylates; Magnetic properties
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(03)00498-5

Three new coordination polymers [M(Pht)(1-MeIm)
2]
n
(where M=Cu (
1), Zn (
2), Co (
3); Pht
2−=dianion of
o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)
6](HPht)
2
·
2H
2O (M=Co (
4), Ni (
5)) have been synthesized and characterized by X-ray crystallography, IR and
1H NMR spectroscopy and thermogravimetric analysis. The structures of
1–
3 consist of [M(1-MeIm)
2] building units connected by 1,6-bridging phthalate ions to form infinite chains. In contrast to polymers
1–
3 the structures of
4 and
5 are made up of the [M(1-MeIm)
6]
2+ cation, two hydrogen phthalate anions (HPht
−) and two H
2O solvate molecules.
Three new coordination polymers [M(Pht)(1-MeIm)
2]
n
(where M=Cu (
1), Zn (
2), Co (
3); Pht
2−=dianion of
o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)
6](HPht)
2
·
2H
2O (M=Co (
4), Ni (
5)) have been synthesized and characterized by X-ray crystallography. The structures of
1–3 (
2 is isostructural to
3) consist of [M(1-MeIm)
2] building units connected by 1,6-bridging phthalate ions to form infinite chains. In complex
1, each copper(II) center adopts a square coordination mode of N
2O
2 type by two O atoms from different phthalate ions and two N atoms of 1-MeIm, whereas in
3 two independent metal atoms are tetrahedrally (N
2O
2) coordinated to a pair of Pht ligands and a pair of 1-MeIm molecules. There are only van der Waals interactions between the chains in
1, while the three-dimensional network in
3 is assembled by C–H⋯O contacts. In contrast to polymers
1–3 the structures of
4 and
5 (complexes are also isostructural) are made up of the [M(1-MeIm)
6]
2+ cation, two hydrogen phthalate anions (HPht
−) and two H
2O solvate molecules. The coordination around each metal(II) atom is octahedral with six nitrogen atoms of 1-MeIm. Extended hydrogen bonding networks embracing the solvate water molecules and a phthalate residue as well as the weak C–H⋯O interactions stabilize the three-dimensional structures. Magnetic studies clearly show that the magnetic ions do not interact with each other. Furthermore, in compound
4 we have another example of a highly anisotropic Co
2+ ion with a rhombic
g-tensor and large zero-field-splitting. The complexes were also characterized by IR and
1H NMR spectroscopy, thermogravimetric analysis, and all data are discussed in the terms of known structures.