title: Synthesis and structure of [2 x 2] molecular grid copper(II) and nickel(II) complexes with a new polydentate oxime-containing Schiff base ligand.
abstract: A new polynucleating oxime-containing Schiff base ligand, 2-hydroxyimino- N'-[1-(2-pyridyl)ethylidene]propanohydrazone (H pop), has been synthesized and fully characterized. pH potentiometric, electrospray ionization mass spectrometric, and spectrophotometric studies of complex formation in H 2O/DMSO solution confirmed the preference for polynuclear complexes with 3d metal ions. Single-crystal X-ray diffraction analyses of [Ni 4( pop) 4(HCOO) 4].7H 2O ( 1), [Cu 4( pop-H) 4(HCOOH) 4].H 2O ( 2), and [Cu 4( pop-H) 4(H 2O) 4].9H 2O ( 3) indicated the presence of a [2 x 2] molecular grid structure in all three compounds but distinct configurations of the cores: a head-to-tail ligand arrangement with overall S 4 symmetry of the grid in the Cu (2+) complexes as opposed to a head-to-head ligand arrangement with (noncrystallographic) C 2 grid symmetry for the Ni (2+) complex. A cryomagnetic study of 3 revealed intramolecular ferromagnetic exchange between copper ions in the grid, while in 1, antiferromagnetic interactions between the metal ions were observed.
authors.affiliation: Department of Chemistry, Kiev National Taras Shevchenko University, 01601 Kiev, Ukraine.
authors.forename: Yurii S
authors.initials: YS
authors.lastname: Moroz
authors.forename: Kinga
authors.initials: K
authors.lastname: Kulon
authors.forename: Matti
authors.initials: M
authors.lastname: Haukka
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Gumienna-Kontecka
authors.forename: Henryk
authors.initials: H
authors.lastname: Kozłowski
authors.forename: Franc
authors.initials: F
authors.lastname: Meyer
authors.forename: Igor O
authors.initials: IO
authors.lastname: Fritsky