Preparation, Structure, Spectral, and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ-2-chloronicotinato-O,O′)-diaquadicopper(II)

Autor: Ján Moncol, Peter Segl'a, Jerzy Mroziński, Tadeusz Głowiak, Markku R. Sundberg, Marian Koman, Dušan Mikloš, Jana Jašková, Maria Korabik, Milan Melnik
Rok vydání: 2007
Předmět:
Zdroj: Zeitschrift für anorganische und allgemeine Chemie. 633:298-305
ISSN: 1521-3749
0044-2313
Popis: The characterization of the complexes [Cu2(2-Clnic)4(H2O)2] (1), [Cu(2,6-Cl2nic)2(H2O)2] (2) and [Cu(5-Brnic)2(H2O)2]n (3) (where 2-Clnic = 2-chloronicotinate, 2,6-Cl2nic = 2,6-dichloronicotinate or 5-Brnic = 5-bromonicotinate) was based on elemental analysis, IR, electronic and EPR spectra, and magnetic susceptibility. Complex 1 was also studied by X-ray analysis at 298 1a and 80 K 1b. The complex 1 contains a dinuclear Cu-acetate molecular structure in which the carboxyl groups of the 2-chloronicotinate ligands act as bridges and water molecules are at apical positions. The stereochemistry about Cu atom at both temperatures is typical for square pyramidal geometry with CuO4O chromophore. The Cu-Cu distance is 2.6513(8) and 2.6382(6) A for 1a and 1b, respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) A, respectively, from the plane containing four oxygen atoms bonded to the Cu atom toward the apical water molecules. Strong and weak hydrogen bonds as well as C–Cl···π interactions in the crystal structure are discussed as well. Both complexes, monomeric [Cu(2,6-Cl2nic)2(H2O)2] (2) and polymeric [Cu(5-Brnic)2(H2O)2]n (3), possess octahedral copper(II) stereochemistry with differing tetragonal distortions.
Databáze: OpenAIRE
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