Preparation,Structure, Spectral,and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ‐2‐chloronicotinato‐O,O′)‐diaquadicopper(II) |
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| Authors: | Jan Moncol Maria Korabik Peter Segl'a Dr Marian Koman Dušan Mikloš Jana Jašková Tadeusz Glowiak Milan Melník Jerzy Mrozinski Markku R Sundberg |
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| Institution: | 1. Bratislava / Slovak Republic, Slovak Technical University;2. Wroclaw / Poland, Faculty of Chemistry, University of Wroclaw;3. Wroclaw / Poland, Faculty of Chemistry, University of Wroclaw
†;4. Helsinki / Finland, Department of Chemistry, University of Helsinki |
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| Abstract: | 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) Å for 1a and 1b , respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) Å, 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. |
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| Keywords: | Copper Crystal structure Nicotinate Magnetic properties Hydrogen bonds Cl· · · π interactions |
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