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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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Synthesis and characterization of four new 2,6-dimethoxynicotinate (2,6-(MeO) 2 nic) copper(II) monomeric complexes [Cu(2,6-(MeO) 2 nic) 2 (py) 2 ] (py is pyridine), [Cu{2,6-(MeO) 2 nic} 2 (Etnic) 2 (H 2 O)] (Etnic is ethylnicotinate), [Cu{2,6-(MeO) 2 nic} 2 (Et 2 nia) 2 (H 2 O) 2 ] (Et 2 nia is N,N-diethylnicotinamide) as well as of the polymeric complex [Cu{2,6-(MeO) 2 nic} 2 (ron) 2 ] n (ron is ronicol) are reported. The characterizations were based on elemental analysis, infrared, electronic and EPR spectra. Crystal structures of two of the complexes have been determined. The copper(II) of [Cu{2,6-(MeO) 2 nic} 2 (py) 2 ] has a distorted tetragonal-bipyramidal (4 þ 2) coordination environment. Both 2,6-(MeO) 2 nic anions are asymmetrically chelating. The Cu(II) of [Cu{2,6-(MeO) 2 nic} 2 (Etnic) 2 (H 2 O)] is pentacoordinate in a slightly distorted tetragonal-pyramidal arrangement by two trans nitrogens, each of one Etnic, by two oxygens, each of the carboxyl group of one unidentate 2,6-(MeO) 2 nic and the axial position occupied by water at a longer distance. Antimicrobial effects of the complexes have been tested on various strains of bacteria, yeasts and filamentous fungi. While the 2,6-(MeO) 2 nicH alone did not influence the model bacteria growth, dimeric [Cu{2,6-(MeO) 2 nic} 2 (H 2 O)] 2 and polymeric [Cu{2,6-(MeO) 2 nic} 2 (ron) 2 ] n have pronounced influence on the growth of Staphylococcus aureus, Escherichia coli and Candida parapsilosis.

In the title complex, [Cu(C8H6NO2)2(C6H7NO)2(H2O)], the Cu2+ ion has a highly distorted square‐bipyramidal (4 + 1 + 1) coordination environment, and is bonded to three carboxyl­ate O atoms of two 3‐pyridylacrylate anions (monodentate and asymetric bidentate), two pyridine N atoms of 3‐pyridylmethanol ligands and one water O atom. O—H⋯O and O–H⋯N hydrogen bonds result in the formation of a two‐dimensional layer structure.