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ABSTRACT: Novel copper(II) X-salicylate complexes with N,N-diethylnicotinamide (dena) of the formula [Cu(RCOO)2(dena)2(H2O)2] (RCOO=3-methylsalicylate anion (3-Mesal, 1), 4-methylsalicylate anion (4-Mesal, 2), 5-methylsalicylate anion (5-Mesal, 3), 5-methoxysalicylate anion (5-MeOsal, 4) or 4-methoxysalicylate anion (4-MeOsal, 5)), and complex [Cu(3-MeOsal)2(dena)2(H2O)2]∙2H2O (3-MeOsal=3-methoxysalicylate anion (6)) have been prepared in the crystalline forms and characterized by spectroscopic methods (IR, Vis–UV, EPR). All the compounds
according to their composition (1–5) seem to possess octahedral copper(II) stereochemistry. The complex 1 has been prepared in two different forms. X-ray analyses of the complexes 1, 4, and 5 were carried out and they featured a tetragonal-bipyramidal geometry around the copper atoms. The tetragonal planes are created
by X-salicylate anions bonded to the copper(II) atoms via unidentate carboxylate oxygen atoms and the pyridine ring nitrogen
atoms of the neutral ligand N,N-diethylnicotinamide, while in axial positions are water molecules. The two forms of complex 1 present conformation polymorphs and supramolecular isomers.
KeywordsCopper complexes-Crystal structure-Hydrogen bonds-Spectra polymorphism-Supramolecular isomerism
Structural Chemistry 05/2012; 21(5):1093-1102. · 1.85 Impact Factor
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ABSTRACT: The title compound, [Cu(4)(C(7)H(4)ClO(2))(4)(C(6)H(6)NO)(4)], consists of isolated tetranuclear clusters, where the Cu(2+) cations are five- and sixfold coordinated by O atoms from the 4-chlorobenzoate anions and by pyridine N and methanolate O atoms from bidentate 2-pyridylmethanolate ligands. While three Cu atoms are six-coordinated by an NO(5) donor set forming distorted octahedra, the fourth Cu atom is five-coordinated by an NO(4) donor set forming a distorted tetragonal-pyramidal coordination around the Cu atom. The nucleus is a deformed cubane-like Cu(4)O(4) structure, with Cu···Cu distances in the range 3.0266 (11)-3.5144 (13) Å.
Acta crystallographica. Section C, Crystal structure communications 09/2011; 67(Pt 9):m318-20. · 0.78 Impact Factor
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ABSTRACT: Polymeric salicylatocopper(II) complexes of unusual composition [Cu(X-sal)2(-denia)1(H2O)1]n (denia = diethylnicotinamide, and X-sal = 5-methylsalicylate (1), 3-methylsalicylate (2), 4-methoxylsalicylate (3), 3,5-dichlorsalicylate (4) and 3,5-dibromsalicylate (5)) have been prepared, analytically and spectrally characterized, as well as their magnetization over the temperature range 1.8–300 K have been measured, and their structures have been solved. The structure unit of all complexes consists of Cu(II) atom monodentately coordinated by the pair of X-salicylate anions in trans-positions and with water and diethylnicotinamide ligands in other two basal plane positions of tetragonal pyramid. The axial positions are occupied by diethylnicotinamide oxygen atom of neighbouring structural units thus forming spiral polymeric molecule parallel to b-axis. Magnetization measurements showed that all complexes (1) – (5) exhibit maximum of magnetic susceptibility about 6÷8 K. The obtained data fit to Bleaney-Bowers equation gave singlet-triplet energy gap 2J = −8.15 cm–1 for (1), 2J = −6.57 cm–1 for (2), 2J = −8.57 cm–1 for (3), 2J = −6.82 cm–1 for (4) and 2J = −6.45 cm–1 for (5). The supramolecular structure based on hydrogen bonds (described by supramoleular synthons R22(10) and R22(10)) is the pathway causing the found antiferromagnetic interactions of the magnetically coupled pairs of Cu atoms of neighboring chains within the 2-D supramolecular layers. The individual magnetic data vs the structure for all five complexes allowed to suggest involvement of COO groups in the pathway of the magnetic interaction.
Zeitschrift für anorganische und allgemeine Chemie 01/2011; 637(2):224. · 1.25 Impact Factor
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ABSTRACT: Complexes of composition [Cu(X-NO2bz)2(-3PM)2]n (X-NO2bz = 2-nitrobenzoate (1), 3-nitrobenzoate (2) or 4-nitrobenzoate (3) and 3PM = 3-pyridylmethanol) have been prepared and studied by elemental analysis, electronic, infrared and EPR spectroscopy. The structure two new complexes (1) and (3) has been solved. The copper atoms of both complexes exhibit an elongated octahedral coordination environment with the equatorial positions occupied by two monodentate nitrobenzoato anions and two 3-pyridylmethanol nitrogen atoms in trans positions. The both axial positions are occupied by oxygen atoms of bridging 3-pyridylmetanol ligands The polymeric structure of complex [Cu(2-NO2bz)2(-3PM)2]n (1) contains two-dimensional layers. The complex (3) exhibits a polymeric chain-like structure [Cu(4-NO2bz)2(-3PM)2]n with copper atoms double bridged by two 3-pyridylmethanol molecules similarly as it was found for complex (2).
Zeitschrift für anorganische und allgemeine Chemie 01/2010; 636(3-4):589. · 1.25 Impact Factor
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ABSTRACT: A new complex of unusual composition [Cu(3-O2Nbz)2(nia)(H2O)2] (1) (nia = nicotinamide, 3-O2Nbz = 3-nitrobenzoate) has been prepared and studied together with two other complexes of composition [Cu(4-O2Nbz)2(nia)2(H2O)2] (2) and [Cu(4-O2Nbz)2(nia)2]∙(4-O2NbzH)2 (3) (4-O2Nbz = 4-nitrobenzoate). The composition of all complexes has been determined by elemental analysis, the complexes have been studied by electronic, infrared and EPR spectroscopy, as well as by magnetization measurements over the temperature range 1.8–300 K, and their structures have been solved. The structure of complex (1) consists of molecules, where Cu(II) atom is monodentately coordinated by the pair of 3-nitrobenzoato anions in trans-positions together with water and nicotinamide molecules, forming nearly tetragonal basal plane, and by another water molecule in axial position of tetragonal-pyramidal coordination polyhedron. The neighbouring molecule coordination polyhedron basal planes are coplanar and allow formation of supramolecular dimmers with strong H-bonds between hydrogen atoms from equatorially coordinated water molecules and uncoordinated carboxylate oxygen atoms thus giving the nearest Cu∙∙∙Cu distance of 4.886(2) Å. Magnetization measurements showed that complex (1) exhibits maximum of magnetic susceptibility at 6.5 K and a fit to Bleaney-Bowers equation gave singlet-triplet energy gap 2J = −6.25 cm–1, and zJ’ = –0,03 cm–1. This might be an experimental proof that the carboxylate bridges extended with hydrogen bonds are the pathway of the spin-spin interactions. The temperature dependence of changes in EPR spectra of (1) and the spectrum at 4.2 K have confirmed its hydrogen bonded dimmeric structure. The calculated Cu∙∙∙Cu distance 4.8 Å is in very good agreement with the value obtained from crystal structure. The complexes (2) and (3) at 300 K exhibit magnetic moment μeff = 1.98 B.M. and μeff = 1.84 B.M., respectively. These values practically do not change with lowering the temperature up to 5 K and only small drops to μeff = 1.87 B.M. (for (2)) and μeff = 1.79 B.M. (for (3)) at 1.8 K have been observed. The EPR spectra of complex (2) at room temperature as well as at 77 K are of axial type with g^ = 2.062 and g|| = 2.285 and exhibit resolved parallel hyperfine splitting with A|| = 160 Gauss. The EPR spectra of complex (3) at room temperature as well as at 77 K are of axial type with g^ = 2.065 and g|| = 2.235 and exhibit unresolved parallel hyperfine splitting. EPR spectra of (2) and (3) are consistent with the X-ray structure.
Polyhedron 01/2010; 29(1):154. · 2.06 Impact Factor
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ABSTRACT: In the crystal structure of the title compound, [Cd(C(15)H(14)NO(2))(2)(C(6)H(7)NO)(2)](n), the Cd atom displays a distorted octa-hedral geometry, including two pyridine N atoms and two hydroxyl O from four symmetry-related 3-pyridylmethanol (3-pyme) ligands and two carboxylate O atoms from mefenamate [2-(2,3-dimethyl-anilino)benzoate] anions. The Cd atoms are connected via the bridging 3-pyme ligands into chains, that extend in the a-axis direction. The Cd atom is located on a center of inversion, whereas the 3-pyme ligands and the mefenamate anions occupy general positions.
Acta Crystallographica Section E Structure Reports Online 01/2008; 64(Pt 3):m440-1. · 0.35 Impact Factor
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Acta Crystallographica Section C Crystal Structure Communications 09/2006; 62(Pt 8):m375-7. · 0.52 Impact Factor
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ABSTRACT: The synthesis and characterization (elemental analysis, IR, electronic and EPR spectra as well as magnetization measurements over the temperature range 1.8 K–300 K) of solid complex, [Cu(5-MeOsal)2(µ-nia)(H2O)]2 (1) (where 5-MeOsal = 5-methoxysalicylate, nia = nicotinamide) is reported together the crystal structure. In blue-green complex (1) two Cu(5-MeOsal)2(H2O) units are held together by a pair of bidentate non-chelating nicotinamide ligands, forming (CuNC3O)2 ring. Each Cu atom adopts a distorted square-pyramidal geometry, with two oxygen atoms of two unidentate 5-MeOsal anions in trans-position, a water molecule and a pyridine N atom of nicotinamide building the basal plane and a carboxamide O atom in the apical position. The separation between two Cu atoms within the dimer is 6.940(2) Ǻ. The dimeric units are self-assembled across a center of symetry by the formation of two pairs of strong hydrogen bonds, creating a one-dimensional polymeric structure with the interdimer Cu∙∙∙Cu separation 4.901(1) Ǻ and it is believed that these via hydrogen bonds interactions between copper(II) atoms are responsible for the compound (1) unique magnetic properties. Magnetic susceptibility of complex (1) exhibits maximum at 6 K and satisfactory explanation was found using Bleaney-Bowers equation with additional molecular field correction. The best fit calculated to experimental values were obtained for g = 2.06, 2J = –6.83 cm–1 and zJ’ = –0.28 cm–1.
European Journal of Inorganic Chemistry 01/2006; · 3.05 Impact Factor
