TY - JOUR A1 - Halaska, Jozef A1 - Pevec, Andrej A1 - Strauch, Peter A1 - Kozlevcar, Bojan A1 - Koman, Marian A1 - Moncol, Jan T1 - Supramolecular hydrogen-bonding networks constructed from copper(II) chlorobenzoates with nicotinamide - Structure and EPR JF - Polyhedron : the international journal of inorganic and organometallic chemistry N2 - Nicotinamide (nia) has been employed as a supramolecular reagent in the synthesis of four copper(II) chloro- and dichlorobenzoate (Clbz/Cl(2)bz) complexes. The structures of the compounds [Cu(2-Clbz)(2) (nia)(2)(H2O)(2)] (1), icu(4-clbz)(2)(nia)(2)(H2O)(2)] (2), [Cu(3,5-Cl(2)bz)(2)(nia)(2)(H2O)(2)] (3), and [Cu(2,5-Cl(2)bz)(2) (nia)(2)(H2O)]center dot H2O (4) were determined. All the investigated compounds 1-4 reveal water molecules as coordinated. Their structures show distorted octahedral chromophores (CuN2O2O)-N-II'(2), though some are better described as square-planar or square-pyramid due to a large deviation of the axial ligand away from the octahedral z-axis along with different Cu center dot center dot center dot O (axial) lengths. The equatorial positions are occupied in all four cases by two nitrogen (nia-py) atoms and two carboxylate oxygen atoms of two Clbz/Cl(2)bz ligands, while the axial positions are occupied by water molecules. The EPR spectra reveal for all 1-4 compounds a spin state of S = 1/2, mostly with axial symmetry of the spectra. Their resolution is clearly dependant to the crystal symmetry related equivalence of the magnetic sites. The coordination molecules of all compounds are connected by N-H center dot center dot center dot O and O-H center dot center dot center dot O H-bonds from nicotinamide NH2 groups, carboxylate anions and/or water molecules, which create supramolecular chains or further H-bonded into 2D sheets. Steric hindering of the chlorine atoms of the Clbz/Cl(2)bz, especially seen at the coordination of the water molecules, demonstrates its role at the coordination sphere appearance. Despite this influence, the water molecules in 1-4 always assist at the similar supramolecular H-bonded network, almost at the same manner. KW - Copper(II) complexes KW - Nicotinamide KW - Crystal structure KW - EPR Y1 - 2013 U6 - https://doi.org/10.1016/j.poly.2013.05.032 SN - 0277-5387 VL - 61 SP - 20 EP - 26 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Kozlevcar, Bojan A1 - Odlazek, Darja A1 - Golobic, Amalija A1 - Pevec, Andrej A1 - Strauch, Peter A1 - Segedin, Primoz T1 - Complexes with lignin model compound vanillic acid : two different carboxylate ligands in the same dinuclear tetracarboxylate complex [Cu-2(C8H7O4)(2)(O2CCH3)(2)(CH3OH)(2)] N2 - Two copper(II) coordination compounds with vanillic acid C8H8O4 (1), namely [Cu- 2(C8H7O4)(2)(O2CCH3)(2)(CH3OH)(2)] (2) and [Cu-2(C8H7O4)(4)(H2O2)(2)] (3), were synthesized and characterized. Single crystals of 1-3 were obtained and their crystal structures determined. The structure of 2 shows dinuclear cage structure of copper acetate hydrate type, however with two different carboxylates, acetates and vanillic acid anions,. respectively. Both bridging anions are in pairs in trans orientation. Methanol molecules are apically coordinated (Cu-O7 2.160(2) angstrom), fulfilling square-pyramidal coordination sphere around both copper ions. The compound 2 decomposes outside mother-liquid (yielding [Cu-2(C8H7O4)(2)(O2CCH3)(2)(H2O)(2)] (2a)) with the removal of methanol, but without significant change of the dicopper tetracarboxylate cage structure, as noticed by mu(eff) 1.48 BM for 2a. Similar was found also in the X-band EPR spectra with three signals H-z1, H-perpendicular to 2 and H-z2 in the region from 0 to 600 mT. The structure of free vanillic acid 1 is composed of dimeric units of two molecules, connected by two parallel hydrogen bonds between carboxylate group of each other (O1-H(...)O2 2.642(3) angstrom), while the structure of 3 is of [Cu-2(O2CCH3)(4)(H2O)(2)] type. Interestingly, an additional signal in the EPR spectra of 3 is found at 80 mT (H- perpendicular to 1) at 298 and at 116 K, next to three signals H-z1, H-perpendicular to 2 and H-z2. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/02775387 U6 - https://doi.org/10.1016/j.poly.2005.08.031 SN - 0277-5387 ER - TY - JOUR A1 - Kozlevcar, Bojan A1 - Kovsca, Igor A1 - Jaglicic, Zvonko A1 - Pevec, Andrej A1 - Kitanovski, Nives A1 - Strauch, Peter A1 - èegedin, Primož T1 - Strong antiferromagnetism in isolated anionic dicopper(II) methanoato paddle-wheel complex N2 - A new ionic compound (C5H6NO)(2)[CU2(mu-O2CH)(4)(O2CH)(2)], 1 formed of 4-hydroxypyridinium cations and a complex anion was synthesized. The anion is a paddle-wheel dicopper carboxylate complex with four syn,syn-bridging and two axial anionic methanoato ligands. The XRD structure determination of 1 reveals that the molecular structure is stabilized by two H-bonds between the cations and the axial paddle-wheel anions (N-H center dot center dot center dot O 2.755(3), O-H center dot center dot center dot O 2.489(2) angstrom). The compound exhibits a very strong (2J = 500 cm(- 1)) intra-binuclear anti ferromagnetic interaction noticed already at room temperature attributed to the methanoato intra-binuclear bridges. The typical EPR S = 1 spin system signals of the dicopper paddle-wheel complexes at 90 and 450- 700 mT are found in the room temperature spectrum, but they are poorly seen in the 110 K spectrum. These signals are of very low intensity and are accompanied by a dominant signal at 320 mT, all closely related to a very strong anti ferromagnetic interaction present in 1. Y1 - 2009 UR - http://public.carnet.hr/ccacaa/ SN - 0011-1643 ER - TY - JOUR A1 - Kozlevcar, Bojan A1 - Kovsca, Igor A1 - Jaglicic, Zvonko A1 - Pevec, Andrej A1 - Kitanovski, Nives A1 - Strauch, Peter A1 - Segedin, Primoz T1 - Strong antiferromagnetism in isolated anionic dicopper(II) methanoato paddle-wheel complex Y1 - 2009 UR - http://public.carnet.hr/ccacaa/ SN - 0011-1643 ER -