@article{VaskovaKitanovskiJaglicicetal.2014,
  author    = {Vaskova, Zuzana and Kitanovski, Nives and Jaglicic, Zvonko and Strauch, Peter and Ruzickova, Zdenka and Valigura, Dusan and Koman, Marian and Kozlevcar, Bojan and Moncol, Jan},
  title     = {Synthesis and magneto-structural characterization of copper(II) nitrobenzoate complexes containing nicotinamide or methylnicotinamide ligands},
  series = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  volume    = {81},
  journal   = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0277-5387},
  doi       = {10.1016/j.poly.2014.07.017},
  pages     = {555 -- 563},
  year      = {2014},
  abstract  = {Three new copper(II) 4-nitrobenzoato coordination compounds (4-NO(2)bz(-) = 4-nitrobenzoate anions) with N-methylnicotinamide (mna) [Cu(4-NO(2)bz)(2)(mna)(2)(H2O)] (1), [Cu(4-NO(2)bz)(2)(mu-mna)(H2O)](2) (2) and [Cu(mu-4-NO(2)bz)(2)(mna)](2) (3) were synthesized and characterized. Due to a comparison, additional two related compounds [Cu(3,5-(NO2)(2)bz)(2)(mna)(2)(H2O)] (4) (nia = nicotinamide, 3,5-(NO2)(2)bz(-) = 3,5-dinitrobenzoate anions) and [Cu(mu-2-NO(2)bz)(2)(mna)](2) (5) (2-NO(2)bz(-) = 2-nitrobenzoate anions) were isolated. The mononuclear compounds with mna 1 and nia 4 show CuO2N2O chromophores with the water molecule placed at the apex of the square pyramid. The square-pyramidal coordination sphere CuO3NO in 2 differs to CuO2N2O in 1 and 4. Differently, the water molecule is in 2 at the basal-plane, while two mna molecules serve also as bridges via N-py and 0-amido enabling a dinuclear molecular structure 1, 2 and 4 are paramagnetic though a dinuclear structure is seen in 2, while a clear-cut strong antiferromagnetic (AFM) coupling (2J -300 cm(-1)) is found for the compounds 3 and 5. (C) 2014 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{HalaskaPevecStrauchetal.2013,
  author    = {Halaska, Jozef and Pevec, Andrej and Strauch, Peter and Kozlevcar, Bojan and Koman, Marian and Moncol, Jan},
  title     = {Supramolecular hydrogen-bonding networks constructed from copper(II) chlorobenzoates with nicotinamide - Structure and EPR},
  series = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  volume    = {61},
  journal   = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0277-5387},
  doi       = {10.1016/j.poly.2013.05.032},
  pages     = {20 -- 26},
  year      = {2013},
  abstract  = {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.},
  language  = {en}
}
@article{KozlevcarGamezdeGelderetal.2011,
  author    = {Kozlevcar, Bojan and Gamez, Patrick and de Gelder, Rene and Jaglicic, Zvonko and Strauch, Peter and Kitanovski, Nives and Reedijk, Jan},
  title     = {Counterion and solvent effects on the primary coordination sphere of copper(II) Bis(3,5-dimethylpyrazol-1-yl)acetic acid coordination compounds},
  series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe},
  journal   = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe},
  number    = {24},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1434-1948},
  doi       = {10.1002/ejic.201100410},
  pages     = {3650 -- 3655},
  year      = {2011},
  abstract  = {Four copper(II) coordination compounds with the neutral ligand bis(3,5-dimethylpyrazol-1-yl)acetic acid (Hbdmpza, C(12)H(16)N(4)O(2)) and its anionic form (bdmpza(-)), namely [Cu(Hbdmpza)(2)](HSO(4))(2) (1), [Cu(Hbdmpza)(2)]Cl(2) (2), [Cu(bdmpza)(2)](CH(3)COOH)(H(2)O) (3), and [Cu(bdmpza)(2)][Cu(2)(O(2)CCH(3))(4)] (4) have been synthesized starting from different metal salts. All the compounds have been fully characterized by physical and analytical methods. In addition, a single-crystal XRD analysis revealed the 3D structure of 1, which exhibits tridentate, vicinal N,N,O-coordination of two symmetry-related Hbdmpza ligands in an elongated octahedral arrangement with four equatorial nitrogen atoms and two axial oxygen atoms. The neutral carboxylic moiety acts as a hydrogen-bond donor to a HSO(4)(-) counterion. The two hydrogensulfates form a unique hydrogen-bonded pair (HSO(4)(-))(2) with very short O center dot center dot center dot O distances (2.59 angstrom) bridged between adjacent [Cu(HL)(2)](2+) coordination units. Also a short O center dot center dot center dot O contact (2.54 angstrom) is present between the C-OH and an 0 of a hydrogensulfate. A characteristic IR C=O vibration is observed at 1700 cm(-1) for 1 and 2, whereas the v(as)(O(2)C) vibration is present at 1650 cm(-1) for 3 and 4. These IR data strongly suggest the presence of Hbdmpza ligands in 1 and 2 and the deprotonated form bdmpza- in 3 and 4. A mononuclear coordination unit [CuL(2)], as proven for 1 by X-ray diffraction, is also proposed for the other compounds 2-4. In compound 4, an additional dinuclear [Cu(2)(O(2)CCH(3))(4)] neutral coordination unit is present, as deduced from the vibration bands v(as)(O(2)C) at 1600 cm(-1) and v(s)(O(2)C) at 1420 cm(-1), which are typical of a carboxylate function, and from the two-species analysis of the chi(M)T(T) curve of the magnetic susceptibility data (2J = -322 cm(-1)). Also, the EPR spectra recorded at different temperatures agree with this structure.},
  language  = {en}
}
@article{KozlevcarKovscaJaglicicetal.2009,
  author    = {Kozlevcar, Bojan and Kovsca, Igor and Jaglicic, Zvonko and Pevec, Andrej and Kitanovski, Nives and Strauch, Peter and Segedin, Primoz},
  title     = {Strong antiferromagnetism in isolated anionic dicopper(II) methanoato paddle-wheel complex},
  issn      = {0011-1643},
  year      = {2009},
  language  = {en}
}
@article{KozlevcarKovscaJaglicicetal.2009,
  author    = {Kozlevcar, Bojan and Kovsca, Igor and Jaglicic, Zvonko and Pevec, Andrej and Kitanovski, Nives and Strauch, Peter and {\`e}egedin, Primož},
  title     = {Strong antiferromagnetism in isolated anionic dicopper(II) methanoato paddle-wheel complex},
  issn      = {0011-1643},
  year      = {2009},
  abstract  = {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.},
  language  = {en}
}
@article{KozlevcarMateJaglicicetal.2009,
  author    = {Kozlevcar, Bojan and Mate, Elizabeta and Jaglicic, Zvonko and Glažar, Lea and Golobic, Amalija and Strauch, Peter and Moncol, Jan and Kitanovski, Nives and {\`e}egedin, Primož},
  title     = {A small methanoato ligand in the structural differentiation of copper(II) complexes},
  issn      = {0277-5387},
  doi       = {10.1016/j.poly.2009.05.066},
  year      = {2009},
  abstract  = {Several copper(II) methanoato complexes, namely mononuclear [Cu(O2CH)(2)(2-mpy)(2)] (1) (2-mpy = 2- methylpyridine), binuclear [Cu-2(mu-O2CH)(4)(2-mpy)(2)] (2), and the polynuclear {[Cu(mu-O2CH)(2)(2-mpy)(2)] [Cu-2(mu- O2CH)(4)]}(n) (3) and {Na-2[Cu(mu-O2CH)(2)(O2CH)(2)][Cu-2(mu-O2CH)(4)]}(n) (4), have been synthesized. The mononuclear complex I is formed by two asymmetric chelate methanoate anions and two 2-methylpyridine molecules, giving a highly distorted 'elongated octahedral' coordination sphere. Complex I decomposes outside the mother-liquid, transforming into a regular isolated binuclear paddle-wheel complex 2 with four intra-binuclear bridging methanoates and two axial 2-mpy ligands. The polynuclear complex 3 is formed of alternate mononuclear and binuclear building blocks resembling the central cores of I and 2, but with significant differences, especially for the methanoates of the mononuclear units. The oxygen atom of the mononuclear unit in the octahedral axial position in 3 is simultaneously coordinated to the axial position of the binuclear paddle-wheel central core, thus enabling a chain type of structure. A chain of alternate mononuclear and binuclear building blocks, as in the neutral compound 3. are found as well in the ionic polymeric compound 4, though two types of bridges are found in 4, while there is only one type in 3. Namely, the axial position of the octahedral mononuclear unit in 4 is occupied by the methanoate oxygen atom that is already a part of the binuclear paddle-wheel unit, while one equatorial methanoate from the mononuclear unit serves as a triatomic bridge to the axial position of the binuclear building block. A very strong antiferromagnetic interaction is found for all the complexes with the paddle-wheel building blocks [Cu-2(mu-O2CH)(4)] 2-4 (-2J = 444-482 cm(-1)), attributed to the methanoate intra-binuclear bridges. On the other hand, this strong antiferromagnetism, found already at room temperature, reduces the intensity of the EPR S = 1 spin signals reported for the isolated paddle-wheel complex 2. For the polymeric 3, only the spin S = 1/2 signals are found in the EPR spectra, and they are assigned to the mononuclear building blocks. No signals with a clear origin are however seen in the room temperature EPR spectrum of the polymeric analogue 4, only the S = 1/2 signals in the low temperature spectra. This feature is suggested to be due to a specific influence between the adjacent S = 1 (binuclear) and S = 1/2 (mononuclear) species via their bridges.},
  language  = {en}
}
@article{KozlevcarOdlazekGolobicetal.2006,
  author    = {Kozlevcar, Bojan and Odlazek, Darja and Golobic, Amalija and Pevec, Andrej and Strauch, Peter and Segedin, Primoz},
  title     = {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)]},
  issn      = {0277-5387},
  doi       = {10.1016/j.poly.2005.08.031},
  year      = {2006},
  abstract  = {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.},
  language  = {en}
}
@article{KozlevcarGolobicStrauch2006,
  author    = {Kozlevcar, Bojan and Golobic, Amalija and Strauch, Peter},
  title     = {Dynamic pseudo Jahn-Teller distortion in a compressed octahedral CuO6 complex},
  series = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  volume    = {25},
  journal   = {Polyhedron : the international journal of inorganic and organometallic chemistry},
  number    = {15},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0277-5387},
  doi       = {10.1016/j.poly.2006.04.009},
  pages     = {2824 -- 2828},
  year      = {2006},
  abstract  = {The crystal structure of cis-[Cu(C8H7O3)(2)(H2O)(2)] (115 K data) reveals bidentate vanillinate ions coordinated via methoxy and deprotonated hydroxy oxygen atoms and water molecules in a distorted octahedral CuO6 chromophore. A cis orientation of the ligands enables two non-identical O(methoxy)-Cu-O(water) coordination axes (2.354(l) + 2.163(1); 2.151(1) + 2.020(1) angstrom), and the third shortest O(hydroxy)-Cu-O(hydroxy) axis (1.919(1) + 1.914(1) angstrom). This 115 K coordination sphere differs importantly to the one obtained from the 293 K data of the same compound, where two long 0(methoxy)-Cu-O(water) axes are of the same length, and only minor changes at the short 0(hydroxy)-Cu-O(hydroxy) axis are noticed. An axial symmetry of the complex with an inverse g(1.2)(g(perpendicular to)) > g(3)(g(parallel to)) pattern is observed in the temperature range from 298 to 180 K. A further decrease of temperature reveals gradual changes from axial to rhombic symmetry (g(1) > g(2) > g(3)) that is reversible. A mean-square displacement amplitude (MDSA) analysis reveals a disorder in the Cu-O(methoxy) bonds, but not in the other metal-ligand Cu-O(hydroxy) and Cu-O(water) bonds at 293 and 115 K. The disorder is significantly weaker in the 115 K structure. The MSDA analysis and the structural-EPR agreement show vibrational disorder in two coordination axes, due to the cis conformation of the complex with two 0(methoxy)-Cu-O(water) axes.},
  language  = {en}
}
@article{KozlevcarHumarStrauchetal.2005,
  author    = {Kozlevcar, Bojan and Humar, M. B. and Strauch, Peter and Leban, I},
  title     = {Fixation of copper(II) ions in aqueous solution to lignin model compound vanillin in an absence of the nitrogen donor ligands : structural and EPR correlation},
  year      = {2005},
  abstract  = {In order to elucidate the interactions of copper with wood, three mononuclear copper(II) coordination compounds with a vanillinate anion, cis-[Cu(C8H7O3)(2)(H2O)(2)] (1), trans-[Cu(C8H7O3)(2)(H2O)(2)].2H(2)O (2), and trans- [Cu(C8H7O3)(2)(H2O)(2)] (3), have been characterized. X-ray structure analysis of the cis isomer 1 reveals two bidentate vanillinate ions coordinated via methoxy (Cu-O1 2.260(2) angstrom) and deprotonated hydroxy oxygen atoms (Cu-O2 1.909(2) angstrom), and two water molecules (Cu-O1w 2.087(2) angstrom) in the octahedral CuO6 chromophore. Two axes O1-Cu- O1w' in the octahedron have the same length, while the third axis O2-Cu-O2' is shorter. This is in agreement with the room temperature EPR spectrum of 1, showing two signals (g(12) 2.302, g(3) 2.005), but interestingly, three signals (g(1) 2.393, g(2) 2.214, g(3) 2.010) in the 115 K spectrum were found. The same coordination atoms were found also in the trans isomer 2 (Cu-O2 1.950(2), Cu-O1w 1.994(2), Cu-O1 2.334(2) angstrom), however here, two axes of almost equal length are short (O2-Cu-O2' O1w-Cu-O1w'), while the third axis is longer (O1-Cu-O1'). On the other hand, three (rhombic) signals (g(1) 2.289, g(2) 2.163, g(3) 2.086) in the room temperature EPR spectrum of 2 suggest three different axes in the coordination octahedron. In the EPR spectrum, of the second trans complex 3, a slightly rhombically distorted elongated axial spectrum is found. The 115 K EPR spectra of the two trans complexes 2 and 3 do not differ significantly from the features observed at room temperature. These results indicate that there is not always a straightforward correlation between the results of XRD structure analysis and EPR spectroscopy. Nevertheless, both methods can act also complementarily and give a deeper insight into the nature of copper(II) chromophores},
  language  = {en}
}