title: Versatile coordination modes of bis[5-(2-pyridine-2-yl)-1,2,4-triazole-3-yl]alkanes in Cu(II) complexes.
abstract: Nine new mononuclear and polynuclear Cu(II) complexes [Cu(H2L(2))Cl]Cl·3H2O (1), [Cu(H2L(3))Cl]Cl·H2O (2), [Cu(H2L(4))Cl]Cl·2.5H2O (3), [Cu3(μ(3)-L(1))2(H2O)3](ClO4)2·H2O (4), [Cu4(μ-HL(1))4](ClO4)8·CH3OH·5H2O (5), [Cu2(HL(3))2](ClO4)2·2H2O (6a), [Cu2(μ-HL(3))2](ClO4)2·H2O (6b), [Cu2(μ-HL(3))(L(3))Cu(teta)](ClO4)3·2H2O (7) and [Cu2(H2L(3))2(ox)](ClO4)2·2H2O·2MeOH (8) containing [5-(2-pyridine-2-yl)-1,2,4-triazole-3-yl]alkanes (H2L(n), n = 1-4) in combination with other ligands, such as chlorido, aqua, triethylenetetramine (teta) and/or oxalato (ox(2-)), were synthesized and characterized by various techniques such as elemental analysis, FTIR, NMR and UV-Vis spectroscopy. X-ray structures of H2L(3) and H2L(4) as well as complexes 1-8 were determined. The X-ray structures revealed that relatively small composition and structural changes in the H2L(n) ligands have a substantial impact on the coordination geometries of the complexes themselves as well as on their resulting magnetic properties. It has been found that the geometries of the complexes vary from square-pyramidal to trigonal-bipyramidal (with τ ranging from 0.00 to 0.96) and, moreover, that the trigonal bipyramidal geometry becomes more preferable with the increase in the length of the polymethylene chain within the corresponding H2L(n) ligand. The magnetic properties of the polynuclear compounds 4, 5, 6, 7 and 8 were analysed using the spin Hamiltonian formalism, which revealed the presence of antiferromagnetic exchange in the polynuclear systems mediated by the title ligands. The significant effect of the geometric parameters on the Cu···Cu exchange interactions in the polynuclear complexes is discussed.
authors.affiliation: General Chemistry Department, Taurida National V.I. Vernadsky University, Simferopol, Ukraine. galex0330@gmail.com.
authors.forename: Alexey N
authors.initials: AN
authors.lastname: Gusev
authors.forename: Ivan
authors.initials: I
authors.lastname: Nemec
authors.forename: Radovan
authors.initials: R
authors.lastname: Herchel
authors.forename: Eziz
authors.initials: E
authors.lastname: Bayjyyev
authors.forename: Galyna A
authors.initials: GA
authors.lastname: Nyshchimenko
authors.forename: Grigory G
authors.initials: GG
authors.lastname: Alexandrov
authors.forename: Igor L
authors.initials: IL
authors.lastname: Eremenko
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Trávníček
authors.forename: Miki
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Linert