title: Cr(III)-Cr(III) interactions in two alkoxo-bridged heterometallic Zn2Cr2 complexes self-assembled from zinc oxide, Reinecke's salt, and diethanolamine.
abstract: Two new tetranuclear complexes, [Zn(2)Cr(2)(NCS)(4)(Dea)(2)(HDea)(2)].4DMSO (1; DMSO = dimethyl sulfoxide) and [Zn(2)Cr(2)(NCS)(4)(Dea)(2)(HDea)(2)].2CH(3)CN (2), were prepared from zinc oxide, Reinecke's salt, NH(4)[Cr(NCS)(4)(NH(3))(2)].H(2)O, ammonium thiocyanate, and a nonaqueous solution of diethanolamine (H(2)Dea) in a reaction carried out under open air. Both compounds have similar centrosymmetric crystal structures based on a tetranuclear {Zn(2)Cr(2)(mu(3)-O)(2)(mu-O)(4)} core. Variable-temperature magnetic susceptibility measurements of 1 and 2 show weak antiferromagnetic coupling between chromium centers. The magnetic data and high-field, high-frequency electron paramagnetic resonance spectra were analyzed in terms of the spin Hamiltonian H = JS(1).S(2) - j(S(1).S(2) + mu(B)B{g(1)}S(1) + D(Cr){S(z1)(2) - S(1)(S(1) + 1)/3} + E(Cr)(S(x1)(2) - S(y1)(2)) + mu(B)B{g(2)}S(2) + D(Cr){S(z2)(2) - S(2)(S(2) + 1)/3} + E(Cr)(S(x2)(2) - S(y2)(2)) + D(12){S(z1)S(z2) - S(1).S(2)/3} + E(12)(S(x1)S(x2) - S(y1)S(y2)) with J = 13.7 cm(-1), j = 1.1 cm(-1), D(Cr) = 0.3864 cm(-1), E(Cr) = -0.1104 cm(-1), D(12) = -0.1873 cm(-1), and E(12) = -0.0155 cm(-1) for 1 and J = 9.4 cm(-1), j = 0.8 cm(-1), D(Cr) = 0.3564 cm(-1), E(Cr) = -0.0647 cm(-1), D(12) = -0.1850 cm(-1), and E(12) = -0.0112 cm(-1) for 2. Density functional theory (DFT) calculations were employed to calculate the zero-field splitting on Cr(3+) ions. Calculations of the exchange integrals J were attempted by using the "broken-symmetry" DFT method.
authors.affiliation: Department of Inorganic Chemistry, National Taras Shevchenko University, Volodymyrska Street 64, Kyiv 01601, Ukraine.
authors.forename: Valentyna V
authors.initials: VV
authors.lastname: Semenaka
authors.forename: Oksana V
authors.initials: OV
authors.lastname: Nesterova
authors.forename: Volodymyr N
authors.initials: VN
authors.lastname: Kokozay
authors.forename: Viktoriya V
authors.initials: VV
authors.lastname: Dyakonenko
authors.forename: Roman I
authors.initials: RI
authors.lastname: Zubatyuk
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Shishkin
authors.forename: Roman
authors.initials: R
authors.lastname: Boca
authors.forename: Julia
authors.initials: J
authors.lastname: Jezierska
authors.forename: Andrew
authors.initials: A
authors.lastname: Ozarowski
mesh_terms: D002857:Chromium / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004983:Ethanolamines / Q000737:chemistry*; D008280:Magnetics; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D012492:Salts; D015032:Zinc / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D004983:Ethanolamines; D009942:Organometallic Compounds; D012492:Salts; D002857:Chromium; C020283:diethanolamine; D015032:Zinc; D015034:Zinc Oxide