Cyano-bridged homodinuclear copper(II) complexes

• Verfasst von: Atanasov, Mihail [VerfasserIn]
• Verfasst von: Comba, Peter [VerfasserIn]
• Verfasst von: Hanson, Graeme R. [VerfasserIn]
• Verfasst von: Hausberg, Sascha [VerfasserIn]
• Verfasst von: Helmle, Stefan [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Titel: Cyano-bridged homodinuclear copper(II) complexes
• Verf.angabe: Mihail Atanasov, Peter Comba, Graeme R. Hanson, Sascha Hausberg, Stefan Helmle, and Hubert Wadepohl
• E-Jahr: 2011
• Jahr: 28 June 2011
• Umfang: 12 S.
• Fussnoten: Gesehen am 23.03.2022
• Titel Quelle: Enthalten in: Inorganic chemistry
• Ort Quelle: Washington, DC : American Chemical Society, 1962
• Jahr Quelle: 2011
• Band/Heft Quelle: 50(2011), 15, Seite 6890-6901
• ISSN Quelle: 1520-510X
• DOI: doi:10.1021/ic102430a
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1796387096

Abstract

The synthesis and structural analysis (single crystal X-ray data) of two mononuclear ([Cu(L1)(CN)]BF4 and [Cu(L3)(CN)](BF4)) and three related, cyanide-bridged homodinuclear complexes ([{Cu(L1)}2(CN)](BF4)3·1.35 H2O, [{Cu(L2)}2(CN)](BF4)3 and [{Ni(L3)}2(CN)](BF4)3) with a tetradentate (L1) and two isomeric pentadentate bispidine ligands (L2, L3; bispidines are 3,7-diazabicyclo[3.3.1]nonane derivatives) are reported, together with experimental magnetic, electron paramagnetic resonance (EPR), and electronic spectroscopic data and a ligand-field-theory-based analysis. The temperature dependence of the magnetic susceptibilities and EPR transitions of the dicopper(II) complexes, together with the simulation of the EPR spectra of the mono- and dinuclear complexes leads to an anisotropic set of g- and A-values, zero-field splitting (ZFS) and magnetic exchange parameters (Cu1: gz = 2.055, gx = 2.096, gy = 2.260, Az = 8, Ax = 8, Ay = 195 × 10-4 cm-1, Cu2: g and A as for Cu1 but rotated by the Euler angles α = −6°, β = 100°, Dexc = −0.07 cm-1, Eexc/Dexc = 0.205 for [{Cu(L1)}2(CN)](BF4)3·1.35 H2O; Cu1,2: gz = 2.025, gx = 2.096, gy = 2.240, Az = 8, Ax = 8, Ay = 190 × 10-4cm-1, Dexc = −0.159 cm-1, Eexc/Dexc = 0.080 for [{Cu(L2)}2(CN)](BF4)3). Thorough ligand-field-theory-based analyses, involving all micro states and all relevant interactions (Jahn-Teller and spin-orbit coupling) and DFT calculations of the magnetic exchange leads to good agreement between the experimental observations and theoretical predictions. The direction of the symmetric magnetic anisotropy tensor Dexc in [{Cu(L2)}2(CN)](BF4)3 is close to the Cu···Cu vector (22°), that is, nearly perpendicular to the Jahn-Teller axis of each of the two CuII centers, and this reflects the crystallographically observed geometry. Antisymmetric exchange in [{Cu(L1)}2(CN)](BF4)3·1.35 H2O causes a mixing between the singlet ground state and the triplet excited state, and this also reflects the observed geometry with a rotation of the two CuII sites around the Cu···Cu axis.