10.6084/m9.figshare.5734785.v1
M. Luisa Calatayud
M. Luisa
Calatayud
Marta Orts-Arroyo
Marta
Orts-Arroyo
Miguel Julve
Miguel
Julve
Francesc Lloret
Francesc
Lloret
Nadia Marino
Nadia
Marino
Giovanni De Munno
Giovanni De
Munno
Rafael Ruiz-García
Rafael
Ruiz-García
Isabel Castro
Isabel
Castro
Magneto-structural correlations in asymmetric oxalato-bridged dicopper(II) complexes with polymethyl-substituted pyrazole ligands
Taylor & Francis Group
2017
Copper
oxalato
pyrazole
magnetic properties
structure elucidation
2017-12-27 07:12:37
Journal contribution
https://tandf.figshare.com/articles/journal_contribution/Magneto-structural_correlations_in_asymmetric_oxalato-bridged_dicopper_II_complexes_with_polymethyl-substituted_pyrazole_ligands/5734785
<p>Two oxalato-bridged dinuclear copper(II) complexes, [{Cu(Hdmpz)<sub>3</sub>}<sub>2</sub>(μ-ox)](ClO<sub>4</sub>)<sub>2</sub>·2H<sub>2</sub>O (<b>1</b>) and [{Cu(Htmpz)<sub>3</sub>}<sub>2</sub>(μ-ox)](ClO<sub>4</sub>)<sub>2</sub>·2H<sub>2</sub>O (<b>2</b>) (Hdmpz = 3,5-dimethyl-1<i>H</i>-pyrazole and Htmpz = 3,4,5-trimethyl-1<i>H</i>-pyrazole), have been synthesized and structurally and magnetically characterized. The crystal structures of <b>1</b> and <b>2</b> consist of asymmetric bis-bidentate μ-oxalatodicopper(II) complex cations with two short [Cu–O = 1.976(2) (<b>1</b>) and 1.973(2) Å (<b>2</b>)] and two long copper–oxygen bonds [Cu–O = 2.122(2) (<b>1</b>) and 2.110(2) Å (<b>2</b>)]. The environment at each Cu<sup>II</sup> ion in <b>1</b> and <b>2</b> is closer to the trigonal bipyramidal geometry than to the square pyramidal [<i>τ</i> = 0.633 (<b>1</b>) and 0.711 (<b>2</b>)]. The magnetic properties of <b>1</b> and <b>2</b> show moderate antiferromagnetic coupling between the Cu<sup>II</sup> ions through the oxalato bridge [<i>J</i> = −129 (<b>1</b>) and 161 cm<sup>−1</sup> (<b>2</b>); <b>H</b> = −<i>J</i><b>S</b><sub><b>1</b></sub> · <b>S</b><sub><b>2</b></sub> with <i>S</i><sub>1</sub> = <i>S</i><sub>2</sub> = <i>S</i><sub>Cu</sub> = ½]. A thorough magneto-structural analysis has been carried out for the family of asymmetric μ-oxalatodicopper(II) complexes with different terminal ligands to determine the influence on the sign and strength of the magnetic coupling of subtle structural factors, such as the trigonal distortion of the metal geometry and the lengthening or the asymmetry of the metal-oxalato bond distances.</p>