Magneto structural correlations of a ‘stepped-wise’ discrete tetranuclear unit of copper(II), [Cu 4(μ 2-OH) 2((μ 3-OH) 2(2,2′-bipy) 4Cl 2]Cl 2·6H 2O

Abstract

A tetranuclear ‘stepped wise’ copper(II) complex, [Cu 4(μ 2-OH) 2(μ 3-OH) 2(2,2′-bipy) 4Cl 2]Cl 2·6H 2O has been synthesized and the crystal structure of the complex redetermined. The magnetic behavior has been investigated in the temperature range 300–4.2 K based on its novel binding modes of the OH −, i.e. OH − anions bridge the copper(II) centers in a bidentate (μ-2) as well as tridentate (μ-3) fashion and this shows ferromagnetic interactions. The fit of the experimental data was made by the irreducible tensor operator formalism (ITO) using the clumag program based on the Hamiltonian; H=− J 1( S 1 S 2+ S 3 S 4)− J 2( S 1 S 4)− J 3( S 1 S 3+ S 2 S 4 ) and the best fit parameters, assuming the g factors are identical and J 2= J 3, leads to J 1=22.71 cm −1; J 2= J 3=0.34 cm −1 and g=2.10. The magnetic results are interpreted with structural parameters.