Structural and magnetic characterisation of the compound [NEt4][Cr2(EtO)3{H2B(pz)2}2(NCS)2](pz = 1-pyrazolyl), a binuclear complex of chromium(III) with three bridging ethoxo groups

Abstract

The crystal and molecular structure of [NEt₄][Cr₂(EtO)₃{H₂B(pz)₂}₂(NCS)₂][H₂B(pz)₂= dihydro-bis(1-pyrazolyl)borate] has been determined by single-crystal X-ray diffraction methods. The crystals are monoclinic, space group P2₁, with a= 9.561(9), b= 15.826(4), c= 12.979(3)Å, β= 93.06(8)° and Z= 2. The complex anion consists of two chromium(III) ions in chemically identical and approximately octahedral environments. The metal ions are bridged by three ethoxo groups. The co-ordination around each metal is completed by two N atoms of a H₂B(pz)₂ ligand and by the N atom of a NCS anion. The temperature dependence of the magnetic susceptibility of the compound has been determined in the range 8–280 K. The exchange interaction between the two chromium(III) ions was found to be antiferromagnetic with J= 87.0(2) cm^–1 and the exchange Hamiltonian is H=JS₁·S₂.