An unusual dichromium(II,II) compound bearing di-2-pyridyl ketone oximate ligands and prepared by the ligand-assisted reduction of a trichromium(III,III,III) complex in air

摘要

The reaction of the oxide-centred triangular,trichromium(III,III,III) complex [Cr_3O(O_2CCM_3)_6(H_2O)_3](O_2CCMe_3) with di-2-pyr-idyl ketone oxime,(py)_2CNOH,in MeCN under aerobic and refluxing conditions yields the pivalate-free,dichromium(II,II) complex [Cr_2{(py)_2CNO}_4] centre dot 2H_2O (1 centre dot 2H_2O).The dinuclear complex can also be prepared by the reaction of [Cr(CO)_6] with (py)_2CNOH in refluxing MeCN/H_2O in air.The two high-spin Cr~(II) atoms are doubly bridged by two 2.1110 oximate ligands,while a chelating 1.0110 (py)_2CNO~- ion completes distorted trigonal bipyramidal coordination at each metal centre.The dimers are stabilized by intramolecular stacking interactions between the terminal (py)_2CNO~- ligands,and the structural effects of these interactions are discussed.