Cobalt(III) compounds of carbanions and their reactivity. Part II. Crystal and molecular structure of malononitrilato[propane-1,2-bis(salicylideneiminato)]pyridinecobalt(III)

Abstract

The structure of the title compound has been determined by a three-dimensional X-ray structural analysis. Crystals were monoclinic with a= 9·25(3), b= 18·14(6), c= 14·00(4)Å, β= 105·3(1)°, space group P2₁/c, and Z= 4. The structure was solved by conventional Patterson and Fourier techniques, and was refined anisotropically by block-diagonal least-squares methods, using of 1369 independent reflections, collected on a diffractometer, to a final R of 0·061. This analysis confirms the presence of a Co–C bond [2·02(1)Å] in the six-co-ordinate cobalt(III) molecule, and trans to it is a long cobalt to pyridine bond [Co–N 2·06(1)Å]. The four donor atoms of the quadri-dentate ligand are in an essentially planar array with normal bond-lengths [Co–O 1·89(1) and 1·88(1); Co–N 1·91(1) and 1·88(1)]. There is disorder in the 1,2-di-iminopropane chelate ring, which appears to include methyl groups which must be axial substituents on nonsymmetrical chelate rings.