METAL CYANONITROSYL COMPLEXES - SYNTHESIS AND CHARACTERIZATION OF SOME NOVEL MIXED-LIGAND CYANONITROSYL (CONO)(8A) COMPLEXES OF CO(I) WITH SOME BIOLOGICALLY-ACTIVE HETEROCYCLIC DONORS

Novel hexa-coordinate mixed-ligand cyanonitrosyl complexes of cobalt(I ) having the general formula K-2[Co(NO)(CN)(4)(L)], where L = 3-methyl -1-phenyl-2-pyrazoline-5-one, 2,3-dimethyl-1-phenyl-3-pyrazoline-5-one , 4-amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one, 2,3-dimethyl-4-dim ethylaminomethanesulphonate sodium monohydrate-1-phenyl-3-pyrazoline-5 -one, benzothiazole or 2-methylbenzothiazole were prepared by the inte raction of K-2[Co(NO)(CN)(4)(H2O)].H2O with L in aqueous ethanol solut ion. The products are characterized by elemental analyses, molar condu ctances, magnetic measurements, EPR and IR spectral studies and thermo gravimetric analysis. Tetragonally distorated octahedral structures ar e proposed. Infrared spectral studies suggest that all 5-pyrazolone an d benzothiazole derivatives act as neutral monodentate ligands which c oordinate through the cyclic oxygen and tertiary nitrogen, respectivel y. Cobalt(I) has a low-spin {CoNO}(8) electron configuration in all th e complexes. These complexes behave as 2:1 electrolytes, and are diama gnetic.