Syntheses and structural studies on picolinoyl, nicotinoyl and isonicotinoyl hydrazone derivatives of dicyclopentadienylzirconium(IV)

Abstract The reactions of dicyclopentadienylzirconium(IV) dichloride with picolinoyl, nicotinoyl and isonicotinoyl hydrazones derived from the appropriate acid hydrazides and acetone, acetophenone, salicylaldehyde or o -hydroxyacetophenone, have been studied in anhydrous tetrahydrofuran or dichloromethane in the presence or absence of amine using different molar ratios. Tentative structural coclusions are drawn for the reaction products based upon elemental analysis, electrical conductance, magnetic moment and spectral data (electronic, infrared and 1 H NMR). These ligands behave as neutral or deprotonated chelating agents. The coordination behaviour depends upon the pH of the medium, the nature of the substituent and the position of the hydrazone group relative to the pyridine nitrogen nucleus.