Metal complexes of pyrazole-4,5-dione-4-oximes: Crystallographic characterization and their reactions with dimethyl acetylenedicarboxylate

Complexes of type ML(2), ML(2)(H2O)(2) and ML(2)(py)(2) (LH = pyrazole-4,5-dione-4-oximes) have been prepared and their IR and LSIMS spectra, magnetic susceptibilities and behaviour towards triphenylphosphine and dimethyl acetylenedicarboxylate (DMAD) have been investigated. The structures of Zn(Mpo)(2)(H2O)(2) (MpoH = 1,3-dimethyl-1H-pyrazole-4,5-dione-4-oxime) and Mn(1-Ppo)(2)(py)(2) (1-PpoH = 3-methyl-1-phenyl-1H-pyrazole-4,5-dione-4-oxime) were determined by X-ray crystallography. In all the complexes, the ligands chelate to the metal, forming six-membered rings. The adducts tire monomeric, whereas the ML(2) complexes are associated in the solid state. All the complexes and their respective ligands react with DMAD at 80 degrees C to give the condensation product, whereas at 20 degrees C, the ligands and their lithium complex give the open chain adduct.