Synthesis and characterization of a hydrazone ligand containing antipyrine and its transition metal complexes

Abstract

The coordination chemistry of N 0 -((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene)-2-hydroxybenzohydrazide with copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), palladium(II), iron(III), ruthenium(III), uranyl(VI), and titanium(IV) has been studied. The ligand and its complexes was characterized by elemental and thermal analyses, magnetic moments and conductivity measurements as well as spectroscopic techniques such as infrared, mass spectra, nuclear magnetic resonance, electron spin resonance and electronic absorption spectra. The spectral data showed that the ligand is monobasic tridentate coordinated via the enolic carbonyl oxygen of the hydrazide moiety, azomethine nitrogen and pyrazolone oxygen atoms.

Preparation, characterization and Microbicide activities of N'-((3-(hydroxyimino)butan-2-ylidene)-2-(phenylamino)acetohydrazide and its complexes

“…The considerable high δ of these hydrogen chemical shifts is related to the proton-attachment to high electronegative atoms (oxygen and nitrogen). This assignment is supported by the apparent intensity decrease of these signals in the deuterated ligand spectrum [43][44][45]. These findings clarified that the ligand exhibits the keto form only and no evidence for the presence of the enol form.…”

“…Three bands were observed in the spectrum of the ligand at 260, 310 and 340 nm. The first band at 260 nm is attributed to π→π* transition of phenyl ring of the ligand which is almost unchanged upon complexation, whereas the second and third bands are attributed to n→π* transitions of azomethine and carbonyl groups which were subjected to shifting in the spectra of metal complexes indicating participation of these groups in the complex formation [65,66].In some complexes, new bands were observed in the 400-440 nm ranges, which may be attributed to charge transfer electronic transitions.…”

“…The broadness of this band indicates unequal energies of the OU charge transfer in the two oxo cations. The other band observed at 410 and 415 nm is assignable to charger transfer from ligand to the uranium(VI) ion (LMCT) [51,65,74].…”

“…They do not show d-d transitions, and the observed bands are only intra-ligand transitions. The zinc(II) complex (6) show band at 400 nm assignable to the ligand to metal charge transfer transitions (LMCT) [65].…”

Synthesis, Characterization and Antimicrobial Activities of Hydrazone Ligands Derived from 2-(phenylamino)acetohydrazide and Their Metal Complexes

“…The first set of the shortest wave length appeared at 250-265 nm may be assigned to the π→π* transition in the benzenoid moieties which nearly unchanged on complexation. 22,42 The second set appears at 310-320 and 345-395 nm may be assigned to n→π* of the azomethine and carbonyl group. 22,39 These bands shifted to higher energy on complexation indicating the participation of these groups in coordination with metal ions.…”