The metal complexes of heterocyclic β-diketones and their derivatives—VI. The synthesis, structure and i.r. spectral studies of some new metal(II) complexes of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP)

✍ Scribed by Emmanuel Chukwuemeka Okafor

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 457 KB
• Volume: 37
• Category: Article
• ISSN: 1386-1425
• DOI: 10.1016/0584-8539(81)80020-7

✦ Synopsis

The monovalent metal complex of Na and the divalent metal complexes of Be, Mn, Co, Ni, Cu. Zn, Mg, Ba, Hg and Pb with l-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP), have been synthesized. It is shown that HPMBP behaves like a bidentate enol forming neutral metal chelates through the carbonyl and enolic hydroxyl groups. Characterization of the complexes were by means of elemental analyses, conductivity measurements, i.r. and proton NMR spectroscopy. The i.r. spectra were recorded between 4000 and 200cm-' and assignments are proposed for the observed frequencies. Replacement of the methyl group of the 4-acetyl moiety by the phenyl group in the metal chelates of I-phenyl-3-methyl-4-acetyl-pyrazolone-5 (HPMAP), is found to decrease the C-O, C.-C and M-O stretching frequencies of the chelate ring. The magnitudes of the M-O stretching frequencies for the transition metals show good agreement with the Irving-Williams stability order Cu>Ni>Co>Zn>Mn.