Synthesis, spectral, and thermal studies of oxomolybdenum(V) Schiff-base complexes derived from heterocyclic β-diketone

Abstract

Six mononuclear Mo(V) Schiff-base complexes were prepared by the reaction of MoCl₅ with Schiff bases, namely HL¹–HL³ and HL⁴–HL⁶, such as 5-hydroxy-3-methyl-1(2-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (I), 5-hydroxy-3-methyl-1(3-chloro)phenyl-1H-pyrazolone-4-carbaldehyde (II), and 5-hydroxy-3-methyl-1(3-sulfoamido)phenyl-1H-pyrazolone-4-carbaldehyde (III) with ethanolamine and propanolamine, respectively, in aqueous ethanolic medium. The resulting complexes have been characterized by elemental analyses, molar conductance, FT-IR, ¹H-NMR, electronic, electron spin resonance (ESR) spectra, magnetic susceptibility, and thermal study. The molar conductivity data show them to be non-electrolytes. IR and ¹H-NMR spectral data suggest that the ligand is a dibasic bidentate with ON donor toward metal ion. Electronic, magnetic, and ESR spectral data suggest that the oxomolybdenum(V) complexes have distorted octahedral geometry. One chloride coordinated to molybdenum is confirmed by thermal study.

Keywords:

• Schiff bases
• Oxomolybdenum(V) complexes
• FT-IR
• ESR spectrometry
• Thermal studies