Zinc(II) 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their adducts with N and P donor ligands: synthesis, spectral, biological, and anti-inflammatory investigations

Abstract

Synthesis, spectral, biological, and anti-inflammatory investigations of a series of complexes of zinc(II) with 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolines of the type (C₁₅H₁₂N₂OX)₂Zn (where X =–H,–Cl,–CH₃,–OCH₃) are presented. The complexes were synthesized by reaction of anhydrous zinc(II) chloride with sodium salts of pyrazoline in 1 : 2 molar ratio. Adducts with N and P donor ligands (2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine) were prepared in 1 : 1 molar ratio. The complexes were characterized by elemental analyses, molecular weight, conductivity, IR, electronic, ¹H, ¹³C, ³¹P NMR, and FAB mass spectral studies. All complexes are amorphous. Tetrahedral geometry around zinc confirms the presence of two bidentate pyrazoline ligands in zinc(II) 5-(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In adducts pyrazoline is monodentate. Bidentate and monodentate pyrazoline were confirmed by IR, ¹H, ¹³C, and ³¹P NMR spectral data. All metal complexes were tested for their antibacterial and antifungal activities. Anti-inflammatory activity was also carried out by the carrageenan-induced rat paw edema test. Brine shrimp bioassay was also carried out to study in-vitro cytotoxic properties.

Keywords:

• Anti-inflammatory activity
• Biological activity
• Cytotoxicity
• Zinc(II) pyrazolinates
• Pyrazoline
• Triphenylphosphine
• 1,10-Phenanthroline
• 2,2′-Bipyridine

Acknowledgments

Authors are thankful to School of Studies in Chemistry, Vikram University, Ujjain (India), RSIC, CDRI, Lucknow (India), A.P.S. University, Rewa (India), SAIF, SIF, Indian Institute of Science, Bangalore (India), and Mahakal Institute of Pharmaceutical Studies, Ujjain (India) for providing spectral and analytical data.