Synthesis of 1‐(1‐H‐Benzotriazolyl‐1‐acetyl)‐5‐hydroxy‐3‐trifluoromethyl‐5‐(2‐thienyl)‐2‐pyrazoline and Its Transition Metal Complexes

Abstract

1‐(1H‐Benzotriazol‐1‐acetyl)‐5‐hydroxy‐3‐trifluoromethyl‐5‐(2‐thienyl)‐2‐pyrazoline (H₂L) has been synthesized by condensing 1H‐benzotriazol‐1‐acetic acid hydrazide with 1‐(2‐thienyl)‐4,4,4‐trifluoro‐1,3‐butanedione. Complexes of the composition [ML]₂ [M = Zn(II), Cu(II), Ni(II)] and [ML(H₂O)]₂ [M = Co(II)] have been prepared by refluxing the pyrazoline and metal acetate hydrates in ethanol. The ligand and its complexes have been characterized by elemental analyses, IR, ¹H NMR, magnetic susceptibility measurements, and thermogravimetric analysis (TGA). The spectra show that the ligand H₂L coordinates as tridentate ligand through the enolic oxygens and the nitrogen of the azomethine group. For the complex [ML(H₂O)]₂, the S atom of the thienyl group also coordinates with the metal.

Keywords:

• Pyrazoline
• Ligand
• Azomethine group
• Transition metal complex

Acknowledgment

This work was sponsored by the Gansu Province Funds of Natural Sciences (ZS981‐A‐25‐002‐Z).