Review on Preparation, Coordination and Clinical Chemistry of 2-Pyrazoline Derivatives: Synthesis and Characterization of 5-(thiophen-2-yl)-3-(pyridin-3-yl)-4,5-Dihydro-1H-Pyrazole-1-Carbothioamide and their Co(II), Ni(II), Cu(II) and Zn(II) Complexes

The N-substituted 2-pyrazoline derivative has received significant encouragement from researchers for their effective roles in wide range of biological activities and has been used as catalysts and colorimetric reagents in the determination of trace heavy metals. This review article focuses on the pyrazolines routes, such as the preparation of pyrazole derivatives via chalcones. It also demonstrates that 2-pyrazoline complexes were biologically active and have had a range of clinical applications. The recent review collects the significances of 2-pyrazoline ligands and main methods of preparation and their role in the field of coordination chemistry. The observed data from update literature investigates the well-known method of Micheal addition of hydrazine or thiosemicarbazide derivatives to the ά-β-unsaturated carbonyl compounds. Furthermore, the chelation ability for most prepared 2-pyrazoline ligands have confirmed the active sites of immine moiety of pyrazole ring beside the sulfur atom forming five-membered ring with the studied d-metals. Likewise, the recent work involves the synthesis of new ligand of 2-pyrazoline from condensation chalcone with 4-thiosemicarbazide in alkaline medium. The new prepared ligand5-(4-thiophen-2-yl)-3-(pyridin-3-yl)-4,5-dihydro-1H-pyrazole-1-carbothioamide and its metal complexes with cobalt(II), nickel(II), copper(II), and zinc(II) were fully characterized with the elemental micro-analyses (C.H.N.S), determination of metal content, FT-IR, and UV-Visible spectra. Furthermore, the magnetic susceptibility of solid metal complexes and molar conductivity measurements of their solutions in DMSO solvent have confirmed their chemical structures. The observed data from analytical methods revealed the octahedral geometry in 2:1 mole ratio (L:M) except the tetrahedral structure in [ZnLC]Cl formula. The diamagnetic complex of nickel(II) was approved as square planner geometry with high value of molar conductance.