Binary and Ternary Zinc(II) Complexes of Acyl Pyrazolones: Synthesis, Spectroscopic Analysis, Crystal Structure and Antimalarial Activity

Abstract

A new series of Zn II metal complexes of ligands 4-(4chlorobenzoyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3one (PCBPMP) and 4-(4-chlorobenzoyl)-5-methyl-2-(p-tolyl)-2,4dihydro-3H-pyrazol-3-one (PCBTPMP) were prepared and characterized. The nature of bonding and the stereochemistry of the complexes were deduced from 1 H and 13 C Nuclear Magnetic Resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Molar conductivity measurements and Single-crystal X-ray diffraction. The analyses indicated that complexes 1, 2 and 3 are mononuclear and exhibited octahedral geometry around Zn II . The potential in silico and in vitro antimalarial activity inhibits Plasmodium falciparum and the same was exhibited by Ligands and Zinc complexes. This would be the first report of the antimalarial activity of Zinc complexes of acyl pyrazolones ligand.[a] I.

Zinc(II) Complex with Pyrazolone-Based Hydrazones is Strongly Effective against Trypanosoma brucei Which Causes African Sleeping Sickness

“…Both proligands H 2 L 1 and H 2 L 2 are found in the solid crystalline state, in the N–H,N–H,CO tautomeric form, crystallizing, in the case of H 2 L 2 in the triclinic space group, differently from the monoclinic phase already reported originating from the unexpected zwitterionic form . Within both ligands, the C(3)–O(1) bond distances of 1.264(3) and 1.253(2) Å, respectively, are similar to the CO double bond found in similar pyrazolone-based hydrazones in the same tautomeric form .…”

“…It is known that pyrazolone also is a structural motif with a broad-spectrum of pharmacological features, including antimicrobial, antitumor, anti-inflammatory, antioxidant, antitubercular, antiviral, lipid-lowering, antihyperglycemic, and protein inhibitory activities . Previous studies of our research team underlined the wide biological activities of a series of Zn­(II) complexes with acylpyrazolones, displaying antiproliferative activity against human breast cancer cells, and of pyrazolone-based hydrazones and their ruthenium­(II) complexes as anticancer multitarget agents. , Moreover, some Cu­(II) and Zn­(II) complexes with acylpyrazolones and acylhydrazone-5-pyrazolones were recently reported and found to display in vitro antimalarial activity with considerable inhibitory effects against Plasmodium falciparum. − Based on these findings, two new pyrazolone-based hydrazones and their corresponding Zn­(II) and Cu­(II) complexes have been synthetized and screened against T. brucei and mammalian Balb/3T3 cells.…”

“… 12 , 13 Moreover, some Cu(II) and Zn(II) complexes with acylpyrazolones and acylhydrazone-5-pyrazolones were recently reported and found to display in vitro antimalarial activity with considerable inhibitory effects against Plasmodium falciparum . 14 − 16 Based on these findings, two new pyrazolone-based hydrazones and their corresponding Zn(II) and Cu(II) complexes have been synthetized and screened against T. brucei and mammalian Balb/3T3 cells. The most active and selective metal complex containing a Zn(II) center was further investigated to identify the mechanism of action and the possible target, focusing the study on the peculiar nucleotide metabolism of T. brucei .…”

Structural Features, Emission Analysis, and Covalency Comparison of Neodymium Acylpyrazolone Complexes using Oscillator Strengths, Covalency and Judd‐Ofelt Parameters**

“…105 °C, Yield 78.84 %), and L 3 ((4‐chlorophenyl)(5‐hydroxy‐3‐methyl‐1‐(p‐tolyl)‐1H‐pyrazol‐4‐yl)methanone) (M.P. 108 °C, Yield 77.27 %) ligands were directly prepared and used as mentioned by us [31–33] . 99.9 % extrapure neodymium(III) nitrate hexahydrate was purchased from SRL Pvt.…”

“…As extraction ability and proficient Antenna effect of acylpyrazolones with lanthanides can be examined through their metal-ligand covalent character, [28][29][30] this study presents a practical technique for determining both the Judd-Ofelt intensity parameters and oscillator strengths of three Nd(III)-acylpyrazolone complexes, NdL 1 , NdL 2 , and NdL 3 , in different solvents which have the general formula [Nd(L) 3 (H 2 O)(EtOH)] and distorted square antiprismatic geometry. [31][32][33] 99.9 % extrapure neodymium(III) nitrate hexahydrate was purchased from SRL Pvt. Ltd.…”