Three mixed ligand mononuclear Zn(II) complexes of 4-acyl pyrazolones: Synthesis, characterization, crystal study and anti-malarial activity

Shaikh, Irfan; Jadeja, R.N.; Patel, Rajesh

doi:10.1016/j.poly.2020.114528

“…The major observations can be identified by comparing the FTIR spectra of the ligands with those of their corresponding complexes. 23 As seen in Table 1 , the υ C=O of pyrazolone and the p -chloro benzoyl group decrease significantly during complexation. The υ C=O of pyrazolone decreases from 1620 cm –1 in PCBPMP to 1577 cm –1 in [UO 2 (PCBPMP) 2 (CH 3 CH 2 OH)], 1625 cm –1 in PCBMCPMP to 1591 cm –1 in [UO 2 (PCBMCPMP) 2 (CH 3 CH 2 OH)], and 1625 cm –1 in PCBPTMP to 1591 cm –1 in [UO 2 (PCBPTMP) 2 (CH 3 CH 2 OH)].…”

Section: Resultsmentioning

confidence: 90%

“…Three ligands, PCBPMP, PCBMCPMP, and PCBPTMP, were prepared following the method reported in a previous study. 23 The preparation of the three uranium complexes I, II, and III was carried out following a process similar to that described in our most recent paper. 25 …”

Section: Experimental Sectionmentioning

confidence: 99%

Synthesis, Covalency Sequence, and Crystal Features of Pentagonal Uranyl Acylpyrazolone Complexes along with DFT Calculation and Hirshfeld Analysis

Travadi

¹

,

Jadeja

²

,

Butcher

³

2022

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Three uranyl acylpyrazolone complexes [UO 2 (PCBPMP) 2 (CH 3 CH 2 OH)] (complex I), [UO 2 (PCBMCPMP) 2 (CH 3 CH 2 OH)] (complex II), and [UO 2 (PCBPTMP) 2 (CH 3 CH 2 OH)] (complex III) were synthesized from σ-donating acypyrazolone ligands to analyze their sequence of covalent characteristics, reactivity, and redox properties (PCBPMP: p -chlorobenzoyl 1-phenyl 3-methyl 5-pyrazolone; PCBMCPMP: p -chlorobenzoyl 1-( m -chlorophenyl) 3-methyl 5-pyrazolone; PCBPTMP: p -chlorobenzoyl 1-( p -tolyl) 3-methyl 5-pyrazolone). An examination of the structure, pentagonal bipyramidal geometry, and composition of these complexes was conducted mainly through their single-crystal X-ray diffraction (XRD) data, 1 H nuclear magnetic resonance (NMR) δ-values, plots of thermogravimetric-differential thermal analysis (TG-DTA), significant Fourier transform infrared (FTIR) vibrations, gravimetric estimation, and molar conductivity values. The covalency order was found to be complex II > III > I, which mainly depends on values of stretching frequencies, average bond lengths of axial uranyl bonds, values of average bond lengths on the pentagonal equatorial plane, solvent coordination on the fifth site of a pentagonal plane, and the type of aryl group on the nitrogen of the pyrazolone ring. This was confirmed by FTIR spectroscopy and single-crystal spectral characterization. To verify experimental results by comparison with theoretical results, density functional theory (DFT) calculations were carried out, which further gives evidence for the covalency order through theoretical frequencies and the gap of highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energies. Theoretical bond properties were also examined by the identification of global index parameters. Intermolecular noncovalent surface interactions were studied by the Hirshfeld surface analysis. The irreversible redox behavior of uranyl species was identified through electrochemical cyclic voltammetry-differential pulse voltammetry (CV-DPV) plot analysis.

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“…In addition, by recording the 1 H NMR spectrum of 2 in dimethylsulfoxide (DMSO), the expected AB quartet of the geminal methylene protons is clearly observed (Figure S49). The { 1 H, 15 N}-HSQC and { 1 H, 15 N}-HMBC of H 2 L 1 and complex 1 in chlorinated solvents are quite interesting; in fact, even if the N3 resonance at 140.6 ppm in the free H 2 L 1 is not observed for the complex 1, the N4−H resonance shifts from 96.2 to 117.3 ppm and that of N2 from 284.9 to 276. 4 In addition, the band observed at 370 nm in the H 2 L 2 spectrum can be ascribed to the π → π* transition of pyridine rings present in the ligand structure (Figure 3a).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…44 Gibbs free energies in chloroform solution were estimated from the equation G solv = E solv + (G gas − E gas ). The GIAO method was used for the NMR calculations ( 1 H-, 13 C-, and 15 N NMR isotropic shielding tensors) which were carried out at the 6-311+ +G** level of theory. The computed IR spectra were scaled by a factor of 0.96.…”

Section: ■ Conclusionmentioning

confidence: 99%

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

Marchetti

¹

,

Tombesi

²

,

Nicola

³

et al. 2022

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Two pyrazolone-based hydrazones H 2 L′ [in general, H 2 L′; in detail, H 2 L 1 = 5-methyl-2-phenyl-4-(2-phenyl-1-(2-(4-(trifluoromethyl)phenyl)hydrazineyl)ethyl)-2,4-dihydro-3 H -pyrazol-3-one, H 2 L 2 = ( Z )-5-methyl-2-phenyl-4-(2-phenyl-1-(2-(pyridin-2-yl)hydrazineyl)ethylidene)-2,4-dihydro-3 H -pyrazol-3-one] were reacted with Zn(II) and Cu(II) acceptors affording the complexes [Zn(HL 1 ) 2 (MeOH) 2 ], [Cu(HL 1 ) 2 ], and [M(HL 2 ) 2 ] (M = Cu or Zn). X-ray and DFT studies showed the free proligands to exist in the N–H,N–H tautomeric form and that in [Zn(HL 1 ) 2 (MeOH) 2 ], zinc is six-coordinated by the N,O-chelated (HL 1 ) ligand and other two oxygen atoms of coordinated methanol molecules, while [Cu(HL 1 ) 2 ] adopts a square planar geometry with the two (HL 1 ) ligands in anti-conformation. Finally, the [M(HL 2 ) 2 ] complexes are octahedral with the two (HL 2 ) ligands acting as κ-O,N,N-donors in planar conformation. Both the proligands and metal complexes were tested against the parasite Trypanosoma brucei and Balb3T3 cells. The Zn(II) complexes were found to be very powerful, more than the starting proligands, while maintaining a good safety level. In detail, H 2 L 1 and its Zn(II) complex have high selective index (55 and >100, respectively) against T. brucei compared to the mammalian Balb/3T3 reference cells. These results encouraged the researchers to investigate the mechanism of action of these compounds that have no structural relations with the already known drugs used against T. brucei . Interestingly, the analysis of NTP and dNTP pools in T. brucei treated by H 2 L 1 and its Zn(II) complex showed that the drugs had a strong impact on the CTP pools, making it likely that CTP synthetase is the targeted enzyme.

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

Travadi,

Jadeja,

Butcher

2023

ChemistrySelect

7

0

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Three distorted square antiprismatic eight coordinated neodymium acylpyrazolone complexes were synthesized having the compositions [Nd(L1)3(H2O)(EtOH)] (NdL1), [Nd(L2)3(H2O)(EtOH)] (NdL2), and [Nd(L3)3(H2O)(EtOH)] (NdL3). The structure of all three complexes was examined using ESI‐mass, FT‐IR, and thermogravimetric methods. According to the single crystal analysis of NdL1, the complex was found eight‐coordinated (NdO8) with a distorted square antiprismatic geometry. A powder XRD pattern confirmed a similar structural arrangement of the other two complexes. In electronic absorption spectra, the transition 4G5/2←4I9/2, which is close to the centre of the visible spectrum (~17,500 cm−1), exhibits hypersensitivity, which stands out in stark contrast to the behaviour of many other typically weak and reliably unchanging, typical 4f–4f transitions. Through a comparative analysis of calculated oscillator strength, Judd‐Ofelt parameters, root mean square deviation, radiative lifetime and covalency parameters in various solvents, hypersensitivity, symmetry characteristics, and covalency have been thoroughly investigated. The promotion of 4f–4f electric‐dipole intensity has been found to be particularly successful with ethanol, pyridine, DMF, and DMSO. Utilizing Judd‐Ofelt Ω4 values and Hirshfeld analysis, long‐range secondary π⋅⋅⋅π stacking or H‐bonding interactions were investigated. The intensity of emission spectra, quantum yield, stokes shift, and antenna effect energy diagram was examined using solid‐state emission spectra.

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Three mixed ligand mononuclear Zn(II) complexes of 4-acyl pyrazolones: Synthesis, characterization, crystal study and anti-malarial activity

Cited by 28 publications

References 27 publications

Synthesis, Covalency Sequence, and Crystal Features of Pentagonal Uranyl Acylpyrazolone Complexes along with DFT Calculation and Hirshfeld Analysis

Synthesis, Covalency Sequence, and Crystal Features of Pentagonal Uranyl Acylpyrazolone Complexes along with DFT Calculation and Hirshfeld Analysis

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

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

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