Nonlinear Optical Properties and All Optical Switching of Curcumin Derivatives

In this work OR1(E1,6E) -1,7-bis (4-propyloxy phenyl) hepta-1,6-diene-3,5 dione compound is synthesized. The compound has been characterized via computational technique by studying the molecule's electronic structures through calculating its HOMO and LUMO energies, and its band gap energy (EHOMO-ELUMO). The nonlinear refractive index (NLRI) of the solution of OR1 compound in DMF solvent is determined using diffraction patterns (DPs) which resulted when a continuous wave laser beam of wavelength 473 nm traversed the compound solution in a glass cell of 1 mm thickness. By counting the number of rings under maximum beam input power, the NLRI of value 10- 6 cm2/W resulted. The NLRI is calculated once more via the Z-scan technique and a value of 0.25 × 10- 7 cm2/W is obtained. The vertical convection current in the OR1 compound solution appears to be responsible for the asymmetries noticed in the DPs. The temporal variation of each DP is noticed together with the evolution of DPs against beam input power. DPs are numerically simulated based on the Fresnel-Kirchhoff integral with good accord compared to the experimental findings. Dynamic and static all-optical switching in the OR1 compound using two laser beams (473 and 532 nm) is tested successfully.

Curcumin Analogue Spectral, Nonlinear Optical Properties and All-optical Switching Using Visible, Low Power Cw Laser Beams

In this study, we conducted the synthesis and diagnosis of compound denoted as 1A3, specifically, (2E,4E,9E,11E)-7-chloro-2,12-diphenyltrideca-2,4,9,11-tetraene-6,8-dione. The photoluminescent and UV-vis spectral properties of this compound are investigated. The compound is dissolved in both chloroform and DMF for analysis purposes. Compound 1A3's nonlinear optical (NLO) characteristics when dissolved in DMF, are extensively studied through a series of experiments including diffraction patterns (DPs) and Z-scan. The optical limiting (OL) property of the 1A3 compound is tested and a threshold value of 12.4 mW at the wavelength 473 nm is obtained. Additionally, we explored its potential for all-optical switching utilizing two low-power visible laser beams. Notably, we achieved a significant nonlinear refractive index (NLRI) reaching up to 5.921 x 10-11 m2/W. To analyze the obtained diffraction patterns, we employed the Fresnel-Kirchhoff integral equation and conducted meticulous simulations. The numerical outcomes showed satisfactory agreement with the experimental observations.

Anticancer, antioxidant activities and molecular docking study of thiazolidine-4-one and thiadiazol derivatives

Liver cancer accounts for a major portion of the global cancer burden. In many nations, the prevalence of this condition has risen in recent decades. New series of thiazolidinones and thiadiazolidine have been designed, synthesized, and evaluated for potential antioxidant and antihepatocarcinogenic activity. The antioxidant activity was evaluated using a DPPH assay. Furthermore, we examined the compounds against Hepg-2 cells using MTT assay, flow cytometry analysis through the cell cycle, reactive oxygen species, and apoptosis. The result showed that compound 6b has the highest antioxidant activity with IC₅₀ = 60.614 ± 0.739 µM. The anticancer activity showed that compounds 5 and 6b have significant toxicity against liver cancer cells Hepg2, IC₅₀ values (9.082 and 4.712) µM, respectively. Flow cytometry experiments revealed that compound 5 arrested Hepg-2 cells in the S process, while compound 6b arrested Hepg-2 cells in the G1. Compound 6b had a greater reduction in reactive oxygen species and late apoptosis than compound 5. Substantially, compound 5 had affinity energies of -7.6 and -8.5 for Akt and CDK4 proteins, respectively, but compound 6b had affinity energies of -7.8 and -10.1 for Akt1 and CDK4 proteins, respectively. Consequently, compound 6b had lower binding energies than compound 5. In this work, we used multiple bioinformatics methods to shed light on the prospective therapeutic use of these series as novel candidates to target immune cells in the tumor microenvironment of hepatocellular carcinomas such as CD8+ T cells, endothelial cells, and hematopoietic stem cells.

A novel series of thiosemicarbazone drugs: from synthesis to structure

A new series of thiosemicarbazones (TSCs) and their 1,3,4-thiadiazolines (TDZs) containing acetamide group have been synthesized from thiosemicarbazide compounds by the reaction of TSCs with cyclic ketones as well as aromatic aldehydes. The structures of newly synthesized 1,3,4-thiadiazole derivatives obtained by heterocyclization of the TSCs with acetic anhydride were experimentally characterized by spectral methods using IR, (1)H NMR, (13)C NMR and mass spectroscopic methods. Furthermore, the structural, thermodynamic, and electronic properties of the studied compounds were also studied theoretically by performing Density Functional Theory (DFT) to access reliable results to the experimental values. The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and Mulliken atomic charges of the studied compounds have been calculated at the B3LYP method and standard 6-31+G(d,p) basis set starting from optimized geometry. The theoretical (13)C chemical shift results were also calculated using the gauge independent atomic orbital (GIAO) approach and their respective linear correlations were obtained.

Oxidation of benzoin catalyzed by oxovanadium(IV) schiff base complexes

Background

The oxidative transformation of benzoin to benzil has been accomplished by the use of a wide variety of reagents or catalysts and different reaction procedures. The conventional oxidizing agents yielded mainly benzaldehyde or/and benzoic acid and only a trace amount of benzil. The limits of practical utilization of these reagents involves the use of stoichiometric amounts of corrosive acids or toxic metallic reagents, which in turn produce undesirable waste materials and required high reaction temperatures.

In recent years, vanadium complexes have attracted much attention for their potential utility as catalysts for various types of reactions.

Results

Active and selective catalytic systems of new unsymmetrical oxovanadium(IV) Schiff base complexes for the oxidation of benzoin is reported. The Schiff base ligands are derived between 2-aminoethanol and 2-hydroxy-1-naphthaldehyde (H₂L¹) or 3-ethoxy salicylaldehyde (H₂L³); and 2-aminophenol and 3-ethoxysalicylaldehyde (H₂L²) or 2-hydroxy-1-naphthaldehyde (H₂L⁴). The unsymmetrical Schiff bases behave as tridentate dibasic ONO donor ligands. Reaction of these Schiff base ligands with oxovanadyl sulphate afforded the mononuclear oxovanadium(IV) complexes (V^IVOL^x.H₂O), which are characterized by various physico-chemical techniques.

The catalytic oxidation activities of these complexes for benzoin were evaluated using H₂O₂ as an oxidant. The best reaction conditions are obtained by considering the effect of solvent, reaction time and temperature. Under the optimized reaction conditions, VOL⁴ catalyst showed high conversion (>99%) with excellent selectivity to benzil (~100%) in a shorter reaction time compared to the other catalysts considered.

Conclusion

Four tridentate ONO type Schiff base ligands were synthesized. Complexation of these ligands with vanadyl(IV) sulphate leads to the formation of new oxovanadium(IV) complexes of type V^IVOL.H₂O.

Elemental analyses and spectral data of the free ligands and their oxovanadium(IV) complexes were found to be in good agreement with their structures, indicating high purity of all the compounds.

Oxovanadium complexes were screened for the oxidation of benzoin to benzil using H₂O₂ as oxidant. The effect of time, solvent and temperature were optimized to obtain maximum yield. The catalytic activity results demonstrate that these catalytic systems are both highly active and selective for the oxidation of benzoin under mild reaction conditions.