Palladium Metal Nanocomposites Based on PEI-Functionalized Nitrogen-Doped Graphene Quantum Dots: Synthesis, Characterization, Density Functional Theory Modeling, and Cell Cycle Arrest Effects on Human Ovarian Cancer Cells.

In this study, the synthesis, characterization, density functional theory calculations (DFT), and effect of polyethylenimine (PEI)-functionalized nitrogen-doped graphene quantum dots (PEI N-GQDs) and their palladium metal nanoparticles nanocomposites (PdNPs/PEI N-GQDs) on cancer cells were extensively investigated. The focus also includes investigating their cytotoxic and apoptotic effects on ovarian cancer cells, which pose a serious risk to women's health and have high death rates from delayed diagnosis, inadequate response to treatment, and decreased survival. Graphene quantum dots and their palladium nanocomposites were differentially effective against ovarian cancer cell lines. In particular, the smaller particle size and morphology of PdNPs/PEI N-GQDs nanocomposites compared with PEI N-GQDs probably enhance their activity through highly improved uptake by cells. These findings emphasize the importance of particle size in composite drugs for efficient cancer treatment. DFT results revealed that the Pd-containing nanocomposite, with a smaller highest occupied molecular orbital-lowest unoccupied molecular orbital gap, exhibited higher reactivity and anticancer effects in human ovarian cancer cell line, OVCAR-3. Significantly, the application of nanocomposites to ovarian cancer cells initiated apoptosis, offering valuable insights into the intricate interplay between nanomaterials and cancer biology.

Two-Photon Absorption Response of Functionalized BODIPY Dyes in Near-IR Region by Tuning Conjugation Length and Meso-Substituents.

BODIPY dyes substituted by phenol or -COOMe units at the meso-position (C8) with and without a distyryl group including a methoxy moiety at the -C3 and -C5 positions of the BODIPY have been synthesized to analyze the photophysical properties. To clarify the ground-state interaction, absorption and emission features were investigated in the THF environment. Extending the π-conjugation with the methoxy moiety at -C3 and -C5 positions of BODIPY leads to a spectral shifting of the absorption maxima toward red by 120 nm. In addition, attaching the -COOMe unit at the meso-position of the BODIPY structure increases nonradiative molecular relaxation as compared to compounds possessing phenol substituents at the same position. We have investigated the effect of phenol and a -COOMe group and π-extended conjugation length with a methoxy moiety on the properties of two-photon absorption (TPA) and electron transfer dynamics by performing open-aperture (OA) Z-scan and femtosecond transient absorption spectroscopy measurements, respectively. The synthesized BODIPY compounds with the distyryl group including the methoxy unit show TPA character due to the longer conjugation length and therefore intramolecular charge transfer ability. Based on the OA Z-scan experiments upon photoexcitation with 800 nm pulsed laser light, TPA cross-section values were obtained as 74 and 81 GM for the compounds possessing phenol and -COOMe units at the meso-position of BODIPY treated by distyryl group with methoxy moieties, respectively. Additionally, optical and electronic properties were calculated theoretically by using the DFT method.

Effects of Heavy Iodine Atoms and π-Expanded Conjugation on Charge Transfer Dynamics in Carboxylic Acid BODIPY Derivatives as Triplet Photosensitizers.

Borondipyrromethene (BODIPY) chromophores are composed of a functional-COOH group at meso position with or without a biphenyl ring, and their compounds with heavy iodine atoms at -2, -6 positions of the BODIPY indacene core were synthesized. The photophysical properties of the compounds were studied with steady-state absorption and fluorescence measurements. It was observed that the absorption band is significantly red-shifted, and fluorescence signals are quenched in the presence of iodine atoms. In addition to that, it was indicated that the biphenyl ring does not affect the spectral shifting in the absorption as well as fluorescence spectra. In an attempt to investigate the effect of π-expanded biphenyl moieties and heavy iodine atoms on charge transfer dynamics, femtosecond transient absorption spectroscopy measurements were carried out in the environment of the tetrahydrofuran (THF) solution. Based on the performed ultrafast pump-probe spectroscopy, BODIPY compounds with iodine atoms lead to intersystem crossing (ISC) and ISC rates were determined as 150 ps and 180 ps for iodine BODIPY compounds with and without π-expanded biphenyl moieties, respectively. According to the theoretical results, the charge transfer in the investigated compounds mostly appears to be intrinsic local excitations, corresponding to high photoluminescence efficiency. These experimental findings are useful for the design and study of the fundamental photochemistry of organic triplet photosensitizers.

Two-photon absorption and triplet excited state quenching of near-IR region aza-BODIPY photosensitizers via a triphenylamine moiety despite heavy bromine atoms.

Aza-BODIPY compounds with methoxy groups at -3 and -5 and triphenylamine moieties at -1 and -7 positions with and without heavy bromine atoms at -2 and -6 positions have been designed and synthesized. The chemical structures of the novel compounds were fully characterized using 1H NMR, 13C NMR, FTIR, and HRMS-TOF-ESI techniques. Steady-state absorption and emission features were investigated to analyze ground-state interactions. The effects of triphenylamine moieties and bromine atoms on charge transfer dynamics and two-photon absorption (TPA) properties were investigated using femtosecond transient absorption spectroscopy measurements and open-aperture (OA) Z-scan experiments, respectively. Contrary to popular belief, the compound containing heavy bromine atoms and triphenylamine moieties did not demonstrate any triplet transition. Since the triphenylamine moiety has high electron-donating properties and a long conjugation length, it exhibited intramolecular charge transfer (ICT) features from electron-donating moieties to the aza-BODIPY core. Additionally, it is concluded that the excited-state lifetime is shortened in the presence of a bromine atom with triphenylamine moieties. This result is rather interesting since the triplet excited state is quenched by the triphenylamine moiety despite the presence of a heavy bromine atom. The performed OA Z-scan experiments revealed that the aza-BODIPY compound containing bromine atoms has a higher TPA cross-section value (116 GM) due to efficient intramolecular charge transfer compared to that without bromine atoms (89 GM). Additionally, in the theoretical calculations, it was found that the charge transfer percentage (CT%) was the strongest in compounds containing bromine atoms.

Molecular simulation of PcCel45A protein expressed from Aspergillus nidulans to understand its structure, dynamics, and thermostability.

PACS and mathematical subject classification numbers as needed. Molecular dynamic simulation is a very usable tool to understand various factors, including structure temperature dependence, dynamics, and stability for protein structure. The three main components, namely endoglucanase, exoglucanase, and ß-glucosidase, effectively convert lignocellulosic biomass into fermentable sugar. Cellulose is the major component of plant cell walls and is the most abundant organic compound on the earth. Somewhat organisms can use cellulose as a food source, possessing cellulases (cellobiohydrolases and endoglucanases) that can catalyze the hydrolysis of the ß-(1,4) glycosidic bonds. In this work, we investigated conformational and structural properties of PcCel45A protein by changing at temperatures with 300 K, 333 K, and 352 K. We found that the ASN92 residue was the major contributor to the stability of structure; some other residues correlated significantly with thermal stability. We also compared the theoretical results of the current study with the experimental ones published in previous studies.

Synthesis, characterization, and evaluation of (E)-methyl 2-((2-oxonaphthalen-1(2H)-ylidene)methylamino)acetate as a biological agent and an anion sensor.

An amino acid based and bidentate Schiff base, (E)-methyl 2-((2-oxonaphthalen-1(2H)-ylidene)methylamino)acetate (ligand), was synthesized from the reaction of glycine-methyl ester hydrochloride with 2-hydroxy-1-naphthaldehyde. Characterization of the ligand was carried out using theoretical quantum-mechanical calculations and experimental spectroscopic methods. The molecular structure of the compound was confirmed using X-ray single-crystal data, NMR, FTIR and UV-Visible spectroscopy, which were in good agreement with the structure predicted by the theoretical calculations using density functional theory (DFT). Antimicrobial activity of the ligand was investigated for its minimum inhibitory concentration (MIC) to several bacteria and yeast cultures. UV-Visible spectroscopy studies also shown that the ligand can bind calf thymus DNA (CT-DNA) electrostatic binding. In addition, DNA cleavage study showed that the ligand cleaved DNA without the need for external agents. Energetically most favorable docked structures were obtained from the rigid molecular docking of the compound with DNA. The compound binds at the active site of the DNA proteins by weak non-covalent interactions. The colorimetric response of the ligand in DMSO to the addition of equivalent amount of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) was investigated and the ligand was shown to be sensitive to CN- anion.

Crystal structure and DFT calculations of 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid.

The title compound, 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid, has been characterized by using elemental analysis, MS, FT-IR, 1H NMR and 13C NMR spectroscopic, and crystallographic techniques. The title compound crystallizes in the triclinic space group P-1 with a=9.612(1), b=9.894(1), c=17.380(1)Å, α=90.213(5)°, ß=104.99(1)°, γ=111.072(5)°, V=1481.3(2)Å3 and Dx=1.483 g cm(-3) respectively. The structure of the compound has also been examined by using quantum chemical methods. The molecular geometry and vibrational frequencies of monomeric and dimeric form of the title compound in the ground state have been calculated by using the B3LYP/6-31G(d,p) level of the theory. The calculated results show that the optimized geometry and the theoretical vibration frequencies of the dimeric form are good agreement with experimental data. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map, thermodynamic properties of the title compound were performed at B3LYP/6-31G(d,p) level of theory.

Pyrazole derivatives as inhibitors of arachidonic acid-induced platelet aggregation.

Antiplatelet drugs are promising therapeutics to intervene with platelet aggregation in arterial thrombosis, most prominently in myocardial infarction and ischemic stroke. Here, we describe the synthesis and structure-activity relationships of potent inhibitors of platelet aggregation based on the 1,5-diarylpyrazol-3-carboxamide scaffold. Analogs from this series demonstrated potent anti-aggregatory activities against arachidonic acid-induced platelet aggregation, as measured by turbidimetric method of Born. 1,5-Diarylpyrazole-3-carboxamides obtained with small-basic amines (7, 8, 50, 51, 61, 62) displayed the strongest activity with IC50 values in low nanomolar range (5.7-83 nM). On the basis of their high potency in cellular environment, these straightforward pyrazole derivatives may possess potential in the design of more potent compounds for intervention with cardiovascular diseases.

Third-order nonlinear optical properties and structures of (E)-N-(4-nitrobenzylidene)-2,6-dimethylaniline and (E)-N-(4-nitrobenzylidene)-2,3-dimethylaniline.

(E)-N-(4-Nitrobenzylidene)-2,6-dimethylaniline (1) and (E)-N-(4-nitrobenzylidene)-2,3-dimethylaniline (2) have been synthesized. The crystal structures of both compounds have been defined by X-ray diffraction analysis. The maximum one-photon absorption (OPA) wavelengths recorded by quantum mechanical computations using a configuration interaction (CI) method are estimated in the UV region to be shorter than 450nm, showing good optical transparency to the visible light. To provide an insight into the microscopic third-order nonlinear optical (NLO) properties of the investigated molecules, both dispersion-free (static) and also frequency-dependent (dynamic) linear polarizabilities (alpha) and second hyperpolarizabilities (gamma) at lambda=825-1125nm and 1050-1600nm wavelength areas have been computed using time-dependent Hartree-Fock (TDHF) method. According to the ab initio calculation results, the title molecules exhibit second hyperpolarizabilities with non-zero values, implying microscopic third-order NLO behavior.

Synthesis, spectroscopic studies and structures of square-planar nickel(II) and copper(II) complexes derived from 2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol.

Two new nickel(II) [Ni(L)(2)] and copper(II) [Cu(L)(2)] complexes have been synthesized with bidentate NO donor Schiff base ligand (2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol) (HL) and both complexes Ni(L)(2) and Cu(L)(2) have been characterized by elemental analyses, IR, UV-vis, (1)H, (13)C NMR, mass spectroscopy and room temperature magnetic susceptibility measurement. The tautomeric equilibria (phenol-imine, O-H...N and keto-amine, O...H-N forms) have been systemetically studied by using UV-vis absorption spectra for the ligand HL. The UV-vis spectra of this ligand HL were recorded and commented in polar, non-polar, acidic and basic media. The crystal structures of these complexes have also been determined by using X-ray crystallographic techniques. The complexes Ni(L)(2) and Cu(L)(2) crystallize in the monoclinic space group P2(1)/n and P2(1)/c with unit cell parameters: a=10.4552(3)A and 12.1667(4)A, b=8.0121(3)A and 10.4792(3)A, c=13.9625(4)A and 129.6616(3)A, V=1155.22(6)A(3) and 1155.22(6)A(3), D(x)=1.493 and 1.476 g cm(-3) and Z=2 and 2, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares to a find R=0.0377 and 0.0336 of for 2340 and 2402 observed reflections, respectively.

Synthesis, Spectroscopic, Spectrophotometric and Crystallographic Investigations of 4-{[(1E)-(3,4-dimethoxyphenyl)methylene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one and 4-{[(1E)-(2-hydroxy-5-methoxyphenyl)methylene]amino}-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one.

Two new Schiff base ligands 4-[(1E)-(3,4-dimethoxyphenyl)methylene]amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (1) and 4-[(1E)-(2-hydroxy-5-methoxyphenyl)methylene]amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (2) have been prepared and characterized using elemental analysis, UV-vis, FT-IR, 1H and 13C NMR spectroscopy, and X-ray crystallographic technique. Tautomeric equilibria (phenol-imine, O-H...N and keto-amine, O...H-N forms) have been studied by using UV-vis absorption spectra for the compound 2 in some solutions. Crystal structure analyses showed that the title molecules 1 and 2 crystallize in the monoclinic space group P21/c and P21 with the unit cell parameters: a = 12.5665(3) Å and 5.6666(2) Å; b = 10.4791(2) Å and 12.2444(5) Å; c = 14.6240(3) Å and 12.1556(4) Å; V =1820.65(7) Å3 and 826.84(5) Å3; Dx = 1.282 g.cm-3 and 1.355 g.cm-3; and Z = 4 and 2, respectively.

Spectroscopic study and structure of (E)-2-[(2-chlorobenzylimino)methyl]methoxyphenol.

(E)-2-[(2-chlorobenzylimino)methyl]methoxyphenol has been synthesized from the reaction of 2-hydroxy-3-methoxy-1-benzaldehyde(o-vanillin) with 2-chlorobenzylamine. The title compound has been characterized by using elemental analysis, FT-IR, (1)H NMR, (13)C NMR and UV-vis spectroscopic techniques. The crystal structure of the title compound has also been examined cyrstallographically. It crystallizes in the orthorhombic space group Pbca with unit cell parameters: a = 7.208(1) A, b = 13.726(2) A, c = 27.858(4) A, V = 2756.0(1) A(3), D(c) = 1.18 g cm(-3) and Z = 8. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R = 0.046 for 2773 observed reflections.

Linear optical transmission measurements and computational study of linear polarizabilities, first hyperpolarizabilities of a dinuclear iron(III) complex.

The optical transmission spectral study of a dinuclear metal complex [FeL(MeOH)Cl]2 (L=N-(5-methylphenyl)-3-methoxysalicylaldimine) has been carried out. The linear optical characterization shows that this molecule has transparency in the visible range. To understand linear optical and microscopic second-order nonlinear optical (NLO) behavior of the compound, we have computed the electric dipole moment (mu) and dispersion-free first hyperpolarizabilities (beta) using Finite Field second-order MØller-Plesset perturbation (FF MP2) procedure; and also dispersion-free linear polarizabilities (alpha), frequency-dependent linear polarizabilities within the linear optical spectrum and first hyperpolarizabilities at lambda=730-1050 and 1000-1400 nm wavelength areas using time-dependent Hartree-Fock (TDHF) method. The ab-initio calculation results reveal that the examined complex might have linear optical and microscopic NLO behavior with non-zero values.

Synthesis, molecular structure, spectroscopic studies and second-order nonlinear optical behaviour of N,N'-(2-hydroxy-propane-1,3-diyl)-bis(5-nitrosalicylaldiminato-N,O)-copper(II).

N,N'-(2-Hydroxy-propane-1,3-diyl)-bis(5-nitrosalicylaldiminato-N,O)-copper(II) has been synthesized. The crystal structure has been determined by X-ray diffraction analysis, and linear optical characterization has been determined by UV-vis spectroscopy. It was found that the molecule under investigation has solvatochromic behaviour in the UV region, implying non-zero microscopic first hyperpolarizability. To reveal the microscopic nonlinear optical (NLO) properties, the static first hyperpolarizabilities (beta) and the electric dipole moments (mu) were evaluated by using the ab initio finite field (FF) method. According to the results of the FF calculations, the synthesized compound exhibits non-zero beta values, and it might have microscopic NLO behaviour.

Nonlinear optical properties, synthesis, structures and spectroscopic studies of N-(4-nitrobenzylidene)-o-fluoroamine and N-(3-nitrobenzylidene)-p-fluoroamine.

N-(4-nitrobenzylidene)-o-fluoroamine (1) and N-(3-nitrobenzylidene)-p-fluoroamine (2) have been synthesized. The crystal structures of both compounds have been defined by X-ray diffraction analysis, and characterized by FT-IR and UV-visible instrumental methods. The recorded spectrum by UV-visible spectroscopy for the investigated compounds show good transparency in the visible region, and have solvatochromic behavior in the UV region, implying nonzero microscopic first hyperpolarizability. We also report ab initio quantum chemical calculations of the electric dipole moments (mu) and the first hyperpolarizabilities (beta) of the studied compounds. Our results suggest that the investigated ligands might have microscopic nonlinear optical (NLO) behavior with nonzero values.

Electrochemical reduction of 1-([(4-halophenyl)imino]methyl)-2-naphthols in aprotic media.

The electrochemical reduction of 1-([(4-halophenyl)imino]methyl)-2-naphthols on graphite electrodes was studied using cyclic voltammetry, chronoamperometry, constant-potential coulometry and preparative constant-potential electrolysis techniques. The data revealed that the reduction on graphite was irreversible and followed an EC mechanism. The diffusion coefficients and the number of electrons transferred were determined using the chronoamperometric Cottrell slope and the ultramicro disc Pt-electrode steady-state current. The number of electrons was also determined by bulk electrolysis. The compounds were subjected to constant-potential preparative electrolysis and the electrolysis products were purified and identified by spectroscopic methods. Based on these findings, a mechanism for the electro-reduction process is proposed.