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The chromophore 2-2-(3-cyano-5,5-dimethyl-4-((2-[thiazol-2-yl]hydrazono)methyl)-furan-2(5H)-ylidene)malononitrile (TzHTCF) was prepared by diazo-coupling of diazotized 2-aminothiazole with 3-cyano-2-(dicyanomethylene)-4,5,5-trimethylfuran (TCF). The TzHTCF absorption solvatochromism, in different polarity solvents, demonstrated a ΔE

A new carbazole chromophore conjugated with substituted thiazolidine-4-one (CzPT) was synthesized by applying the Knoevenagel reaction between 3,6-diformyl-N-hexylcarbazole and ethyl 2-aceto-2-(5-oxo-3-phenylthiazolidin-2-ylidene)acetate. The chemical structure of the new derivative (CzPT) was elucidated by spectral studies. The CzPT absorption spectra in different solvents exhibited a red shift for λmax by increasing solvent polarity. Bands at 430-474 nm appeared and were attributed to intramolecular charge transfer with high π-π* characteristics. CzPT fluorescence spectra exhibited a red shift after increasing the solvent polarity. To understand the Stokes' shift ( ∆ν¯) behaviour of the CzPT derivative referring to the polarity of solvents, Lippert-Mataga and linear solvation-energy relationship (LSER) models were employed in which the LSER exhibited respectable results compared with Lippert-Mataga (r2 = 0.9707). Moreover, time-dependent density functional theory absorption spectra in hexane and dimethylformamide showed that λmax had a major contribution in the highest occupied molecular orbital to lowest unoccupied molecular orbital transition in both solvents. In addition, the reduced uniformity of crystal features may lead to dislocation or anomalous arrangement of crystals with irregular spacing, which automatically enhances the optical properties of such crystals.

Synthesis for new pyrazolin derivatives, which oriented for coordination with Cr(III) ion then all new synthesizes were characterized with reliable techniques. Octahedral geometry was the only form suggested from bi-negative tetra-dentate mode of bonding within bi-nuclear complexes. Such offering is based on analytical and spectral tools (IR, UV–Vis and MS). TGA confirms and discriminates water molecules profiles with relative to coordination sphere. Practical and computational XRD patterns appeared having high extent of similarity attributing to nano-crystalline particulate sizes. Hirshfeld surface properties and the efficiency of molecular-contact in crystal-packing, were obtained upon Crystal explorer 3.1 software beside VESTA package. Some physical indices were estimated based on frontier energy gaps over optimized structures upon Gauss-view software. Computational simulation approach was implemented to monitor changes on cancer cell proteins after treatment by new Cr(III) complexes, for assessment. Promising antitumor activity might be expected for Cr(III)-L4, Cr(III)-L3 and Cr(III)-L2 complexes, based on exported interaction parameters. It is worthy to note that, in-vitro assay reflects an excellent cytotoxicity recorded for such three complexes, in excellent harmony with simulation suggestions.

Background Cataract is an extremely serious cause of visual impairment in paediatric patients worldwide, with untreated cataract being the leading cause of blindness in children. Aims The aim of the present study was to assess the level of awareness and knowledge about paediatric cataract among the general population of Jeddah, Saudi Arabia. Methods This survey-based cross-sectional study was conducted between June and July 2018 and included a representative sample of the general population of Jeddah, Saudi Arabia. The questionnaire included a set of questions pertaining to paediatric cataract knowledge and awareness. The gathered data were analysed using Statistical Package for Social Sciences (SPSS) version 21, and the results were acquired by Pearson’s chi square tests and frequency calculations. Results In total, 678 individuals, including 51.6per cent women and 48.4per cent men, participated in the survey. Approximately 39.7per cent participants did not know whether cataract can affect the paediatric population or not. Although the majority could not recognize the risk factors and symptoms of the disease, 75.2per cent realized that it is treatable. Surgical intervention was identified as the main treatment modality by 46.9per cent participants. Conclusion Our findings suggest that the general population of Jeddah has limited knowledge about paediatric cataract. Thus, educational campaigns and programs are necessary to increase public awareness. In addition, further studies on awareness about this condition should be considered in order to prevent serious eye complications in children.

Two thiazole-based complexes were prepared from Co(II) and Cu(II) ions. The new ligand and its complexes were fully characterized by analytical and spectral techniques. The ligand behaved as a neutral tridentate in its keto-form towards the metals via O(8), O(10) and O(18) atoms. This was suggested based on the lower shift of υ(CH=O), υ(C=O)amide and υ(C-O) vibrations. The electronic transitions in Co(II)-HL and Cu(II)-HL complexes displayed d-d- transitions which belong to 4T1g→4A2g(F) & 4T1g(F)→4T1g (P) and 2Eg →2T2g, in the two complexes, respectively. ESR spectrum of Cu(II)-HL complex displayed g-factor by the following order; g//(2.1740)>g⊥(2.0935)>2.0023, which agrees with octahedral geometry. The geometry optimization was executed by DFT/B3LYP method under valence double zeta polarized basis set (6-31G*), to confirm the structural forms and the mode of bonding. The orientation and the charges of O(8), O(10) and O(18) atoms, support the coordination of the ligand in its keto-form with the metal ions. Pharmacophore profiles were obtained regarding thiazole ligand and other recommended drugs (arbidol, avigan and idoxuridine) that used in treatment protocol of COVID-19 pandemic. Also, query was run in MolPort-library to obtain antiviral analogues, to broaden the search for an effective treatment. Three analogues were obtained for arbidol, avigan and idoxuridine drugs, which have the following numbers; MolPort-047-605-644, MolPort-004-768-508 and MolPort-028-750-709, respectively. Moreover, molecular docking was carried out to obtain all interaction details and rank the efficiency of thiazole compound versus the three antivirals in their interaction with the two COVID-19 proteins. The outcomes suggested the significant antiviral activity of idoxuridine and thiazole (enol-form), which not reach to eliminate the pandemic exactly. While, arbidol and avigan did not have an effective antiviral role, although they still used in COVID-19 treatment protocol., graphical abstract Image, graphical abstract

Ball milling was used to obtain new Schiff-base complexes from Co(II), Fe(III), Ni(II), and Zn(II) ions in their solid form, which is considered a green method of preparation. Several spectroscopic (IR, UV–Vis, 1H NMR, Mass, SEM, EDX, XRD) and analytical approaches were used to suggest the geometries of isolated compounds. Coats–Redfern and Horowitz–Metzger methods were used to compute the kinetic and thermodynamic parameters of Zn(II) complex (i.e.). Furthermore, conductometry was used to estimate both formation/association constants of Co(II) complex (i.e.) in solution at 290.15 K. The feature of the complex in solution may offer a good view about it in its solid state. Standard methods were applied to test the antibacterial activity of ligand and complexes to TOS aureus, E. coli and Candida albicans fungus. To assess their inhibitory effect, ABTS-antioxidant screening and cytotoxicity against liver cancer cells (HepG2) were also performed. Most complexes showed mild to considerable activity towards the selected microorganisms and liver cancer cell line, respectively. The structural forms were optimized using molecular modeling, which then confirmed the binding mechanism provided by spectral analyses. To investigate the degree of inhibition for new drugs versus three selected proteins (1dee, 5uw2 and 7jx9), two in-silico techniques were used: Pharmit link and Molecular Operating Environmental module (MOE, vs 2018). The docking patterns as well as the interaction data were acquired and analyzed. The high consistency of in-vitro and in-silico outcomes lends credence to computational treatments that must be done on developed medications before they can be used in practice.

An alternative sequence of bioactive series, using novel Schiff base derivative (1-Quinolin-8-yliminomethyl-naphthalen-2-ol), was produced (HNQ). Elements analysis, molar conductivity, magnetic moment, IR, 1H NMR, UV-Vis, and TGA were used to define the chemical forms. As a result, an appropriate geometry has been proposed for each complex. The HNQ ligand functions as a tri-dentate via NNO donors to the metal ions within octahedral geometry with Cr3+, square pyramidal with VO2+, tetrahedral with Zn2+, and square planner with Pd2+ ion. The Coats-Redfern approach was used to determine the kinetic and thermodynamic characteristics of complexes, and their values revealed the ordered state of active complexes. The binding effectiveness of the examined compounds with calf thymus DNA (ct-DNA) was analyzed using various methods, and the binding function was assumed to be electrostatic, intercalation, or replacement mode. Furthermore, the compounds' antibacterial and anticancer efficacy was tested in vitro. In a concentration-dependent way, the chemicals had a considerable influence on lowering cell viability of breast cancer cells (MCF-7). The antioxidant activity of the compounds was examined in vitro, and the results revealed that the ligand's activity was similar to that of the reference drug. This study was reinforced by different theoretical implementations. The geometry optimization process supported the manner of ligand-metal ion interaction. The stability of complexes was shined and the reduced polarity was recorded with HNQ, HNQPd and HNQVO, which is promising in biological applications. Biological simulation was performed using Pharmit link to search on drug-like compounds and to discover the extent of interaction with DNA-protein (1bna). In addition, MOE-docking was implemented to put a clear view about the interaction features between the compounds and 1bna protein. The simulation study reveals the priority of HNQ ligand towards the DNA and the negligible role of complexes, was expected. While, comparing in-vitro with in-silico results, this difference was noticed, which may suggest a presence of any unknown mechanism improves the behavior of complexes inside living-cells.

The present work describes the fabrication and electrochemical characterization of a novel iron oxide nanopowder-based carbon paste electrodes (CPE) for the sensitive voltammetric quantification of midodrine (MD) in pharmaceutical formulations and biological fluids. At the electrode surface, the postulated reaction mechanism involved the irreversible oxidation of the terminal amino group of midodrine through the participation of two-electron as elucidated by the sweep rate studies and molecular orbital calculations. Calibration graphs were linear in the MD concentration range from 0.16 × 10-6 to 2.12 × 10-6 mol L-1 with LOD 0.04 × 10-6 mol L-1. Prolonged stability with an operational lifetime of more than 4 months and high measurement reproducibility were the promising futures of the fabricated sensors. The proposed electroanalytical approach was free from interference and suggested for assaying of midodrine in its pharmaceutical formulations and biological samples with recovery agreed with the official methods.

A novel momonuclear metal chelates were derived from Zn(II), Pd(II), VO(II) and Cr(III) ions with azomethine (BSQ) [BSQ = 4-Bromo-2-(quinolin-8-yliminomethyl)-phenol] ligand. The prepared compounds were subjected to different analytical and spectroscopic techniques as, IR, 1H NMR, UV–Vis, molar conductivity, magnetic moment and thermogravimetric analysis (TGA) to elucidate their structures. Accordingly, the most fitted geometry has been suggested for each complex. The ligand acts as a tri-dentate via NNO donors towards the metal ions inside octahedral geometry with Cr3+, square pyramidal with VO2+, tetrahedral with Zn2+ and square planner with Pd2+ ion. Thermo-kinetic parameters for the complexes have been determined and the values suggest the presence of ordered activated complexes. The reactivity of new compounds towards DNA was examined by different methods and the binding kinds seem to electrostatic, intercalation, or replacement. Also, in-vitro antimicrobial and anticancer potency of the compounds were evaluated. In addition, the therapeutic behavior of the complexes appeared promising towards breast cancer cells (MCF-7) in a concentration-dependent manner. Moreover, the redox potential of the newly synthesized compounds was evaluated and the results reflect suitability of Pd(II) complex in controlling the free radicals. Variable theoretical treatments were performed aiming to confirm the structural formulae as well as the biological assay results. A promising antimicrobial and anticancer behavior was recorded with Pd(II) complex (BSQPd) via in-vitro and in-silico ways.

The diazotization, coupling and metallization process was employed to create hydrazone chelating ligand (HL) and its Co(II), Cu(II) and Ni(II) complexes. Elemental analysis, FT-IR, UV–visible, thermal analysis, 1H NMR, and 13C NMR were utilized to propose their structures. The reaction between metal (II) with HL produced mononuclear complexes and the molar conductivity results demonstrated that the complexes are all non-electrolytes that fall within a certain range 8–12 Ω−1 cm2 mol−1. Co(II) and Ni(II) complexes have pseudooctahedral coordination geometry, whereas Cu(II) complexes have square planar coordination geometry. The metal ion interacts with the ligand. as a monobasic bidentate by (C O) as well as deprotonating hydrazone moiety ( NH ). Besides, the optimized structure, bond lengths, and angles of the ligand and its complexes determined quantum chemical parameters were estimated by molecular modeling. Electronic absorption dilution and viscosity analysis techniques were used to study the compounds' DNA binding activities. With a binding constant in the 5.13 × 105 M−1 range. The results revealed that the complexes bind to CT-DNA in grooves followed by partial incorporation of the ligand between the DNA base stacks. The cytotoxicity of the new complexes was examined versus human carcinoma cell lines, HepG-2 & MCF-7, and compared to positive controls as vinblastine and colchicine. The DPPH free radical-scavenging assay was used to evaluate the anti-oxidant capacity of all compounds in-vitro. Finally, the antimicrobial activities of the complexes against fungal (Candida albicans), gram negative bacteria (Escherichia coli), and gram positive bacteria (Escherichia coli) were investigated using the disc-diffusion process (Staphylococcus aureus).

New Cd(II), Hg(II), Zn(II), UO2(II) complexes were prepared from cyclohexanone-[N-(3-hydroxy-2-naphthoyl)]hydrazone (H2CHNH) ligand by using ball milling technique. The formed compounds were elucidated by spectral (IR, NMR, SEM, EDX, Mass), analytical and conformational techniques. Schiff base ligand exhibited variable binding modes towards the metal ions within 1:1 M ratio mostly. Tetrahedral configuration was proposed for all d10 coordination systems except UO2(II) complex which basically desired to octahedral geometry. Conductometric measurements estimated association (KA, ΔGA) and formation constants (Kf and ΔGf) for Cd(II)- H2CHNH complex in solution. DFT/B3LYP computation was applied to optimize structures of compounds and extract important physical characteristics. In-vitro assay was applied to investigate antimicrobial, antioxidant and antitumor activity of new synthesizes. Best antioxidant and antitumor activity was recorded with Zn(II) complexes. For clarification, in-silico assay was executed by drug-like procedure as well as MOE-docking approach. Pharmit link was used to search on the most fitted drug-like to Zn(II) complexes. After 1,602,203 hits in MolPort library, the drug numbered by MolPort-000–810-252 was the most fitted one. MOE-docking was utilized with respect to Zn(II) complexes towards liver cancer cell proteins (3 h80, 4ndn & 8adh). [Zn(HCHNH)2].2H2O complex reveals high docking score in true interaction poses. Limited allosteric binding was recorded from O11, N15 and O42 sites towards amino acid residues or dummies. Finally, two Zn(II) complexes may be promising in controlling free radicals or liver cancer cells.

Graphical abstract, Highlights • Synthesis of Aurintricarboxylic acid complexes from alkaline earth metal ions. • Characterizing the new complexes by analytical and spectral techniques. • Conformational study was executed by using Gaussian09 program. • Effective simulation against COVID-19 virus in comparing to drugs used now., The salt of Aurintricarboxylic acid (ATA) was utilized in this study to synthesize new alkaline earth metal ion complexes. The analytical results proposed the isolation of mononuclear (Sr+2&Ba+2) and binuclear complexes (Mg+2&Ca+2). These complexes were analyzed by available analytical and spectral techniques. The tetrahedral geometry was suggested for all complexes (SP3) through bidentate binding mode of ligand with each central atom. UV–Vis spectra reveal the influence of L → M charge transfer and the estimated optical band gap mostly appeared close to that for known semiconductors. XRD, SEM and TEM studies were executed for new complexes and reflects the nano-crystallinity and homogeneous morphology. The structural forms of ATA and its complexes were optimized by DFT/B3LYP under 6-31G and LANL2DZ basis sets. The output files (log, chk &fchk) were visualized on program screen and according to numbering scheme, many physical features were obtained. It is worthy to note that, a virtual simulation for the inhibition affinity towards COVID-19 proteins as proactive study before the actual application, was done for ATA and its complexes. This was done in addition to drugs currently applied in curing (Hydroxychloroquine & Lopinavir), for comparison and recommendation. Drug-likeness parameters were obtained to evaluate the optimal pharmacokinetics to ensure efficacy. Furthermore, simulated inhibition for COVID-19 cell-growth, was conducted by MOE-docking module. The negative allosteric binding mode represents good inhibitory behavior of ATA, Ba(II)-ATA complex and Lopinavir only. All interaction outcomes of Hydroxychloroquine drug reflect unsuitability of this drug in treating COVID-19. On the other hand, there is optimism for ATA and Lopinvir behaviors in controlling COVID-19 proliferation.

Francisella tularensis is a Gram-negative, facultative intracellular pathogen and the causative agent of a lethal human disease known as tularemia. Due to its extremely high virulence and potential to be used as a bioterror agent, F. tularensis is classified by the CDC as a Category A Select Agent. As an intracellular pathogen, F. tularensis during its intracellular residence encounters a number of oxidative and nitrosative stresses. The roles of the primary antioxidant enzymes SodB, SodC and KatG in oxidative stress resistance and virulence of F. tularensis live vaccine strain (LVS) have been characterized in previous studies. However, very fragmentary information is available regarding the role of peroxiredoxin of the AhpC/TSA family (annotated as AhpC) of F. tularensis SchuS4; whereas the role of AhpC of F. tularensis LVS in tularemia pathogenesis is not known. This study was undertaken to exhaustively investigate the role of AhpC in oxidative stress resistance of F. tularensis LVS and SchuS4. We report that AhpC of F. tularensis LVS confers resistance against a wide range of reactive oxygen and nitrogen species, and serves as a virulence factor. In highly virulent F. tularensis SchuS4 strain, AhpC serves as a key antioxidant enzyme and contributes to its robust oxidative and nitrosative stress resistance, and intramacrophage survival. We also demonstrate that there is functional redundancy among primary antioxidant enzymes AhpC, SodC, and KatG of F. tularensis SchuS4. Collectively, this study highlights the differences in antioxidant defense mechanisms of F. tularensis LVS and SchuS4.

In recent years, merocyanine photoacids have been utilized to control various chemical processes using visible light and have found applications in materials, energy, and biomedical areas. Molecular merocyanine photoacids are commonly used in the previous works. Covalently linking the photoacids to polymers improves their compatibility with different media, avoids leakage problems, and allows a localized proton concentration to be produced. However, the phenolic and indolinium moieties of the photoacids make them difficult to be polymerized with common methods. In this work, the monomer of a merocyanine photoacid is converted to a spiropyran in situ by adding trimethylamine to a dimethyl sulfoxide (DMSO) solution of the monomer. Free radical polymerization yields the polymers of the spiropyran, which is acidified to regenerate the photoacid. The photoacid polymers prepared show good solubility, photoacidity, and reversibility. Irradiating a thin film of a photoacid polymer doped with methyl orange through a mask copies the pattern of the mask to the film. The pattern can be erased by heating the film at 80 °C for 10 min, and a new pattern is created by irradiation through a different mask.