Azaneylylidene-based tetradentate Schiff base as a new "ON-OFF" fluorescent probe for the detection of Cu(II) ion: Synthesis, characterization and real sample analysis.

Herein we describe the synthesis of Cu2+ sensor, 2,2'-((1E,1'E)-((4-chloro-1,2-phenylene)bis(azaneylylidene))bis(methane-ylylidene))bis(4-bromophenol) (CPMB) and characterization using various spectral and analytical techniques. CPMB exhibited high selectivity towards Cu2+ ions via fluorescence quenching mechanism, which combined the character of high selectivity towards Cu2+ assay even in the presence of other common metal ions such as Cu2+, Al3+, Co2+, Ni2+, Mn2+, Zn2+ Pb2+ Cd2+, Fe2+, Hg2+, Mg2+ and Fe3+ (30 µM) ethanol-water (1:9 v/v) system. Upon the addition of the solution of Cu2+ ions to CPMB, the complexation of Cu2+ with CPMB leads to the immediate formation of light green color, indicating that CPMB can act as simple colorimetric sensor, particularly for Cu2+ in the presence of most interfering metal ions in ethanol-water medium. More interestingly, the ability of sensing behavior of CPMB for Cu2+ ion in the real water samples (tap water and lake water samples) was also investigated. Further, Job's plot confirmed that the complexation occurred in 1:1 ratio (ligand:metal). Furthermore, the fluorescence inhibiting factor showed a good linear relationship with the concentration of Cu2+ with detection limit of 0.302 µM. The electronic transitions of the complex in ethanol were studied using DFT calculations.

Novel Benzimidazole Derived Imine Ligand and Its Co(III) and Cu(II) Complexes as Anticancer Agents: Chemical Synthesis, DFT Studies, In Vitro and In Vivo Biological Investigations.

The emerging interest in the field of coordination chemistry and their biological applications has created a novel impact in the field of chemical biology. With this motivation, in this work we have synthesized a novel benzimidazole derived imine ligand, 2-((E)-((1H-benzo[d]-2-yl)methylimino)methyl)-4-fluorophenol (HBMF) and its Co(III) and Cu(II) complexes. The metal complexes (C1-C4) were synthesized in 2:1 (HBMF: metal ion) and 1:1:1 (HBMF: metal ion: 1,10-phen) ratios. Structural elucidations of all the synthesized compounds were performed using FT-IR, UV-Visible, NMR, Mass spectroscopy and elemental analysis techniques. A combination of first principles calculations and molecular dynamics simulations was applied to computationally investigate the structural, reactive, and spectroscopic properties of the newly synthesized HBMF ligand and its complexes with copper and cobalt metal ions. Quantum-mechanical calculations in this study were based on the density functional theory (DFT), while molecular dynamics (MD) simulations were based on the OPLS4 force field. The DFT calculations were used to obtain the reactive and spectroscopic properties of the ligand and its complexes, while molecular dynamics (MD) simulations were used to address the ligand's reactivity with water. Further, the in vitro anti-proliferative activity of the compounds was tested against the A549, Ehrlich-Lettre ascites carcinoma (EAC), SIHA and NIH3T3 cell lines. The biological results depicted that the compound C4, with molecular formula C27H23Cl2CoFN5O3 exhibited profound anti-proliferative activity against the EAC cell line with a significant IC50 value of 10 µm when compared to its parent ligand and other remaining metal complexes under study. Various assays of hematological parameters (alkaline phosphate, creatinine, urea, RBC and WBC) were performed, and significant results were obtained from the experiments. Furthermore, the effect of C4 on neovascularization was evaluated by stimulating the angiogenesis with rVEGF165, which was compared with non-tumor models. The EAC cells were cultured in vivo and administrated with 50 and 75 mg/kg of two doses and tumor parameters were evaluated.

Click synthesis of 1,2,3-triazole based imidazoles: Antitubercular evaluation, molecular docking and HSA binding studies.

Using Cu(I)-catalyzed cycloaddition of alkyne and azide reaction (CuAAC), a series of novel 1,2,3-triazole based imidazole derivatives (3a-e) have been synthesized. The synthesized molecules were characterized by spectroscopic techniques such as 1H NMR, 13C NMR, mass and elemental analysis. Antitubercular activity (anti-TB) against Mycobacterium tuberculosis H37Rv (Mtb) and cytotoxic activity against the mammalian Vero cell line was screened for the synthesized compounds. The compounds 3d and 3e displayed potent in vitro antitubercular activity and may serve as a lead for further optimization. Besides, the experimental findings were in line with the results of molecular docking. Also, the synthesized compounds have also been analyzed for ADME properties and the experimental finding facilitates the development of new and more potent anti-TB agents in this series in the future. Using fluorescence and UV-vis absorption spectroscopy, the binding interaction of compounds (3d and 3e) with human serum albumin (HSA) was investigated. The results showed that, as a result of HSA-compound complex, the fluorescence quenching of HSA by test compounds was a static quenching process. According to Forster's theory, energy transfer efficiency is calculated.

Synthesis and Characterization of Oxidovanadium(IV) Complexes of 2-((E)-(6-Fluorobenzo[d]thiazol-2-ylimino)methyl)-6-methoxyphenol and Their Antimicrobial, Antioxidant, and DNA-Binding Studies.

Two novel oxidovanadium(IV) complexes with a new bidentate (O- and N-) imine-based ligand 2-((E)-(6-fluorobenzo[d]thiazol-2-ylimino)methyl)-6-methoxyphenol (HL) were synthesized under in situ experimental condition where VOSO4 acts as a kinetic template in the ratio 2 : 1 (L : M) and mixed ligand complex using 1,10-phenanthroline (phen) in 1 : 1 : 1 (L : M : phen) ratio. The synthesized compounds were structurally characterized by microanalysis, magnetic susceptibility, FTIR, electronic spectra, TG/DTA, ESR, and molar conductance studies. Based on the spectral studies, the complexes have the general composition [VO(L)2] (C 1 ) and [VO(L)phen] (C 2 ) in a square pyramid geometrical fashion. The synthesized compounds were primarily screened for their in vitro growth inhibiting activity against different strains of bacteria, namely, E. coli, B. subtilis, S. aureus, and P. aeruginosa by the disc diffusion method. Also, the antifungal activity was determined against C. albicans and A. niger by the Bateman poisoned technique. The in vitro antioxidant activity of all the compounds was determined by DPPH free radical-scavenging assay. Intercalative mode of DNA-binding properties of the oxidovanadium(IV) complexes with calf-thymus DNA (CT-DNA) was investigated using UV, fluorescence spectra, and viscosity measurements.

1-(6-Chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)-3-(2-chloro-phen-yl)urea.

In the title compound, C14H11Cl2N5O, the plane of the 1H-imidazo[4,5-c]pyridine ring system [r.m.s. deviation = 0.087 (19) Å] makes a dihedral angle of 4.87 (10)° with the terminal phenyl ring. An intra-molecular N-H⋯N hydrogen bond stabilizes the mol-ecular conformation. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into inversion dimers. These dimers are connected by π-π inter-actions between imidazole rings [shortest centroid-centroid distance = 3.4443 (14) Å].

Synthesis, Characterization, and BSA Binding Studies of Some New Benzamides Related to Schiff Base.

Condensation of amine 1 with aldehyde 2 gives Schiff base, N-(4-((benzofuran-2-ylmethylene) amino)phenyl)acetamide 3. Schiff base on N-acylation with different substituted acid chlorides in the presence of triethylamine gives the corresponding benzamides, N-acetyl-N-(4-((benzofuran-2-ylmethylene)amino)phenyl)substitutedbenzamide (NABP) 5a-j. The structures of newly synthesized compounds were characterized by elemental analysis, (1)H NMR, (13)C NMR FT-IR, and mass spectral studies. Compounds 3 and 5a-j have been screened for their antimicrobial activity using the disc diffusion and minimum inhibitory concentration (MIC) method against the selected bacterial and fungal strain. Compounds 5a, 5e, 5g, and 5h were found to be more active against all tested strains. The antioxidant properties were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging methods. Compounds 5i and 5j showed predominant antioxidant activities among the synthesized analogues. The interaction between NABP and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopic techniques at 298 K under imitated physiological conditions. The results revealed that NABP caused the fluorescence quenching of BSA through a static quenching procedure. The binding constants and the number of binding sites were calculated. The binding distance between the donor (BSA) and acceptor (NABP) was determined based on Forster's theory.

Synthesis, anticonvulsant, antioxidant and binding interaction of novel N-substituted methylquinazoline-2,4(1H,3H)-dione derivatives to bovine serum albumin: a structure-activity relationship study.

A novel class of N-substituted glycosmicine derivatives was synthesized, and their anticonvulsant, antioxidant activity and interaction with bovine serum albumin (BSA) were evaluated. The synthesized compounds 4a-j were examined for anticonvulsant activity by maximal electroshock induced seizures (MESs) test and their neurotoxic effects were determined by rotorod test in mice. The structure-activity relationships (SARs) of these compounds were also investigated. Compounds 4d, 4g, 4i and 4j were found to have good protective effect from seizure. The in vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assay. The interaction between novel N-substituted methylquinazoline-2,4(1H,3H)-dione (NMQ) and BSA was analyzed by fluorescence and ultraviolet spectroscopy at 304K under simulative physiological conditions. BSA fluorescence quenched by NMQ is discussed according to the Stern-Volmer equation. The binding constant and binding sites of NMQ with BSA were calculated. According to Forster non-radiation energy transfer theory, the binding distance (r) between NMQ and BSA was calculated.

Spectrophotometric Determination of Mycophenolate Mofetil as Its Charge-Transfer Complexes with Two π-Acceptors.

Two simple, selective, and rapid spectrophotometric methods are described for the determination of mycophenolate mofetil (MPM) in pure form and in tablets. Both methods are based on charge-transfer complexation reaction of MPM with p-chloranilic acid (p-CA) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dioxane-acetonitrile medium resulting in coloured product measurable at 520 nm (p-CA) or 580 nm (DDQ). Beer's law is obeyed over the concentration ranges of 40-400 and 12-120 µg mL(-1) MPM for p-CA and DDQ, respectively, with correlation coefficients (r) of 0.9995 and 0.9947. The apparent molar absorptivity values are calculated to be 1.06 × 10(3) and 3.87 × 10(3) L mol(-1) cm(-1), respectively, and the corresponding Sandell's sensitivities are 0.4106 and 0.1119 µg cm(-1). The limits of detection (LOD) and quantification (LOQ) are also reported for both methods. The described methods were successfully applied to the determination of MPM in tablets. Statistical comparison of the results with those of the reference method showed excellent agreement. No interference was observed from the common excipients present in tablets. Both methods were validated statistically for accuracy and precision. The accuracy and reliability of the methods were further ascertained by recovery studies via standard addition procedure.

N-[3-(4-Fluoro-benz-yl)-2,4-dioxo-1,3-diaza-spiro-[4.5]dec-8-yl]-2-methyl-benzene-sulfonamide.

In the title compound, C(22)H(24)FN(3)O(4)S, the cyclo-hexane ring adopts a chair conformation and the five-membered ring is essentially planar, with a maximum deviation of 0.040 (2) Å. The dihedral angles between the five-membered ring and the tolyl and fluoro-benzene rings are 56.74 (12) and 89.88 (12)°, respectively. The two terminal benzene rings make a dihedral angle of 63.53 (12)°. The crystal structure displays inter-molecular C-H⋯O and N-H⋯O hydrogen bonds. An intra-molecular C-H⋯O hydrogen bond also occurs.

N-{3-[2-(4-Fluoro-phen-oxy)eth-yl]-2,4-dioxo-1,3-diaza-spiro-[4.5]decan-7-yl}-4-meth-oxy-benzene-sulfonamide.

In the title compound, C(23)H(26)FN(3)O(6)S, the two terminal aromatic rings form a dihedral angle of 49.26 (12)°. The cyclo-hexane ring adopts a chair conformation and the five-membered ring is essentially planar, with a maximum deviation from planarity of 0.0456 (19) Å. The dihedral angles between the five-membered ring and the meth-oxy-benzene and fluoro-benzene rings are 33.56 (11) and 81.94 (12)°, respectively. The crystal structure displays N-H⋯O hydrogen bonds as well as weak inter-molecular C-H⋯O inter-actions.

N-{3-[2-(4-Fluoro-phen-oxy)eth-yl]-2,4-dioxo-1,3-diaza-spiro-[4.5]decan-7-yl}-4-methyl-benzamide.

In the title compound, C(24)H(26)FN(3)O(4), the two aromatic rings form a dihedral angle of 88.81 (15)°. The cyclo-hexane ring adopts a chair conformation and the five-membered ring is essentially planar, with a maximum deviation from planarity of 0.041 (2) Å. The crystal structure displays inter-molecular C-H⋯O and N-H⋯O hydrogen bonds.

Bis[N,N-dimethyl-1-(10H-pyrido[3,2-b][1,4]benzothia-zin-10-yl)propan-2-aminium] tetrakis-(thio-cyanato-κN)cobaltate(II).

The asymmetric unit of the title salt, (C(16)H(20)N(3)S)(2)[Co(NCS)(4)], comprises one monovalent isothio-pendylium cation and one-half of a divalent thio-cyanatocobaltate(II) anion (2 symmetry). The central thia-zine ring of the cation is slightly twisted in a boat-like fashion, with r.m.s. deviations from the mean plane of 0.272 (1) and 0.2852 (8) Šfor the N and S atoms. The mol-ecular structure of the cation is stabilized by an intra-molecular N-H⋯N hydrogen bond. Within the complex anion, the Co(II) atom is tetra-hedrally surrounded by four N atoms of the thio-cyanate ligands. π-π stacking, with a distance of 3.7615 (10) Šbetween the centroids of benzene and pyridine rings, helps to consolidate the packing.

2-{[(E)-2-Hy-droxy-benzyl-idene]amino}-1H-isoindole-1,3(2H)-dione.

In the title compound, C(15)H(10)N(2)O(3), the isoindoline ring system is almost planar [maximum deviation = 0.020 (2) Å] and makes a dihedral angle of 1.57 (7)° with the benzene ring. Intra-molecular O-H⋯N and C-H⋯O hydrogen bonds are observed.

Micellanized spectrophotometric method for the determination of beryllium using haematoxylin.

A simple and sensitized spectrophotometric method for the determination of trace amounts of beryllium has been described. The method is based on the formation of a ternary complex by the reaction of beryllium with haematoxylin in the presence of micellar medium (cationic surfactant, cetyltrimethylammonium bromide). The ternary complex of beryllium has a maximum absorbance at 592 nm and showed an excellent sensitivity (molar absorption coefficient of 7.07 x 10(4)L mol(-1)cm(-1) and the Sandell's sensitivity being 1.27 x 10(-4) microg cm(-2)) and reproducibility (within-day precision: R.S.D.

Rapid and sensitive spectrophotometric determination of trace amounts of iron(III) using leuco Xylene cyanol FF.

A new, simple, sensitive, and reliable method is presented for the rapid spectrophotometric determination of trace amounts of iron(III) using leuco Xylene cyanol FF. The method is based on the oxidation of leuco Xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by iron(III) in sulfuric acid medium (pH 2.0-3.0), the absorbance of the formed dye is measured in an acetate buffer medium (pH()2.8-4.4) at 615 nm. The method obeys Beer's law over a concentration range of 0.15-0.9 microg mL(-1) iron, having a molar absorptivity of 5.6 x 10(4) L mol(-1) cm(-1) and a Sandell's sensitivity of 0.0001 microg cm(-2). The optimum reaction conditions and other analytical parameters have been evaluated. The developed method has been successfully applied to the determination of iron in water, soil, industrial effluent, plant material, pharmaceutical preparations, synthetic mixtures, and aluminum alloys.

A highly sensitive spectrophotometric determination of chromium using leuco Xylene cyanol FF.

A highly sensitive and selective spectrophotometric method was developed for the determination of trace amounts of chromium with leuco Xylene cynaol FF. The method is based on the oxidation of leuco Xylene cyanol FF (LXCFF) to its blue form of Xylene cyanol FF by chromium(VI) in sulphuric acid medium (pH 1.2-2.4), the absorbance of the formed dye is measured in an acetate buffer medium (pH 3.0-4.6) at 615 nm. The method obeys Beer's law in the concentration range of 0.05-0.45 mug ml(-l) chromium, having molar absorptivity and Sandell's sensitivity of 8.23x10(4) l mol(-1) cm(-l) and 0.00063 mug cm(-2), respectively. All the variables were studied in order to optimise the reaction conditions. The developed method has been successfully applied to the determination of chromium in steels, pharmaceutical samples, industrial effluents, natural water, and soil.

Spectrophotometric determination of selenium by use of thionin.

A simple, rapid, and sensitive spectrophotometric method has been developed for the determination of selenium in real samples of water, soil, plant materials, human hair, and synthetic cosmetic and in pharmaceutical preparations. The method is based on the reaction of selenium with potassium iodide in an acidic medium to liberate iodine. The liberated iodine bleaches the violet color of thionin, and which is measured at 600 nm. This decrease in absorbance is directly proportional to selenium concentration and obeys Beer's law in the range 1-5 micro g selenium in a final volume of 10 mL (0.1-0.5 microg mL(-1)). The molar absorptivity and Sandell's sensitivity of the method were found to be 7.33 x 10(4) L mol(-1) cm(-1) and 0.0011 microg cm(-2), respectively. The optimum reaction conditions and other analytical conditions were evaluated. The effect of interfering ions on the determination is described.

Spectrophotometric determination of some chemotherapeutic agents using acetyl acetone.

Acetyl acetone is introduced as a new coupling agent for the spectrophotometric determination of some chemotherapeutic agents, such as metoclopramide, dapsone, p-aminobenzoic acid, and cisapride in both pure and dosage forms. The method is based on the diazo-coupling reaction of these chemotherapeutic agents with a new coupling agent, acetyl acetone, in an alkaline medium. The optimum reaction conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with these chemotherapeutic agents has been studied. The method is simple, rapid, and sensitive. The results obtained compare favorably with those obtained with other reference methods.

Spectrophotometric methods for the determination of ritodrine hydrochloride and its application to pharmaceutical preparations.

Two simple and sensitive spectrophotometric methods are described for the determination of ritodrine hydrochloride (RTH) in both pure and dosage forms. The methods are based on the interaction of diazotised p-nitroaniline (DPNA) and sulphanilic acid (DSNA) with RTH in an alkaline medium. The resulting azo dyes are measured at 480 nm (for the DPNA method) and at 440 nm (for the DSNA method) and are stable for more than 1 h. The optimum reaction conditions and other analytical parameters are evaluated. A study of the effect of commonly associated excipients and additives do not interfere with the determinations. Statistical analysis of results indicates that the methods are precise and accurate.

A spectrophotometric method for the determination of metoclopramide HCl and dapsone.

A rapid, sensitive and selective spectrophotometric method has been developed for the quantitative determination of metoclopramide hydrochloride (MCP) and dapsone (DAP) in both pure and dosage forms. The method is based on the diazo coupling reaction of the drugs with a new coupling agent, dibenzoyl methane in an alkaline medium. The resulting coloured azo dyes exhibit maximum absorption at 440 nm for MCP and at 470 nm for DAP with a molar absorptivity of 2.85x10(4) and 1.71x10(4) l mol(-1) cm(-1) for MCP and DAP, respectively. All variables have been optimized. No interferences were observed from excipients and the validity of the method was tested against reference method.