Saleh N. Al-Busafi

Study on the spectral and inclusion properties of a sensitive dye, 3-naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline, in solvents and β-cyclodextrin

3-Naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline (NPFP), a fluorogenic probe and its derivative NPFP-Phenylephrine were synthesized and their absorption and fluorescence properties were recorded in solvents of varying polarity. Spectroscopic studies reveal that, the solvatochromic behavior of the compounds depend not only on the polarity but also on the hydrogen-bonding properties of the solvents. The effects of β-cyclodextrin on the fluorescence properties of both compounds were studied. It was found that there is an enhancement in the fluorescence intensity of labeled drug (NPFP-Phenylephrine) in the presence of β-cyclodextrin. In the present study, the molecular motions of NPFP-Phenylephrine embedded in a β-cyclodextrin cavity have been investigated by fluorescence techniques in steady-state and time resolved modes.

Synthesis, characterization and DFT calculation of 4-fluorophenyl substituted tris(8-hydroxyquinoline)aluminum(III) complexes.

New 4-fluorophenyl substituted 8-hydroxyquinoline derivatives, 5-(4-fluorophenyl)quinolin-8-ol and 5,7-bis(4-fluorophenyl)quinolin-8-ol, were synthesized and characterized by spectroscopic methods. The aluminum complexes of 5-(4-fluorophenyl)quinolin-8-ol (AlQF) and of 5,7-bis(4-fluorophenyl)quinolin-8-ol (AlQF2) exhibit strong fluorescence emission centered at 525 nm and 530 nm respectively. The quantum yield of both complexes were enhanced compared to the parent tris(8-hydroxyquinolinato)aluminum(III) complex. Electronic structures and photophysical properties of the new complexes were investigated theoretically by ab initio and density functional theory (DFT) and time dependent DFT (TD-DFT). Geometries of the ground state (S0) and the first excited state (S1) of the new complexes were optimized at the B3LYP/6-31G(d) functional and configuration interaction singles (CIS) method respectively. The aryl substituents were found to contribute significantly to the frontier molecular orbitals (FMOs). We have observed that in both cases the lowest occupied molecular orbital (LUMO) energy decreases while the energy of the highest occupied molecular orbital is slightly increased. The most significant increase was observed for AlQF2.

Tuning the constrained photophysics of a pyrazoline dye 3-naphthyl-1-phenyl-5-(4-carboxyphenyl)-2-pyrazoline inside the cyclodextrin nanocavities: A detailed insight via experimental and theoretical approach

The modulation in the photophysics of a pyrazoline dye 3-naphthyl-1-phenyl-5-(4-carboxyphenyl)-2-pyrazoline (NPCP), when it drifts from bulk water into the nanocages of aqueous cyclodextrin solutions was investigated. The intramolecular charge transfer (ICT) fluorescence band intensity was found to increase with a blue shift in the presence of cyclodextrins. The results from 1H NMR and 1HH COSY NMR spectral analysis clearly points out the position of pyrazoline ring inside the cavity and its role in complexation process. A quantitative assessment of the emission intensity data on Benesi-Hildebrand (B-H) equation along with ESI-MS spectra reveals the probable stoichiometry of NPCP-CD complexes. Molecular docking and molecular dynamics studies were conducted for β/γ cyclodextrin associated inclusion complexes of NPCP. The results obtained by computational studies are in good relation with the data obtained through experimental methods and both ascertain the encapsulation of NPCP into cyclodextrins.

Pomegranate seed oil: Effect on 3-nitropropionic acid-induced neurotoxicity in PC12 cells and elucidation of unsaturated fatty acids composition

Background: Seed oils are used as cosmetics or topical treatment for wounds, allergy, dandruff, and other purposes. Natural antioxidants from plants were recently reported to delay the onset or progress of various neurodegenerative conditions. Over one thousand cultivars of Punica granatum (Punicaceae) are known and some are traditionally used to treat various ailments. Aim: The effect of pomegranate oil on 3-nitropropionic acid- (3-NP) induced cytotoxicity in rat pheochromocytoma (PC12) neuronal cells was analyzed in this study. Furthermore, the analysis of unsaturated fatty acid composition of the seed oil of pomegranate by gas chromatography-electron impact mass spectrometry (GC-MS) was done. Results: GC-MS study showed the presence of 6,9-octadecadiynoic acid (C18:2(6,9)) as a major component (60%) as 4,4-dimethyloxazoline derivative. The total extractable oil with light petroleum ether by Soxhlet from the dry seed of P. granatum was 4–6%. The oil analyzed for 48.90 ± 1.50 mg gallic acid equivalents/g of oil, and demonstrated radical-scavenging-linked antioxidant activities in various in vitro assays like the DPPH (2,2-diphenyl-l-picrylhydrazyl, % IP = 35.2 ± 0.9%), ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), % IP 2.2 ± 0.1%), and β-carotene bleaching assay (% IP = 26 ± 3%), respectively, which could be due the possible role of one methylene interrupted diynoic acid system for its radical-scavenging/antioxidant properties of oil. The oil also reduced lipid peroxidation, suppressed reactive oxygen species, extracellular nitric oxide, lactate/pyruvate ratio, and lactase dehydrogenase generated by 3-NP- (100 mM) induced neurotoxicity in PC12 cells, and enhanced the levels of enzymatic and non-enzymatic antioxidants at 40 μg of gallic acid equivalents. Conclusion: The protective effect of pomegranate seed oil might be due to the ability of an oil to neutralize ROS or enhance the expression of antioxidant gene and the exact mechanism of action yet to be elucidated.

Short Synthesis of COX-2 Inhibitor Inotilone

An efficient three-step synthesis of COX-2 inhibitor inotilone from acetaldoxime is described. The structure of inotilone was elucidated via an aldol reaction between 5-methyl-3(2H)-furanone and 3,4-dihydroxybenzaldehyde. This approach describes a convenient pathway to 5-alkyl-3-furanones through isoxazole chemistry.

3-Naphthyl-1-phenyl-5-(4-carboxyphenyl)-2-pyrazoline – a pyrazoline based heterocyclic dye as a fluorescent label for biomolecules containing an amino group and its evaluation using HPLC

The use of 3-naphthyl-1-phenyl-5-(4-carboxyphenyl)-2-pyrazoline as a pre-column derivatization agent for the HPLC analysis of biomolecules containing an –NH2 group is proposed in this article. The derivatization conditions to obtain quantitative reaction were optimized by considering different parameters (time, temperature, pH and reagent concentration) using seven amino acids as model analytes. The resulting derivatives were well separated on a reversed-phase column with an isocratic elution profile and detected fluorimetrically at excitation and emission wavelengths of 370 and 480 nm, respectively. The proposed method was validated for accuracy, precision, sample stability, linearity, and detection and quantification limits and were all found to be satisfactory. Through this study, we are forecasting the emergence of pyrazoline based heterocyclic dyes as organic fluorescent markers for the labelling of diagnostically important compounds, for their determination and quantification of practical interest.

3(2H)-Furanone as a promising scaffold for the synthesis of novel fluorescent organic dyes: an experimental and theoretical investigation

3(2H)-Furanones are a type of five-membered heterocyclic compounds of synthetic and biological importance. For exploring the utilities of this “sweet” aroma component for bio-analytical purposes we have prepared and characterized two novel fluorophores (2Z)-2-(5-fluoro-2-ntro benzylidene)-5-phenyl-3(2H)-furanone (FNPF) and (2Z)-2-(4-carboxy benzylidene)-5-phenyl-3-(2H)-furanone (CBPF) on a 3-furanone skeleton. In order to expand their application potential, the photophysical properties have been investigated using absorption and emission spectroscopy, in combination with quantum chemical calculations. As expected, both compounds showed efficient solvatochromic properties and the excited state dipole moments are larger than those of the ground state. Solvent dependent spectral data using TD-DFT calculations on the optimized ground and excited state structures of both compounds were found to correlate well with the experimental findings.

Unveiling a versatile heterocycle: pyrazoline – a review

The design and synthesis of novel fluorescent heterocyclic dyes is a “hotspot” research area, due to their favourable photophysical properties and crucial role in charge transfer processes, which could allow huge advances in the fields of physics, chemistry and biology. One group of electron-rich nitrogen carriers, pyrazolines, are enjoying brisk growth, since they combine exciting electronic properties with the potential for dynamic applications. Concerning multi-functional applications, pyrazolines could provide a new range of applications that would revolutionize various fields. As reported in many studies, the potential applications of pyrazolines are vast and ever growing, but they have yet to make in-roads into real-life applications. This review provides an overview on the current status of pyrazoline derivatives in terms of synthesis, physico-chemical properties and various applications in order to realize their full potential for practical applications, and to trigger the synthesis and study of novel pyrazoline based compounds with much promise. We also present our conclusions and outlook for the future.

Spectrofluorimetric determination of Zn2+ ions in aqueous medium using 5-(4-flourophenyl)-quinolin-8-ol

Abstract A spectrofluorimetric method based on complex formation between Zn2+ ions and 5-(4-flourophenyl)-quinolin-8-ol has been developed for the rapid determination of trace levels of zinc ions. The method is sensitive and selective. The complex formed emit strongly at 535 nm with excitation wavelength at 394 nm. Complexation formation was optimized by studying the effect of pH, molar ratio of the metal to the ligand and the type of buffers. The study indicated that maximum complexation resulted when the pH of the mixture was maintained at 8.0 with 0.2 M carbonate buffer and metal to ligand was at a stoichiometric ratio of 1:2. Under the optimum conditions, the detection limit was 3 ppb. Appropriate validation of the method, yielded acceptable relative standard deviations of less than 2% (n = 5). The method was applied to the trace determination of Zn2+ ions in tap water, mineral water, fresh milk and cream samples successfully.

Competitive removal of heavy metals from spiked hospital wastewater on acidic and chelating dehydrated carbons

ABSTRACT Date palm leaflets were carbonised using sulphuric acid dehydration, producing acidic dehydrated carbon (DC) that was converted to chelating dehydrated carbon (CDC) using ethylene diamine functionalisation. Both carbons were surface characterised and tested for competitive removal of Cd2+, Cu2+, Co2+, Ni2+ and Zn2+ from metal mixtures in hospital wastewater (HWW) and deionised water (DW). Sorption kinetics data follow pseudo-second-order model. Equilibrium sorption data follow the Langmuir model with better performance for CDC than DC. Sorption of metals from metal mixture from DW is clearly higher than from HWW because of the high content of organic moieties in HWW.