Hikmat Hilal
An-Najah National University, Chemistry, Faculty Member
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Tris (acetylacetonato) cobalt (III), (Co(acac)3), has been used to catalyze o-silylation reactions of R 3 Siff (R.z.Et,Et0) with R OH (Rt-Et, i-Pr, t-.Bu and C6Hj-). No reaction has been observed at room temperature, but the reaction is... more
Tris (acetylacetonato) cobalt (III), (Co(acac)3), has been used to catalyze o-silylation reactions of R 3 Siff (R.z.Et,Et0) with R OH (Rt-Et, i-Pr, t-.Bu and C6Hj-). No reaction has been observed at room temperature, but the reaction is apparently enhanced when carried out at a higher temperature. The rate of the reaction varies with varying the concentration of the saline or the alcohol. Using different types of alcohols and silanes greatly affects the rate of the reaction. The rate of the reaction is affected by varying the concentration of the complex (Co(acaci6)).
Research Interests: Chemistry, Analytical Chemistry, Catalysis, Cobalt, Silylation, and 4 moreTris, Reaction Rate, Homogeneous, and silanes
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Research Interests: Chemistry, Organic Chemistry, Magnetic Resonance Spectroscopy, Medicine, Antifungal, and 11 moreAnti-Bacterial Agents, Cytotoxic Activity, Fourier transform infrared spectroscopy, Gas Chromatography/mass Spectrometry, Antifungal Agents, Microbial Sensitivity Tests, Condensation, Benzothiazole, Aminopyridine, Heterocyclic compounds, and Pharmacology and pharmaceutical sciences
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Twelve various quinoxaline derivative dyes, so coded from Q1–1 to Q1–12, have been investigated as sensitizers in dye-sensitized solar cells (DSSCs). The simulation study has been performed using the density functional theory and time... more
Twelve various quinoxaline derivative dyes, so coded from Q1–1 to Q1–12, have been investigated as sensitizers in dye-sensitized solar cells (DSSCs). The simulation study has been performed using the density functional theory and time dependent (TD–DFT) methods. All derivatives have the same backbone structures, with two oxygens in fixed positions, and varying numbers and/or positions of hydroxyl groups. The TD–DFT calculations have been soundly useful to predict various dye excitation energies and absorption spectra. The influence of varying numbers and positions of oxygen atoms and hydroxyl groups on optical properties for the free dyes has been studied. With such variation, DSSC characteristics such as light-harvesting efficiency (LHE), electronic injection driving force (ΔGinj) and dye regeneration spontaneity (ΔGreg) have all been studied. Among the series, the Q1–7@ ZnTiO3 interface shows the highest (ΔGinj) (−2.829 eV) and LHE (0.677). The results indicate that hydroxyl group (OH) numbers and positions influence the DSSC microscopic properties, and consequently the macroscopic properties such as short circuit current density (JSC) and open circuit potential (VOC).
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Silica-supported iridium catalysts have been evaluated in the reactions of HSiR 3 (R = Et, OEt) and Me 3 SiO[Si(H)(Me)O] n SiMe 3 (PS1, n = 1; PS50, n 50) with awide variety of primary alcohols. Catalysts obtained by reaction of... more
Silica-supported iridium catalysts have been evaluated in the reactions of HSiR 3 (R = Et, OEt) and Me 3 SiO[Si(H)(Me)O] n SiMe 3 (PS1, n = 1; PS50, n 50) with awide variety of primary alcohols. Catalysts obtained by reaction of IrCl(CO)[Ph 2 P(CH 2 ) 2 Si(OEt) 3 ] 2 with ...
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Abstract Four polyene-diphenylaniline dyes (D5, D7, D9 and D11) are simulated here, for the first time, as sensitizers for nano-ZnTiO3-based dye-sensitized solar cells (DSSCs). First-principles calculations method has been used to... more
Abstract Four polyene-diphenylaniline dyes (D5, D7, D9 and D11) are simulated here, for the first time, as sensitizers for nano-ZnTiO3-based dye-sensitized solar cells (DSSCs). First-principles calculations method has been used to describe dye-semiconductor surface interactions. Bonding between the ZnTiO3 nanoparticle, considered as (ZnTiO3)8 cluster, is studied using density-functional theory (DFT) and time-dependent (TD-DFT). Dye parameters have been used in analyzing electron-transfer processes from dye excited molecules into semiconductor. Electronic structures and simulated UV–Vis spectra of four dyes (isolated and ZnTiO3-bound forms) are described together with energy level diagrams and electrochemical parameters. Results are compared with earlier experimental results and used to discuss parameters that affect DSSC performance. The excited D11 (with −2.0173 eV level) has highest electron injection rate toward the ZnTiO3 conduction band. D9 (with −0.5369 eV level) is regenerated, by I − / I 3 − redox couple, more efficiently than D5, D7 and D11 dyes, with minimal charge-recombination rates. Moreover, D9 displays highest peak absorption, in both free form (at 544 nm) and adsorbed form (at 563 nm). D5 and D9 exhibit high Light Harvesting Efficiency values 0.7752 and 0.8416, respectively, between dye LUMO and ZnTiO3 conduction-band, compared to D7 (0.4921) and D11 (0.5441). D9 exhibits highest open-circuit potential (VOC, 0.88 eV) while D5, D7 and D11 have 0.79, 0.47 and 0.29 eV, respectively. The D9@ZnTiO3 interface shows highest stability with largest adsorption energy (−47.16 eV, −4550.62 kJ/mol) among different systems. Results indicate that D9@ZnTiO3-based DSSCs should exhibit highest power conversion efficiency (PCE) among the series.
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Preparation and characterization of several supported metalloporphyrins are known, and have been evaluated as electrocatalysts for redoxreactions [l-6]. The support used was either the electrode itself or a polymer coating modification of... more
Preparation and characterization of several supported metalloporphyrins are known, and have been evaluated as electrocatalysts for redoxreactions [l-6]. The support used was either the electrode itself or a polymer coating modification of the electrode surface. Modified organic polymer surfaces have also been reported as supports for metalloporphyrins [7, 81. In our search for new supported catalysts for olefin oxidation reactions, we have employed halogenated poly(siloxane) surfaces [9a] Sil-(CH&X, as supports for the metalloporphyrin catalyst, [Mn”‘(TPyP)]. Quatemization reactions have been used to bind the [Mn’n(TPyP)] species to the surface [9b]. We now report our studies of the effect of support on the electronic absorption spectra of several supported metalloporphyrins [M(TPyP)].
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Light-emitting devices (LEDs) with higher performance, lower energy demand and minimal environmental impact are needed. With wide-band gaps and high emission efficiencies, III-V nitride semiconductors are useful for LEDs in... more
Light-emitting devices (LEDs) with higher performance, lower energy demand and minimal environmental impact are needed. With wide-band gaps and high emission efficiencies, III-V nitride semiconductors are useful for LEDs in short-wavelength regions. A multiple quantum well (MQW LED), based on InGaN/GaN, is proposed. The structure involves GaN(n)/InxGa1−xN(i)/GaN(i)/AlGaN(p)/GaN(p), where GaN(n) and GaN(p) have different dopants to formulate the junction at which electric field occurs, InxGa1−xN(i) is a 3 nm-thick intrinsic quantum well with (x) as indium mole fraction, GaN(i) is barrier intrinsic layer and AlGaN(p) is a 15 nm-thick electron blocking layer (EBL). Simulation is performed by Tcad-Silvaco. Various characteristics such as current versus voltage (I-V) plots, luminosity power, band diagram, spectrum response, radiative recombination rate and electric field effect, have been investigated. By controlling the InxGa1−xN(i) number of quantum wells and their indium mole fraction...
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Drinking-water contamination with nitrate ions is inevitable and wide spreading, which demands feasible removal. Water de-nitration by potentiostatic electroreduction is described here. A novel electrocatalyst based on nano-copper... more
Drinking-water contamination with nitrate ions is inevitable and wide spreading, which demands feasible removal. Water de-nitration by potentiostatic electroreduction is described here. A novel electrocatalyst based on nano-copper particles, supported onto multi-walled carbon nanotubes (MWCNTs), and spray-deposited onto fluorine doped tin oxide-glass substrates, is described. The Cu/MWCNT/FTO electrode has been characterized by several methods and assessed as a working electrode in aqueous nitrate ion electroreduction, in comparison with MWCNT sprayed on FTO (MWCNT/FTO) with no copper. Comparison with earlier reported electrodes is also described. XRD patterns confirm the presence of nano-copper crystallites, in the electrode, with average size ⁓45 nm. Within 2 h of electrolysis, Cu/MWVNT/FTO exhibits more than 65% removal of nitrate at -1.80 V (vs. SCE). In longer time (7 h) the electrode completely converts the nitrate into N2 (∼65%) and (NH4+) ∼35% with no NO2- ions. The kinetics show 0.76 order with respect to nitrate, and a rate constant 4.53 × 10-2 min-1 higher than earlier counterparts. The new electrode functions under various conditions of temperature, pH, electrolyte type and concentration and inter-electrode spacing, only at ambient applied potential. Moreover, the electrode exhibits stability under nitrate electroreduction conditions, and can be recovered and reused for multiple times without efficiency loss. XRD and EDS results also confirm the electrode stability after multiple reuse. Compared to earlier systems, the Cu/MWCNT/FTO is environmentally stable, safe, non-costly with high nitrate removal efficiency and selectivity.
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Research Interests: Pharmacology, Chemistry, Drug delivery, Micelle, Prodrug, and 4 moreRSC, Polyethylene Glycol, Diclofenac, and PEG Ratio
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Research Interests: Chemistry, Organic Chemistry, Magnetic Resonance Spectroscopy, Elemental analysis, Antifungal, and 10 moreAnti-Bacterial Agents, Fourier transform infrared spectroscopy, Gas Chromatography/mass Spectrometry, Antifungal Agents, Microbial Sensitivity Tests, Condensation, Benzothiazole, Aminopyridine, Heterocyclic compounds, and Pharmacology and pharmaceutical sciences
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Carbon nanodots with different optical properties and photoactivity degrees as photocatalysts for the degradation of methylene blue are successfully synthesized from olive solid wastes at different carbonization temperatures.