Badr Elsayed | Alazhar University, Faculty of Science, Chemistry Department - Cairo, Egypt (original) (raw)

Chemistry by Badr Elsayed

Papers by Badr Elsayed

Research paper thumbnail of Study of phytotoxicity, remarkable photocatalytic activity, recycling process and energy consumption cost of TiO2 quantum dots photocatalyst for photodegradation of Coomassie brilliant blue R dye

Research paper thumbnail of Remarkable Recycling Process of ZnO Quantum Dots for Photodegradation of Reactive Yellow Dye and Solar Photocatalytic Treatment Process of Industrial Wastewater

Nanomaterials

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and t... more The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. An improved sol-gel process at a low calcination temperature that ranged between 350 and 450 °C was employed to synthesize ZnO quantum dots (ZQDs). The purity, high crystallinity, and structure of the prepared catalysts were determined by TEM and XRD analysis. The energy bandgap, the crystal size values, and the surface area for Z1 and Z2 were determined based on the TEMs, DRSs, and EBTs, which were equal to 6.9 nm, 3.49 eV, and 160.95 m2/g for Z1 and 8.3 nm, 3.44 eV, and 122.15 m2/g for Z2. The investigation of the prepared samples was carried out by studying the photocatalytic activity and photoluminescence, and it was found that the degradation rate of reactive yellow dye as an industrial p...

Research paper thumbnail of Photocatalytic degradation of rhodamine B in the visible region using nanostructured CoAl2-xLaxO4 (x =0, 0.01, 0.03, 0.07, and 0.09) series: photocatalytic activity and DFT calculations

Inorganic Chemistry Communications, 2021

Research paper thumbnail of The electrochemical sensing of nalbuphine hydrochloride drug substance in vitro by the cyclic voltammetric and conductometric titration techniques

Al-Azhar Bulletin of Science

The electrochemical sensing of Nalbuphine hydrochloride drug substance in vitro by the cyclic vol... more The electrochemical sensing of Nalbuphine hydrochloride drug substance in vitro by the cyclic voltammetry technique using the activated glassy carbon electrode. The solvation of CdCl2 alone or in the presence of Nalbuphine HCl was studied by CV technique in 0.05 M KCl supporting electrolyte and different concentrations from CdCl2 at 305.15K. The cyclic voltammograms were preceded at different scan rates 0.1, 0.05, 0.02 and 0.01 V Sec-1. Also, different Nalbuphine HCl concentrations were utilized for studying their effect as electrochemical sensors on the solvation and kinetics parameters of CdCl2. The redox mechanism of the system was determined from the resulted data. Moreover, the Gibbs free energies of the complex formation were evaluated. The formation constants and Gibbs free energies were calculated from the conductometric titration curves. The molar ratios of the complexes were obtained indicating the formation of 1:2 and 1:1 (M:L). The formation constants of different complexes in water: methanol solvent followed the order: Kf (1:2) > Kf (1:1) for (M:L). The (∆H) and (∆S) of formation and association of complexes were also estimated and discussed. The solvation ∆G o , ∆Hs and ∆Ss were calculated from solubility measurements for nalbuphine HCl at different temperatures.

Research paper thumbnail of Synthesis, Characterization, Antimicrobial and Cytotoxic Studies on Some Novel Transition Metal Complexes of Schiff Base Ligand Derived From Sulfadiazine with Molecular Orbital Calculations

Some selected solid complexes of the Schiff base ligand HL derived from Sulfadiazine with Co(II),... more Some selected solid complexes of the Schiff base ligand HL derived from Sulfadiazine with Co(II), Ni(II) and Cu(II) ions were synthesized and characterized by Micro-analysis, FTIR, Electronic, Mass, and ESR Spectral Analyses, Magnetic susceptibility and Molar Conductance Measurements. The disappearance of ν(O-H) hydroxyl band of the phenolic and the lowering shift of the stretching frequency of the ν(CH=N) azomethine band in the ligand after complexation, indicated the coordination through the phenolic oxygen atom (after deprotonation) and azomethine nitrogen atom respectively of the Schiff base ligand HL. The lower values of molar conductance indicate the non-electrolytic nature of these complexes. The ESR spectrum of the HL copper complex has octahedral geometry. The molecular structures of the investigated compounds were studied by PM3 method, also the heat of formations, HOMO, LUMO and dipole moments were calculated to confirm the geometry of the ligand and the it’s complexes. T...

Research paper thumbnail of Temperature dependence of the electrical conductivity of urea and thiourea

Research paper thumbnail of Photophysical, DFT and molecular docking studies of Sm(III) and Eu(III) complexes of newly synthesized coumarin ligand

Inorganic Chemistry Communications

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Highly sensitive spectrofluorimetric analysis and Molecular Docking using benzocoumarin hydrazide derivative doped in sol-gel matrix as optical sensor

Sensors and Actuators B: Chemical, 2016

Research paper thumbnail of Synthesis , spectroscopic characterization and thermal behavior on novel binuclear Transition metal complexes of hydrazones

Research paper thumbnail of Journal of Atoms and Molecules SYNTHESIS STRUCTURAL CHARACTERIZATION, ANTIMICROBIAL AND CYTOTOXIC STUDIES ON SOME NOVEL TRANSITION COMPLEXES WITH NO BIDENTATE SCHIFF'S BASE LIGAND DERIVED FROM SULFAGUANIDINE WITH MOLECULAR ORBITAL CALCULATIONS

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Synthesis, Characterization and Photoluminescence Study of Novel Sulfobetaine Polyelectrolytes

Journal of Fluorescence, 2011

A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melami... more A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melamine, condenses with a diketone, 5,5-dimethyl-1,3-cyclohexane (dimedone) to produce polyimine chain based on Schiff base chemistry. Dimedone-[N,N’ melaminium] propane sulfonate copolymer crystals were obtained on treatment of the polyimine with sulfopropylating agent, 1,3-propane sultone with a crosslinker, di(ethylene glycol diacrylate) (DEGDA). This crosslinked sulfobetaine polymer yielded fine needle like

Research paper thumbnail of Electrical transport as a function of temperature in hexacyanoferrate complexes

Journal of Materials Science-materials in Electronics, 2003

The electrical conductivity as a function of temperature and the current–voltage dependences of p... more The electrical conductivity as a function of temperature and the current–voltage dependences of potassium and nickel hexacyanoferro and ferri complexes, have been determined. Charge transfer via the electron delocalization along overlapping dz2 orbitals of the iron to p* orbitals of the ligands (–C=N) as well as the ionic conduction via Fe2+, Fe3+, K+, and Ni2+ cations are considered as the

Research paper thumbnail of Photophysics and dynamics of rigidized coumarin laser dyes

Journal of Photochemistry and Photobiology A: Chemistry, 1989

This paper describes some photophysical properties, the results of CNDO molecular orbital (MO) ca... more This paper describes some photophysical properties, the results of CNDO molecular orbital (MO) calculations and excited state complex formation for two solvatochromic coumarin laser dyes of the rigidized multichromophoric electron donor-acceptor type (coumarins 314 and 337). Light absorption results in the population of an almost fully fluorescent polar charge transfer singlet state characterized by non-alternate electron density distributions and a remarkable sensitivity to solvent properties. Useful nonlinear, linear and multiparameter relationships between the quantum yield of fluorescence, the emission and absorption maxima and the Stokes shift and some solvent parameters are established. Hydrogen-bonding solvents such as ethanol cause quenching and a bathochromic shift of fluorescence due to ground state complexation. Excited state equilibrium studies reveal the formation of weak (with equilibrium constant of 2 -19 1 mol-') hydrogenbonding complexes with a stoichiometry of 2: 1 (dye:ethanol). The fluorescence polarization behaviour in glycerol at various temperatures shows that the molecular rotational diffusion is controlled by the free volume of the medium. The results point to a possible use of these highly fluorescent dyes as bifunctional fluorescent probes for determining the rigidity and polarity of the surrounding medium of interest. lOlO-6030/89/$3.50 @ Elsevier Sequoia/Printed in*The Netherlands 260 interest to predict and control the properties of fluorescent dyes. In recent years many investigations have focused on the role of the solvent in controlling the intramolecular charge transfer (ICT) process for electron donoracceptor (EDA) dye molecules in solution [4, 6, 7, 15,21 -311, as well as in the gas phase using supersonic jet expansion techniques [32]. Certain dye families of the EDA type are good fluorescers (e.g. the oxazines, rhodamines and coumarins) [4, 331 and they have been used as laser dyes and solar energy concentrators.

Research paper thumbnail of The temperature dependent electrical transport in biphenyl derivatives

Current Applied Physics, 2006

The d.c. electrical conductivity measurements as a function of temperature of 4,4-dibromobiphenyl... more The d.c. electrical conductivity measurements as a function of temperature of 4,4-dibromobiphenyl (DBrBP), 4,4-dichlorobiphenyl (DClBP) and 4,4-dimethoxybiphenyl (DMOBP) compounds have been carried out. The effects of conformational change within skeleton of these compounds upon optical or thermal excitation (S 1 S 0 ) and of para substituents on the electrical conductivity have been discussed. The conduction processes were interpreted in the light of their molecular spectroscopic data of the infrared, ultraviolet and emission spectra as a hopping processes. The semiconducting properties of the investigated compounds were arising from electron-delocalization via intramolecular interaction of p-electrons of (C@C) bonds and electron-donating groups in para positions. The conductivity was found to increase in the higher temperature range than in lower due to the planar structure which increases the possibility of electron-delocalization and the interaction of p-electron system.

Research paper thumbnail of Photophysics and dynamics of coumarin laser dyes and their analytical implications

Journal of Chemical …, 1992

Research paper thumbnail of Structural and optical studies on ortho-hydroxy acetophenone azine thin films

Journal of materials science, 2002

BA EL-SAYED ∗ Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Eg... more BA EL-SAYED ∗ Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt E-mail: badr elsayed@hotmail.com ... EA EL-SAYAD Physics Departments, National Research Center, Dokki, Cairo, Egypt ... The bulk material and deposited thin films of ...

Research paper thumbnail of Study of phytotoxicity, remarkable photocatalytic activity, recycling process and energy consumption cost of TiO2 quantum dots photocatalyst for photodegradation of Coomassie brilliant blue R dye

Research paper thumbnail of Remarkable Recycling Process of ZnO Quantum Dots for Photodegradation of Reactive Yellow Dye and Solar Photocatalytic Treatment Process of Industrial Wastewater

Nanomaterials

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and t... more The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. An improved sol-gel process at a low calcination temperature that ranged between 350 and 450 °C was employed to synthesize ZnO quantum dots (ZQDs). The purity, high crystallinity, and structure of the prepared catalysts were determined by TEM and XRD analysis. The energy bandgap, the crystal size values, and the surface area for Z1 and Z2 were determined based on the TEMs, DRSs, and EBTs, which were equal to 6.9 nm, 3.49 eV, and 160.95 m2/g for Z1 and 8.3 nm, 3.44 eV, and 122.15 m2/g for Z2. The investigation of the prepared samples was carried out by studying the photocatalytic activity and photoluminescence, and it was found that the degradation rate of reactive yellow dye as an industrial p...

Research paper thumbnail of Photocatalytic degradation of rhodamine B in the visible region using nanostructured CoAl2-xLaxO4 (x =0, 0.01, 0.03, 0.07, and 0.09) series: photocatalytic activity and DFT calculations

Inorganic Chemistry Communications, 2021

Research paper thumbnail of The electrochemical sensing of nalbuphine hydrochloride drug substance in vitro by the cyclic voltammetric and conductometric titration techniques

Al-Azhar Bulletin of Science

The electrochemical sensing of Nalbuphine hydrochloride drug substance in vitro by the cyclic vol... more The electrochemical sensing of Nalbuphine hydrochloride drug substance in vitro by the cyclic voltammetry technique using the activated glassy carbon electrode. The solvation of CdCl2 alone or in the presence of Nalbuphine HCl was studied by CV technique in 0.05 M KCl supporting electrolyte and different concentrations from CdCl2 at 305.15K. The cyclic voltammograms were preceded at different scan rates 0.1, 0.05, 0.02 and 0.01 V Sec-1. Also, different Nalbuphine HCl concentrations were utilized for studying their effect as electrochemical sensors on the solvation and kinetics parameters of CdCl2. The redox mechanism of the system was determined from the resulted data. Moreover, the Gibbs free energies of the complex formation were evaluated. The formation constants and Gibbs free energies were calculated from the conductometric titration curves. The molar ratios of the complexes were obtained indicating the formation of 1:2 and 1:1 (M:L). The formation constants of different complexes in water: methanol solvent followed the order: Kf (1:2) > Kf (1:1) for (M:L). The (∆H) and (∆S) of formation and association of complexes were also estimated and discussed. The solvation ∆G o , ∆Hs and ∆Ss were calculated from solubility measurements for nalbuphine HCl at different temperatures.

Research paper thumbnail of Synthesis, Characterization, Antimicrobial and Cytotoxic Studies on Some Novel Transition Metal Complexes of Schiff Base Ligand Derived From Sulfadiazine with Molecular Orbital Calculations

Some selected solid complexes of the Schiff base ligand HL derived from Sulfadiazine with Co(II),... more Some selected solid complexes of the Schiff base ligand HL derived from Sulfadiazine with Co(II), Ni(II) and Cu(II) ions were synthesized and characterized by Micro-analysis, FTIR, Electronic, Mass, and ESR Spectral Analyses, Magnetic susceptibility and Molar Conductance Measurements. The disappearance of ν(O-H) hydroxyl band of the phenolic and the lowering shift of the stretching frequency of the ν(CH=N) azomethine band in the ligand after complexation, indicated the coordination through the phenolic oxygen atom (after deprotonation) and azomethine nitrogen atom respectively of the Schiff base ligand HL. The lower values of molar conductance indicate the non-electrolytic nature of these complexes. The ESR spectrum of the HL copper complex has octahedral geometry. The molecular structures of the investigated compounds were studied by PM3 method, also the heat of formations, HOMO, LUMO and dipole moments were calculated to confirm the geometry of the ligand and the it’s complexes. T...

Research paper thumbnail of Temperature dependence of the electrical conductivity of urea and thiourea

Research paper thumbnail of Photophysical, DFT and molecular docking studies of Sm(III) and Eu(III) complexes of newly synthesized coumarin ligand

Inorganic Chemistry Communications

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Highly sensitive spectrofluorimetric analysis and Molecular Docking using benzocoumarin hydrazide derivative doped in sol-gel matrix as optical sensor

Sensors and Actuators B: Chemical, 2016

Research paper thumbnail of Synthesis , spectroscopic characterization and thermal behavior on novel binuclear Transition metal complexes of hydrazones

Research paper thumbnail of Journal of Atoms and Molecules SYNTHESIS STRUCTURAL CHARACTERIZATION, ANTIMICROBIAL AND CYTOTOXIC STUDIES ON SOME NOVEL TRANSITION COMPLEXES WITH NO BIDENTATE SCHIFF'S BASE LIGAND DERIVED FROM SULFAGUANIDINE WITH MOLECULAR ORBITAL CALCULATIONS

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Photodecontamination of Vat Green 1 and Dianix Blue dyes by MWCNTs/x%TiO2 nanocomposites synthesized using evaporation method

Al-Azhar Bulletin of Science

Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) metho... more Multi-walled carbon nanotubes (MWCNTs) were prepared using chemical vapour deposition (CVD) method. MWCNTs/titanium dioxide nanocomposites (MWCNTs/x%TiO 2) with different weight ratios of TiO 2 (x = 3, 6 and 10%) were synthesized using a simple modified evaporation method and used as a photocatalysts. Their photocatalytic activity investigated by studying the decontamination of two local textile dyes (Vat Green 1 and Dianix Blue Dyes) as an industrial organic pollutants commonly used in dyeing factories. The structure of the synthesized photocatalysts were characterized using XRD, SEM, diffused reflectance UV-Vis spectroscopic and N 2 adsorption-desorption method. Also, their optical band gaps were estimated, by Kubelka-Munk equation, as 3.51, 2.89, 2.80, 2.69 eV for MWCNTs and MWCNTs/x%TiO 2 respectively. The mineralization of Vat Green 1 and Dianix Blue dyes in presence of MWCNTs and MWCNTs/x%TiO 2 nanocomposites were investigated by determining the decrease in chemical oxygen demand (COD). In addition, the suggested possible mechanism of the photodegradation processes was studied.

Research paper thumbnail of Synthesis, Characterization and Photoluminescence Study of Novel Sulfobetaine Polyelectrolytes

Journal of Fluorescence, 2011

A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melami... more A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melamine, condenses with a diketone, 5,5-dimethyl-1,3-cyclohexane (dimedone) to produce polyimine chain based on Schiff base chemistry. Dimedone-[N,N’ melaminium] propane sulfonate copolymer crystals were obtained on treatment of the polyimine with sulfopropylating agent, 1,3-propane sultone with a crosslinker, di(ethylene glycol diacrylate) (DEGDA). This crosslinked sulfobetaine polymer yielded fine needle like

Research paper thumbnail of Electrical transport as a function of temperature in hexacyanoferrate complexes

Journal of Materials Science-materials in Electronics, 2003

The electrical conductivity as a function of temperature and the current–voltage dependences of p... more The electrical conductivity as a function of temperature and the current–voltage dependences of potassium and nickel hexacyanoferro and ferri complexes, have been determined. Charge transfer via the electron delocalization along overlapping dz2 orbitals of the iron to p* orbitals of the ligands (–C=N) as well as the ionic conduction via Fe2+, Fe3+, K+, and Ni2+ cations are considered as the

Research paper thumbnail of Photophysics and dynamics of rigidized coumarin laser dyes

Journal of Photochemistry and Photobiology A: Chemistry, 1989

This paper describes some photophysical properties, the results of CNDO molecular orbital (MO) ca... more This paper describes some photophysical properties, the results of CNDO molecular orbital (MO) calculations and excited state complex formation for two solvatochromic coumarin laser dyes of the rigidized multichromophoric electron donor-acceptor type (coumarins 314 and 337). Light absorption results in the population of an almost fully fluorescent polar charge transfer singlet state characterized by non-alternate electron density distributions and a remarkable sensitivity to solvent properties. Useful nonlinear, linear and multiparameter relationships between the quantum yield of fluorescence, the emission and absorption maxima and the Stokes shift and some solvent parameters are established. Hydrogen-bonding solvents such as ethanol cause quenching and a bathochromic shift of fluorescence due to ground state complexation. Excited state equilibrium studies reveal the formation of weak (with equilibrium constant of 2 -19 1 mol-') hydrogenbonding complexes with a stoichiometry of 2: 1 (dye:ethanol). The fluorescence polarization behaviour in glycerol at various temperatures shows that the molecular rotational diffusion is controlled by the free volume of the medium. The results point to a possible use of these highly fluorescent dyes as bifunctional fluorescent probes for determining the rigidity and polarity of the surrounding medium of interest. lOlO-6030/89/$3.50 @ Elsevier Sequoia/Printed in*The Netherlands 260 interest to predict and control the properties of fluorescent dyes. In recent years many investigations have focused on the role of the solvent in controlling the intramolecular charge transfer (ICT) process for electron donoracceptor (EDA) dye molecules in solution [4, 6, 7, 15,21 -311, as well as in the gas phase using supersonic jet expansion techniques [32]. Certain dye families of the EDA type are good fluorescers (e.g. the oxazines, rhodamines and coumarins) [4, 331 and they have been used as laser dyes and solar energy concentrators.

Research paper thumbnail of The temperature dependent electrical transport in biphenyl derivatives

Current Applied Physics, 2006

The d.c. electrical conductivity measurements as a function of temperature of 4,4-dibromobiphenyl... more The d.c. electrical conductivity measurements as a function of temperature of 4,4-dibromobiphenyl (DBrBP), 4,4-dichlorobiphenyl (DClBP) and 4,4-dimethoxybiphenyl (DMOBP) compounds have been carried out. The effects of conformational change within skeleton of these compounds upon optical or thermal excitation (S 1 S 0 ) and of para substituents on the electrical conductivity have been discussed. The conduction processes were interpreted in the light of their molecular spectroscopic data of the infrared, ultraviolet and emission spectra as a hopping processes. The semiconducting properties of the investigated compounds were arising from electron-delocalization via intramolecular interaction of p-electrons of (C@C) bonds and electron-donating groups in para positions. The conductivity was found to increase in the higher temperature range than in lower due to the planar structure which increases the possibility of electron-delocalization and the interaction of p-electron system.

Research paper thumbnail of Photophysics and dynamics of coumarin laser dyes and their analytical implications

Journal of Chemical …, 1992

Research paper thumbnail of Structural and optical studies on ortho-hydroxy acetophenone azine thin films

Journal of materials science, 2002

BA EL-SAYED ∗ Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Eg... more BA EL-SAYED ∗ Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt E-mail: badr elsayed@hotmail.com ... EA EL-SAYAD Physics Departments, National Research Center, Dokki, Cairo, Egypt ... The bulk material and deposited thin films of ...