UV-vis Absorption Studies Research Articles

Probing the binding interaction of ortho-vanillin derived chalcone with lysozyme: A biophysical studies aided by in silico calculations

The principal intent of this study is to elucidate the binding interaction between the scaffold Chalcone (C1) and Lysozyme (LYZ) in detail employing biophysical studies aided by in silico calculations. UV–Vis absorption study, Fluorescence, and Time-resolved fluorescence spectroscopy studies indicated the formation of the ground-state complex between C1 and LYZ. Quenching of corrected fluorescence spectra of LYZ in the presence of C1 at varied concentrations has been estimated from Stern-Volmer (SV) plot and Double Logarithmic plot. The binding constant value indicates the moderate affinity of LYZ to the scaffold C1. Time-resolved fluorescence spectroscopy confirmed the static mechanism of quenching. Binding constant, the number of binding sites, and the thermodynamic parameters are also estimated. Conformational changes in the structure of LYZ have been analyzed using Circular Dichroism Spectroscopy. The distance (ro) between the acceptor (C1) and donor (LYZ) and critical energy transfer distance (Ro) has been calculated based on Forster non-radiative energy transfer theory. Molecular docking further revealed the existence of hydrogen bonding along with hydrophobic interactions as the primary forces for the formation of a stable complex between LYZ and C1.

A study on the interaction of nile blue with Uracils: A spectroscopic and computational approach.

The present work focuses the investigation on fluorescence quenching of nile blue (NB) in presence of various substituted uracil molecules. UV-Visible absorption studies signify the possibility of ground state complex formation between NB and uracil molecules. The increase in concentration of quencher molecules greatly influences the emission spectra of NB. The bimolecular quenching rate constant (kq) were calculated and found to depend on the position and electronic properties of substituent in quencher molecules. Fluorescence quenching experiments were performed at different temperature to calculate the thermodynamic parameters. The fluorescence lifetime measurements show that the quenching process proceeds through static quenching. The mechanism of fluorescence quenching includes the possibility of proton transfer. The bond dissociation enthalpy (BDE) reveals the release of H from the quencher molecules. The quencher molecules possess antioxidant activity and identified using deoxyribose degradation assay. The position of substituent and its electronic property are key features to address the antioxidant activity of uracil molecules.

Enhancement of photocatalytic activity of synthesized Cobalt doped Zinc Oxide nanoparticles under visible light irradiation

Abstract In the present work, pure Zinc Oxide (ZnO) and Cobalt (Co) doped ZnO nanoparticles with various dopant concentrations are synthesized by chemical precipitation method. All the synthesized samples are subjected to characterization by different instrumentation tools such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Ultra Violet–visible (UV–vis) absorption spectroscopy and Photoluminescence (PL) spectroscopy respectively. XRD results show the decrease in crystallite size of the synthesized samples with the increase of Co content. SEM image reveals that Co doping in ZnO results in change of the morphology of ZnO to nearly flower-like structures. The UV–vis absorption study shows that the energy band gap decreases as compared to pure ZnO with the increase of the content of Co dopant. PL spectra exhibit UV emission peak along with defect related visible emission. The intensity of visible emission reduces as the content of Co dopant increases. The photocatalytic activity of the synthesized samples is investigated for the degradation of Methylene Blue (MB) dye under visible light irradiation. The total organic carbon (TOC) analysis is done to evaluate the mineralization of the MB dye during photocatalytic process. Further, the effects of various parameters such as dopant concentration, catalyst dosage and initial concentration of the dye on the photocatalytic degradation process are extensively studied.

Growth and Characterisation of Copper Complex of 2, 4, 6-Trioxypyrimidine: A Novel Luminescent and Active Pharmaceutical Material in Metal Organic Framework

Emerald coloured crystal of copper complex of barbituric acid (CuB) (C8H10CuN4O9) is grown by conventional gel method. The crystal structure is orthorhombic with space group Fdd2 and has unit cell dimensions a = 11.6951(7) A, b = 30.1113(19) A, c = 7.1767(7) A and α = β = γ = 90°. Analysis of the crystal by Hall–Williomson plot revealed the strain free nature of the grown crystals. Identification of the functional groups by FTIR and the study of thermal behaviour of the crystal by TGA/DTA were done.The optical band gap is determined as 1.57 eV from UV–visible absorption studies. The photoluminescence study provides information about the structural quality and purity of the crystal. Antibacterial studies of the sample revealed its medicinal applications. The high hardness value of the crystal is identified by Vickers micro hardness test.

Electrochemical, Photophysical and Theoretical Studies of Novel Zinc Phthalocyanines.

In this research, we successfully synthesized three novel zinc phthalocyanines and applied for electrochemical and photo physical properties. These phthalocyanines are naphthoxy derivatives with methyl, benzyl and butyl-benzyl, with halo substitution (PCME, PCBN and PCBBN) and poses very good solubility in all industrial solvents. To check the preliminary results of LCD green color filter properties of these molecules, we taken the UV-Visible absorption and transmittance studies in Propylene glycol monomethyl ether acetate and achieved around 90% of transmittance in the region of 400-550 nm. Further understand the solubility of our phthalocyanines, we checked the aggregation property in PGMEA and we observed no any aggregation. All compounds showed very nice electro chemical properties with nice oxidation and reduction peaks. These phthalocyanines are fit for LCD color filter applications. Finally to get insights of the electronic and UV-Visible properties of the new dyes, the DFT calculations were performed.

Tetra-(benzo-24-crown-8)-phthalocyanines as a platform for supramolecular ensembles: Synthesis and interaction with viologen

The synthesis of a series of novel tetra-(benzo-24-crown-8)-phthalocyanines (Mg(II), Ni(II) and Co(II)) as well as a modified procedure for the free-base ligand and its Zn(II) and Cu(II) complexes are reported. The tendency of these phthalocyanines to undergo supramolecular cofacial dimerization induced by interaction with a viologen ([Formula: see text]-di(but-3-ynyl)-4,4[Formula: see text]-bipyridinium) was investigated by UV-vis absorption and EPR spectral studies in solution. The nature of the metal cation in phthalocyanine, the concentration, as well as the solvent all influenced the assembly processes.

Investigates interaction between abscisic acid and bovine serum albumin using various spectroscopic and in-silico techniques

The binding interaction and binding mechanism of abscisic acid with bovine serum albumin (BSA) in physiological solution (Phosphate buffer pH 7.4) have been studied using various spectroscopic methods in combination with in-silico techniques. The fluorescence data has shown abscisic acid has strongly quenched the intrinsic fluorescence of bovine serum albumin due to the formation of abscisic acid-BSA complex and binding was found to be static and spontaneous in nature. The UV-Visible absorption and 1H NMR studies have also indicated the interaction of abscisic acid with BSA. Finally, the molecular docking and molecular dynamics studies have also shown the stable interaction of abscisic acid with the amino acids of BSA. In conclusion, these findings could be beneficial and supports for the transportation, distribution of abscisic acid in human body.

Enhancing the SHG effect of zinc chloride-doped DAST single crystals: new potential materials for nonlinear optical device applications

The ionic organic salts of 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) single crystal hold the predominant place on potential organic nonlinear crystalline materials and electro-optic applications. In this present work, we have reported the synthesis and growth of ZnCl2-doped DAST single crystals with different concentrations. The crystal was grown by the slow evaporation technique at room temperature. Structural and lattice constants of the grown crystals were determined by the powder X-ray diffraction (PXRD), and furthermore, confirm along with single-crystal X-ray diffraction (SXRD). FTIR studies affirm the presence of different vibrational modes of assignments and the presence of elements in the grown crystals was identified by EDAX study. The linear optical properties confirmed by UV–Vis absorption studies, and the calculated bandgap energies for pure 2.19 eV and dopants have 3.46, 3.41 and 3.36 eV for suitable materials for insulating and semiconductor behaviors. The second harmonic generation (SHG) output received from the pure and doped DAST crystal with applied input laser energy is 1.1 mJ/pulse using Kurtz–Perry powder technique. The obtained SHG efficiency for 0.01 mol ratio dopants have slightly less than the pure is 0.96, and 0.03, 0.05 mol, has 1.20 and 1.80 times greater than that of DAST. Hence, the results reveal that the doped crystal is very useful for optoelectronic and terahertz applications.

Colossal Dielectric Responses from the Wide Band Gap 2D-Semiconducting Amine Templated Hybrid Framework Materials.

Two unprecedented organic amine templated silver organophosphonate hybrid solids have been synthesized hydrothermally by varying the molar ratio of the reactants. Both of the compounds consist of novel tetra- and penta-nuclear silver phosphonate basic building units. The dielectric constants are extremely large due to the charge separation of anionic metal phosphonate frameworks and cationic templated piperazine moieties in the compounds, as found for the first time in a hybrid organophosphate family. The conductivity and UV-visible absorption studies provide strong evidence about the semiconducting nature of the present compounds.

Effect of reaction temperature on the structural and electronic properties of stannic oxide nanostructures

Different nanostructured materials are having important roles in optoelectronics, gas sensing and photocatalytic applications due to their high surface to volume ratio. In this study, stannic oxide (SnO2) nanostructures are prepared by hydrothermal method under optimal conditions at different temperatures (160, 180 and 200°C) using surfactant cetyltrimethyl ammonium bromide. X-ray diffraction studies reveal rutile tetragonal structures of SnO2 nanostructures, showing that average crystallite size is less than 10 nm. Field emission scanning electron microscope imaging reveals the morphological analysis of SnO2 nanostructures fabricated at different reaction temperatures (160, 180 and 200°C). Energy dispersive X-ray spectroscopy confirmed the elemental analysis of SnO2 nanostructures. FTIR spectrum is recorded to confirm the presence of various functional and vibrational groups in the prepared SnO2 nanostructures. Optical properties of these nanostructures are analysed by UV–vis absorption studies. Bandgap of prepared SnO2 decreased with increasing reaction temperature. Two-probe setup along with Keithley source metre is used for analysis of electrical properties of SnO2 nanostructures.

Simple-chemical synthetic route for the preparation of Ag nanoparticles supported on reduced graphene oxide

A simple-chemical synthetic approach to the preparation of reduced graphene oxide (rGO) decorated with silver nanoparticles (AgNPs) is demonstrated, which are appealing as a promising composite to treat the various diseases. The one-step strategy was used to reduce synthetic graphene oxide (GO) and to prepare AgNPs. EDX element mapping analysis presented the Ag content in the prepared rGO-Ag composite. HRTEM revealed that mono-dispersed AgNPs anchored on the rGO. The functional groups present on the surface of the materials were identified by Fourier-transform infrared spectroscopy (FTIR). UV-Vis absorption study provided information about the electronic states of the materials. The results showed the highly transparent rGO sheets decorated with AgNPs.

Highly efficient separation of ruthenium from alkaline radioactive feeds using an anion exchange resin

Abstract Ruthenium recovery from the alkaline media was attempted using solid phase extraction. UV-Vis and X-ray absorption studies were performed to understand the ruthenium speciation under different conditions relevant to its extraction from alkaline medium. Since Ru forms anionic complex in the alkaline solution, an anion exchange resin (Dowex 1x8) was selected for its recovery from alkaline media. The precipitation of black RuO2 at the resin surface hinders its back exaction. Experimental conditions were optimized for the quantitative uptake of Ru from alkaline feed and its subsequent back extraction by a series of batch studies. About 90 % of the Ruthenium was back extracted from the resin using alkaline hypochlorite solution and nitric acid solution at different stages in the Ru back extraction cycle. The column studies were done under the optimized condition and showed ~80 % Ru recovery with 5 mL of the eluent (8 M HNO3) and ~90 % recovery in 10 mL including the tailing. The mechanism for the ruthenium extraction from alkaline medium and its back extraction from the resin was proposed.

Bulk electrolysis of Zn-phthalocyanine unveils self assembled nanospheres via anion binding

Stimuli responsive π-conjugated macrocyclic systems has shown significant attention in organic electronics, however, amongst them, porphyrins and phthalocyanines unveiled remarkable growth towards materials and biological applications. Herein, we report bulk electrolysis of Zn-phthalocyanine system (ZnPc-OMe) under potential difference of 1.5 V in chloroform results anion binding mechanism directs the formation of self-assembled nanospheres by diffusion controlled approach. Electrochemical and UV–Vis absorption studies of ZnPc-OMe suggest that anion (Cl−) binding ability towards ‘Zn‘ whilst applied potential leads to the formation of H+[(Cl)ZnPc-OMe]- promote the enhanced current and charge generation. Microscopic analysis revealed that ZnPc-OMe and H+[(Cl)ZnPc-OMe]- exhibit the nanosheets and spheres with an average diameter of 0.5–1 μm and 300–500 nm, respectively. Powder X-ray diffraction analysis and raman spectra revealed the changes in crystalline phase transitions via ion-dipole and π-π stacking interactions. Thus, these unique features are atypical for phthalocyanine derivative hitherto unknown.

Unstable cell efficiency in CdS quantum dot sensitized solar cell using low cost lugols iodine aqueous electrolyte

We have designed and synthesis rutile TiO2 rod like nanoflower on the FTO glass by one step hydrothermal method operating at 150 °C for 15 h. The lower concentration of CdS Quantum dots was deposited on the surface of TiO2 through chemical bath deposition (CBD) method. The samples were characterized x-ray diffraction pattern (XRD), Scanning electron microscopy (SEM) and UV–Vis absorption studies. In this work lugols iodine was used as an aqueous electrolyte between FTO/TiO2/CdS photoanode and Cu2S as counter electrode respectively. The result of photo conversion efficiency (PCE) is decreased from 0.13 to 0.033%, this may be the reason photo degradation and corrosion were happened in CdS.

Effects of Ru doping and of oxygen vacancies on the optical properties in α-Fe2O3 powders

Fe2−xRuxO3 (0 ≤ x≤ 0.08) powders were prepared by solid-state method. X-ray diffraction patterns revealed that the Fe2O3 powders crystallize in a hexagonal structure typical of α-Fe2O3 phase (hematite). The crystallite size was found to decrease from 141 to 84 nm with increasing Ru content from 0 to 0.08, respectively. UV–visible absorption study was performed at room temperature. The direct energy band gap of un-doped α-Fe2O3 was 2.22 eV and found to increase with increasing Ru concentration to reach 2.45 eV for x = 0.08. This increase in band gap was attributed to the decrease in oxygen vacancies with increasing Ru as indicated by calculations of the oxygen occupancy rate using Rietveld refinement. Other properties such as the absorption coefficient, refractive index, the extinction coefficient, real and imaginary dielectric constant, real and imaginary electrical conductivity were calculated using spectrophotometric measurements.

Donor-Pi-Acceptor Fluorene Conjugates, Based on Chalcone and Pyrimidine Derivatives: an Insight into Structure-Property Relationship, Photophysical and Electrochemical Properties.

A small set of four new fluorenyl chromophores (5-5a-c) was accomplished by stepwise nucleophilic substitution, Friedel-Crafts acylation, Ullman coupling, aldol condensation and cyclization reactions. The fluorene moiety was substituted at 2,7,9 and 9' positions with diverse groups. The synthesized derivatives were characterized by FTIR, 1H-NMR and 13C-NMR spectroscopic techniques. The optical properties were evaluated by by UV-VIS absorption and Fluorescence studies. HOMO and LUMO energy levels were evaluated by electrochemical studies and were found at -5.37-5.83eV and - 2.47-2.94eV respectively with band gap energy values 2.88 to 2.91eV. The band gap energy values suggested that these synthesized molecules can be manipulated in the designing of blue and green OLEDS. Graphical Abstract.

Syntheses, crystal structures, optical, Raman spectroscopy, and magnetic properties of two polymorphs of NaMnPO4

The monophasic natrophilite form of NaMnPO4 was synthesized using a simple and scalable one-step hydrothermal method. The heat treatment of the natrophilite NaMnPO4 in the air resulted in the formation of the high-temperature maricite polymorph of NaMnPO4. The crystal structures of these two polymorphs were confirmed by the Rietveld refinements and Raman spectroscopy. The DSC study of the natrophilite form shows a broad exothermic peak indicative of a second-order phase transition to high-temperature maricite form. The band gaps (Eg) of 5.18(2) and 1.88(2) eV were estimated for natrophilite and maricite forms, respectively, by the UV–vis absorption studies. Magnetic studies on polycrystalline natrophilite NaMnPO4 show a complex temperature dependence of magnetic susceptibility, which could be attributed to a canted antiferromagnetic behavior with the Néel’s temperature (TN) of 31 K and an anomaly temperature (T*) of 29 K. Maricite NaMnPO4 also show antiferromagnetic interaction of Mn2+ spins with TN of 18 K.

Thermal and nonlinear optical properties of semiorganic single crystal: L-Threonine p-nitrophenolate (LTPNP)

The single crystal of L-Threonine 4-nitrophenolate developed by uncomplicated solution growth process. The grown crystal is analysed by using various characterization techniques. The structural analyses have been carried out by using Powder XRD method. Fourier Transform Infrared and Nuclear Magnetic Resonance spectra analysis confirms the functional groups exist in grown crystal. The thermal steadiness of L-Threonine 4-nitrophenolate crystals analysed by Thermo-gravimetric (TG) and Differential Thermal analyses (DTA). The sharp diffraction peaks in XRD pattern confirms the well crystalline nature of the synthesized sample. TG and DTA analysis prove that the synthesized sample possess good thermal constancy up to150°C. The UV-visible absorption studies show that the crystal is clearly visible in the whole visible region of the spectrum. Kurtz -Perry powder technique and Z-scan technique reveals the excellence of the synthesized samples for non linear optical (NLO) uses.

Optical studies of acefylline piperazine, chlorpheniramine maleate, thiamine hydrochloride in aqueous, aqueous methanol and aqueous ethylene glycol systems

Refractive index, FTIR and Uv–vis absorption study of acefylline piperazine, chlorpheniramine maleate, thiamine hydrochloride was done to investigate the solute-solvent interactions. The interaction of drugs (AP, CPM, TAD) studied in aqueous, aqueous methanol and aqueous ethylene glycol systems at 303 K. Specific refraction, Molar refraction and polarizability of drugs in aqueous and aqueous alcoholic systems was calculated by using Lorentz-Lorentz equation. FTIR study of drugs in aqueous and aqueous alcoholic systems was undertaken to analyze the compatibility of drugs in studied systems. The UV–vis absorption study has also been done to interpret the interaction patterns occurring in drugs and solvent systems.

Synthesis, characterisation, and DNA interaction studies of novel Cu(II), Ni(II), and Co(II) mono and bisligand complexes of N-(1,10-phenanthrolin-5-yl)acridine-9-carboxamide

A novel acridine-linked phenanthroline ligand, N-(1,10-phenanthrolin-5-yl)acridine-9-carboxamide, (PAC) was synthesized by N,N’-dicyclohexylcarbodiimide (DCC) coupling between acridine-9-carboxylic acid and 1,10-phenanthroline-5-amine. A set of new complexes of general formulae [M(PAC)(N3)2] and [M(PAC)2(N3)2] where M = Cu(II), Ni(II), and Co(II) metal ions were synthesized and characterised by spectroscopic, electrochemical, and thermogravimetric methods. Interactions of complexes with Calf Thymus DNA were investigated using UV–visible absorption studies, fluorescent intercalator displacement assays, viscosity measurements, and cyclic voltammetric studies in phosphate buffer at pH 7.2. All the synthesized complexes were found to be potential DNA-binding agents, with significant quenching of fluorescence with the addition of DNA. Hypochromic shifts of the absorption bands with well-defined isosbestic points were observed for all complexes in the presence of the nucleic acid and the binding constants (Kb) calculated revealed high binding affinities of the complexes. Viscosity and cyclic voltammetric measurements supported appreciable intercalative interactions between the complexes and DNA.