Effect of anthracene doping on potassium hydrogen phthalate crystals

The influence of the highly fluorescent dopant, anthracene (over a concentration range from 5 × 10^?4 to 1.2 × 10^?2 mol dm^?3) on the nonlinear optical properties and fluorescence intensity of potassium hydrogen phthalate (KHP) single crystals grown at 30 °C by a slow evaporation solution growth technique (SEST) has been investigated. Powder XRD and FTIR spectral analyses confirm the slight distortion of the structure of crystal because of doping. UV–Visible study shows that the transparency is not affected much by the dopant. The SEM investigation reveals that KHP suffers from crack development. Thermal analysis indicates that there is no decomposition of the crystal up to the melting point. It is interesting to observe that additions of small quantity anthracene to KHP results in the enhancement of fluorescence intensity. The fluorescence intensity dependence on dopant concentration is observed. Interestingly, second harmonic generation (SHG) efficiency of KHP is dramatically improved by doping with small quantities of anthracene.     

Effect of zinc(II) doping on thermal and optical properties of potassium hydrogen phthalate (KHP) crystals

The influence of doping the transition metal Zn(II) on potassium hydrogen phthalate (KHP) crystals has been studied. A close observation of FT-IR and XRD profiles of doped and undoped samples reveals some minor structural variations. It appears that the crystal undergoes considerable lattice stress as a result of doping the bivalent zinc. Furthermore, the possibility of cation vacancies aroused owing to the substitution of K¹⁺ by Zn²⁺ could result in a defective crystal system. Energy dispersive spectra reveal the incorporation of Zn(II) in the crystalline matrix of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed below the melting point. Small quantity additions of Zn(II) enhance the fluorescence intensity of KHP crystals. The doping results in morphological changes and significantly improves the second harmonic generation (SHG) efficiency of the host crystal.     

Effect of chelating agent (1,10-phenanthroline) on potassium hydrogen phthalate crystals

The influence of a new organic additive, chelating agent 1,10-phenanthroline (Phen) (∼5.0·10⁻³ M L⁻¹) on potassium hydrogen phthalate (KHP) single crystals at 30° is investigated. The crystals were grown from the aqueous solutions of pH ∼4.5 at constant temperature by solvent evaporation technique. The chelating agent leads to an increase in metastable zone width and assists the bulk growth process. The growth rate of crystals in the presence of Phen decreases considerably with an increase in impurity concentration. Not much variation is observed in FTIR and cell parameter values, determined by XRD analysis. It appears that the growth promoting effect (GPE) of Phen is caused by the adsorption of the organic additive on the prism of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed up to the melting point. Scanning electron microscope (SEM) photographs exhibit the effectiveness of the impurity in changing the surface morphology of KHP crystals. Contrary to expectations, Phen depresses the NLO efficiency of KHP, suggesting that the molecular alignments in the presence of Phen results in cancellation effects disturbing the non-linearity.     

Os(VIII) doping effects on the properties and crystalline perfection of potassium hydrogen phthalate (KHP) crystals

The effect of dopant, Os(VIII) on the growth process, crystalline perfection and properties of potassium hydrogen phthalate (KHP) single crystals grown by a slow evaporation solution growth technique has been investigated. The XRD analysis of black-colored doped specimen reveals slight structural changes as a result of doping. The SEM images exhibit defect centers and crystal voids. The complex formation of KHP with Os(VIII) is evidenced by the considerable shift in λ_max of the doped specimen and enhanced fluorescence intensity is observed by doping. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed up to the melting point. The high resolution X-ray diffraction (HRXRD) studies used to evaluate the crystalline perfection reveal some features on the capability of accommodating the dopant in the crystalline matrix. The diffraction curve (DC) patterns indicate that the high valence transition metal predominantly occupies the interstitial positions and the doping depresses the second harmonic generation (SHG) efficiency owing to the deterioration of crystalline perfection disturbing the charge transfer and nonlinearity.     

Preparation and characterization of a bis thiourea sodium iodide (BTSI)

A semi-organic nonlinear optical single crystal of bis thiourea sodium iodide (BTSI) has been successfully grown from aqueous solution using the slow evaporation solvent technique (SEST) at room temperature. Obtained crystals using the SEST method were characterized by using different characterization techniques. Structural studies of the grown crystals have been carried out by single-crystal XRD to confirm the crystal system and functional groups by FT-IR spectroscopy. Single-crystal XRD reveals orthorhombic structure of semi-organic BTSI single crystals and its unit cell parameters. Metal complex coordination of the single crystal is studied by FT-IR spectroscopy. The optical absorption study revealed excellent optical transparency of BTSI crystal in the entire visible region with a sharp lower cutoff wavelength 298 nm. The energy band gap of BTSI is found to be 4.16 eV. Thermal stability and thermal decomposition of BTSI single crystals were investigated by TGA–DTA and DSC analysis. The surface appearance of BTSI crystals by scanning electron microscopy reveals the formation of layer growth pattern. The structural perfection and growth features of the grown crystal were analyzed by wet chemical etching studies. The above studies reveal the effect of incorporation of sodium iodide into the lattice of thiourea crystals. The as-grown BTSI single crystals can be used as a potential candidate for NLO material as well as in electronic and optoelectronic devices.     

Thermal, FTIR and Raman spectral analysis of Cu(II)-doped lead iodate crystals

The 0.04 M copper-doped lead iodate crystals grown in silica gel were characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and thermo analytical techniques (TG, DTA, DTG and DSC). Raman and FTIR spectrum clearly indicate that the functional groups of undoped lead iodate were not altered by the addition of the dopant. Thermal analysis suggests that the thermal stability of lead iodate crystals decreases due to copper doping.     

Employment of [Amim] Cl in the effort to upgrade the properties of cellulose acetate based polymer electrolytes

Transparent thin film polymer electrolytes were prepared by solvent casting technique with the doping of environmental-friendly ionic liquid, 1-allyl-3-methylimidazolium chloride ([Amim] Cl) into the matrix formed by cellulose acetate (CA) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The ionic conducting nature of this system improves significantly from the order of 10^?7–10^?2 S cm^?1 upon increasing doping of [Amim] Cl content till a maximum of 4.68 × 10^?2 S cm^?1 is attained for the composition CA:LiTFSI:[Amim] Cl (14:6:80 wt%). The improving trend in ionic conductivity results from the bond weakening between the connecting atoms in the crystalline region that induces to the increase in amorphous counterpart fractions in the CA matrix. This observation was proved via the accountancies in the reduction of relative viscosity, root mean square value and increase in void as increase in [Amim] Cl doping. The resultant phase conversion hence permits immense lithium ion (Li⁺) fluidity along the polymer backbone and assisting the improvement in ionic conductivity. The thin film polymer electrolyte is found to be elastic in the presence of crystalline fraction and radically deforms upon the chains diffusion into the amorphous fraction. The linear curvatures of the Arrhenius plot justify the conductivity improvement as via the increasing frequency of Li⁺ ions hopping as the temperature increases. The increasing addition of [Amim] Cl diminishes both the heat-resistivity and thermal stability of CA:LiTFSI:[Amim] Cl matrix.     

Electrical conductivity of potassium titanyl phosphate KTiOPO<Subscript>4</Subscript> pure crystals and those doped with Na<Superscript>+</Superscript>, Rb<Superscript>+</Superscript>, and F<Superscript>–</Superscript> ions

KTiOPO₄ crystals, both pure and doped with rubidium Rb⁺ and fluorine F^– ions, were grown in temperature range from 1060 to 846°С from salt solvent containing potassium metaphosphate КРО₃ and potassium orthophosphate К3РО₄ by using a Czochralski modified method. Potassium–sodium titanyl phosphate crystals were obtained from KTiOPO₄ crystals by the potassium isomorphic replacement with sodium; to this purpose, sodium chemical diffusion from NaNO₃ melt was used. Their ionic conductivity was studied by the electrochemical impedance spectroscopy method. The KTiOPO₄ crystal doping with rubidium and sodium ions was shown to lower the conductivity, whereas the doping with fluorine ions results in increased conductivity.     

Microstructure, distribution and properties of conductive polypyrrole/cellulose fiber composites

Highly intrinsic conductive polypyrrole/cellulose fiber composites (CF) were successfully prepared through in situ chemical oxidation polymerization simply by increasing fiber concentration at the same dosage of pyrrole, oxidant and dopant (based on the weight of dry fiber). FeCl₃ and anthraquinone-2-sulfonic acid sodium salt (AQSNa) were utilized as oxidant and dopant. As fiber concentration increased from 1 % (CF1) to 20 % (CF20), N and S content increased from 0.24 and 0.25 % to 1.24 and 0.89 %, and great increase in the retention of PPy and AQSNa was confirmed by elemental analysis. In addition, on the surface of conductive fiber, PPy of compact fibroid structure was detected instead of interconnected globular structure at higher fiber concentration. Furthermore, scanning transmission electron microscope and X-ray photoelectron spectroscopy (XPS)-depth profile analysis demonstrated denser and more uniformly distributed PPy inside fiber wall for CF20, while PPy tended to deposit on the surface of fiber for CF1. Fourier transform infrared spectroscopy, together with XPS certified that the PPy with longer conjugation length and higher doping level across the conductive fiber was obtained at higher fiber concentration. The doping level for CF10 decreased from 21.55 to 16.39 % with increasing fiber wall thickness, while that of CF20 decreased slightly from 30.73 to 24.10 %. The resulting CF20 showed lowest surface resistivity of 0.433 KΩ/square, as well as improved electro-conductivity stability. The incorporation of more PPy in CF improved the thermal stability.     

Enhanced UV photosensing properties of ZnO nanowires prepared by electrodeposition and atomic layer deposition

A new process enabling the synthesis of zinc oxide (ZnO) and Al-doped ZnO nanowires (NWs) for photosensing applications is reported. By combining atomic layer deposition (ALD) for the seed layer preparation and electrodeposition for the NW growth, high-quality ZnO nanomaterials were prepared and tested as ultraviolet (UV) sensors. The obtained NWs are grown as arrays perpendicular to the substrate surface and present diameters between 70 and 130 nm depending on the Al doping, as seen from scanning electron microscopy (SEM) studies. Their hexagonal microstructure has been determined using X-ray diffraction and Raman spectroscopy. An excellent performance in UV sensing has been observed for the ZnO NWs with low Al doping, and a maximal photoresponse current of 11.1 mA has been measured. In addition, initial studies on the stability have shown that the NW photoresponse currents are stable, even after ten UV on/off cycles.     

TEMPO-mediated surface oxidation of cellulose nanocrystals (CNCs)

Cellulose nanocrystals were successfully oxidized with sodium hypochlorite using catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical at pH 10 in water. Carboxylate groups were selectively introduced at the surface of the crystals up to a total acid content of 1200 mmol kg^?1 without damaging the integrity of the crystals. The final acid content can easily be tuned by varying the amount of oxidant introduced. The effect of temperature, the quantity of oxidant and co-catalyst on the reaction kinetics were studied. Several methods were used for the characterization of the oxidized material like field emission scanning electron microscopy, diffuse reflectance infrared spectroscopy and thermogravimetric analysis.     

Effect of alkali metal doping on the properties and crystalline perfection of bis(thiourea)zinc(II) chloride crystals

The influence of sodium doping on the properties of bis(thiourea)zinc(II) chloride crystals has been described. The reduction in the intensity observed in powder X-ray diffraction of doped specimen and slight shifts in vibrational frequencies confirm the lattice stress as a result of doping. The incorporation of Na(I) into the crystal lattice was confirmed by energy dispersive X-ray spectroscopy. Surface morphological changes due to doping of the alkali metal are observed by scanning electron microscopy. The TG?CDTA studies reveal the purity of the material and no decomposition is observed up to the melting point. The high resolution X-ray diffraction studies reveal that the crystalline quality is improved considerably by doping with alkali metal. High transmittance is observed and cut off ?? is ~270?nm.     

Cucurbit[7]uril complexations of bis(isoquinolinium)alkane dications in aqueous solution

The 1:1 and 2:1 host–guest complexation of a series of 1,n-bis(isoquinolinium)alkane dications (Iq(CH₂)_nIq²⁺, n = 2, 4, 5, 6, 8, 9, 10 and 12, and Iq(p-xylene)Iq²⁺) by cucurbit[7]uril (CB[7]) in aqueous solution has been investigated by ¹H NMR spectroscopy and ESI mass spectrometry. The site of binding of the first CB[7] is dependent on the nature of the central linker group, with encapsulation of the p-xylene group or the polymethylene chain when n = 6–10.With shorter (n = 2–5) or longer (n = 12) chains, the first CB[7] binds over an isoquinolinium group. With a second CB[7], the binding of the central group is abandoned in favour of the CB[7] hosts encapsulating the two cationic isoquinolinium termini. The 1:1 and 2:1 host–guest stability constants are related to modes of binding and the nature of the central linkers, and are compared with dicationic guests bearing different terminal groups.     

Polyethylene oxide-based nanocomposite polymer electrolytes for redox capacitors

In this work, the use of a polyethylene oxide-based nanocomposite polymer electrolyte (NCPE) in a redox capacitor with polypyrrole electrodes has been studied. To the best of our knowledge, not much work has been reported in the literature on redox capacitors fabricated using NCPEs. The composition of the polyethylene oxide (PEO)-based NCPE was fine tuned to obtain films with the highest ionic conductivity. They were mechanically stable to handle for any purpose without damaging the film. The optimized composition was {[(10PEO:NaClO₄) molar ratio]: 75 wt.% propylene carbonate (PC)}: 5 wt.% TiO₂. This electrolyte film showed an ambient temperature ionic conductivity of 5.42 × 10^?3 S cm^?1. It was employed in a redox capacitor with polypyrrole electrodes polymerized in the presence of sodium perchlorate in non-aqueous medium. Performance of the redox capacitors were observed using cycling voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge discharge test. It was possible to observe a satisfactory capacitive behavior in the range 58–83 F/g. Further, the redox capacitors had the ability to retain for continuous charge discharge processes.     

Effect of ultrasound on the thermal behavior of the mixtures for the LTA zeolite synthesis based on metakaolin

The effect of ultrasonic treatment on the thermal behavior of the mixtures from metakaolin, sodium hydroxide and alumina designed for LTA zeolites synthesis was studied. X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy and synchronous thermal analysis have been used. It was shown that after evaporation of the suspension, LTA zeolite (24 mass%) is contained in the samples. It was established that the new phase (sodium aluminum silicate) is formed at a calcination temperature of about 600 °C. It was demonstrated that at a calcination temperature over 800 °C, nepheline is synthesized. The reaction of nepheline formation has been described by the topochemical equation of four-dimensional nucleation/nucleus growth according to Avrami/Erofeev. Using the Ozawa–Flynn–Wall analysis for non-isothermal data, the values of the activation energy and the pre-exponential factor have been calculated. It is shown that after the ultrasonic treatment the activation energy of the nepheline synthesis reaction has smaller values than in the sample without pretreatment. These phenomena have been explained by differences between the structural parameters of the particles (dimension of the coherent scattering region, the value of microdeformations).     

Orientational control of liquid crystal molecules via carbon nanotubes and dichroic dye in polymer dispersed liquid crystal

Polymer dispersed liquid crystals (PDLCs) using nematic liquid crystal and photo-curable polymer (NOA 65) were prepared by polymerisation-induced phase separation technique, in equal ratio (1:1) of polymer and liquid crystal (LC). We demonstrate that doping of small amount (0.125%, wt./wt.) of multiwall carbon nanotubes (CNTs) and orange azo dichroic dye in PDLC generously controlled the molecular orientation, dynamics of LC in droplet and size of droplets. The effects of multiwall CNTs and dye on PDLCs were studied in terms of transition temperature, droplet morphology, transmittance characteristic, contrast ratio and response time. The results exhibited that the values of the threshold electric fields were reduced from 8 V/µm (pure PDLC) to 1.18 and 1.72 V/µm, doped with multiwall CNTs and dye, respectively. The CNTs-doped PDLC shows faster switching response as compared with pure PDLC and dye-doped PDLC. However, dye-doped PDLC shows much higher contrast among all PDLC samples. Further, the results also illustrate that the birefringence value of LC in PDLCs was changed with doping of CNTs and dye.     

Preparation and photocatalytic performance of the Mn/BiOCl albizia flower

Different molar ratio manganese-doped BiOCl composites (Mn/BiClO) were prepared by the hydrothermal method with imidazole hydrochloride [HMIM]Cl as the chlorine source and template. The Mn/BiClO composites were analyzed by X-ray diffraction (XRD) for crystalline structure, scanning electron micrography (SEM) for morphology, energy dispersive spectroscopy for element analysis, BET for the specific surface area and pore volume of the sample, diffuse reflectance spectra for optical properties, and X-ray photoemission spectroscopy (XPS) for the composition and the valence of the ions on the surface layer of the sample. The XRD analysis indicates that there is an increase in the peak intensity of Mn/BiOCl. The ultraviolet–visible measure result shows that the optical absorption edge appears to red-shift, which demonstrates the band gap of BiClO reduction by doping with Mn. The BiClO microflower completely spread in a hexapetalous manner in the ionic liquid (IL), increasing the chance of contact between catalyst and dye. The 23.5 % Mn/BiClO completely spread resembling an albizia flower. SEM and BET show that the Mn/BiClO albizia flower possessed greater surface area than the hexapetalous BiClO. XPS proves that Mn, Cl, O, and Bi are all present in Mn/BiOCl. These results show that doping with Mn not only improves ultraviolet photocatalytic activity, but also enhances visible photocatalystic performance of BiClO in the degradation of rhodamine. The results can be attributed to the prolongation of the lifetime of photogenerating electron–hole pairs, increase of surface area, and enlargement of optical absorption range by doping with Mn. Mn/BiClO completely degrades rhodamine B in just 40 min under ultraviolet light; moreover, Mn/BiClO can degrade 72 % of rhodamine B within 120 min under visible light. The photocatalyst experiment can be implemented in conditions of ice and water without adding any other chemical agent such as H₂O₂. This highly effective catalyst that can make full use of the sunlight has been seldom reported and demonstrated in the current literature.     

Growth, structure, and characterization of tris(thiourea)silver(I) nitrate

Single crystals of tris(thiourea)silver(I) nitrate have been grown by slow evaporation solution growth technique from an aqueous solution at 25 °C. The single crystal X-ray diffraction study reveals that the crystal belongs to tetragonal system and cell parameters are a = b = 14.2790(4) Å, c = 24.8900(7) Å, and V = 5074.8(2) Å³. The various functional groups present in the molecule are confirmed by Fourier transformed infrared spectroscopy (FT-IR). The structure and the crystallinity of the materials were further confirmed by powder X-ray diffraction analysis. Thermogravimetric and differential thermal analysis reveal the purity of the sample and no decomposition is observed up to the melting point. The crystal is further characterized by UV–Vis and Vickers microhardness analysis.     

Complexes of Co (II) and Cu (II) with nonsteroidal anticancer drug Letrozole and their interaction with DNA and BSA by spectroscopic methods and cytotoxic activity

DNA and BSA binding properties of mononuclear Co (II) and Cu (II) complexes containing letrozole [M(Le)₄Cl₂]·(H2O)](Le=[4,4-(1H-1,2,4-triazol-1-ylmethylene)bisbenzonitrile] have been investigated under physiological conditions. The interaction ability of the two complexes with native calf thymus DNA(CT-DNA) has been monitored as a function of the metal complex-DNA molar ratio by UV–Vis absorption spectrophotometry, fluorescence spectroscopy, circular dichroism(CD) and thermal denaturation studies. The intrinsic binding constants, K_b, of complexes 1 and 2 with CT-DNA, obtained from UV–Vis absorption studies, were 3.15 ± 0.02 × 10⁴ and 4.37 ± 0.02 × 10⁴ M^?1, respectively. The addition of the complexes to CT-DNA (1:2) leads to an increase in the melting temperature of DNA up to around 4 °C, which has revealed that complexes could interact with DNA through intercalation mode. Fluorimetric studies have been performed using methylene blue (MB) as a fluorescence probe and competitive studies have shown the ability of the complexes to displace the DNA-bound MB, suggesting competition with MB. To explore the potential biological value of the complexes, the binding interaction between Co (II) and Cu (II) complexes and bovine serum albumin (BSA) has also been studied by fluorescence spectroscopy. The results indicate that the reaction between the complexes and BSA is a static quenching procedure. The site marker displacement experiment has suggested the location of the complexes binding to BSA at Sudlow’s site I in subdomain IIA. Finally, MTT assay studies have shown that the bioactive complexes exert significantly high selective dose-dependent cytotoxicity against a panel of cancer cell lines including MCF-7, JURKAT, SKOV3 and U87.     

The Synthesis,Characterization and DC Electrical Conductivity of Polypyrrole‐Zirconium Complex

Polypyrrole‐zirconium complex has been synthesized by reacting 2‐amino‐3,4‐dicyano‐5‐mercaptopyrrole with zirconium nitrate in absolute ethanol under reflux for 24 h. The product has been characterized by elemental analyses, FTIR spectroscopy, in addition to thermal analysis (TGA and DSC) and its solubility has been investigated. The DC electrical conductivity variation of polypyrrole‐zirconium complex has been studied in the temperature range 300–500 K after annealing for 24 h at 100°C and doping with I₂, FeCl₃ and CuCl₂ · H₂O for comparison. An attempt has been made to interpret the DC electrical conductivity behavior and thermal properties to chain length, dopant used, polymer structure and attached groups.