Fourier Transform Infrared Studies Research Articles

FTIR studies on interactions among components in PVdF-HFP:PC:MPII electrolytes

Liquid electrolytes are known to have high conductivities. However, they suffer from leakage, corrosion of electrodes and other stability issues. Solid polymer electrolytes eliminate the problems of liquid electrolytes at the cost of lower conductivity. Quasi-solid-state polymer electrolytes (QSSPE) overcome the shortcomings of both liquid electrolytes and solid polymer electrolytes. In this work, QSSPE is prepared by incorporating poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) in a propylene carbonate (PC) and 1-methyl-3-propyl imidazolium iodide (MPII) liquid electrolyte. Fourier transform infrared (FTIR) studies have been carried out to investigate the interactions among PVdF-HFP, PC and MPII. A comprehensive spectroscopic investigation on ion-solvent-polymer interactions helps to understand the mechanism of ionic conduction in the PVdF-HFP/PC/MPII electrolyte system. Interaction between MPII and PC has occurred from the changes in the ν(C=O), ν(C-O) + ω(C-H), ω(C-H) + δ(C-H) and τ of ring of PC as well as the C-N bond oscillation and of (N-C-H) of MPII. Interaction occurs via the coordination of MPIm+ cations with both oxygen atoms of PC. Complexation between PVdF-HFP and MPII has been noted. MPII suppresses the non-polar α-phase and induces the polar β and -phases of PVdF-HFP. Shift of peaks belong to the CF2 and CF3 groups of PVdF-HFP suggests the complexation occurs at the fluorine atoms in CF2 and CF3 groups. Evidence of interaction between PC and PVdF-HFP has been manifested through the change of the ν(C=O), τ(C-H) + δ(C-H) and ν of the CF2 group of PVdF-HFP. Disappearance of non-polar α-phase of PVdF-HFP is noted in the presence of PC. From this work, the authors hope to shed some light on understanding the conduction mechanism in PVdF-HFP:PC:MPII electrolytes. Understanding the conduction mechanism is important in order to find ways for conductivity improvement.

Formation of amphibole lamellae in mantle pyroxene by fluid-mediated metasomatism: A focal plane array FTIR study from the Carpathian-Pannonian region

Abstract Amphiboles in the upper mantle (most frequently pargasitic in composition) have recently gained attention due to their role in the water budget and potential control on the rheology and physical discontinuity of layers of the mantle. Although nominally anhydrous minerals are often analyzed with Fourier transform infrared (FTIR) spectroscopy, amphiboles, especially in natural samples, are only rarely the focus of such studies because of their complex structure and variable composition. In mantle xenoliths, amphibole occurs not only interstitially or forming veins, but also as lamellae within orthopyroxene and/or clinopyroxene grains. The genesis of such lamellae is often ambiguous, as they could either be meta-somatic products, or form by exsolution without an external H2O source upon decreasing P-T conditions and consequent destabilization of hydrous point defects in the host pyroxene. To constrain the origin of amphibole lamellae in pyroxenes, we studied mantle xenoliths from the Carpathian-Pannonian region (CPR) by applying hyperspectral imaging using an FTIR equipped with focal plane array (FPA) detector. Amphibole lamellae are absent in xenoliths of the central part of the CPR, but appear in those from the marginal localities that represent a well-hydrated supra-subduction mantle environment. Some of the lamella-hosting pyroxene grains are in contact with interstitial amphibole, suggesting that the formation of the lamellae is related to the amphibole-producing metasomatism; however, others have no adjacent amphibole. To determine the origin of the amphibole lamellae in pyroxenes without neighboring amphibole, hyperspectral images were used to give an estimation of their volume proportion (0.8–5.1 vol%) in the pyroxenes. Using these volume proportions, we calculated that a bulk water content of ~330–670 (orthopyroxene) and ~740–1430 (clinopyroxene) wt. ppm is needed to be contained in the host grain to be able to facilitate subsolidus exsolution of the observed amount of amphibole lamellae. These water contents are, however, too high for mantle pyroxenes, even for an aqueous-fluid saturated upper mantle. This suggests that the formation of amphibole lamellae is related to a metasomatic event with fluid input from an external water source (e.g., melt/fluid inclusion or metasomatic agent on the grain boundary).

Effect of Europium Substitution on the Structural, Magnetic and Relaxivity Properties of Mn-Zn Ferrite Nanoparticles: A Dual-Mode MRI Contrast-Agent Candidate

Magnetic nanoparticles (MNPs) have been widely applied as magnetic resonance imaging (MRI) contrast agents. MNPs offer significant contrast improvements in MRI through their tunable relaxivities, but to apply them as clinical contrast agents effectively, they should exhibit a high saturation magnetization, good colloidal stability and sufficient biocompatibility. In this work, we present a detailed description of the synthesis and the characterizations of europium-substituted Mn-Zn ferrite (Mn0.6Zn0.4EuxFe2-xO4, x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, and 0.15, herein named MZF for x = 0.00 and EuMZF for others). MNPs were synthesized by the coprecipitation method and subsequent hydrothermal treatment, coated with citric acid (CA) or pluronic F127 (PF-127) and finally characterized by X-ray Diffraction (XRD), Inductively Coupled Plasma (ICP), Vibrating Sample Magnetometry (VSM), Fourier-Transform Infrared (FTIR), Dynamic Light Scattering (DLS) and MRI Relaxometry at 3T methods. The XRD studies revealed that all main diffraction peaks are matched with the spinel structure very well, so they are nearly single phase. Furthermore, XRD study showed that, although there are no significant changes in lattice constants, crystallite sizes are affected by europium substitution significantly. Room-temperature magnetometry showed that, in addition to coercivity, both saturation and remnant magnetizations decrease with increasing europium substitution and coating with pluronic F127. FTIR study confirmed the presence of citric acid and poloxamer (pluronic F127) coatings on the surface of the nanoparticles. Relaxometry measurements illustrated that, although the europium-free sample is an excellent negative contrast agent with a high r2 relaxivity, it does not show a positive contrast enhancement as the concentration of nanoparticles increases. By increasing the europium to x = 0.15, r1 relaxivity increased significantly. On the contrary, europium substitution decreased r2 relaxivity due to a reduction in saturation magnetization. The ratio of r2/r1 decreased from 152 for the europium-free sample to 11.2 for x = 0.15, which indicates that Mn0.6Zn0.4Eu0.15Fe1.85O4 is a suitable candidate for dual-mode MRI contrast agent potentially. The samples with citric acid coating had higher r1 and lower r2 relaxivities than those of pluronic F127-coated samples.

Radiation-induced transformations of matrix-isolated ethanol molecules at cryogenic temperatures: an FTIR study.

Ethanol (C2H5OH) is one of the most common alcohol molecules observed in various space media (molecular clouds, star formation regions, and, highly likely, interstellar ices), where it is exposed to light and ionizing radiation, leading to more complex organic molecules and eventually to the biologically important species. To better understand the radiation-induced evolution of ethanol molecules in icy media, we have examined the transformations of isolated C2H5OH and C2D5OH under the action of X-rays and vacuum ultraviolet (VUV) radiation in solid inert matrices (Ne, Ar, Kr, and Xe) at 4.4 K using Fourier transform infrared (FTIR) spectroscopy. The results obtained with X-ray irradiation demonstrate the formation of a variety of radiolysis products corresponding to dehydrogenation (CH3CHOH˙, CH3CHO, CH2CHOH, CH3CO˙, H2CCO-H2, H2CCO, HCCO˙, CCO) and C-C bond rupture (H2CO, HCO˙, CO, CH4, and CH3˙). The absorptions of the CH3CHOH˙ radical related to the CCO stretching (the bands at 1249.1, 1247.0, 1246.2, and 1245.1 cm-1, in Ne, Ar, Kr, and Xe, respectively) were first tentatively characterized on the basis of comparison with available computational data. In addition, the C2H2⋯H2O complex, which corresponds to dehydrogenation, was found followed by C-O bond cleavage. The results were confirmed by experiments with isotopic substitution. It was found that dehydrogenation strongly predominated in a xenon matrix, while skeleton bond rupture is more feasible in neon and argon. The matrix effect was attributed to a significant role of "hot" reaction channels in neon and argon, which are efficiently quenched due to relaxation in more polarizable xenon. The VUV photolysis (185 nm) in Ar and Xe matrices yields a similar set of products, except for CH3CHOH˙ and CH2CHOH, which were not found (the nonobservation of the former species may be explained by its efficient secondary photolysis). The plausible mechanisms of product formation and astrochemical implications of the results are discussed.

Mechanical, optical, and physicochemical properties of HPMC-based doxazosin mesylate orodispersible films

In this study, orodispersible films formed from hydroxypropyl methylcellulose (HPMC) E6 (2, 2.5, and 3%) and plasticizers ((glycerin (Gly), propylene glycol (PP), or polyethylene glycol (PEG)), containing doxazosin mesylate, were prepared by the solvent casting method and characterized. Design of experiments (DoE) was used as a statistical tool to facilitate the interpretation of the experimental data and allow the identification of optimal levels of factors for maximum formulation performance. Differential scanning calorimetry (DSC) curves and X-ray powder diffraction (XRPD) diffractograms showed doxazosin mesylate amorphization, probably due to complexation with the polymer (HPMC E6), and the glass transition temperature of the polymer was reduced by adding a plasticizer. Fourier transformed infrared (FTIR) spectroscopy results showed that the chemical structure of doxazosin mesylate was preserved when introduced into the polymer matrix, and the plasticizers, glycerin and PEG, affected the polymer matrix with high intensity. The addition of plasticizers increased the elongation at break and adhesiveness (Gly > PEG > PP), confirming the greater plasticizer effect of Gly observed in DSC and FTIR studies. Greater transparency was observed for the orodispersible films prepared using PP. The addition of citric acid as a pH modifier was fundamental for the release of doxazosin mesylate, and the desirability formulation had a release profile similar to that of the reference product.

Influence of Li2O on physical, structural, thermal, optical and EPR properties of TeO2-MoO3-Li2O-V2O5 glass system

Glass composition with the formula 75TeO2 - (24-x) MoO3 - xLi2O −1V2O5 where x varying from 0 mol% to 24 mol% in steps of 6 mol% is synthesized using melt quenching technique. Density, molar volume along with OPD were determined. To understand the structural characteristics Fourier Transform Infrared (FTIR), Raman techniques were used. Transformations of TeO4 (tbp) to TeO3+1 and then to TeO3 (tp) units was observed and the change in ligancy of Mo from +4 to +6 shows that there is a reduction in the number of oxygen dangling bonds with rise in Li2O in the glass network was revealed by Raman and FTIR studies. Thermal properties like glass transition temperatures and its resistance to degradation of ductility and toughness were evaluated by DSC and also the effect of Li2O and MoO3 on these properties was presented. UV–VIS spectroscopic technique is employed for determining optical parameters of the TML samples. Spin Hamiltonian parameters are also evaluated by analyzing EPR spectroscopy which revealed that VO2+ ion exists in octahedral site in the glass matrix with tetragonal distortion.

In-situ FTIR spectroscopy investigation of carbon-supported PdAuNi electrocatalysts for ethanol oxidation

• Adding Au and Ni to Pd/C enhances its ethanol oxidation performance. • In-situ FTIR studies suggest acetate is the ethanol oxidation final product. • Adding Ni and Au to Pd/C does not enhance the ethanol CO 2 selectivity. • The SBIPA method produces the ethanol most active catalyst. This work demonstrates novel in situ measurements of direct ethanol fuel cells (DEFCs), and shows that the synthesis procedure can exert a substantial influence over their activity, with exceptional activity demonstrated for a trimetallic PdAuNi/C catalyst prepared via NaBH 4 -2-propanol reduction (SBIPA). Furthermore, in situ Fourier transform infrared (FTIR) spectroscopy shows that the final ethanol electrooxidation reaction (EOR) over all catalysts investigated is acetate, thereby yielding valuable insights into the reaction mechanism. DEFCs present a sustainable net-zero technological solution which can supply diverse energy needs without increasing greenhouse gas (GHG) emissions. Ethanol can be produced from biomass precusors, and therefore its direct application in fuel cells can mitigate climate change and ensure environmental sustainability. In this work, PdAuNi/C catalysts are synthesized via three synthetic routes and applied in EOR. The catalysts are charachrterised via X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Their electrocatalytic performance is evaluated by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). SBIPA exhibits excellent electrocatalytic results with an oxidation current peak of 9.6 A/mg Pd . This is 4 times greater than that recorded for its monometallic counterpart prepared via the same procedure. It is, also, over twice as great as the other two trimetallic samples prepared by alternative protocols. Although adding Au and Ni to Pd significantly enhances EOR activity, it does not increase the CO 2 yield of EOR.

Multifunctional Ternary NLP/ZnO@l-cysteine-grafted-PANI Bionanocomposites for the Selective Removal of Anionic and Cationic Dyes from Synthetic and Real Water Samples.

The development of competent adsorbents based on agro-waste materials with multifunctional groups and porosity for the removal of toxic dyes from aqueous solutions is still a challenge. Herein, a bionanocomposite made up of neem leaf powder (NLP), zinc oxide (ZnO), and amino acid (l-cysteine)-functionalized polyaniline (PANI), namely, NLP/ZnO@l-cysteine-grafted-PANI (NZC-g-PANI), has been prepared by an in situ polymerization method. The as-prepared bionanocomposite was tested for the adsorptive removal of three anionic dyes, namely, methyl orange (MO), amido black 10B (AB 10B), and eriochrome black T (EBT), as well as three cationic dyes, namely, brilliant green (BG), crystal violet (CV), and methylene blue (MB), from synthetic aqueous medium. The morphological and structural characteristics of the NZC-g-PANI nanocomposite were examined with the help of HR field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopy. FTIR and Raman studies show that the formulated NZC-g-PANI have an ample number of functional moieties such as carboxyl (-COOH), hydroxyl (-OH), amines (-NH2), and imines (-N=), thus demonstrating outstanding dye removal capacity. C-S linkage helps to attach l-cysteine with polyaniline. Moreover, the predominance of chemisorption via ionic/pi-pi interaction and hydrogen bonding between the NZC-g-PANI nanocomposite and dyes (BG and MO) has been realized by FTIR and fitting of kinetics data to the PSO model. For both BG and MO dyes, the biosorption isotherm was precisely accounted for by the Langmuir isotherm with q max values of up to 218.27 mg g-1 for BG at pH 6 and 558.34 mg g-1 for MO at pH 1. Additionally, thermodynamic studies revealed the endothermic and spontaneous nature of adsorption. NZC-g-PANI showed six successive regeneration cycles for cationic (MO: from 96.3 to 90.4%) and anionic (BG: from 94.7 to 88.7%) dyes. Also, batch adsorption operations were validated to demonstrate dye biosorption from real wastewater, such as tap water, river water, and laundry wastewater. Overall, this study indicates that the prepared NZC-g-PANI biosorbent could be used as an effective adsorbent for the removal of various types of anionic as well as cationic dyes from different aqueous solutions.

Ruscogenin interacts with DPPC and DPPG model membranes and increases the membrane fluidity: FTIR and DSC studies

Ruscogenin, a kind of steroid saponin, has been shown to have significant anti-oxidant, anti-inflammatory, and anti-thrombotic characteristics. Furthermore, it has the potential to be employed as a medicinal medication to treat a variety of acute and chronic disorders. The interaction of a drug molecule with cell membranes can help to elucidate its system-wide protective and therapeutic effects, and it's also important for its pharmacological activity. The molecular mechanism by which ruscogenin affects membrane architecture is still a mystery. Ruscogenin's interaction with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) and anionic dipalmitoyl phosphatidylglycerol (DPPG) multilamellar vesicles (MLVs) was studied utilizing two non-invasive approaches, including: Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry. Ruscogenin caused considerable alterations in the phase transition profile, order, dynamics and hydration state of head groups and glycerol backbone of DPPC and DPPG MLVs at all concentrations. The DSC results indicated that the presence of ruscogenin decreased the main phase transition temperature (Tm) and enthalpy (ΔH) values of both membranes and increased half height width of the main transition (ΔT1/2). The FTIR results demonstrated that all concentrations (1, 3, 6, 9, 15, 24 and 30 mol percent) of ruscogenin disordered the DPPC MLVs both in the gel and liquid crystalline phases while it increased the order of DPPG MLVs in the liquid crystalline phase. Moreover, ruscogenin caused an increase in the dynamics of DPPC and DPPG MLVs in both phases. Additionally, it enhanced the hydration of the head groups of lipids and the surrounding water molecules implying ruscogenin to interact strongly with both zwitterionic and charged model membranes.

Spectroscopic evidence of the radioresistance of Chroococcidiopsis biosignatures: A combined Raman, FT-IR and THz-TDs spectroscopy study

In the last decades, Mars has been widely studied with on-site missions and observations, showing a planet that could have hosted life in the past. For this reason, the recent and future space missions on the red planet will search for traces of past and, possibly, present life. As a basis for these missions, Space Agencies, such as the European Space Agency, have conducted many experiments on living organisms, studying their behavior in extraterrestrial conditions, learning to recognize their biosignatures with techniques remotely controllable such as Raman spectroscopy. Among these organisms, the radioresistant cyanobacterium Chroococcidiopsis was irradiated during the STARLIFE campaign with strong radiative insults. In this article we have investigated this cyanobacterium using Raman spectroscopy and extended the characterization of its biosignatures and its response to the radiative stress to the mid- Infrared and Terahertz spectral region using the Fourier Transform InfraRed (FT-IR) and Terahertz Time Domain spectroscopy (THz- TDs), which demonstrates the compatibility and suitability of these techniques for future space missions.

In-situ polymerization of polycarbazole-zinc oxide nanocomposite: An in silico docking model and in vitro antibacterial biomaterial

The current study focuses on the synthesis of polycarbazole-zinc oxide (PCz/ZnO) nanocomposite and its application as an in vitro antibacterial biomaterial as well as an in silico docking model. The synthesized pristine polymer, polycarbazole (PCz) and its nanocomposite PCz/ZnO were characterized by Fourier transform infrared (FT-IR), Thermo-gravimetry/Differential Thermo-gravimetry (TG-DTG), X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), Energy-dispersive X-ray (EDX), Raman and X-ray photoelectron spectroscopic (XPS) techniques. FT-IR, XRD, FE-SEM, and XPS studies revealed that the polymerization of Cz has been successfully achieved on the surfaces of ZnO nanoparticles, indicating the strong interfacial interaction between PCz and ZnO nanoparticles. However, TG-DTG studies revealed that the nanocomposite, PCz/ZnO, proved thermally more stable compared to the pristine polymer, PCz. Further, the pristine PCz and PCz/ZnO nanocomposite were evaluated for antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. The nanocomposite PCz/ZnO showed the highest zone of inhibition against K. Pneumoniae (17 mm), followed by P. aeruginosa (16 mm), then S. aureus (14 mm) and E. coli (19 mm) at 80 mg ml−1. Significantly, the in silico molecular docking predicts the modes of interactions of PCz and PCz/ZnO with B-DNA. Briefly, the results obtained from in silico molecular docking studies of the pristine PCz and PCz/ZnO nanocomposite with negative free binding energies (-7.1 kcal mol−1 of PCz and −6.23 kcal mol−1 of PCz/ZnO) imply an excellent and favourable binding affinity vis-à-vis interaction modes of both pristine PCz and PCz/ZnO nanocomposite (drugs) with B-DNA bases (target).

Proton conducting polymer blend electrolytes based on MC: FTIR, ion transport and electrochemical studies

In this work, the free-standing plasticized solid polymer electrolyte films were made utilizing methylcellulose (MC) and dextran (DN) doped with ammonium fluoride (NH 4 F) and plasticized with glycerol by a typical solution casting approach. Based on the characterizations, MC-DN-NH 4 F electrolyte has been shown to improve the structural, electrical, and electrochemical properties resulting from the dispersion of glycerol plasticizer. The electrochemical impedance spectroscopy (EIS) measurement for the highest inclusion of plasticizer revealed a conductivity of 2.25 × 10 -3 S/cm. The electrical equivalent circuit (EEC) model has established the circuit elements for each electrolyte. The variation trend of dielectric constant and DC conductivity was matched and confirmed by the EIS data. The fourier transform infrared (FTIR) analysis displayed credible confirmation of polymers-ion-plasticizer interactions. The dielectric study is extra highlighted the conductivity behavior. The dielectric constant and loss (ε′ and ε″) quantities were reported to be high at low frequencies. On the other hand, the irregular shape of the imaginary part of modulus (M“) spectra denotes the non-Debye behaviors of relaxation. The ion transference number (t ion ) value for the maximum plasticized system is 0.944, where the ions are the primary components for the charge transfer process. Stability of the highest conducting sample is determined to be 1.6 V, using linear sweep voltammetry (LSV).

CO₂ Adsorption on Zeolites and Fe-MOF for Carbon Capture and Storage (CCS)

This research focused on the development of suitable materials for capturing and storing CO2 (CCS). Ferum-metal organic framework (Fe-MOF) and zeolite were prepared as adsorbents for the CO2 adsorption process. These adsorbents were characterised by employing X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysers. The adsorptive capacity of CO2 was conducted in an assembled facility containing of a metallic tubular container set up with a pure CO2 gas stream from a cylinder-shaped tank. The performance of these two adsorbents was investigated using two different parameters which are operating pressure and dosage of adsorbents. The exit concentration of CO2 was analyzed periodically using gas chromatography. Based on the FTIR and XRD studies, the findings suggest that the zeolite and Fe-MOF were successfully formed. The optimal adsorption conditions obtained for both adsorbents were 0.3 g of adsorbent dose and 1 bar of operating pressure. In conclusion, zeolite exhibits better performance as a CO2 adsorber due to its higher adsorption capacity than Fe-MOF.

Effects of Fiber Volume Fraction and Length on the Mechanical Properties of Milled Glass Fiber/Polyurea Composites.

Composites of polyurea (PU) reinforced with milled glass fiber (MGf) were fabricated. The volume fraction and length of the milled glass fiber were varied to study their effects on the morphological and mechanical properties of the MGf/PU composites. The morphological attributes were characterized with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The SEM investigations revealed a uniform distribution and arbitrary orientation of milled glass fiber in the polyurea matrix. Moreover, it seems that the composites with longer fiber exhibit better interfacial bonding. It was found from the FTIR studies that the incorporation of milled glass fiber into polyurea leads to more phase mixing and decreases the hydrogen bonding of the polyurea matrix, while having a negligible effect on the H-bond strength. The compression tests at different strain rates (0.001, 0.01, 0.1, 1, 2000 and 3000 s−1) and dynamic mechanical properties over the temperature range from −30 to 100 °C at 1 Hz were performed. Experimental results show that the compressive behavior of MGf/PU composites is nonlinear and strain-rate-dependent. Both elastic modulus and flow stress at any given strain increased with strain rate. The composites with higher fiber volume fraction and longer fiber length are more sensitive to strain rate. Furthermore, the elastic modulus, stress at 65% strain and energy absorption capability were studied, taking into account both the effect of fiber volume fraction and mean fiber length. It is noted that an increase in fiber volume fraction and fiber length leads to an increase in elastic modulus, stress at 65% strain and absorbed energy up to ~103%, 83.0% and 137.5%, respectively. The storage and loss moduli of the composites also increase with fiber volume fraction and fiber length. It can be concluded that the addition of milled glass fiber into polyurea not only improves the stiffness of the composites but also increases their energy dissipative capability.

Sn(IV) Porphyrin-Based Ionic Self-Assembled Nanostructures and Their Application in Visible Light Photo-Degradation of Malachite Green

A series of porphyrin-based ionic complexes were prepared through the reaction of two porphyrin precursors, 5,10,15,20-tetrakis(4-(2-pyridyl)phenyl)porphyrin H2TPhPyP (1) and trans-dihydroxo [5,10,15,20-tetrakis(4-(2-pyridyl)phenyl)porphyrinato]tin(IV) Sn(OH)2TPhPyP (2), with various acids (HCl, HNO3, CF3COOH, H2SO4, H2CO3, and H3PO4). The complexes were characterized via elemental analysis, 1H nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV)-visible spectroscopy, fluorescence spectroscopy, and field-emission scanning electron microscopy (FE-SEM). Each compound exhibited different results for UV-visible, fluorescence, FT-IR, and FE-SEM studies depending on the counter anions. The complexes possessed different self-assembled nanostructures based on electronic interactions between the cations of compounds 1 and 2 with different counter anions. These aggregated species are stabilized by electrostatic forces and the π-π stacking interactions between the two porphyrin rings, in which the counter anions play an important bridging role. The counter anions also play an important role in controlling the morphology and photocatalytic properties of the as-developed materials. The complexes were then used for the photocatalytic degradation of the malachite green (MG) dye in aqueous media under visible light irradiation for up to 70 min. A morphology-dependent photocatalytic degradation of the MG dye was observed for all the ionic complexes, with efficiencies ranging from 50% to 95%.

Structural characteristics and opto-electrical properties of in-situ synthesized polyaniline films

In the present study, polyaniline (PAni) thin films have been deposited on glass substrates by in-situ chemical polymerization method using simple dip-coating technique and their opto-electrical properties have been studied. The structure of deposited films have been analysed with Fourier transform infrared (FTIR) and Raman spectroscopic techniques to investigate the effect of deposition times on the conjugation length, polaron/bipolaron concentrations and other molecular structure conformations. FTIR and Raman spectroscopy studies reveal increase in both the conjugation length and the polaron/bipolaron carrier concentration with increasing deposition time of the prepared PAni films. The optical properties and optical band-gap of the deposited films have been estimated through UV–visible spectroscopy. The optical band-gap of the deposited films has been found to decrease from 3.31 eV to 3.13 eV with increase in deposition time from 1.5 h to 2.5 h, and further it has been increased slightly to 3.19 eV for the PAni film deposited for 3 h. The electrical conductivity of the deposited films has been found to increase with decrease in optical band gap. The parameters estimated from FTIR, Raman, UV–visible spectroscopy and electrical measurements are in good agreement with each other. It has been observed that the optical and electrical properties of the deposited films depend on the conjugation length of PAni. The polymerization time of 2.5 h has been found to be optimum for obtaining PAni thin films with good electrical conductivity and low optical band gap.

Cilostazol-loaded solid lipid nanoparticles: Bioavailability and safety evaluation in an animal model

Cilostazol (CLZ) is an antiplatelet agent with limited solubility (∼6 μg/ml at 25 °C), poor absorption and low oral bioavailability. In this study, solid lipid nanoparticles (SLNs) were used as a drug delivery system to improve the CLZ dissolution, absorption and bioavailability. Micro-emulsion method was used to fabricate CLZ-loaded SLNs. The SLNs were composed of palmityl alcohol, Tween® 80, and Span® 40 as solid lipid, surfactant, and co-surfactant, respectively. Additionally, Myrj 52 was used as a steric stabiliser. The SLNs were characterised in terms of particle size, zeta potential, polydispersity index (PDI), and incorporation efficiency (IE). Transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and Fourier transform infrared (FTIR) spectroscopy were also performed. In vitro release and pharmacokinetic studies were carried out, followed by evaluation of the safety and stability of the formulated SLNs. Optimised CLZ-loaded SLNs showed a spherical morphology with particle sizes below 200 nm, with excellent PDI (0.18), zeta potential (−29.7 mV), and %IE (92%). FTIR and PXRD studies indicated no chemical interaction between the constituents of the SLNs and the conversion of crystalline form of drug to amorphous form, respectively. CLZ-loaded SLNs demonstrated a significantly enhanced release (p < 0.05) and meaningfully improved bioavailability (p < 0.05) as compared with the CLZ suspension. Histopathological evaluation showed that CLZ-loaded SLNs were nontoxic to the cells lining the intestinal tract. They were found to have a stable shelf life during the three-month evaluation period. Hence, it was concluded that CLZ-loaded SLNs have the potential to improve the oral bioavailability of CLZ without toxicity.

Statistical Design for Formulation Optimization of Diclofenac Sodium-Loaded Ethylcellulose Microsponges

For a better use of the drug, a decrease in side effects, an improvement in effectiveness, and a uniform release of the active ingredients, sustained-release forms have been developed. The objective of this study is to estimate the effect of the factors on the responses involved in the formulation of Diclofenac Sodium (DC) loaded ethylcellulose (EC) microsponges (MP) using Central Composite Design (CCD). Quasi emulsion solvent diffusion method was used to formulate MP. The ratio of ethylcellulose to Diclofenac Sodium and polyvinyl alcohol (PVA) concentration (w/v%) were selected as independent variables for CCD. Entrapment efficiency (EE) and production yield (PY) were selected as dependent variables. The optimal formulation was characterized by Fourier Transform Infrared (FTIR), Optical Microscopy, and in vitro release. Optimized MP showed an EE of 31.02% and a PY of 66.44%, FTIR studies revealed no chemical interaction between drug and polymer used, MP were spherical and present an average size of 9.21±0.3µm. Kinetic studies revealed that drug release from optimized formulation followed Higuchi model. The results demonstrated the effectiveness of proposed design for development of DC microsponges for the sustained release.

Development and Characterization of Novel co-processed excipients to enhance compressibility profile for Formulation of Tablet Dosage Form

The present work deals with the development of a novel co-processed excipients using melt- granulation technique that would serve as an inbuilt multifunction adjuvant and can be used for the preparation of tablet as solid dosage form with poorly compressible drugs like Paracetamol, Diclofenac, and Ibuprofen etc. by direct compression method. In the formulation DCP (Dicalcium phosphate) and Potato Starch were used as a filler in 2:1 ratio; Croscarmellose as a superdisintegrant and 20% w/v PEG 6000 (polyethylene glycol) as a binder, to develop the co-processed excipient. This resulted in formation of co-processed agglomerates, which had exhibited better flowability, compressibility and compaction properties when compared to an individual excipient and/or the physical mixture of compounds. Being a poorly compressible drug, PCM (Paracetamol) was used as a model drug to prepare tablets. The finally developed tablet dosage form of PCM along with co-processed excipient, were subjected to Fourier Transform Infra-Red (FTIR) study to ensure the absence of any drug-excipient interaction. The dosage form was also evaluated for capping and lamination to assure the better compressibility profile. The surface characteristics of developed co-processed agglomerated mass was characterised using Scanning Electron Microscopy (SEM). From the results obtained, it was concluded that the co-processed excipient is superior in flowability and compression characteristics in comparison to the physical mixture of excipients and individual components both. FTIR studies explained that there is no drug-excipient interaction and SEM also shown the spherical shapes of the agglomerated mass proving the better flowability properties of co-processed excipients.

FTIR study on the cellular chemical composition of Allium cepa L. seedlings under salt stress

The current study is to investigate the effects of salinity on cellular chemical composition in four cultivars of onion seedlings (Agrifound rose, Bellary, Prema-178 and Nasik red) at different time intervals through the Fourier-transform infrared (FTIR) spectroscopy. Onion seedlings were treated with 0, 50 and 150 mM NaCl for 3 h and 48 h intervals and dried samples were used for analysing the biochemical changes using FTIR spectroscopy. The results provided insights at 50 and 150 mM NaCl and clear differences were noticed in profiles related to lipids, proteins and carbohydrate functional groups compared with untreated control. In principal component analysis (PCA), the first two principal components (PC1 and PC2) of four onion cultivars and salt treatments explained 95.7 % of total variations whereas 71.8 % of total variations were accounted with FTIR spectra of 4000-1000 cm-1 region. Multiple linear regression (MLR) analysis exhibited significant correlation values of R2 &gt; 0.9. At both the intervals of salt treatment, the Bellary cultivar showed good responses, thereafter Prema-178 cultivar at each concentration when compared with control. In conclusion, FTIR spectroscopy can elucidate early salt stress-induced chemical changes in various compounds as well as the salt adaptive process in onion metabolism.