Single-beam Spectrophotometer Research Articles

Determination of ionization constants for sequinidazole in aqueous solutions and mixtures of water with isopropanol, acetonitrile and ethanol

Seknidazole is a drug from the 5-nitroimidazole group with a number of side-effects. This drug is virtually unexplored from the point of view of chemico-toxicological analysis (CTA). Therefore, the development of a set of methods for the detection and quantification of secnidazole in biological fluids for use in CTA is an urgent task. Aim. To study the acid-base equilibrium of secnidazole in aqueous solutions and mixtures of water with amphiphilic solvents and determine the corresponding ionization constants. Materials and methods. Spectrophotometric measurements were performed using a SPEKOL®1500 single-beam spectrophotometer. An EV-74 ionomer was used to control the pH of the solutions. Seknidazole solutions in the concentrationof 1000 μg/ml were used in the experiment. Results and discussion. Absorption spectra of secnidazole in water and mixtures of water and amphiphilic solvents in the pH range studied showed four isobestic points characterizing two protolytic equilibria (equilibrium 1 – 240 and 295 nm, equilibrium 2 – 261 and 297 nm). The position of the isobestic points of equilibrium 2 fluctuated in the range ± 3 nm; it was due to the presence of tautomeric transformations for the molecular form of secnidazole. Conclusions. The acid-base equilibria of secnidazole in aqueous solutions and mixtures of water with amphiphilic solvents have been studied. It has been shown that in a strongly alkaline medium there is an anionic form of secnidazole R–, with further decrease in the pH value the molecular form HR appears, in a strongly acidic medium the final product – a protonated form H2R+ – is formed. The ionization constant 1 has been determined for aqueous solutions of secnidazole, mixtures of water with isopropanol, acetonitrile and ethanol. It is impossible to determine the equilibrium constant 2 by the method specified.

Method Development and Validation of Azelnidipine Drug by Ultraviolet Visible Double Beam Spectrophotometer

Azelnidipine is a ca2 channel blocker used for treatment of patients with hypertension. The main objective was to develop UltraViolet- visible spectroscopy method for Azelnidipine which should be fast error-free exact sensitive and validate the processed method according to ICH guidelines by use of API and tablet formulations of Azelnidipine by UV-visible spectroscopy. UV-visible Spectrophotometric resolution was carried out with Thermo scientific GENESYS 10S single beam spectrophotometer. A simple rapid precise accurate and sensitive UV-visible Spectroscopy method has been developed for the determination of Azelnidipine by using acetone as a medium. The spectrum of the standard solution was run from 200-400 nm range for the determination of lambdamax and lambdamax of Azelnidipine was found at 255 nm. Different validation parameters such as Linearity Accuracy Precision LOD and LOQ and Robustness and various Quality Control tests like here evaluated as per ICH guidelines. Linearity for the UV-visible Spectroscopy was noted in the concentration range of 2-14microgml and mean correlation coefficient of 0.9993. Accuracy was found to be 98- 100. The precision demonstrates as relative standard deviation of Intraday and Interday which was 1.058-1.029 and 1.144-1.316 with RSD less than 2 and the limit of detection which was LOD and limit of Quantitation LOQ for Azelnidipine was found to be 2.086 and 8.68 microgmml respectively. The proposed UV-visible spectroscopy method and its validation according to the ICH guidelines shown that method is sensitive precise accurate and simple for the estimation of Azelnidipine API and tablet formulation.

Color ruler to confirm spectrophotometer results for nitro compound content in acidic wastewater from TNT processes

This study aimed to find an additional analytical reference procedure to verify the accuracy of single beam Spectrophotometer results that used to determine the concentration of nitro compound pollutants such as TNT, DNT, and MNT (Tri Nitro Toluene, Di Nitro toluene, and Mono Nitro Toluene respectively) in treated acidic wastewater generated from TNT manufacturing. This procedure was tested and confirmed to be a reference for a single-beam spectrophotometer. In this study 10 samples with known concentrations were taken and prepared for colorimetric analysis, the concentrations gradient from 10mg/L up to 60mg/L to make a ruler with gradient color, this ruler was suitable for high concentration samples but to specify the low concentration samples the procedure depended on adding a known concentration to the unknown concentration sample then this added concentration transferred the samples from unspecified color to specified color on the ruler consisted by known concentration mentioned above, the concentration of unknown concentration samples were specified by taking the concentration corresponding to the ruler color a subtracting the value of added concentration and the value of the remains was sample concentration. This study proved the reliability of this procedure to confirm single-beam spectrophotometer results, determining low concentration value of unknown concentration sample of TNT acidic wastewater, and then it can be used as a substituent of spectrophotometer in the event of malfunctions.

Determination of catechins in green tea leaves by HPLC compared to spectrophotometry

Aim. To study the qualitative composition, the quantitative content of catechins in green tea leaves and compare the data obtained with those evaluated by spectrophotometry.Materials and methods. Green tea leaves used for the analysis were collected in Anhui Province, China. The extract for the HPLC analysis was obtained by the maceration method with 60 % ethanol twice in the raw material/extractant ratio of 1 : 20. In the case of the spectrophotometric analysis, green tea leaves were extracted with 70 % ethanol twice by the maceration method in the raw material/extractant ratio of 1 : 20. The analysis of the extract from green tea leaves was performed by high performance liquid chromatography using a Prominence LC-20 Shimadzu chromatographic system (Japan) with a SPD-20AV spectrophotometric detector, an Agilent Technologies Microsorb-MV-150 column (reversed phase, C18 modified silica gel, length – 150 mm, diameter – 4.6 mm, particles size – 5 μm). Substances in the extract were identified by comparing the retention time and the spectral characteristics of the test substances with the same characteristics of the reference standards. Spectrophotometric measurements were carried out using a UV-1000 single beam spectrophotometer (China) with the pair of S90-309Q quartz square cells.Results and discussion. Using high performance liquid chromatography 5 catechins were identified. Among them epigallocatechin-3-O-gallate (10.85 %) predominated, while catechin (0.61 %) had the lowest concentration. The total amount of catechins in green tea leaves was 30.56 and 24.79 % by HPLC and spectrophotometry, respectively. The F- and t-tests showed that there was no significant difference between the results of HPLC and spectrophotometry.Conclusions. The qualitative composition and the quantitative content of catechins have been determined in the extract from green tea leaves by high performance liquid chromatography and spectrophotometry. Both HPLC and spectrophotometric methods can be used to determine the total catechin content in green tea leaves. The high content of catechins makes the extract promising for further study and creation of new herbal medicinal products and dietary supplements. The results obtained will be used for standardization of green tea leaves and for future pharmacological research of its extract.

On the structural and optical properties investigation of annealed Zn nanorods in the oxygen flux* *Project supported by the University of Mohaghegh Ardabili.

Zn nano rods were produced on glass substrates using oblique angle deposition method at different deposition angles. For oxidation, the samples were placed in a furnace under oxygen flux. AFM and FESEM images were used to morphology analysis of the structures. The results showed that with increasing the angle of deposition, the grain size decreases and the porosity of the structures increases. XRD pattern and XPS depth profile analysis were used to crystallography and oxide thickness investigations, respectively. The XRD results confirmed oxide phase formation, and the XPS results analyzed the oxide layer thickness. The result showed that as the deposition angle of the nanorods increases, the thickness of the oxide layer increases. The reason for the increase in the thickness of the oxide layer with increasing deposition angle was investigated and attributed to the increase in the porosity of the thin films. The optical spectra of the structures for p polarized light at 10° incident light angle were obtained using single beam spectrophotometer in the 300 nm to 1000 nm wavelengths. The results showed that the formed structures although annealed in oxygen flux, tend to behave like metal. To calculate the optical constant of the structures, the reverse homogenization theory was used and the void fraction and complex refractive index of the structures were obtained. Finally, by calculating permittivity and optical conductivity of the structures, their changes with the deposition angle were investigated.

Effect of doping of molybdenum on the optical properties of glasses of the As—S system

This article discusses the spectral dependences of the absorption coefficient of thin arsenic sulphide films obtained by spin-coating, identified using a single-beam spectrophotometer in the wavelength range of 400–1000 nm. The effect of doping of molybdenum on the optical band gap is studied. While for a pure glass the band gap decreases with higher sulphur concentration, the opposite trend is observed in glass doped with molybdenum. Molybdenum doping also leads to an increase in Urbach energy. The obtained experimental curves are compared with theoretical ab-initio calculations.

Synthesis and characterization of silver nanoparticles-doped titanium (IV) oxide thin films

Current advancements in nanotechnology appear to open a more efficient, stable, and cheaper way of producing solar cells to replace the too expensive means of inorganic solar cells production. The creation of nanoscale materials for advanced structures has led to a growing research interest in the area of photovoltaic energy conversion using photovoltaic devices. This research investigates the impact of annealing temperature on the optical properties of silver nanoparticles-doped titanium (IV) oxide thin film (TiO2:AgNPs) deposited by spin-coating method on glass substrate. AgNPs were prepared using the leaf extract of Gliricidia sepium as a reducing agent for silver nitrate. Deposition of TiO2:AgNPs composite solution was performed in different volume ratio. Deposition of TiO2:AgNPs volume ratio (1: 0.2) was performed with different spin-coating speed for 30 seconds at 7 different thicknesses. Characterization of the optical properties of thin films was carried out by using a UV-vis single beam spectrophotometer; this was used to calculate the absorbance and the bandgap energy. Sixteen 16 samples of TiO2:AgNPs deposited at 1000 rpm on the glass substrate were annealed at temperature range of 50 to 425 °C with step of 10 °C interval in a tubular furnace. It was observed from the results that the peak absorption of photon energy occurred at 375 °C in the visible spectrum of the wavelength band. The optimal thickness for peak absorbance of the TiO2:AgNPs blend layer occurred at 115 nm in the visible spectrum and at the corresponding spin speed of 1000 rpm. The optimized fabrication process with blend layer thickness of 115 nm yielded the best absorbance at an annealed temperature of 375 °C in the visible spectrum. The volume ratio of (1:0.2) gave the peak absorption at 0.75 au. At 1000 rpm with the corresponding thickness of 115 nm, TiO2:AgNPs blend has the peak absorbance. The energy band gap of the blend thin film is 3.58 eV at 375 °C in the visible spectrum of wavelength band. The result obtained showed that AgNPs enhanced light absorption, broadened absorption spectral range and thermal stability of titanium (IV) oxide film. The result can be used as a guideline in the design and fabrication of solar cells.

Hyper Gravity-Induced Transients in <i>Phycomyces</i> as Measured by Single Beam Spectrophotometer on the Sounding Rocket TEXUS 50

In the first paper of two referring to the TEXUS 50 campaign using micro dual wavelength spectrometers (MDWS) we kinetically determined the threshold1 for GIACs (gravity-induced absorption changes) in Phycomyces to be lower than 25 × 10−3 g (http://file.scirp.org/pdf/JMP_2015082810060783.pdf). In this second paper, we attended measurement of GIAC-spectra. Unexpectedly, during the upwards movement, i.e. the hypergravity phase up to top acceleration values reaching 11.6 g at 35.4 s after liftoff we observed transient GIAC-spectra ranging from 380 to 750 nm. In addition, during the whole acceleration phase of 68.2 s, another component near 700 nm develops which remains stable during the whole “free fall trajectory parabola” for 381.3 s. The subsequent reentry of the rocket leads to extraordinary deceleration values up 37.8 g, completely destroying Phycomyces sporangiophores excluding their spectral measurement. During the microgravity phase and by centrifuge operation we were unable to detect any GIAC-spectra (in contrast to kinetic MDWS-measurements, first paper).

Optical properties of manganese chiral single ring by glancing angle deposition technique

Embracing physical vapor deposition system, GLAD method defines the deposition angle, α, in terms of vapor flux and normal substrate. The substrate rotation angle, φ, defines the azimuthal substrate position relative to an arbitrary starting position. We have fabricated periodic nanostructure through utilizing GLAD to control the film deposition conditions over these arrays. Manganese chiral single ring nanostructure have been created using oblique angle deposition method in conjunction with rotation of normal surface substrate. Employing AFM measurement and J-Microvision software, we obtained structure morphology, the size of grains, surface physical roughness and surface void fraction. The optical spectra of the samples were obtained using a single beam spectrophotometer for the incident light of the surface normal. Moreover, it should be mentioned here that Fresnel formulas and experimental measurements of reflectance and absorption spectra could be applied to obtain the refractive index n and the absorption index k. Since Manganese chiral single ring of fabricated nanostructure with GLAD technique is porous, the plot of the refractive index that was observed as a function of the wavelength index aspect has lower values in comparison with homogeneous Manganese thin film associated with longer wavelengths. Therefore, we can control the refractive index of nanostructure with regard to the film density and porous. It is suggested that GLAD may offer an effective method to attain tailor able refractive index.

Study of zinc oxide thin film characteristics

This paper presents the characterization of ZnO thin films with the thickness of 8nm, 30nm, and 200nm. The thin films were prepared using sol-gel method and has been deposited onto different substrate of silicon wafer, glass and quartz. The thin films were annealed at 400, 500 and 600°C. By using UV-Vis, the optical transmittance measurement were recorded by using a single beam spectrophotometer in the wavelength 250nm to 800nm. However, the transmittance in the visible range is hardly influenced by the film thickness, substrate used and annealed temperature and the averages are all above 80%. On surface morphology observed by AFM and FESEM, the results show that the increase of film thickness and annealed temperature will increase the mean grain size, surface-to-volume ration and RMS roughness. Besides that, higher annealing temperature cause the crystalline quality to gradually improve and the wurtzite structure of ZnO can be seen more clearly. Nonetheless, the substrate used had no effect on surface morphology, yet the uniformity of deposition on silicon wafer is better than glass and quartz.

Influence of number of pitches and substrate on the nanostructure and optical properties of ZnS helical sculptured thin films

ZnS helical sculptured thin films with different number of pitches were produced on glass (microscope slides) and pre-deposited 7nm ZnS on glass substrate. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were used for structural analyses. Crystallographic structure of samples was obtained using x-ray diffraction (XRD) method which confirmed the formation of ZnS films on the substrates. Optical spectra of the samples were measured using a single beam spectrophotometer for both s- and p-polarized light and at different incident light angles. Optical results showed a strong dependence on the structural void fraction and number of pitches and, due to anisotropy of the helical structure, a dependence on the incident light angle. It is shown that by controlling the growth of these structures the optical spectra can be controlled.The reversed homogenization theory was used to calculate the complex refractive index of these structures and the percentage of the void fraction in the produced samples. This investigation showed that both real and imaginary parts of the refractive index are dependent on the structural void fraction; structures with larger grains and higher percentage of void fraction having larger real and imaginary parts of the refractive index. Band gap calculations showed that structures with larger grains and higher void fraction have smaller band gaps. A correlation is obtained between the band gap energies and the nano-strain developed in the structure of the produced films; band gap energy decreases with nano-strain.

Geogenic Contamination: Hydrogeochemical processes and relationships in Shallow Aquifers of Ibadan, South-West Nigeria

Abstract The result of the spatial analysis as applied to the hydrogeochemical data set in the shallow aquifer of Ibadan provides an insight into the underlying factors controlling hydrogeochemical processes in the area. A total of thirty drinking water samples (six samples each from the five major lithologic formations of the study area) were collected from shallow aquifers during the rainy and dry season. Atomic Absorption Spectrophotometry (AAS) and the Beckan DU-7500 single beam spectrophotometer were used to determine concentrations of arsenic, iron and fluoride in drinking water samples and the concentrations of other chemical parameters that could affect the concentrations of the geogenic contaminants including Ca, Mg, Na and SO4 2− were also analysed. pH and TDS were also determined. The Pearson Correlation and Factor Analysis were used to examine the relationship between the geogenic contaminants and concentration of other hydrogeochemical parameters while isopleth maps were drawn to ascertain lines of equal geogenic concentration (Isogeogenic lines). Factor analysis reduced the dataset into three major components representing the different sources of the contaminant. Major contributors to factor 1 and 3 (Salinization and Sulphate factors respectively) are natural phenomena while factor 2 is partly geogenic. The Isogeogenic lines show places of equal geogenic concentration and also with 3D Elevation modelling showed a high peak of Arsenic and Fluoride in the Sango area. The correlation test showed that there is a positive relationship between As and SO4 2− 0.889 (P < 0.05) and also a positive relationship between As and Mg 0.43 (P < 0.05). The significant relationship between As and SO4 2−, shows a partly geogenic source resulting from the reduction of sulphate to sulphide for the mobilization of As. The positive relationship between Fluoride and pH 0.242 (P > 0.05) implies that the concentration of F within the rock formation depends on high pH value.

Effect of Annealing Temperature on the Structural and Optical Properties of Zinc Oxide (ZnO) Thin Films Prepared by Spin Coating Process

ZnO thin films were deposited onto the glass substrates by spin coating method. Zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine (MEA) were used as starting materials for the thin film preparation. Films were obtained by spin coating at 4000 rpm for 30 sec at room temperature and were annealed at different temperatures ranging from 200°C to 400°C. The effect of annealing temperature on the structural and optical properties of the ZnO thin films was investigated. Surface morphology of thin films was studied using atomic force microscope (AFM). The optical absorbance and transmittance measurements were recorded by using a single beam spectrophotometer in the wavelength range 300 nm to 900 nm. Evaluated optical band gap value agrees approximately with that of bulk ZnO. It is observed that band gap decreases as the annealing temperature is increased from 200°C to 400°C.

Extinction Spectra and Electric Near-Field Distribution of Mn Nano-Rod Based Sculptured Thin Films: Experimental and Discrete Dipole Approximation Results

Mn columnar (nano-rod shaped) sculptured thin films including helical square, helical rectangle, and helical pentagon with different dimensions were deposited on glass substrates, using oblique angle deposition technique (OAD) together with the rotation of the substrate holder about its surface normal. Field emission electron microscope (FESEM) was used for the structural analysis. Optical spectra of the samples were measured using single beam spectrophotometer for both s- and p-polarized lights and at different incident light angles and different azimuthal angles. The discrete dipole approximation (DDA) method is used to obtain the extinction spectra for nano-rods positioned at different orientations with respect to the incidence light direction. The electric near-field distributions were also investigated for these structures. Results showed that the experimental extinction spectra of structures consisting of a combination of nano-rods (e.g., square, rectangle, and pentagon in this work) are due to overlap of spectra of single nano-rods. It is found that when the electric field of the incident light is parallel or normal to the long axis of the nano-rod, the extinction is maximized or minimized, respectively. Theoretical DDA calculations showed that the latter effect is due to entrapment of light when its electric field is normal to the nano-rod axis.

Groundwater contamination in Ibadan, South-West Nigeria.

Groundwater is the main source of water for domestic use in Nigeria because it is perceived to be clean. The presence of geogenic contaminants (arsenic and fluoride), and the level of awareness of their presence in groundwater in Ibadan, Nigeria was examined in this study. A total of one hundred and twenty groundwater samples were collected from hand dug wells which tap into shallow aquifers and their location taken with the aid of a GPS. The concentration of arsenic was determined by Atomic Absorption Spectrophotometry (AAS) while concentration of fluoride was determined by single beam spectrophotometer. Three hundred and fifty semi structured questionnaires were also administered within the study area to determine the level of awareness of contamination problem. Simple summary statistics including mean (m) standard deviation (s) and minimum-maximum values of the hydro-chemical data was used in the data analyses, while spatial concentrations were mapped using ArcGIS. The results showed arsenic concentration exceeding the WHO (2011) recommended concentration for drinking water in 98% and 100% of the dry and wet season samples. Concentration of Fluoride exceeded the recommended limits in 13% and 100% of the dry and wet season samples. Questionnaire analyses revealed that 85% of respondents have never tested their wells, 55% have no knowledge of geogenic contamination, while 92% never heard of arsenic or fluoride (52%). The study recommends enlightenment on geogenic contamination and testing of wells for remediation purposes.

Absorption Spectroscopy for the Estimation of Glycated Hemoglobin (HbA1c) for the Diagnosis and Management of Diabetes Mellitus: A Pilot Study

The purpose of this study was to explore the possibility of using absorption spectroscopy technique for the estimation of glycated hemoglobin HbA1c (%). Glycated hemoglobin (HbA1c) is an important marker in the diagnosis and management of diabetes mellitus. Different assay techniques have been employed for the estimation of glycated hemoglobin, including ion exchange high performance liquid chromatography (HPLC), electrophoresis, affinity chromatography, immunoturbidimetric assay and colorimetric assays, which measure different glycated products and report using different units. Spectroscopic measurements have been shown to be very sensitive and nondestructive, and require very little quantity of material for analysis. In the present study, we have employed absorption spectroscopy technique for the estimation of glycated hemoglobin in hemolysate samples of diabetic patients. The blood samples of individuals with normal glycemic status and confirmed diabetic patients were collected from the Clinical Biochemistry Laboratory, Kasturba Hospital, Manipal. The absorption spectra of glycated hemoglobin (HbA1c) samples were recorded in the spectral range 200-850 nm using an optic fiber based Ocean Optics CHEMUSB4-UV-VIS single beam spectrophotometer. The parameter "area under the curve" of each baseline corrected absorption spectrum was used for the estimation of HbA1c (%). The glycated hemoglobin values obtained by this spectroscopic method were compared with the values reported by the standard ion exchange HPLC method. A total of 30 absorption spectra were recorded from hemolysate samples with HbA1c (%) in the range 4-10.5%. A good correlation was observed between the glycated hemoglobin values obtained by the spectroscopic method and those obtained by the standard HPLC method. It appears that the direct absorption spectroscopy of hemolysate samples, therefore, may be utilized as a supplementary technique for the estimation of HbA1c (%), even at the primary healthcare centers.

Nano-structural characteristics and optical properties of silver chiral nano-flower sculptured thin films

Silver chiral nano-flowers with 3-, 4- and 5-fold symmetry were produced using oblique angle deposition method in conjunction with the rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM), were employed to obtain morphology and nano-structure of the films. Optical characteristics of silver chiral nano-flower thin films were obtained using single beam spectrophotometer with both s- and p-polarization incident light at 30° and 70° incidence angles and at different azimuthal angles ( φ). Optical spectra showed both TM (TDM (transverse dipole mode) and TQM (transverse quadruple mode)) and LM (longitudinal mode) Plasmon resonance peaks. For 3- and 4-fold symmetry chiral nano-flowers the s-polarization extinction spectra obtained at different azimuthal angles did not show significant change in the Plasmon peak position while 5-fold symmetry chiral nano-flower showed a completely different behavior, which may be the result of increased surface anisotropy, so when the φ angle is changed the s-polarization response from the surface can change more significantly than that for lower symmetries. In general, for 3-, 4- and 5-fold symmetry chiral nano-flowers a sharp peak at lower wavelengths (<450 nm) is observed in the s-polarization spectra, while in addition to this peak a broad peak at longer wavelengths (i.e., LM) observed in the p-polarization spectra, which is more dominant for 70° incidence angle.

Spectrophotometers

Spectrophotometers

Synthesis and characterization of a novel kind soluble, conjugated, and fluorescent chelate polymer containing fluorene ring in the backbone: Optical, electrical, and electrochemical properties

A novel highly soluble coordination polymer, poly(3,4-HBA-Cr-FDA), containing Cr(III) ion in the backbone was synthesized. Monomeric model compounds (MC-1 and MC-2) were also synthesized as the comparison materials. The structures were characterized by FT-IR, UV–vis, 1H and 13C NMR, and size exclusion chromatography (SEC). SEC results showed that the novel polymer had 65–68 repeated units. ICP-AES was used to determine the chromium content of MC-2. Thermal data were obtained by TGA and DSC techniques showing that MC-2 and the novel polymer had high rate of hydrate water. Cyclic voltammetry (CV) measurements were carried out and the HOMO–LUMO energy levels and electrochemical band gaps (E′g) were calculated. Additionally, the optical band gaps (Eg) were determined using UV–vis spectra of the materials. Electrical conductivity measurements of the doped (with iodine) and undoped polymer related to temperature and doping time were carried out by four point probe technique using a Keithley 2400 electrometer. Measurements were made using the polymeric film deposited on ITO glass plate by dip-coating method. Also, absorption spectra of doped polymeric film were recorded by a single beam spectrophotometer showing that doping procedure causes peak growing in absorption spectra. Ability of processing of poly(3,4-HBA-Cr-FDA) in gas sensors was discussed. Fluorescence spectra of the polymer in a series of solvents were obtained and it was found that poly(3,4-HBA-Cr-FDA) had green–red emitting emission in different solvents.

Soluble semi-conductive chelate polymers containing Cr(III) in the backbone: Synthesis, characterization, optical, electrochemical, and electrical properties

Soluble kinds of coordination polymers containing Cr(III) ion in the backbone were synthesized. Structures of the polymers were characterized by FT-IR, UV–vis, 1H and 13C NMR, and size exclusion chromatography (SEC). Thermal degradation data were obtained by TG–DTA and DSC techniques. Cyclic voltammetry (CV) measurements were carried out and the HOMO–LUMO energy levels and electrochemical band gaps (Eg′) were calculated. Additionally, the optical band gaps (Eg) were determined by using UV–vis spectra of the materials. Electrical conductivity measurements of doped (with iodine) and undoped polymers related to temperature were carried out by four-point probe technique using a Keithley 2400 electrometer. Measurements were made by using the polymeric films deposited on ITO glass plate by dip-coating method. Also, absorption spectra of doped polymeric films were recorded by a single beam spectrophotometer showing that doping procedure causes shifting in absorption spectra. Their abilities of processing in gas sensors were also discussed. According to obtained results the synthesized chelate polymers are semi-conductors having polyconjugated structures. Also, P-2 is the most electro-conductive polymer among the synthesized, while P-1 is the most thermally stable one.