Camphorsulfonic Acid Research Articles

Supramolecular Assembly of Nanostructured Conducting Polymer Hydrogels by Hydrotropic Agents for Outstanding Supercapacitive Energy Storage

Conducting polymer hydrogels (CPHs) are relevant to energy storage due to their micro-nanoscale three-dimensional network combined with a high electronic conductivity and electrochemical activity. The successful implementation of CPHs as an energy storage material requires solving two barriers: (1) low capacitance and electronic conductivity of current CPHs and (2) the lack of simple and scalable chemical synthesis routes. In this work, we propose a different approach for the synthesis of CPHs based on a supramolecular self-assembly induced by hydrotropic agents. The proposed synthesis method induces the formation of networks with superior electronic conductivity which does not require the addition of costly additives. Herein, para-toluene sulfonic acid (p-TSA) was proposed to produce CPHs of polypyrrole (PPy). The method was further extended to other polymer and hydrotropic agents as polyaniline and camphor sulfonic acid, demonstrating the versatility of the synthesis method. It was found that morphology and physical–chemical and electrochemical properties of PPy-CPHs can be fine-tuned with the amount of doping agents. The optimized PPy-CPHs sample possesses a high specific gravimetric capacitance of 560 F g–1 and an areal capacitance of 695 mF cm–2 at 0.75 A g–1 in addition to a capacitance retention of 72% at 10 A g–1, significantly higher than most state of the art PPy electrodes. Characterization suggests that CPH’s faster charge transfer and enhanced ionic and electronic conductivity are due to the higher degree of conjugation, porosity, and size of polymer clusters. Moreover, the symmetric supercapacitor devices with liquid and solid electrolytes exhibit an excellent energy storage performance with a maximum energy density of 13 W h kg–1 and power density of 3.6 kW kg–1. These devices also exhibit a capacitance retention of 82% after 5000 cycles at 5 A g–1.

Templated growth of polyaniline for enhanced gas sensing response in flexible sensors: experiments and simulations

Gas sensors using polyaniline structures fabricated from non-templated structures (homogeneous solution growth) and templated structures (heterogeneous growth using a functionalized substrate) have shown different sensing performances in the literature, and the sensing mechanism explaining variation of their sensing performance is not well understood. This is the motivation of the present work. In this study, camphor sulphonic acid doped polyaniline structures, synthesized utilizing both non-templated and templated growth approach, fabricated on polyethylene terephthalate substrates were used for gas sensing. The detailed characterizations of the sensing films were done by FE-SEM, FTIR, UV–vis spectroscopy and then the films were utilized for the sensing of NH3, CO2 and NO2 gases in N2 medium. Vertical arrangement of the facile polyaniline structures in templated grown films was useful for gas sensing application. Gas sensing responses were studied and found to improve in comparison to that of non-templated structures. For both templated and non-templated grown films, a response trend was observed as NO2 > NH3 > CO2. Computational studies were performed and showed that templated grown structures formed cages due to entanglement of the functional groups, which were not seen with non-templated grown structures. Cages serve as the strong van der Waals dominated binding sites for the analytes due to the presence of the surrounding aromatic rings. In addition, with binding energy calculations, the sensing interactions for different analytes were observed to be higher for the templated grown films, compared to that of the non-templated grown ones. Also based on energy considerations, the barrier of interactions for the different analytes was studied for the templated grown films and the reason for the trend of preferential response to different analytes was explained through energy barrier consideration. Results from both simulations studies and experimental observations showed a similar response trend towards gas sensing.

(±)-Camphor sulfonic acid assisted IBX based oxidation of 1° and 2° alcohols

• Efficient methodology has been developed for the oxidation of primary and secondary alcohols using IBX-Camphor sulfonic acid catalytic system. • The methodology is compatible with a variety of substrates having arene, heteroarene and alkene functionalities. • The reaction works well in the binary solvent system.

The Role of Formic Acid as Secondary Dopant and Solvent for Poly(O-Toluidine) Intrinsically Doped with Camphor Sulfonic Acid

The role of formic acid as Secondary Dopant for Poly (O-toluidine) Intrinsically Doped with Camphor Sulfonic-Acid (POT-CSA) nanoparticles were prepared by chemical polymerization had been studied. Spin coating and casting method have been used to deposit good adhesion and uniform thin films of (POT-CSA) on a glass substrates at room temperature. the properties of (POT-CSA) nanoparticles which examined by FTIR, SEM, AFM, XRD, I-V characteristics and UV-VIS. FTIR studies show the several bending and stretching modes of POT. XRD examination demonstrated that NPS. has a semi-crystalline pattern . The synthesized film well covered by the nanoparticles over the entire substrate surface, exhibits uniform, porous, and spherical granular surface morphology, A narrow size distribution is observed and the average size of particles about 80 nm. The band gap (Eg) has been determined which is equal to 3.1 ev. The room temperature conductivity of POT-CSA was 3 * 10-1 S.cm-1,which increases with increasing temperature. Electrical conductivity enhances up to three order after the secondary doping process. Keywords: POT-Chemical polymerization-Conducting polymer-SEM-AFM

A Study on Camphor Derivatives and Its Applications: A Review

Natural compounds are the prominent sources for the synthesis of abundant biologically active substances in medicinal chemistry. Camphor exists in two enantiomeric forms i.e., R and S, or both, which are readily obtainable. Camphor is a small molecule with chirality property that binds to some active site, together with its low cost and convenience to transform into synthetically useful derivatives and one of the most important monoterpenoids widely spread in plants and has been used as starting material for the various camphor based derivatives which exhibit several biological activities include antimicrobial, antiviral, antioxidant, analgesic and anti-cancer. Many of those simple derivatives are commercially available in the form of camphor sulfonic acid or ketopinic acid that can be easily be produced from camphor. This compound is primarily used as a chiral starting material in the enantiospecific synthesis of natural products is because of its available methods for the direct or indirect introduction of functionality at C-3, C-5, C-8, C-9, and C-10 carbon atoms. In this study, heterocyclic compounds derived from camphor are arranged in different groups as Camphor-Derived Simple Heterocycles, Fused Camphor-Derived Heterocycles, Spiro Camphor-Derived Heterocycles, Ring Expanded Camphor-Derived Heterocycles and Camphor derived metal complexes. This study summarizes the transformations of camphor and its derivatives along with their biological activities.

Regioselective Synthesis, Spectroscopic Characterization, and Computational Chemical Study of Spiro[Indoline-3,4’-Pyrazolo[3,4-b] Pyridine Derivatives as Agrochemical Agents

Herein, new four-component domino reactions are described and utilized to synthesize spiro[indoline-3,4’-pyrazolo[3,4-b]pyridine derivatives via one-pot reaction. Different hydrazine derivatives such as hydrazine hydrate, methyl hydrazine, and phenylhydrazine were allowed to react with active methylene precursors (CH2CN) as malononitrile, ethyl cyanoacetate, isatin, and 1,3-dicarbonyl compounds in the presence of (+)-camphor-10-sulfonic acid (CSA) as the acid catalyst under microwave condition using water as the solvent. Two and three fused heterocyclic rings were obtained in a single synthetic operation with a facile work-up and less waste generation due to the absence of extraction and purification steps. Structural features of the obtained compounds were confirmed by utilizing elemental analyses, mass spectrometry, 1H-NMR, and 13C-NMR microanalyses. Insecticidal assessments for some of the synthesized pyrazole derivatives against the cotton leafworm Spodoptera littoralis were conducted. In addition, fungicidal activities against Rhizoctonia solani and Fusarium solani soil-borne fungi were also performed. The tested compounds showed poor insecticidal activity compared with the standard insecticide chlorpyrifos ethyl. Meanwhile, they showed remarkable fungicidal activity against tested pathogens. Analysis of the fungicidal study indicated that R. solani fungus was found to be more sensitive to the tested compounds than F. solani fungus. Some pyrazole derivatives particularly possessed close or even higher fungicidal activities than the standard fungicide Pencycuron (Monceren 25%WP). The density functional theory was then applied to explore the structural and electronic characteristics of these materials.

Diazotization of Aminopyridines in the Presence of Camphorsulfonic Acid. Synthesis and Some Properties of Pyridinyl Camphorsulfonates

Diazotization of Aminopyridines in the Presence of Camphorsulfonic Acid. Synthesis and Some Properties of Pyridinyl Camphorsulfonates

Chiral Charge Carriers Chiralions for Polyaniline Examined with Optical Rotation Spectroelectrochemistry

In this study, the optical active polyaniline film was examined with optical rotatory dispersion (ORD) through change in potential with spectroelectrochemical method. Polyaniline is one of the representative conducting polymers. Preparation of polyaniline is convenient because synthesis of polyaniline can perform in water medium. Conducting polymers shows electrochromism via change in the electronic state upon electrochemical redox process. Polyaniline forms various electronic states such as emeraldine base, emeraldine salt, and pernigraniline. This change allows to color tuning through electrochemical method. Further, optically active polyanilines have been synthesized in the presence of (+) or (-)-camphorsulfonic acid (CSA) by electrochemical polymerization or chemical polymerization with ammonium persulfate (oxidizing agent). Both electrochemical method and chemical method produce polyaniline through radical polymerization process. Polyaniline emeraldine salt as prepared form of polyaniline is doped with CSA, showing optical activity in the circular dichroism. In this research, we carried out to synthesis of polyaniline in the presence of optically active CSA, according to previously reported method (by Wallace et al). Here, we have found that the polyaniline thus prepared showed optically active electrochromism via electrochemical redox process in circular dichroism spectroscopy measurements. In our previous study, we calculated the ORD spectra for the polymer by Kramars - Kronich (K-K) conversion from circular dichromism. In the present research, we successfully obtained experimental data of optical rotation-spectroelectrochemical result, as a first example of optical rotation control of natural optical activity for conjugated polymers based on electrochemical method. In the case of low potential for the polymer in the electrochemical redox process, the polymer shows intense optical rotation at visible wavelength range. On the other hands, higher potential at around 1 V affords to give doping process for the polymer, resulting generation of polaron as charge carrier, which shows optical activity at near infrared region. We referred this optical charge carrier as “chiral charge carrier chiralions”. The electrochemical oxidation equivalents to electrochemical doping from the polymer. In other words, electrochemical oxidation gives electrochemical doping which results change in degree of optical rotation for the polymer. The control of optical ration for materials can be driven by magnetic field (Faraday rotation), and electric field (Kerr rotation). We propose a new phenomenon as ‘‘electrochemical optical rotation’’. The electro-conductivity of the polymer is measured with four-probe method. The polymer which is electronic doped state with (+)-CSA as electric dopant for production of radical cation (polarons) or dication (bipolarons) as charge carriers and chiral inducer for twisting main-chain. The polymer film was synthesized as followed. First, electrochemical polymerization of aniline as a monomer was carried out in excessive optically active (+)-CSA with three electrode system consisting of working electrode (indium-tin oxide coated glass), counter electrode (platinum wire), and reference electrode (SCE) in water. The polymerization reaction is rapidly progressed with formation of polymer thin film onto the counter electrode. The polymer was washed with excess amount of water, acetone. The electroactive polymer film was thus deposited on the electrode was used for optical activity measurements. Cyclic voltammetry (CV) measurements were carried out for the resultant polymer (monomer free) deposited on to the ITO coated glass electrode. The CV results with change in scan rate from 10-100 mV/s indicates electroactive. Increase of scan rate increases current density for the polymer due to increase of diffusion of ion in the electrolyte solution. Oxidation signals of the polymer are observed due to change in electronic state of the polymer. Corresponding reduction signals against oxidation process are observed, indicating reversible redox activity for the polymer. ORD measurement reveled that the polymer film thus obtained is optically active. The polyaniline can be formed helical structure due to doping of optically active CSA. We carried out in-situ ORD measurement with potential change, evaluating electrochemical driven change in optical rotation. Chemical structure of the double layer polymer is examined with Fourie transform infrared optical absorption spectroscopy measurements which reveled this polymer is polyaniline, and CSA as a dopant. Ultra-violet optical absorption measurements for the polymer film indicates intense and wide range absorptions from invisible to infrared range as charge carriers the delocalized along the main-chain, indicating the polymers are conductive materials. The advantages of the polymer film are formation of self-standing redox activity, tuning of optical activity and color coordination. This paper reports novel function of control optical rotation with electrochemical method examined with spectroelectrochemistry. This concept can be a first example as optical rotation effect of electro-optically active conducting polymers. This paper reports the charge carries of helical polyaniline as chiralions can tune via electrochemical method.

Full-Color and White Circularly Polarized Luminescence of Hydrogen-Bonded Ionic Organic Microcrystals.

A simple and general method is presented herein for the in situ preparations of circularly polarized luminescence (CPL)-active microcrystals with a large luminescence dissymmetry factor glum , high fluorescence quantum efficiency (ΦFL ), wide emission color tenability, and well-ordered morphology. The reactions of pyridine-containing achiral molecules 1-7 with chiral camphor sulfonic acid ((±)-CSA) gave crystalline microplates formed by hydrogen bonding interactions between the protonated pyridinium units and the sulfonic anions. The chiral information of CSA are effectively transferred to the microcrystals by hydrogen bonding to afford full-color CPL from deep-blue to red with glum in the order of 10-2 and ΦFL up to 80 %. Moreover, organic microcrystals with high-performance white CPL (ΦFL =46 %; |glum |=0.025) are achieved via the light-harvesting energy transfer between blue and yellow emitters.

Full‐Color and White Circularly Polarized Luminescence of Hydrogen‐Bonded Ionic Organic Microcrystals

AbstractA simple and general method is presented herein for the in situ preparations of circularly polarized luminescence (CPL)‐active microcrystals with a large luminescence dissymmetry factor glum, high fluorescence quantum efficiency (ΦFL), wide emission color tenability, and well‐ordered morphology. The reactions of pyridine‐containing achiral molecules 1–7 with chiral camphor sulfonic acid ((±)‐CSA) gave crystalline microplates formed by hydrogen bonding interactions between the protonated pyridinium units and the sulfonic anions. The chiral information of CSA are effectively transferred to the microcrystals by hydrogen bonding to afford full‐color CPL from deep‐blue to red with glum in the order of 10−2 and ΦFL up to 80 %. Moreover, organic microcrystals with high‐performance white CPL (ΦFL=46 %; |glum|=0.025) are achieved via the light‐harvesting energy transfer between blue and yellow emitters.

Cost-Effective MIL-53(Cr) Metal–Organic Framework-Based Supercapacitors Encompassing Fast-Ion (Li+/H+/Na+) Conductors

A chromium-based low-cost metal-organic framework (MOF) cathode, MIL (Materiaux de l′Institut Lavoisier)-53(Cr), is coupled with a bioderived porous carbon (BPC) anode, produced from abundantly available agricultural waste betel nut shells in an asymmetric supercapacitor, for the first time. The impact of the electrolyte on the electrochemical behavior of an asymmetric BPC//MIL-53(Cr) supercapacitor was assessed by constructing cells with the following electrolytes: proton-conducting camphorsulfonic acid (CSA), Li+-ion-conducting solutions of LiClO4, Na+-ion-conducting sodium poly(4-styrene sulfonate) solution, and ionic liquid (IL:1-butyl-1-methyl-pyrrolidinium trifluoromethanesulfonate)-based solutions. The aqueous H+-ion-based CSA electrolyte shows a superior ionic conductivity (270 mS cm-1) and an enhanced transport number (0.96), carries larger ionic currents, and retains high conductivity even at subambient temperatures, clearly outperforming all the other Li+/Na+/IL electrolytes. The BPC/aqueous CSA or LiClO4/MIL-53(Cr) supercapacitors show enhanced storage performances, with the H+ cell having a specific capacitance of 70 F g-1 and energy and power density maxima of 9.7 Wh kg-1 and 0.25 kW kg-1 and enduring 104 cycles. A detailed account of the dependence of the electrolyte cation/anion- and solvent-type on electrochemical charge storage provides a basis for adapting these design principles to developing high-performance MOF-based supercapacitors.

Chiral Self‐Sorting of Diformylated N‐Hetero‐ortho‐phenylene Hexamers by Macrocyclization with Aromatic Diamines

AbstractAbstract: Diformylated N‐Hetero‐ortho‐phenylene hexamers (4 a and 4 b) were prepared from 2,3‐dichloropyrydine by palladium‐catalyzed coupling reactions and deprotection. Three helical conformers of 4, corresponding to the rotations of the terminal phenylenes, were observed in 1H‐NMR spectra of solution state. Chiral self‐sorting of 4 a occurred by macrocyclization with para‐phenylenediamine in the presence of para‐toluenesulfonic acid. The homochiral structure (PP and MM) containing two N‐hetero‐ortho‐phenylene hexamer (N‐oP6) moieties was revealed by 1H‐NMR and mass spectra, as well as single‐crystal X‐ray analysis. Using (+)‐ or (−)‐camphorsulfonic acid was also effective in the formation of the homochiral macrocycle and also induced a chiral bias in the helical folding of N‐oP6 moieties. Moreover, planar chiral self‐sorting of the bridged moieties was also achieved by using 4 a and 1,5‐diaminonaphthalene.

Engineering doping level for enhanced thermoelectric performance of carbon nanotubes/polyaniline composites

Thermoelectric (TE) properties of pure polyaniline (PANI) have been extensively investigated and significant progress has been achieved with proper modulation of doping level, there is however few reports to illustrate the crucial role of doping level in modulating the microstructure and optimizing the TE performance of carbon nanotubes (CNTs)/PANI composites. Herein, a series of CNTs/PANI composites with varied CNTs loadings are doped with various amount of camphorsulfonic acid to control doping level of PANI. As the doping level decreases, PANI chains are transformed from extended coil with delocaliztion polarons to compact with polarons localized. All the CNTs/PANI composites exhibit increased Seebeck coefficient, while show less deteriorated conductivity compared with pure PANI film. With high CNTs loading more than 69 wt%, greatly enhanced power factor of 321 ± 24 μW m−1 K−2 could be achieved at low doping level, ascribing to not only strong π-π interaction and doping effect of CNTs which promote PANI chains ordered stacking, but also intrinsic conductive CNTs network which provides extra pathways to facilitate carrier transport. This work demonstrates the effective strategy of precise tuning doping level to improve TE properties of CNTs/PANI composites.

Understanding of mechanistic perspective in sensing of energetic nitro compounds through spectroscopic and electrochemical studies

AbstractUnderstanding the probable mechanism of detection plays a significant role in selecting a particular fluorophore for the detection of the complicated and low volatile analyte namely, nitroaromatic and non‐aromatic high energy materials (HEMs) in the development of detection devices when compared with the existing techniques. The fluorescence quenching employing conducting polymers‐based response of HEMs have attained great significance in recent times. Amongst all conducting polymers, functionalized polyaniline can act as a fluorophore in quenching studies. This report also reveals the importance of studying electrochemical methods associated with the changes observed in the oxidation potential and its resemblance with fluorescence quenching study in establishing the probable mechanism associated with the sensing study of HEMs (viz., RDX, PETN, CL‐20 and RDX: CL‐20 Cocrystal). FTIR and resonance Raman characterization helped us to understand the interaction between nitro groups present in HEMs with benzenoid unit or polaronic or bipolaronic nitrogen of camphor sulfonic acid doped polyaniline (CSA[PANi]). Employing Stern Volmer plot, the efficiency of quenching and quenching mechanisms of complex structure formed between the fluorophore and HEMs is understood.

Investigation of polyaniline doped with camphorsulfonic acid in chloroform solution as a hole transporting layer in PTB7: PCBM and perovskite-based solar cells

Polyaniline was chemically synthesized and protonated (doped) with CSA in chloroform with different PANI:CSA molar ratios, ranging from 6:1 to 1:4. Protonation level of the polymer was monitored by means of UV–Vis spectra of the solution and FTIR measurements of thin films. The results were correlated with the changes of specific conductivity in a function of PANI:CSA molar ratio in the films. A broad maximum of conductivity was found in the range from 1:1 to 1:3, i.e. for over-protonated polymer. The solutions with various PANI doping levels were used as hole transport layers (HTLs) in the polymer-fullerene (PTB7:PC70BM) and perovskite (MAPbI3) solar cells. The highest power conversion efficiency (PCE=3.8%) obtained for the organic cell with molar ratio PANI:CSA=1:1 was only slightly lower than that of the reference cell with PEDOT:PSS HTL (4%). The best perovskite cells achieved PCE of about 4% which was markedly lower that the efficiency of cells with Spiro-OMeTAD HTL. However, some of the perovskite cells with PANI:CSA revealed very high short current density, of about 20 mA cm−2 but relatively low open circuit photovoltage (0.42 V). The changes of the PCE in a function of PANI protonation level were discussed in terms of alignment of HOMO and LUMO levels of HTL, donor and acceptor layers in the solar cells as well as quality of interfacial layers.

Polyaniline/Graphitic Carbon Nitride Nanocomposites with Improved Thermoelectric Properties

In this study, we aimed to investigate the effects of graphitic carbon nitride (g-C3N4) on the thermoelectric (TE) properties of camphorsulfonic acid (CSA) doped polyaniline (PANI). For this purpose, g-C3N4 was synthesized at 550°C using guanidine hydrochloride as a precursor. Later, PANI was synthesized by oxidative chemical polymerization and doped with CSA. Finally, PANI-CSA/g-C3N4 composites were prepared by ultrasonic homogenization with different weight ratios of g-C3N4. The composites showed positive Seebeck coefficients which are the characteristics of p-type semiconductors. The Seebeck coefficient of PANI-CSA enhanced from 10 μV K−1 to 472 μV K−1 with the incorporation of g-C3N4. Furthermore, the power factor (PF) of the composites reached a maximum at 70.75 μW m−1 K−2 which is almost 500 times higher compared to pristine PANI-CSA. This indicates that g-C3N4 is a promising additive to be used in polymer-based TE materials that can be used around room temperature.

Ion-pairing effects by organic anions on the supramolecular assembling kinetics of sulfonated porphyrins

Camphorsulfonic (CSA) and p-toluenesulfonic (p-TsOH) acids promote the self-assembling process of the diacid meso-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS4) into J-aggregates. A general decrease of the rate constants on increasing the acid concentration has been observed for these organic acids. For camphorsulfonic acid the formation of chiral J-aggregates, whose handedness is related to that of the acid, has been revealed by circular dichroism spectra. Changes in the aggregation rates, kinetic profiles and g-factors but no chiral discrimination have been observed for the two different enantiomers, when using different mixing protocols. Moreover, at high acid concentration, aggregation is inhibited and the formation of a new porphyrin species has been detected for both acids. This species has been characterized by steady-state and time-resolved spectroscopic techniques and has been ascribed to an ion pair between the diacid porphyrin and the organic counter-anion. Its role in the aggregation of the initial diacid species has been discussed.

A general method for the synthesis of structurally diverse quinoxalines and pyrido-pyrazine derivatives using camphor sulfonic acid as an efficient organo-catalyst at room temperature

A mild, convenient, eco-friendly, general and practical approach has been developed for the synthesis of a series of structurally diverse quinoxaline derivatives via the condensation reactions of various 1,2-diaminobenzene derivatives and 1,2-dicarbonyls such as phenanthrene-9,10-dione, acenaphthylene-1,2-dione or benzil using a catalytic amount of camphor sulfonic acid as an efficient, commercially available, low cost, organo-catalyst in aqueous ethanol at room temperature. Under the same optimized conditions we were also able to synthesis dibenzo[f,h]pyrido[2,3-b]quinoxaline as well as 10-bromoacenaphtho[1,2-b]pyrido[2,3-e]pyrazine from the reactions of pyridine-2,3-diamines and phenanthrene-9,10-dione or acenaphthylene-1,2-dione respectively.

Albedo parameters and effective atomic numbers of PEDOT/Carbon black composites

In this work, albedo parameters and effective atomic numbers of the PEDOT/carbon black (C) composites were determined by the gamma ray spectrometry. EDOT monomers were polymerized on carbon black (Cabot, Vulcan XC 72R) at room temperature. Ammonium persulphate (APS) was used as the oxidant. The primary dopants including polystyrene sulfonic acid (PSSA), p-toluenesulfonic acid (p-TSA) and camphor sulfonic acid (CSA) were added with the secondary ethylene glycol (EG) or DMSO dopants. Synthesized composites were physically characterized by using Raman spectroscopy in order to determine the defective sites. Albedo parameters and effective atomic numbers of PEDOT/C composites were carried out by using a HPGe detector and 59.54 keV gamma-rays emitted from a radioactive source of 241Am (59.54 keV). Compton and coherent peaks were determined at XRF spectra. It is observed that albedo parameters of the composites appear to be enhanced significantly with the CSA dopant. The impact of p-TSA dopant decreased the reflective power of the PEDOT surface. The S2 composite with low effective atomic number (Zeff.exp.=5.68) is more scatterer than the S4 composite with high effective atomic number (Zeff.exp.=6.78). It can be said that the effective atomic number results obtained by scattering experiments are more reliable than WinXCOM since the material components and geometric modeling technology for absorption are generally assumed to be uniform distribution, and parameters related to sample properties are not taken into account.

Camphor sulfonic acid catalyzed a simple, facile, and general method for the synthesis of 2-arylbenzothiazoles, 2-arylbenzimidazoles, and 3H-spiro[benzo[d]thiazole-2,3′-indolin]-2′-ones at room temperature

A simple, mild, eco-friendly, general, and convenient approach has been developed for the synthesis of structurally diverse 2-arylbenzothiazole derivatives from the reactions of 2-aminothiophenol and various aromatic aldehydes using camphor sulfonic acid a low cost, commercially available, efficient organo-catalyst in aqueous ethanol at room temperature. Under the same optimized conditions, a series of 2-arylbenzimidazoles was also synthesized starting from o-phenylenediamines and various aldehydes whereas synthesis of 3H-spiro[benzo[d]thiazole-2,3′-indolin]-2′-ones was accomplished from the reactions of 2-aminothiophenol and substituted isatins.