Tetracyanoethylene Research Articles

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies.

UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.

Engineering the electronic properties of siligraphene sheets by organic molecules: a density functional theory investigation

The effect of molecular adsorption on the electronic properties of siligraphene sheets is investigated through density functional theory (DFT) calculations. Adsorption of the organic molecules tetracyanoethylene (TCNE), tetrathiafulvalene (TTF), as well as tetracyanoquinodimethane (TCNQ) on siligraphene (SiC x with x = 1, 2, 3, 5 and 7) is studied. The three types of SiC x : SiC, SiC2 and SiC7 have semiconductor properties, while SiC3 and SiC5 are semimetals. P-type and n-type semiconductors are obtained via charge transfer between the organic molecules and SiCx sheets. The SiC, SiC2 and SiC7 sheets exhibit p-type semiconductor behaviour after TCNE and TCNQ adsorption, while they exhibit n-type semiconductor behaviour due to TTF adsorption. The adsorbed molecules have no significant effect on the band gap energy of SiC3 and SiC5. The results provide an effective method to model the electronic properties of siligraphene sheets.

Preparation, spectroscopic, characterizations and biological studies of new charge transfer complexes formed between fluconazole drug with various acceptors

Charge transfer complexes developed during the interaction of Fluconazole drug (FLU) as an electron donor with different types of electron acceptors, including σ-type as iodine (I2), and π-types as 2,3-dinitrosalsylic acid (HDNS), Tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The formed complexes were characterized using various techniques as UV–Vis spectra, Thermal analyses, spectrophotometric measurements, 1H NMR and FTIR Spectroscopy. It was found that the stoichiometry of all developed complexes was a 1:1 M ratio between fluconazole and acceptors (I2, HDNS, TCNE and DDQ). The characteristic physical parameters data such as ionization potential (ID), The oscillator strength (ƒ), formation constant (KCT), transition dipole moment (μ), free energy (ΔG), and energy of interaction (ECT) of the formed CT-complexes have also been reported. Eventually, the synthesized complexes were screened for their microbial and antioxidant activities.

Maximized Hole Trapping in a Polystyrene Transistor Dielectric from a Highly Branched Iminobis(aminoarene) Side Chain.

We synthesized highly branched and electron-donating side chain subunits and attached them to polystyrene (PS) used as a dielectric layer in a pentacene field-effect transistor. The influence of these groups on dielectric function, charge retention, and threshold voltage shifts (ΔVth) depending on their positions in dielectric multilayers was determined. We compared the observations made on an N-perphenylated iminobisaniline side chain with those from the same side chains modified with ZnO nanoparticles and with an adduct formed from tetracyanoethylene (TCNE). We also synthesized an analogue in which six methoxy groups are present instead of two amine nitrogens. At 6 mol % side chain, hopping transport was sufficient to cause shorting of the gate, while at 2 mol %, charge trapping was observable as transistor threshold voltage shifts (ΔVth). We created three types of devices: with the substituted PS layer as single-layer dielectric, on top of a cross-linked PS layer but in contact with the pentacene (bilayers), and sandwiched between two PS layers in trilayers. Especially large bias stress effects and ΔVth, larger than those in the case of the hexamethoxy and previously studied dimethoxy analogues, were observed in the second case, and the effects increased with the increasing electron-donating properties of the modified side chains. The highest ΔVth was consistent with a majority of the side chains stabilizing the trapped charge. Trilayer devices showed decreased charge storage capability compared to previous work in which we used less donating side chains but in higher concentrations. The ZnO and TCNE modifications resulted in slightly more and less negative ΔVth, respectively, when the side chain polystyrene was not in contact with the pentacene and isolated from the gate electrode. The results indicate a likely maximum combination of molecular charge stabilizing activity and side chain concentration that still allows gate dielectric function.

The Effect of TCNE and TCNQ Acceptor Units on Triphenylamine‐Naphthalenediimide Push‐Pull Chromophore Properties

AbstractAsymmetrical and symmetrical push‐pull chromophore‐based on triphenylamine (TPA) donors and naphthalenediimide (NDI) acceptors are designed and successfully synthesized via [2+2] cycloaddition‐retroelectrocyclization (CA‐RE) reaction with well‐known electron‐accepting tetracyanoethylene (TCNE) and 7,7,8,8, ‐tetracyanoquinodimethane (TCNQ) groups. The novel series of compounds NDI‐TPA‐1 to NDI‐TPA‐6 were characterized to identify the influence of the TCNE and TCNQ π‐conjugated linkers on the optical, electrochemical, and electronic properties of these molecules. We found that in dichloromethane the NDI‐TPAs 1, 4, 5, and 6 display absorbance peaks at increasing wavelengths 605, 641, 646, and 645 nm, respectively. We demonstrated that through simple chemical modification we could drop the lowest occupied molecular orbital of NDI‐TPA‐1 to 6. Furthermore, NDI‐TPA‐1 to 6 were integrated into organic thin‐film transistors (OTFTs) via spin‐coating technique, and charge transfer properties were investigated. We found that the choice of the functional group led to either p‐type, n‐type, or ambipolar characteristics.

Liquid− and solid−state study of charge-transfer (CT) interaction between drug triamterene as a donor and tetracyanoethylene (TCNE) as an acceptor

In this work, the liquid–liquid and solid–solid charge-transfer (CT) interactions of drug triamterene (TA) with tetracyanoethylene (TCNE) were reported. The soluble TA-TCNE CT complex was easily generated by mixing acetonitrile solution of TA as the donor and TCNE as the acceptor at room temperature. The solid TA-TCNE CT complex was easily generated by grinding equimolar amounts of TA and TCNE in powder form without any solvent. The results confirmed that the donor interacted with the acceptor via a strong, liquid-state or solid-state reaction generating a CT complex linked by an n → π* transition. The TEM results showed that the CT complex was composed of mixed spherical, oval, and elliptical particles with a mean diameter of ~15 nm. The solid–solid approach proved to be a highly efficient, time- and cost-effective, eco-friendly, and straight-forward means of forming a CT complex with excellent yield (96%).

Effect of electron donor and acceptor on the photovoltaic properties of organic dyes for efficient dye-sensitized solar cells

In this work, the molecular engineering approach was applied to the organic dyes of AE, AQ, TE, and TQ having the donor-acceptor (D-A) configuration to investigate the solar cell efficiency. In these structures, dimethylaniline and triphenylamine were used as the electron donors and 1,1,4,4-tetracyanobuta-1,3-dienes (originating from TCNE) and 2-(4-(4,4-dicyanobut-3-en-2-ylidene)cyclohexa-2,5-dien-1-ylidene)malononitrile (originating from TCNQ) as the electron acceptors. The incorporation of tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) due to the strong electron-withdrawing ability enhance the performance of the dye-sensitized solar cell (DSSC). The results reveal that a change in the electron donor and acceptor moieties affects the photovoltaic processes. Also, the dyes having 2-(4-(4,4-dicyanobut-3-en-2-ylidene)cyclohexa-2,5-dien-1-ylidene)malononitrile electron acceptor (AQ and TQ) have better charge transfer indices such as longer charge transfer distance (DCT) and lower overlap of electron-hole distribution (S) in comparison with the dyes having 1,1,4,4-tetracyanobuta-1,3-dienes as an electron acceptor (AE and TE). Moreover, the properties of the absorption spectra indicate that TCNQ-adduct dyes (AQ and TQ) illustrate a red-shift compared with TCNE-adduct dyes (AE and TE) due to the higher ability of the electron-withdrawing. Finally, AQ and TQ dyes are the preferred candidates to improve the efficiency of the studied DSSCs because of higher charge transfer, electron transfer rate constant, and lower chemical hardness.

2-Amino-5-chloro-1H-pyrrole-3,4-dicarbonitrile

The reaction of tetracyanoethylene (TCNE) with HCl (g) in the presence of Sn (1 equiv) and AcOH resulted in 2-amino-5-chloro-1H-pyrrole-3,4-dicarbonitrile in a 74% yield. The compound was fully characterized.

Improved ion dissociation and amorphous region of PEO based solid polymer electrolyte by incorporating tetracyanoethylene

Solid polymer electrolytes (SPEs) are key materials in safety and flexibility of rechargeable lithium-ion batteries but their ionic conductivities are very low compared with that of liquid electrolytes. One of the reasons for the low ionic conductivity was the low ion dissociation due to low dielectric constant of polymer. So, it should be required to increase the dielectric constant of polymer matrix. We prepared poly (ethylene oxide) (PEO)-based composite polymer electrolyte incorporated with tetracyanoethylene (TCNE) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Compare with dielectric constant of pure PEO (k = 5), TCNE has high dielectric constant (k ≈ 148). The dielectric constant of polymer matrix increased to 50.83 by the incorporation TCNE into PEO. Hence, incorporating LiTFSI into PEO12-TCNE complex, the ion dissociation fraction was also increased from 42.61% to 77.88%. The DSC results showed that the melting temperature (Tm) shifted to low temperature region and glass transition temperature (Tg) also decreased. After incorporation of tetracyanoethylene, the maximum ionic conductivity was obtained as 1.11 × 10−4 S/cm at room temperature.

No evidence for room temperature ferromagnetism in the high temperature metal-organic material: Ni2TCNQ

The search for ferromagnetic organic-based compounds has been a particular challenge to both chemists and physicists over the past few decades. The synthesis of the Ni2A, where A is an organic acceptor; tetracyanoethene (TCNE), 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) (Jain et al 2007 Nature 445 291), was reported to be a great advancement with claims that the ferromagnetism persisted to well above room temperature. There were, however some substantial flaws in the methodology associated with the synthesis and physical characterisation. Our work solely studies the Ni2TCNQ compound where we find no evidence for the existence of inherent ferromagnetism within the material that was reported in the original paper. Instead, we find that the magnetism is due to superparamagnetic nickel nanoparticles embedded in an amorphous matrix. It is hoped that our work will also show that one must be careful when using Ni(COD)2 as a precursor in the synthesis of magnetic materials and that the usefulness of the reported synthetic method is extremely limited.

Noncovalently functionalization of Janus MoSSe monolayer with organic molecules

Because the crystal structure of Janus MoSSe is between from MoS 2 and MoSe 2 , and the Janus MoSSe probably exhibited to outstanding characteristics difference from MoS 2 and MoSe 2 . Adsorption of organic molecules is a prospective and effective pattern to modify the optoelectronic properties of 2D materials . For this purpose, the optical and electronic characteristics of organic molecules adsorbed Janus MoSSe monolayer were discussed by the first principles calculations. The results indicate that p -doped Janus MoSSe can be obtained by molecular doping with tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE), whereas n -doped Janus MoSSe can be realized by doping with tetrathiafulvalene (TTF). Importantly, a dipole moment is produced between Janus MoSSe and organic molecule, and the dipole moment can to a great extent alter the work function values of Janus MoSSe ranged from 3.76 eV to 6.17 eV. Interestingly, the impurity band near the Fermi level appears in the band structures of Janus MoSSe after different organic molecules adsorption, which demonstrates that electron is more prone to transition. Furthermore, Adsorption of organic molecules on Janus MoSSe can significantly expand its optical absorption spectrum in the visible light region. This study gives a theoretical guidance for the fabrication of Janus MoSSe-based photovoltaics nanodevices . • Effective p-type doping of MoSSe can be realized by adsorption of TCNE and TCNQ molecules, while n-doped MoSSe can be obtained by adsorption of TTF molecule. • A dipole moment is formed between organic molecule and Janus MoSSe, and this dipole moment can significantly tune the work function values of Janus MoSSe. • Adsorption of organic molecules on Janus MoSSe can significantly expand its optical absorption spectrum in the visible light region.

A Linear Relationship between the Charge Transfer Amount and Level Alignment in Molecule/Two-Dimensional Adsorption Systems.

We systematically study the adsorption of tetrathiafulvalene (TTF), tetracyanoquinodimethane (TCNQ), and tetracyanoethylene (TCNE) on a variety of two-dimensional (2D) monolayers with weak van der Waals (vdW) interactions based on density functional theory. We confirm that TTF can act as an effective donor when its highest occupied molecular orbital (HOMO) level is higher than the conduction band minimum (CBM) state of 2D materials, while TCNQ and TCNE can act as effective acceptors when their lowest unoccupied molecular orbital (LUMO) levels are lower than the valence band maximum (VBM) state of 2D materials. Moreover, our calculations reveal a linear relationship between the charge transfer amount and level alignment between the molecule and 2D monolayer. In other words, the charge transfer is linearly dependent on the energy difference between the HOMO level and 2D CBM state for the donor molecule or the energy difference between the LUMO level and 2D VBM state for the acceptor molecule. The linear relationship indicates that the charge transfer is insensitive to the local binding environments due to the weak vdW interaction. However, the linear relationship cannot be applied to atoms or molecules that are chemisorbed on 2D materials.

Suppression of Ionic Doping by Molecular Dopants in Conjugated Polymers for Improving Specificity and Sensitivity in Biosensing Applications.

Ionic doping effects in conjugated polymers often cause nonspecific signaling and a low selectivity of bioelectronic sensing. Using remote-gate field-effect transistor characterization of molecular and ionic doping in poly(3-hexylthiophene) (P3HT) and acid-functionalized polythiophene, poly[3-(3-carboxypropyl) thiophene-2,5-diyl] (PT-COOH), we discovered that proton doping effects on the interfacial potential occurring in P3HT could be suppressed by sequentially doping P3HT by 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). To be specific, intrinsic pH sensitivity shown by pure P3HT (18 mV/pH in a range from pH 3 to 9) was fully dissipated for doped P3HT:F4TCNQ. However, F4TCNQ sequential doping instead increases pH sensitivity of acid-functionalized polythiophene, PT-COOH (40 mV/pH), compared to that of a pure PT-COOH (30 mV/pH). Interactions between polythiophene backbone and side chains, which constrain the activity of COOH, are weakened by stronger F4TCNQ doping leaving behind responsive COOH groups exposed to aqueous solutions. This is supported by the reduced pH sensitivity of PT-COOH sequentially doped by a weaker dopant, tetracyanoethylene (TCNE) (21 mV/pH). Thus, doping is shown to stabilize a nonpolar conjugated polymer to pH-induced fluctuations on one hand, and to activate a COOH side chain to pH-induced response on the other.

Charge-Transfer Excitation Energies Expressed as Orbital Energies of Kohn-Sham Density Functional Theory with Long-Range Corrected Functionals.

Previously proposed theoretical schemes for estimating one-electron excitation energies using Kohn-Sham (KS) solutions with long-range corrected (LC) functionals are applied to the charge-transfer (CT) excitations of the ethylene···tetrafluoroethylene (C2H4-C2F4) system, and the CT complex between an aromatic donor (Ar = benzene, toluene, o-xylene, naphthalene, anthracene, and various meso-substituted anthracenes) and the tetracyanoethylene (TCNE) acceptor. The CT excited state is described well as a single-electron excitation between specific orbitals of donor and acceptor. Thus, CT excitation energies are well approximated by the orbital energies because of the satisfaction of the Koopmans-type theorem and the asymptotic behavior of the LC functional. We have examined three computational schemes: scheme 1 employs the orbital energies for the neutral and cationic systems, scheme 2 utilizes orbital energies of just the cation, and in scheme 3, because the electron affinity of a molecule is the ionization energy of its anion, a scale factor is applied to enforce this identity. The present schemes reproduce the correct asymptotic behavior of CT excitation energy of C2H4···C2F4 for the long intermolecular distances and give good agreement with accurate ab initio results. Calculated CT excitation energies for Ar-TCNE are compared with those of TD-DFT and ΔSCF methods. Scheme 1 with the optimal range-separation parameter μ accurately reproduces CT excitation energies for all Ar-TCNE systems and gives good agreement with the best TD-DFT calculations and experiment. Scheme 1, scheme 3, and TD-DFT show similar tendencies with respect to the variation in μ. Scheme 2 and ΔSCF approaches are rather insensitive to changes in μ, but both considerably underestimate the CT excitation energies for these systems. KS orbital energies are physically meaningful and they are practically useful; if the range-separation parameter is tuned, then good results can be obtained.

A facile approach for enhancing device performance of excitonic solar cells with an innovative SnO2/TCNE electron transport layer

The spread of the Internet of things created the need for huge amounts of off-grid energy sources for tens of billions of electronic devices with low power consumption for indoor applications. Excitonic solar cells may provide a better solution as compared with other solar cells due to their advantages such as low-cost, large-area module, and fabrication by solution printing and coating techniques. However, the organic solar cells (OSCs) or perovskite solar cells (PSCs) should have a low energy loss, suitable absorption spectrum, and minimum trap mediated charge recombination for its proper commercialization. Interface engineering is one of the ways of achieving better performance for these devices. Herein, we report a facile and effective strategy for interfacial modulation to achieve the improved performance of inverted bulk heterojunction (BHJ) solar cells with a solution-processable SnO2 electron transport layer (ETL) modified by an organic small molecule tetracyanoethylene (TCNE). We can say that a few nano-meter thin film of TCNE supports to reduce the energy barrier of SnO2, resulting in the efficient extraction and transport of negative charge carriers toward the cathode. The TCNE also passivates the surface defects of SnO2 and hence decreases the charge recombination rate for iOSCs. Furthermore, it brings the better interfacial contact between SnO2 and BHJ blend in which the polymer PTB7 and fullerene PC71BM are the donor and acceptor, respectively, showing average power conversion efficiencies of ∼4.58%, ∼4.98%, and ∼2.95% with varying concentrations of TCNE (0.5 mg/ml, 1 mg/ml, and 2 mg/ml), respectively, in methanol, on top of SnO2, as ETLs, which are comparably better than that of pristine SnO2 (3.28%). We assumed that the TCNE modified SnO2 method is a potent and easy way to get efficient inverted BHJ solar cells with higher efficiency and may also be an appropriate alternative for other organic semiconducting devices where an ETL is required, such as organic light-emitting diodes and PSCs.

Low-Bandgap, Donor-Acceptor Conjugates Based on Tetracyanobutadiene (TCBD) and Dicyanoquinodimethane (DCNQ): Synthesis, Structure and Photochemical Properties

Ground and excited state charge transfer interactions in donor-acceptor conjugates has been one of the most widely studied topics by the scientific community over the last two decades as its significance is profound in solar energy conversion, and building optoelectronic devices. Among these, p-conjugated donor-acceptor conjugates are appealing because of their applications in the field of non-linear optics and electroluminescent devices. The photonic properties of p-conjugated donor-acceptor conjugates can be tuned by altering the strength of the donor or acceptor units, and by varying the connecting p-linker. Photosensitizer, electron donors such as porphyrins, phthalocyanines and BODIPYs have been traditionally used as building blocks in the construction of such light-powered ensembles due to their easily modifiable spectral and redox properties.In the present contribution, we report development of a new class of intramolecular charge transfer complexes derived from nonplanar, push-pull substituted buta-1,3-dienes by [2+2] cycloaddition of either tetracyanoethene (TCNE) or tetracyano-p-quinodimethane (TCNQ) with a variety of photosensitizer (electron donor) functionalized alkynes. This reaction efficiently converted the TCNE and TCNQ entities to highly electron-deficient, tetracyanobutadiene (TCBD) and dicyanodiquinodimethane (DCNQ) entities at the buta-1,3-dienes site.1-3 These charge transfer complexes are engineered to have small bandgap to extend the absorption well into the near-IR region; that is, to provide a better optical window for optoelectronic applications, especially in organic photovoltaics that use the majority of available sunlight. The newly synthesized complexes have been fully characterized using spectral, electrochemical, spectroelectrochemical and computational methods, and occurrence of ground state charge transfer interactions have been established. Further, excited state charge transfer in the complexes has been confirmed by photochemical studies performed using time-resolved emission and femtosecond transient absorption studies in solvents of varying polarity. Ultrafast charge separation has been witnessed in these closely spaced, strongly interacting triads.1-3 1. Sharma, M. B. Thomas, R. Misra, F. D’Souza, ‘Strong Ground and Excited State Charge Transfer in C3‐Symmetric Truxene Derived, Low‐Band Gap, Phenothiazine‐Tetracyanobutadine (TCBD) and Expanded TCBD Conjugates’, Angew. Chem. Int. Ed. 2019, 58, 4350-4355.2. Y. Rout, Y. Jang, H. B. Gobeze, R. Misra, F. D’Souza, ‘Conversion of Large Bandgap Triphenylamine-Benzothiadiazole to Low Bandgap, Wide-Band Capturing Donor-Acceptor Systems by Tetracyanobutadiene and/or Dicyanoquinodimethane Insertion for Ultrafast Charge Separation’ J. Phys. Chem. C. 2019, 123, 13382-23389.3. P. Gautam, R. Misra, M. B. Thomas, F. D’Souza, Ultrafast Charge-Separation in Triphenylamine-BODIPY-Derived Triads Carrying Centrally Positioned, Highly Electron- Deficient, Dicyanoquinodimethane or Tetracyanobutadiene Electron-Acceptors’ Chem. Eur. J. 2017, 23, 9192-9200.

Building Conjugated Donor-Acceptor Cross-Links into Metal-Organic Frameworks for Photo- and Electroactivity.

We convert a coordination network into a covalent solid, while maintaining the crystallinity and greatly enhancing the framework rigidity and redox-active and photochemical properties. Specifically, intensely light-absorbing push-pull functions are postsynthetically installed by reacting the electrophilic TCNE (tetracyanoethylene) guests and the electron-rich alkyne side arms on a microporous Zr-organic framework, generating black microporous crystallites with a band gap smaller than 1.0 eV. The reaction proceeds in the known [2 + 2] cycloaddition-retroelectrocyclization mechanism and extensively establishes conjugated (polyene) bridges across the linker molecules. The donor (4-methoxyphenyl) and acceptor (dicyanovinyl) couples of the polyene bridges also act as an efficient fluorescent quencher and can be selectively installed in a thin outer layer of the host crystallite to form a core-shell assembly for turn-on fluorescent sensing of small amine molecules in water solutions.

The use of tetracyanoethylene as a photometric reagent in analysis of pharmaceutical preparations

A possibility of using tetracyanoethylene (TCNE) as a photometric reagent for determination of the dipyrone content in pharmaceuticals is considered. A photometric form was obtained in the aqueous phase in an acetate buffer medium (pH 3.13). The resulting π -complex revealed two absorption bands at (400 and 420) nm with molar absorption coefficients of 1.56 Ч 10 4 and 1.62 Ч 10 4 , respectively. Due to a high lability of the photometric reagent, the optical density of the complex thus formed must be measured immediately after preparation. The composition and possible mechanism of π -complex formation were determined using the methods of molar ratios and isomolar series: the active substance interacts with the reagent in a molar ratio 1:1. The calculated value of the stability constant of the formed π -complex was 1.42 Ч 10 6 . Proceeding from the obtained data, a spectrophotometric method of dipyrone determination in drugs is developed with a detection limit of 42.63 μg/ml (the error of determination being below 3.0%). The linear dependence of the analytical signal on the concentration of the active substance is observed in the range of 20 – 100 μg/ml. Testing of the spectrophotometric method for dipyrone determination was carried out on tablets and injection solutions manufactured in Russia. There is a good convergence between the results of dipyrone determination by the developed and arbitration methods (pharmacopoeia monograph 2.1.0003.15). The analysis revealed that the content of dipyrone in the dosage form corresponds to the declared. The developed technique is easy to use accessible in equipment and can be recommended for determination of dipyrone in conditions of a conventional analytical laboratory.

Utilization of tannic acid into spherical structured carbons based on charge-transfer complexation with tetracyanoethylene acceptor: Liquid-liquid and solid-solid interactions

In this study, liquid-liquid and solid-solid interactions between tannic acid (TA) as a donor with tetracyanoethylene (TCNE) acceptor were investigated toward understanding the effect of starting material phase on the end product of a charge transfer (CT) reaction. The liquid-liquid interaction generated a reddish-brown, soluble CT complex, while the solid-solid interaction produced a deep-violet, solid CT complex. The stoichiometry of the interaction was obtained using an elemental analysis of the solid product and spectrophotometric titration and Job's method for the soluble product and these data both indicated a 1:5 (TA:TCNE) molar ratio. The UV–visible and IR measurements support the presence of π-π interactions between the TA donor and TCNE acceptor. The two CT complexes obtained from the two interactions were directly carbonized into particles. These resultant carbon particles were fully characterized using IR, XRD, SEM, and TEM. These analyses revealed that carbon particles with spherical morphology were obtained after the carbonization of the CT complex generated through the solid-solid interaction, while the liquid-liquid interaction led to carbon particles with semi-porous, irregular morphology.

Reactivity of N-substituted alkenylidene hydrazinecarbothioamides toward tetracyanoethylene, an efficient synthesis stereoselective 1,3-thiazole compounds

The reaction between N-substituted alkenylidene hydrazinecarbothioamides and two molar amounts of tetracyanoethylene (TCNE) in anhydrous THF at room temperature without using any catalyst affords (Z)-4-amino-3-((Z)substituted amino)-2-(substituted imino)-2,3-dihydrothiazole-5-carbonitriles and (Z)-(4-amino-5-cyano-thiazol-2(3H)-ylidene)carbonhydrazonoyl dicyanides. Rationales for these transformations are presented. The structures of the obtained products were confirmed via single-crystal X-ray analyses. Here, we synthesize (Z)-4-amino-3-amino-2-imino-2,3-dihydrothiazole-5-carbonitriles and (Z)-(4-amino-5-cyano-thiazol-2(3H)-ylidene)carbonhydrazonoyl dicyanides from the reaction of N-substituted alkenylidene hydrazinecarbothioamides with (TCNE) in anhydrous THF at room temperature without using any catalyst.