Cyanoacetic Acid Research Articles

STUDY OF REGIOSELECTIVITY IN CYANOMETHYLATION OF 4-(TRIFLUOROMETHYL)PYRIMIDIN-2(1 Н )-ONES

Cyanoacetic acid reacted selectively with 4-(trifluoromethyl)pyrimidin-2(1Н)-ones with the formation of Michael addition–decarboxylation products in DMSO solution at 85°С and Mannich reaction products when the reagents were fused together under solvent-free conditions.

Grafting Copper and Gallium Corroles onto Zinc Oxide Nanoparticles.

Two different copper and gallium arylcorroles have been functionalized using the Vilsmeier-Haack reaction. A further Knoevenagel reaction with cyanoacetic acid was performed on both complexes, affording the desired products with yields above 90 %. The newly synthesized compounds have been thoroughly characterized by a combination of spectroscopic methods, optical analyses, and X-ray crystallography. Moreover, they have been tested as anchoring groups for the hydrothermal synthesis of ZnO nanoparticles. The morphology of the heterogeneous composites has been studied by SEM, EDS and fluorescence microscopy analyses, thus confirming the presence of the corrole macrocycle in the hybrid material.

Theoretical Study of the Use of Cyano Acid Derivatives as Electron Acceptors in Cyanidin as Compounds of Dye Sensitized Solar Cells (DSSC)

Theoretical study of the use of cyano acid derivatives as electron acceptor groups in cyanidine as dye compounds of dye sensitized solar cells (DSSC) has been carried out based on energy parameters of HOMO-LUMO, LUMO electron localization, spectra, light absorption efficiency, coupling constants, and sensitizer bond length with TiO2. This study aims to determine the effect of cyanoacetic acid, cyanoacrylic benzothiadizole, cyanovinyl acid and cyanosynamic acid as electron acceptors on the photoelectric characteristics of cyanidine and determine the cyanoic acid derivative which can produce cyanidine photoelectric characteristics better based on energy parameters HOMO-LUMO, LUMO electron localization, spectra, light harvesting efficiency, coupling constant (VRP), and bond length of sensitizer with TiO2. This research begun with molecular optimization using DFT and TDDFT method with basis set of 6.311G *. HOMO-LUMO parameters used the same method with analysis technique using ECCE. The LUMO electron localization parameters use the same method, but the analysis technique used ECCE. Spectra using DFT method, using analytical technique using Chemcraft. Parameters of light absorption efficiency using DFT and TDDFT method with calculation technique using existing equations. Coupling constant parameters using the same method, the calculation technique used the energy equation of dye compounds were calculated in the conditions of HOMO, LUMO and TiO2 energy. Parameter length of the sensitizer bond with TiO2 were calculated used DFT method with avogadro analysis technique. Cyanidin cyanoacetate became the best modification based on HOMO LUMO energy parameter -4.569 and -1.01 eV, respesctively. In the electron localization parameter, the best modification was produced in cyanidine cyanoacetate with an electron-centered pattern on the cyanoacetic group. Spectra parameters produced the best modification, cyanoacetic cyanidine with a wavelength of 378.811 nm with osillator strength of 0.633. The light absorption efficiency parameters resulted in the best modification of cyanidin cyanoacetate with a value of 0.767. For parameter of clutch constant, best modification is cyanidin benzothiadizol sianoakrilik with a value -0.269. The best modification on the parameter length of the sensitizer bond with TiO2 was cyanidine cyanoacetate with a bond length of 1.926 Å.

Molecular engineering and investigation of new efficient photosensitizers/co-sensitizers based on bulky donor enriched with EDOT for DSSCs

Herein, we report design, synthesis and photovoltaic performance of four novel metal-free heteroaromatic photosensitizers coded IA 1-4 with (D-D)2-D-A architecture carrying electron donating triphenylamine coupled with EDOT core which is directly connected to four different electron withdrawing/anchoring groups, viz. rhodamine-3-acetic acid, cyano acetic acid, 2-methyl quinoline-6-carboxylic acid and 1-phenyl-pyrazol-5-one-3-carboxylic acid without any π-spacer. The newly designed IA 1-4 were applied as sensitizers and co-sensitizers in DSSCs. Their structures were confirmed by FT-IR, 1H NMR, MS and elemental analyses. The photosensitizers were subjected to optical and electrochemical studies in order to investigate their absorption/emission behavior as well as HOMO/LUMO energies. The UV–Vis revealed that IA 1-4 exhibited at 464, 497, 531 and 412 nm,λmax respectively. Their optical band gap is in the range of 1.95–2.28 eV. From the energy level diagram of the named photosensitizer, it is clear that all the dyes have good thermodynamically favorable ground and excited state oxidation potentials for electron injection into CB edge of TiO2 as well as dye regeneration. The photovoltaic performance studies indicate that, dye IA-1 anchored with cyanoacetic acid displayed the highest IPCE (61.5%), resulting in PCE of 5.92% (JSC = 12.3 mA cm−2, VOC = 0.68 V, FF = 70.29%). Furthermore, when IA-1 was used as a co-sensitizer with MH-13, a total PCE of 8.43% (JSC = 22.8 mA cm−2, VOC = 0.66 V, FF = 54.1%) was achieved to gain more insights into the equilibrium molecular geometry (EMG), thermodynamic parameters and vertical electronic excitation, DFT studies were performed using GAUSSIAN 09 software to calculate the EMG of each photosensitizer, its and electron cloud delocalization of HOMO/LUMO levels and vertical electronic excitation. Results from FMO revealed that dyes IA 1-4 showed effective charge separation, which translated into greater ICT behavior with IA-1 being the highest in photovoltaic performance.

Novel metal-free organic dyes containing linear planar 11,12-dihydroindolo[2,3-a]carbazole donor for dye-sensitized solar cells: Effects of π spacer and alkyl chain

Three novel D−π−A type dyes DC1∼3, which consisting of indolo[2,3-a]carbazole as donor scaffold linked to the acceptor/anchoring unit cyanoacetic acid via different π-spacers, were successfully designed and synthesized. The structure, photophysical and electrochemical properties, and photovoltaic properties of the three sensitizers were investigated in detail. The results indicate that the donor 11,12-bis(2-ethylhexyl)-11,12-dihydroindolo[2,3-a]carbazole with two branched alkyl chains is effective in inhibiting the intermolecular π−π aggregation effects, and the auxiliary alkyl chains in the π-bridge cause the DC3-based DSSCs to exhibit higher open circuit voltages than that of the devices based on dye DC2. Among all of the devices fabricated with the dyes, the DC3-based cells without chenodeoxycholic acid (CDCA) exhibit the best photovoltaic performance, with a short-circuit current density of 10.98 mA cm−2, an open circuit voltage of 752 mV and a fill factor of 0.725, corresponding to a highest power conversion efficiency of 5.98% in liquid electrolyte.

Modification of the electronic properties of the π-spacer of chromophores linked to calix[4]arene platform for DSSCs applications

We have developed two novel dyes based on p-tert-butyl-calix[4]arene in order to evaluate their behavior as sensitizer in photovoltaic devices. These dyes consist in a difunctionalized calix[4]arene with triphenylamine (TPA)-donor, a heteroaromatic π-conjugated spacer, thiophene and benzothiadiazole-phenyl ring, respectively and cyanoacetic acid as acceptor group. The effect of the π-spacer has been studied by UV–vis spectroscopy and Differential Pulse Voltammetry and the models compounds have been theoretically investigated. The dye bearing phenylbenzothiadiazole results in a bathochromic shifted absorption and an adequate efficiency to transfer charge from D to A. The considerable increase of the photocurrent density results in a better efficiency of the devices prepared with these novel dyes with respect to the p-tert-butyl-calix[4]arene derivatives bearing TPA dye. In particular, p-tert-butyl-calix[4]arene derivative based on phenylbenzothiadiazole has reached an efficiency value of 5.84% which means an increase of 33% of the efficiency over those calix[4]arene derivatives with TPA dye.

Synthesis and characterization of novel bis(pyridine-2(1H)-thiones) and their bis(2-methylsulfanylpyridines) incorporating 2,6-dibromophenoxy moiety

The novel 1,4-bis(2,6-dibromo-4-formylphenoxy)butane (3), prepared from 3,5-dibromobenzaldehyde (1), reacted with different hydrazines 4a–4d and active methylene containing compounds 9a–9d to give the corresponding bis(hydrazones) 5a–5d and bis(cinnamonitriles) 11a–11d, respectively. Both bis(2-cyanoacetic acid hydrazide) derivative 5d and bis(thioacrylamide) derivative 11a were taken as synthetic precursors for the synthesis of the target molecules bis(pyridine-2(1H)-thione) derivative 10 and 13a–13c and their bis(2-methylsulfanylpyridine) derivative 14 and 17a–17c. Another synthetic route was designed to prepare the target molecules 14 and 17a–17c in a better yield using pyridine-2(1H)-thione) derivative 15 and 19a–19c. Characterization of the newly prepared compounds via elemental analyses and spectral data are established.

Study of regioselectivity in cyanomethylation of 4-(trifluoromethyl)pyrimidin-2(1Н)-ones

Cyanoacetic acid reacted selectively with 4-(trifluoromethyl)pyrimidin-2(1Н)-ones with the formation of Michael addition–decarboxylation products in DMSO solution at 85°С and Mannich reaction products when the reagents were fused together under solventfree conditions.

The comparative study of new carboxylated 1,3-indanedione sensitizers with standard cyanoacetic acid dyes using co-adsorbents in dye-sensitized solar cells

Two new carboxylated 1,3-indanedione sensitizers (MPhe-ind and BPhe-ind) were synthesized and their dye-sensitized solar cells (DSSC) performance were compared with the corresponding standard cyanoacetic acid sensitizers (MPhe-cn and BPhe-cn). The carboxylated 1,3-indanedione sensitizers have shown almost 100 nm enhanced absorption curves compared to the cyanoacetic acid dyes with an extended IPCE curve up to 800 nm. Despite greater absorption and electrochemical properties, the synthesized dyes showed moderate efficiencies (2.10% and 2.67%) than standard dyes. The low electron injection efficiency and recombination of carboxylated 1,3-indanedione might be responsible for low efficiency. Detailed investigation studies have been performed and complemented with the theoretical studies.

Conventional and Microwave Synthesis of some new pyridine derivatives and evaluation their antimicrobial and cytotoxic activities.

The newly synthesized compounds based on 2-amino-6-(2,4-dimethoxyphenyl)-4-(4-methoxyphenyl)nicotinonitrile 1. The reactivity of pyridine derivative 1 was studied towards different reagents by its reaction with malononitrile, 2-(4-chlorobenzylidene)malononitrile, ethyl cyanoacetate, cyano acetic acid, m-nitro benzaldehyde, sodium azide, formamide, acetic anhydride and/or acetic anhydride/H2SO4 to give compounds 2-5,7, 10-13, respectively. The reaction of 5 with acetyl acetone gave the bipyridine derivative 6, while reaction of compound 7 with chloroacetyl chloride and phenacyl bromide gave the azetidinone derivatives 8 and 9. The formimidate 14 were obtained via reaction of compound 1 with triethylorthoformate, while reaction of 14 with phenylene diamine and/or acetamide gave the formimidamide and pyridopyrimidine derivatives 15 and 16 respectively. Compound 1 was also allowed to react with urea, thiourea, phthalic anhydride, succinic anhydride, benzoyl chloride, chloroacetonitrile, chloroacetyl chloride, p-toluenesulfonylchloride and ethyl bromoacetate to give compounds 17a,b - 24. Reaction of compound 1 with dichloro reagents in 1:1 ratio gave the bicyclic derivatives 25a–c, while its reaction with oxalyl chloride, dichloro and tetrachlorobenzoquinone derivatives, and/or dichloronaphthoquinone gave the imidazopyridine derivatives 26-29. Reaction of compound 29 with o-phenylenediamine in 1:2 ratio afforded the di-condenesed product 30 while, reaction of compound 1 with dichlororeagents in 1:2 ratio gave the polyalkyl derivatives 31a-b. The newly synthesized compounds were characterized by IR, 1H-NMR, 13C-NMR and mass spectra. On the other hand the antimicrobial and anticancer activities of some of the newly synthesized compounds was studied and evaluated.

Organocatalytic Decarboxylative Cyanomethylation of Difluoromethyl and Trifluoromethyl Ketones.

An efficient organocatalytic method for the synthesis of difluoromethyl and trifluoromethyl substituted β-hydroxynitriles is introduced. The decarboxylative cyanomethylation of fluorinated ketones with readily available cyanoacetic acid gives a variety of tertiary alcohols in high yields and without concomitant water elimination. The reaction occurs in the presence of catalytic amounts of triethylamine, can be upscaled and applied to chlorofluoromethyl ketones and difluoromethyl ketimines.

Synthesis of novel diketopyrrolopyrrole-based dyes

Three novel diketopyrrolopyrrole-based molecules for potential application in dye-sensitized solar cells are synthesized starting from a common and easily available key intermediate with a bis-thienyl diketopyrrolopyrrole structure. The synthetic sequence is based upon transition-metal catalyzed coupling reactions involving commercial boronic acid followed by condensation reactions with 2-cyanoacetic acid. Absorption and fluorescence spectra of the molecules are also reported.

A facile synthesis of formazan dyes conjugated with plasmonic nanoparticles as photosensitizers in photodynamic therapy against leukemia cell line

A series of 1,5-bis(4-aryl/heteryl)-3-cyanoformazan derivatives was synthesized and characterized by spectral analysis. The synthesis strategy involved an easy and practical diazo coupling of different aryl (heteryl) diazonium salts with cyanoacetic acid. The synthesized compounds were electrostatically conjugated to gold and/or silver nanoparticles in dimethylsulfoxide and were examined as photosensitizers for photodynamic therapy (PDT). The PDT activity of the formazan derivatives alone and conjugated with metal nanoparticles was investigated against HL-60 cells under dark and light conditions. Formazan derivatives and their conjugates showed variable promising anticancer activity in dark and light conditions related to their structures. The interaction of synthesized formazan derivatives with metal nanoparticles enhanced the light absorption of the dyes and thus showed remarkable increase in PDT against cancer cells.

Push-Pull N,N-Diphenylhydrazones Bearing Bithiophene or Thienothiophene Spacers as Nonlinear Optical Second Harmonic Generators and as Photosensitizers for Nanocrystalline TiO2 Dye-Sensitized Solar Cells.

A series of push–pull heterocyclic N,N-diphenylhydrazones were prepared to study the effect of structural modifications (different π-spacers and electron-withdrawing groups) on the optical (linear and nonlinear) and electronic properties of the molecules. The photovoltaic response of dye-sensitized solar cells assembled using nanocrystalline titania photosensitized with the synthesized dyes was also studied. These heterocyclic push–pull conjugated dyes involve N,N-diphenylhydrazones as electron donors linked to bithiophene or thieno[3,2-b]thiophene spacers and were functionalized with carboxylic acid, cyanoacetic acid, or dicyanovinyl acceptor groups. A combination of Suzuki–Miyaura cross-coupling, Vilsmeier formylation, and condensation reactions was used to synthesize the intermediates and final products. Density functional theory (DFT) and time dependent-DFT calculations were used to obtain information on conformation, electronic structure, and electron distribution, both for the free dyes and those adsorbed on TiO2. The results of this multidisciplinary study indicate that dyes 5b and 6b have the strongest second-order nonlinear optical response with hyperpolarizability values in the range of β = 2330 × 10–30 to 2750 × 10–30 esu, whereas photovoltaic power conversion efficiencies reach values in the range of 0.7–3.0% for dyes 5a–b and 7c and were enhanced by coadsorbing deoxycholic acid (0.8–5.1%).

Synthesis and properties of merocyanine dyes derived from N-aryl-substituted pyridinium salts and cyanoacetic acids

A series of merocyanine dyes were synthesized by two-component condensation of N-aryl-4-picolinium salts and cyanoacetic acid derivatives. Physicochemical properties of the synthesized dyes were studied.

New D–D′–A Configured Dye for Efficient Dye-Sensitized Solar Cells

D−π–A, D–A−π–A, and other configuration-based organic dyes have shown great potential in the field of dye-sensitized solar cells (DSCs). Compared with traditional configurations, D–D′–A offers several advantages such as enrichment of the electron-donating ability, absorption spectral region, and molar extinction coefficient and inhibits dye aggregation. Hence, in this work, a novel D–D′–A-type dye has been designed and synthesized for DSC applications. In this configuration, substituted imidazole has been used as a primary donor, phenothiazine as an auxiliary donor, and cyanoacetic acid as an acceptor/anchoring group. Structural characterizations of a D–D′–A-type dye were done by using NMR and electron ionization–mass spectrometry. Photophysical, electrochemical, and computational studies were systematically performed to evaluate its electronic transitions, light-harvesting property, highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) levels, and redox behavior. The photop...

Analgesic molecules interleaved between layered double hydroxide: Exchange versus in situ reaction and release properties

The encapsulation of molecules of therapeutic interest is emerging as an attractive tool to increase the stability of an active ingredient, to control its release over time and to prevent drug overdose. In this drug delivery approach, several analgesic molecules are considered, including (2E)–2-cyano-3-(furan-3-yl)acrylic acid (CFAA), and the host structure, lamellar double hydroxides (LDH) of the hydrotalcite type, as a vector. These organic compounds are prepared by Knoevenagel condensation between cyanoacetic acid and an aldehyde. Two strategies were employed: direct insertion of the organic compounds by ion exchange versus in situ 2D confinement by Knoevenagel condensation from LDH organo-modified with cyanoacetic acid. The physicochemical characterization (XRD and SS-MAS-NMR) of the hybrid organic/inorganic complexes allows comparison of the two approaches and their release properties complete the study.

High-Efficiency All-Small-Molecule Organic Solar Cells Based on an Organic Molecule Donor with Alkylsilyl-Thienyl Conjugated Side Chains.

Two medium-bandgap p-type organic small molecules H21 and H22 with an alkylsily-thienyl conjugated side chain on benzo[1,2-b:4,5-b']dithiophene central units are synthesized and used as donors in all-small-molecule organic solar cells (SM-OSCs) with a narrow-bandgap n-type small molecule 2,2'-((2Z,2'Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC) as the acceptor. In comparison to H21 with 3-ethyl rhodanine as the terminal group, H22 with cyanoacetic acid esters as the terminal group shows blueshifted absorption, higher charge-carrier mobility and better 3D charge pathway in blend films. The power conversion efficiency (PCE) of the SM-OSCs based on H22:IDIC reaches 10.29% with a higher open-circuit voltage of 0.942 V and a higher fill factor of 71.15%. The PCE of 10.29% is among the top efficiencies of nonfullerene SM-OSCs reported in the literature to date.

Molecular engineering and synthesis of novel metal-free organic sensitizers with D-π-A-π-A architecture for DSSC applications: The effect of the anchoring group

Herein, we report the design and synthesis of two metal-free organic sensitizers (MR-5 & MR-6) with a D-π-A-π-A architecture based on a trimethoxy benzene donor core carrying two different withdrawing/anchoring groups including cyanoacetic acid and rhodanine-3-acetic acid via thiophene as a π-spacer. Benzothiadiazole was incorporated as a strong auxiliary electron acceptor, which greatly improved the molar extinction coefficient and electronic coupling across the molecular diameter of the dyes. The optical and electrochemical properties of the two dyes were investigated. The photovoltaic studies revealed that MR-5 anchored with cyanoacetic acid showed significantly greater light harvesting (IPCE), which resulted in improved PCE with better photovoltaic parameters than MR-6. MR-5 achieved the higher total solar-to-electric conversion efficiency of 6.03% and showed an IPCE of 65% at 420 nm. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were used to study equilibrium molecular geometries, frontier molecular orbitals, vertical electronic excitations, and the theoretical data were consistent with experimental results.

Molecular engineering of rhodanine dyes for highly efficient D-π-A organic sensitizer

Due to the strong electron-withdrawing capability, the rhodanine unit is widely used as the acceptor of the D-π-A organic sensitizer. However, in this unit, the carboxyl group is shut out from the whole conjugation system, which affects the injection of the excited electrons, leading to poor photovoltaic performance. Herein, with the introduction of cyanoacetic acid into the rhodanine segment, two novel indoline sensitizers, CS-22 and CS-24, based on D-π-A construction are designed and synthesized. With this modification, the carboxyl group is conjugated with the whole molecule, leading to sharp enhance of light-harvesting capability of the dye and more important, quite smooth electron injection process. Moreover, the introduced long alkyl chain can also prevent the π-aggregation on TiO2 surface and restrain the charge recombination effectively. Accordingly, using the modified acceptor, the photovoltaic performance is significantly improved: an extremly high PCE of 8.48% is obtained by CS-22 sensitized DSSC, which is the highest value among rhodanine dyes without any co-adsorbent. Our work demonstrates that the introduction of conjugated carboxyl group is greatly benefit for the improvement of rhodanine dyes in photovoltaic performance, providing a powerful strategy for the development of rhodanine based highly efficient D-π-A organic sensitizer in the future.