Ethoxy Substituents Research Articles

Impact of Alkoxy Side Chains on the Quinoxaline-Based Electron Acceptors for Efficient Organic Solar Cells.

In this work, three alkoxy-substituted quinoxaline core-based small-molecule acceptors (BQO-F, BQDO-F, and BQDO-Cl) are developed to elucidate the impact of ethoxy substituents on the physicochemical and photoelectric properties. Comparative analysis reveals that dialkoxy-substituted BQDO-F has a more planar molecular skeleton, a red-shifted absorption spectrum, upshifted energy levels, stronger crystallinity, and reduced energetic disorder compared to the monoalkoxy-substituted BQO-F. Although the replacement of fluorine atoms with chlorine atoms on the end-capped units of BQDO-F leads to a bathochromically shifted absorption spectrum, the resulting molecule BQDO-Cl shows worse π-π packing order compared to BQDO-F. Benefiting from the more favorable active layer morphology and improved carrier dynamics, the PBDB-T:BQDO-F-based organic solar cell achieves a much higher power conversion efficiency (PCE) of 16.41% compared to that of 14.48% obtained in the BQO-F-based device. In comparison with the BQDO-F-based device, the higher voltage loss of the BQDO-Cl-based device results in a lower PCE of 15.89%. The results clarify the effects of ethoxy substituents and end-capped substitutions of quinoxaline core-based small-molecule acceptors on efficient organic solar cells.

The Role of -OEt Substituents in Molybdenum-Assisted Pentathiepine Formation-Access to Diversely Functionalized Azines.

1,2,3,4,5-pentathiepines (PTEs) are naturally occurring polysulfides of increasing scientific interest based on their identified pharmacological activities. Artificial PTEs with N-heterocyclic backbones are efficiently synthesized via mediation by a molybdenum-oxo-bistetrasulfido complex. A common feature of all precursor alkynes successfully used to date in this reaction is the presence of a -CH(OEt)2 group since the previously postulated mechanism requires the presence of one OEt- as the leaving group, and the second must become a transient ethoxonium moiety. This raised the question of whether there really is a need for two, maybe only one, or possibly even zero ethoxy substituents. This research problem was systematically addressed by respective variations in the precursor-alkyne derivatives and by employing one related allene species. It was found that the total absence of ethoxy substituents prevents the formation of PTEs entirely, while the presence of a single ethoxy group results in the possibility to distinctly functionalize the position on the resulting N-heterocyclic pyrrole five ring in the target compound. This position was previously exclusively occupied by an -OEt for all products of the molybdenum-mediated reaction. The allene was applied with similar success as precursor as with the related alkyne. The now-employable significant change in precursor composition gives access to a whole new PTE subfamily, allowing further modulation of (physico)-chemical properties such as solubility, and provides additional insight into the mechanism of PTE formation; it comprises a merely partial validation of the previous hypothesis. The new alkyne precursors and pentathiepines were characterized by a variety of instrumental analyses (NMR, mass spec, UV-vis) and in six cases (one alkyne precursor, one unexpected side product, and four PTEs) by single-crystal X-ray diffraction. Syntheses, isolation procedures, analytical data, and the impact of the findings on the previously proposed mechanism are described in detail herein.

Synthesis of New Chroman-4-one Based 1,2,3-Triazole Analogues as Antioxidant and Anti-Inflammatory Agents.

A library of new chroman-4-one based 1,2,3-triazole analogues were synthesized involving a series of condensation, cyclization, Suzuki coupling and copper catalysed click chemistry protocols. The newly synthesized compounds 8a-l were screened for their invitro antioxidant and anti-inflammatory activities by employing Ascorbic acid and Diclofenac as reference drugs respectively. The compound without any substituent on benzyl ring (8a), compound with -Cl substituent in para position of benzyl ring (8i), and compound with ethoxy substituent in para position of benzyl ring (8k) exhibited potent antioxidant and anti-inflammatory activities with higher percentage of inhibition. To understand their binding affinities, molecular docking study of these three compounds performed against NADPH oxidase with presented outstanding docking scores and promising binding interactions like H-bond and hydrophobic.

Chiral 1-D coordination polymer chains featuring 1,1′-binaphthyl

Four 1-D chain coordination polymers containing bent 1,1′-binaphthyl ligands were synthesised with NiII, CuII and AgI. The use of (R)-4,4′-(2,2′-diethoxy-[1,1′-binaphthalene]-6,6′)dipyridine as a ligand yielded isostructural 1-D looping chains with NiII and CuII, whereas the use of AgI yielded both linear and helical 1-D chains. Changing the dipyridyl coordination groups to dicarboxylates in (S)-6,6′-dicarboxyl-2,2′-diethoxy-1,1′-binaphthalene yielded a 1-D looping chain with a CuII paddlewheel motif. The AgI 1-D chain features two crystallographically distinct 1-D chain morphologies with a triple helix and linear strips. The packing arrangement of the 1-D chains differs because of the intermolecular interactions present, with the steric bulk of the ethoxy substituent on the 1,1′-binaphthyl enabling the formation of large void spaces.

Non-Isocyanate Poly(Siloxane-Urethanes) Based on Oligodimethylsiloxanes Containing Aminopropyl and Ethoxy Substituents

Environmentally friendly method for the synthesis of crosslinked poly(siloxane-urethanes) avoiding the use of toxic isocyanates has been presented. The synthesis has been performed in two stages: at the first stage, non-isocyanate poly(siloxane-urethanes) have been synthesized via aminolysis of cyclocarbonates (differing in the structure and functionality) with oligomer dimethylsiloxanes bearing aminopropyl and ethoxy substituents, and crosslinked non-isocyanate poly(siloxane-urethanes) have been obtained via hydrolysis of the ethoxy groups with air moisture. According to the TGA data, processes of thermooxidative decomposition of the non-isocyanate poly(siloxane-urethanes) begin at 240‒260°C, depending on the structure of the organic block. Structural organization of the films has been investigated and glass transition temperature of two blocks (flexible siloxane and rigid urethane ones) has been determined by means of DSC and TMA. Surface of the film samples of non-isocyanate poly(siloxane-urethanes) has been assessed by means of scanning electron microscopy.

SYNTHESIS AND STRUCTURE OF NEW [5]FERROCENOPHANE

The first example of intramolecular diastereoselective domino reaction of ferrocene 1,1'-bis-enone to [5]ferrocenophane initiated with sodium ethylate was found. The product is [5]ferrocenophane with two pyridyl and one ethoxy substituents arranged asymmetrically in five carbon bridge. Diffraction studies showed that ferrocene is in almost ideal eclipsed conformation. The fan conformation found in the crystal is also preserved in solution, which was determined by NMR spectroscopy.

Effect of extended π-conjugation on photophysical characteristics of chalcone and cinnamylideneacetophenone

The photophysical and spectral characteristics of two unsaturated carbonyl compounds, a chalcone and a cinnamylideneacetophenone, were systematically analyzed using various analytical techniques such as IR, 1H and 13C NMR spectroscopy, ESI mass spectrometry, absorption and emission spectra. Dimethylamino and ethoxy substituents were purposefully introduced into appropriate positions of the aromatic rings on the studied structures in order to results in highly fluorescent compounds. Both compounds showed bright visible-light emission upon ultraviolet light excitation, in which the cinnamylideneacetophenone derivative in dimethyl sulfoxide was found to emit in the red at 612 nm with a substantial Stoke shift of 6335 cm−1. The solvent effect on the photophysical properties, such as absorption, emission, and Stokes shift, was investigated and the results were compared to evaluate the impact of extended π-conjugation. The experimental findings are consistent with the theoretical results calculated by using time-dependent density functional theory.

Synthesis and Spectroscopic Properties of Selected Acrylic and Methacrylic Derivatives of 2-Mercaptobenzothiazole

One of the most basic properties of chemical compounds is structural symmetry or asymmetry. This property can be considered at different levels of structural organization. The physical, chemical, biological, and technological properties of organic compounds depend on their chemical structure and are systematically related to it. The presented paper is focused on the synthesis and study of the spectroscopic properties of selected photoinitiators from the acrylate and methacrylate derivatives of 2-(benzothiazolylthio)ethyl. The indicated compounds can find potential application in medicine. The 2-(benzothiazolylthio)ethyl acrylate and methacrylate derivatives were characterized using infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectroscopy. Their spectroscopic properties were determined on the basis of UV–Vis spectra. The calculated DFT energies and Frontier Molecular Orbitals calculations of the studied compounds were proved to be consistent with the experimental observations. The results have showed that the introduction of the ethoxy substituent increases the reactivity of the compounds and results in the slight bathochromic shift (~19 nm) of the absorption spectra maxima.

Z‐Selective Alkene Formation from Reductive Aldehyde Homo‐Couplings

AbstractCurrent methodologies for the direct reductive coupling of two aldehydes to alkenes afford almost exclusively the thermodynamically favouredE‐isomer. Recent efforts to find phosphorus‐based reagents as replacements for the low‐valent Ti species in McMurry couplings present opportunities to change this shortcoming, and to design new reagents that allow for the formation of high proportions ofZ‐alkenes under kinetic control. Here, we report the first example of such a reagent, a phosphanyl phosphonate MesFP(H)P(O)(OEt)2,6, with an electron‐deficient MesF=2,4,6‐(CF3)3Ph substituent that promotes the reductive homo‐coupling of (hetero)aromatic aldehydes to alkenes with highZ‐selectivity. Computational results indicate that the selectivity stems from the electron deficient MesF, which results in lowered activation barriers for the collapse of a cis‐oxaphosphetane intermediate. In the absence of MesF, theE‐isomer is exclusively observed experimentally. Directing the isomeric outcome of alkene formation by introducing electron withdrawing P‐substituents bears resemblance to the Still‐Gennari modification of the Horner‐Wadsworth‐Emmons reaction where perfluorinated ethoxy substituents in the former also lead to high proportions of theZ‐isomer.

Promising Photocytotoxicity of Water-Soluble Phtalocyanine against Planktonic and Biofilm Pseudomonas aeruginosa Isolates from Lower Respiratory Tract and Chronic Wounds

Alternative methods of killing microbes have been extensively researched in connection with the widespread appearance of antibiotic resistance among pathogenic bacteria. In this study, we report on in vitro antimicrobial phototoxicity research of cationic phthalocyanine with 2-(4-N-methylmorpholin-4-ium-4-yl)ethoxy substituents against selected clinical strains of Pseudomonas aeruginosa isolated from the lower respiratory tract and chronic wounds. The microorganisms tested in the research were analyzed in terms of drug resistance and biofilm formation. The photocytotoxic effect of phthalocyanine was determined by the reduction factor of bacteria. The studied cationic phthalocyanine at a concentration of 1.0 × 10−4 M, when activated by light, revealed a significant reduction factor, ranging from nearly 4 to 6 log, of P. aeruginosa cells when compared to the untreated control group. After single irradiation, a decrease in the number of bacteria in biofilm ranging from 1.3 to 4.2 log was observed, whereas the second treatment significantly improved the bacterial reduction factor from 3.4 to 5.5 log. It is worth mentioning that a boosted cell-death response was observed after the third irradiation, with a bacterial reduction factor ranging from 4.6 to 6.4 log. According to the obtained results, the tested photosensitizer can be considered as a potential antimicrobial photodynamic therapy against multidrug-resistant P. aeruginosa.

Electrocatalysts Derived from Copper Complexes Transform CO into C2+ Products Effectively in a Flow Cell.

Electrochemical reactors that electrolytically convert CO2 into higher-value chemicals and fuels often pass a concentrated hydroxide electrolyte across the cathode. This strongly alkaline medium converts the majority of CO2 into unreactive HCO3 - and CO3 2- byproducts rather than into CO2 reduction reaction (CO2RR) products. The electrolysis of CO (instead of CO2 ) does not suffer from this undesirable reaction chemistry because CO does not react with OH- . Moreover, CO can be more readily reduced into products containing two or more carbon atoms (i. e., C2+ products) compared to CO2 . We demonstrate here that an electrocatalyst layer derived from copper phthalocyanine (CuPc) mediates this conversion effectively in a flow cell. This catalyst achieved a 25 % higher selectivity for acetate formation at 200 mA/cm2 than a known state-of-art oxide-derived Cu catalyst tested in the same flow cell. A gas diffusion electrode coated with CuPc electrolyzed CO into C2+ products at high rates of product formation (i. e., current densities ≥200 mA/cm2 ), and at high faradaic efficiencies for C2+ production (FEC2+ ; >70 % at 200 mA/cm2 ). While operando Raman spectroscopy did not reveal evidence of structural changes to the copper molecular complex, X-ray photoelectron spectroscopy suggests that the catalyst undergoes conversion to a metallic copper species during catalysis. Notwithstanding, the ligand environment about the metal still impacts catalysis, which we demonstrated through the study of a homologous CuPc bearing ethoxy substituents. These findings reveal new strategies for using metal complexes for the formation of carbon-neutral chemicals and fuels at industrially relevant conditions.

Synthesis and phase transition behavior of calamitic liquid crystals containing heterocyclic core and lateral ethoxy substituent

ABSTRACT A series of new calamitic liquid crystals, 2-[3-ethoxy-(4-alkyloxybenzoyloxy)phenyl]benzothiazoles comprising a benzothiazole core, terminal alkoxy chain, ester linker and lateral ethoxy substituent were synthesized and characterized. This series comprises nine members wherein the members differ by the length of alkyloxy chain (CnH2n + 1O-, where n = 2, 4, 6, 8, 10, 12, 14, 16, 18). The thermal properties of the compounds were analyzed by differential scanning calorimetry (DSC), and the textures were identified by polarized optical microscope (POM). The member with the shortest alkoxy chain (n = 2) is a non-mesogen. The remaining members exhibited monotropic nematic phase ranging from the low member (n = 4) until the highest member (n = 18) of the series. The influence of alkoxy chain length on the mesomorphic was studied. In addition, the mesomorphic properties of the benzothiazole liquid crystals were compared with these compounds and the effect of the lateral substituents on their mesomorphism was studied.

A Fischer-Type Ruthenium Carbene Complex as a Metathesis Catalyst for the Synthesis of Enol Ethers.

The Grubbs G-I or G-II catalyst gives the ruthenium ethoxy carbene complex, which catalyzes ring-opening cross metathesis (ROCM) of a strained cyclic alkene to give a diene where one of the two alkene moieties in the product contains an ethoxy substituent. No polymeric products are detected. Hydrocarbons such as parent norbornene or substituted cyclopropenes can proceed with the reaction smoothly. Tertiary amines, N-alkylimides, esters, and aryl or alkyl bromides remain intact under the reaction conditions. In addition to vinyl ethers, vinylic esters can also be used. The time required to reach a 50% yield of the ROCM product t50 varies from 0.01 to 140 h depending on the strain and nucleophilicity of the double bond. Anchimeric participation of an electron-rich group would result in significant enhancement of the reactivity, and the t50 could be as short as several minutes. A similar substrate without such a neighboring group shows a much slower rate. An exo-norborne derivative reacts much faster than the corresponding endo-isomer. Alkenes with poor nucleophilicity are less favored for the ROCM process, so is less strained cyclooctene.

Effect of side groups on glass transition temperatures of Poly(ethoxy/phenoxy)phosphazenes: Prediction and synthesis

Poly(aryloxyphosphazenes) are thermally stable, insulative, fire proof, and ablative resistant in extreme combustion, and can be applied as an insulated covering of high voltage cable and thermal shielding material for aircraft and spacecraft. However, being an elastomer, its higher glass transition temperature (Tg above −15 °C) limits the application in certain aspects. Therefore, adjustment of the Tg of poly(aryloxyphosphazenes) has become a research focus to improve overall performance. Introducing substituents such as alkoxy groups has been identified as an effective approach to lower the polymer Tg. In this study, based on the introduction of the different ratios of the ethoxy substituents in poly(bisphenoxyphosphazene), a series of simulations and experimental studies have been carried out for predicting the Tg of polyphosphazenes, along with establishing the relationships among synthesis, structure, and Tg. Molecular dynamics (MD) simulations using COMPASS force field and empirical Flory-Fox equation have been used to predict the Tg of the polymers and confirm the compatibility with the experimental data. Overall, the simulation results are noted to be in good agreement with the experimental values, and the Tg of the polymers gradually decreases with an increase in the ethoxy content. The proposed methods are efficient for the prediction of the Tg values of polyphosphazenes and can also be used for the structure prediction via the desired Tg, which is likely to have broad application for targeted polyphosphazenes synthesis.

Sustainable Catalytic Synthesis of Diethyl Carbonate.

New sustainable approaches should be developed to overcome equilibrium limitation of dialkyl carbonate synthesis from CO2 and alcohols. Using tetraethyl orthosilicate (TEOS) and CO2 with Zr catalysts, we report the first example of sustainable catalytic synthesis of diethyl carbonate (DEC). The disiloxane byproduct can be reverted to TEOS. Under the same conditions, DEC can be synthesized using a wide range of alkoxysilane substrates by investigating the effects of the number of ethoxy substituent in alkoxysilane substrates, alkyl chain, and unsaturated moiety on the fundamental property of this reaction. Mechanistic insights obtained by kinetic studies, labeling experiments, and spectroscopic investigations reveal that DEC is generated via nucleophilic ethoxylation of a CO2 -inserted Zr catalyst and catalyst regeneration by TEOS. The unprecedented transformation offers a new approach toward a cleaner route for DEC synthesis using recyclable alkoxysilane.

Intramolecular Spodium Bonds in Zn(II) Complexes: Insights from Theory and Experiment

Two new dinuclear zinc(II) complexes, [Zn2(µ1,3-OAc)(L1)2]I·MeOH (1) and [Zn2(µ1,3-OAc)(L2)(NCS)] (2), (where HL1 = 2-(((3-(dimethylamino)propyl)amino)methyl)-6-methoxy-phenol and H2L2 = 2,2′-[(1-Methyl-1,2-ethanediyl)bis(iminomethylene)]bis[6-ethoxyphenol]) have been synthesized and characterized by elemental and spectral analysis. Their X-ray solid state structures have been determined, revealing the existence of intramolecular Zn···O spodium bonds in both complexes due to the presence of methoxy (1) or ethoxy (2) substituents adjacent to the coordinated phenolic O-atom. These noncovalent interactions have been studied using density functional theory (DFT) calculations, the quantum theory of “atoms-in-molecules” and the noncovalent interaction plot. Moreover, a search in the Cambridge structure database (CSD) has been conducted in order to investigate the prevalence of intramolecular spodium bonds in Zn complexes. To our knowledge this is the first investigation dealing with intramolecular spodium bonds.

Ineffective OH Pinning of the Flipping Dynamics of a Spherical Guest within a Tight‐Fitting Tube

AbstractA supramolecular/synthetic method has been devised to affix a sterically hindered substituent onto a fullerene guest encapsulated in a tubular host. A two‐wheeled complex of (C59N)‐(C59N) with a tubular host was oxidatively bisected to afford a C59N+ cation captured in the tube. The C59N+ cation in the tube was then trapped by ethanol or water, which led to an oxy substituent pinned on the guest. The guest motions within the tube were modulated by the pinned substituent, and up‐and‐down flipping motions were halted by an ethoxy substituent. A hydroxy substituent, however, was ineffective in halting the flipping motions, despite the tight‐fitting relationship between the tubular host and the spherical guest. Theoretical calculations of the dynamics revealed that the flipping motions were assisted by OH‐π hydrogen bonds between the guest and the carbon‐rich wall and that sliding motions of the OH group were also facilitated by deformations of the tube.

Ineffective OH Pinning of the Flipping Dynamics of a Spherical Guest within a Tight-Fitting Tube.

A supramolecular/synthetic method has been devised to affix a sterically hindered substituent onto a fullerene guest encapsulated in a tubular host. A two-wheeled complex of (C59 N)-(C59 N) with a tubular host was oxidatively bisected to afford a C59 N+ cation captured in the tube. The C59 N+ cation in the tube was then trapped by ethanol or water, which led to an oxy substituent pinned on the guest. The guest motions within the tube were modulated by the pinned substituent, and up-and-down flipping motions were halted by an ethoxy substituent. A hydroxy substituent, however, was ineffective in halting the flipping motions, despite the tight-fitting relationship between the tubular host and the spherical guest. Theoretical calculations of the dynamics revealed that the flipping motions were assisted by OH-π hydrogen bonds between the guest and the carbon-rich wall and that sliding motions of the OH group were also facilitated by deformations of the tube.

Antidiabetic Activity of Dihydropyrimidine Scaffolds and Structural Insight by Single Crystal X-ray Studies

This research project is designed to identify the anti-diabetic effects of the newly synthesized compounds to conclude the perspective of consuming one or more of these new synthetic compounds for diabetes management. A series of dihydropyrimidine (DHPM) derivative bearing electron releasing and electron-withdrawing substituent's on phenyl ring (a-j) were synthesized and screened for antihyperglycemic( anti-diabetic) activity on streptozotocin (STZ) induced diabetic rat model. The newly synthesized compounds were characterized by using FT-IR, melting point, 1H and 13C NMR analysis. The crystal structure and supramolecular features were analyzed through single-crystal X-ray study. Anti-diabetic activity testing of newly prepared DHPM scaffolds was mainly based on their relative substituent on the phenyl ring along with urea and thiourea. Among the synthesized DHPM scaffold, the test compound c having chlorine group on phenyl ring at the ortho position to the hydropyrimidine ring with urea and methyl acetoacetate derivative shows moderate lowering of glucose level. However, the title compounds methyl 4-(4-hydroxy-3-methoxyphenyl)- 6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate(g) and ethyl 4-(3-ethoxy-4- hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate(h) having methoxy and ethoxy substituents on phenyl ring show significant hypoglycemic activity compared to the remaining compounds from the Scheme 1. The experimental rat models for the study were divided into 13 groups (n = 10); group 1 animals were treated with 0.5% CMC (0.5mL) (vehicle); group 2 were considered the streptozotocin (STZ)/nicotinamide diabetic control group (DC) and untreated, group 3 diabetic animals were administered with gliclazide 50 mg/kg and act as a reference drug group. The remaining groups of the diabetic animals were administered with the newly synthesized dihydropyrimidine compounds in a single dose of 50 mg/kg orally using the oral gavage, daily for 7 days continuously. The blood glucose level was measured before and 72 hrs after nicotinamide-STZ injection, for confirmation of hyperglycemia and type 2 diabetes development. Blood glucose levels were significantly (p<0.05) reduced after treatment with these derivatives. The mean percentage reduction for gliclazide was 50%, while that of synthesized compounds were approximately 36%. Our result suggests that the synthesized new DHPM derivative containing alkoxy group on the phenyl ring shows a significant lowering of glucose level compared to other derivatives.

Physicochemical properties of liposome-incorporated 2-(morpholin-4-yl)ethoxy phthalocyanines and their photodynamic activity against oral cancer cells

Three 2-(morpholin-4-yl)ethoxy-substituted phthalocyanines with zinc(II) or magnesium(II) ion in the core were subjected to optical and photochemical studies, and their photodynamic activity against oral cancer cell lines was evaluated. Phthalocyanine derivatives were studied both as free compounds and after incorporation into liposomes used as drug delivery vehicles. The introduction of electron-donating 2-(morpholin-4-yl)ethoxy groups in non-peripheral positions significantly affected physicochemical and optical properties of the phthalocyanines. The increased number of substituents led to increased hydrophilicity, decreased tendency to aggregate, and a larger shift of the phthalocyanine Q band toward the red region of the spectra. The incorporation of the hydrophobic zinc(II) phthalocyanine derivative possessing two 2-(morpholin-4-yl)ethoxy substituents into liposomes triggered most pronounced changes in its physicochemical properties compared to octasubstituted compounds. The disubstituted derivative expressed a promising biological effect against oral squamous cell carcinoma with IC50 values of 22nM and 29nM for the free and encapsulated compound, respectively. Our results indicate that liposomes can be used as a drug delivery vehicle for hydrophobic phthalocyanines in further biological studies.