Pyridinium Bromide Research Articles

Tuning the push-pull dyes: Construction of polarity insensitive probes for G4 DNA

We report here the design and synthesis of two new polarity-insensitive push-pull dyes TCP-SO3 and TCP-COOH and developed as fluorescent probes for G-quadruplex (G4) DNAs. The strategy involved in this study is to use the traditional D-π-A building block of carbazole-pyridinium (CP), while introducing of a diphenylimidazole group as a secondary donor as well as molecular rotor to form the D-D-π-A configuration, thus ascertaining the effect of the auxiliary group on the photophysics of the dyes. Additionally, N-sulfobutylpyridinium and N-(carboxyethyl) pyridinium bromide moieties are employed as electron-withdrawing anchoring groups, respectively, due to their hydrophilicity and electronic characters, thereby regulating the G4 DNA binding affinity and photophysical properties. It was found that the introduction of diphenylimidazole group to form the D-D-π-A configuration brought superior performance, in terms of polarity-insensitive property with a fluorescence-off state in various polarity solvents. Both dyes exhibited a clear-cut off-on sensing preference for G4 over non-G4 DNA structures, dye TCP-SO3 having a hydrophilic sulfonate group at electron-acceptor part displayed superior G4 DNA binding and selectivity compared to TCP-COOH with a carboxylic acid group. Detailed investigation on the relationship between the structure, photophysical properties, and G4 DNA sensing performance was described.

2-Chloro-3-cyano-4-nitrobenzyl pyridinium bromide as a potent anti-lung cancer molecule prepared using a single-step solvent-free method.

Mono-/dimeric-substituted pyridinium and pyrazolium bromides were prepared under conventional and solvent-free silica-supported domestic microwave conditions. The atom economy, environmental product mass intensity and product mass intensity for solvent-free reactions showed significant importance for the synthesis of target molecules. 4-Nitrobenzyl-substituted pyridinium bromide showed potent anticancer properties compared with mono-/dimeric-substituted pyridinium and pyrazolium bromides against a lung cancer cell line (A-549). Molecular simulation studies were carried out for mono-/dimeric-substituted pyridinium and pyrazolium bromide against protein human CDK1/cyclinB1/CKS2 using the AutoDock program.

Crystal structure and Hirshfeld surface analysis of two iHOFs based on CH...NC hydrogen bonding.

Two ionic hydrogen-bonded organic frameworks (iHOFs) assembled from 4-cyano-N-(4-cyanobenzyl)pyridinium, have been crystallized with Br- and antimony(III) pentabromide, [SbBr5]2-, as counter-ions and characterized. These are 4-cyano-N-(4-cyanobenzyl)pyridinium bromide, C14H10N3+·Br-, and bis[4-cyano-N-(4-cyanobenzyl)pyridinium] antimony(III) pentabromide, (C14H10N3)2[SbBr5]. The CH...NC interactions induced by templating anions construct disparate frameworks. Hirshfeld surface analysis indicated that these crystals exhibit two types of hydrogen-bonding interactions, specifically CH...NC and CH...Br. Consecutive reverse-parallel CH...NC hydrogen-bonding interactions in these crystals induced the formation of a large number of CH...NC bonds which exhibit both cis and trans configurations.

Dynamic color‐tunable ultra‐long room temperature phosphorescence polymers with photo‐chromism and water‐stimuli response for multilevel anti‐counterfeiting

AbstractDeveloping dynamic color‐tunable ultra‐long room temperature phosphorescence (URTP) polymers with afterglow of over 1 s, photo‐chromism, and multi‐stimuli response for practical anti‐counterfeiting and information security applications is attractive but very challenging. Herein, by doping multicolor phosphorescence pyridinium bromide L block or viologen‐based photo‐chromic V block into polyvinyl alcohol matrixes, the water‐stimuli‐responsive color‐tunable URTP polymer films with afterglow of up to 8 s and the reversible viologen‐based photochromic polymer films have been developed. More significantly, a series of dynamic color‐tunable URTP polymer films with ultra‐long afterglow of over 6 s, photo‐chromism, and water‐stimuli response have been successfully exploited by integrating L and V blocks into one polymer system. Mechanistic investigations have revealed that their photo‐chromism mainly comes from the photo‐generated viologen free radicals. Furthermore, their dynamic multilevel anti‐counterfeiting applications have been demonstrated. These results pave the way to develop smarter multifunctional URTP materials for anti‐counterfeiting and optical sensing.

Ionic hyper-cross-linked porous polymer networks with achiral and chiral pyridinium-type segments

A new type of ionic porous polymer networks (PPNs) is reported containing (i) N-alkyl pyridinium bromide ionic groups and (ii) a hyper-cross-linked scaffold based on polyacetylene (polyene) chains the rigidity of which contributes to the permanent porosity the PPNs. The ionic PPNs were prepared by a combination of chain-growth polymerization of acetylenic monomers and quaternization reactions of pyridine and alkyl bromide moieties. The wide variability of this synthetic concept enabled the preparation of covalently diverse PPNs with ionic groups located either in the pendant groups or in the knots of the networks, as well as the preparation of PPNs with chiral ionic groups. The content of ionic groups in PPNs ranged from 1.5 to 4.2 mmol/g, and the BET area was from 67 to 744 m2/g. The mode of quaternization used (prepolymerization or postpolymerization) controlled the contribution of micropores and mesopores to the porosity of the ionic PPNs. The polyacetylene ionic PPNs were active as heterogeneous organocatalysts (applied without a cocatalyst) for the cycloaddition of CO2 to styrene oxide yielding styrene carbonate as the only product (up to 96 %). PPNs with chiral ionic groups showed potential for enantioselective catalysis of this reaction. The catalytic activity was controlled by the accessibility of pyridinium active centres for the substrate molecules. Ionic PPNs prepared were also efficient in reversible water vapour capturing and releasing (capacity up to 361 mg/g at 298 K and RH = 90 %). Both surface adsorption and capillary condensation of H2O contributed to the water vapour capture on reported PPNs.

Improved synthesis, molecular modeling and anti-inflammatory activity of new fluorinated dihydrofurano-naphthoquinone compounds

A series of new fluorinated dihydrofurano-napthoquinone compounds were sucessfully synthesized in good yields using microwave-assisted multi-component reactions of 2-hydroxy-1,4-naphthoquinone, fluorinated aromatic aldehydes, and pyridinium bromide. The products were fully characterized using spectroscopic techniques and evaluated for their anti-inflammatory activity using lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. Among 12 new compounds, compounds 8b, 8d, and 8e showed high potent NO inhibitory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells with IC50 values ranging from 1.54 to 3.92 µM. The levels of pro-inflammatory cytokines IL-1β and IL-6 in LPS-stimulated RAW264.7 macrophages were remarkably decreased after the application of 8b, 8d, 8e and 8k. Molecular docking simulations revealed structure–activity relationships of 8b, 8d, and 8e toward NO synthase, cyclooxygenase (COX-2 over COX-1), and prostaglandin E synthase-1 (mPGES-1). Further physicochemical and pharmacokinetic computations also demonstrated the drug-like characteristics of synthesized compounds. These findings demonstrated the importance of fluorinated dihydrofurano-napthoquinone moieties in the development of potential anti-inflammatory agents.

High-performance and selective catalyst for the chemical fixation of CO2 into cyclic carbonates based on pyridinium-based deep eutectic solvent

Rising atmospheric CO2 levels have prompted interest in chemical fixation routes to convert CO2 into value-added cyclic carbonates. This study reports a high-performance catalyst based on a pyridinium-based deep eutectic solvent (DES) for CO2 cycloaddition with epoxides under mild conditions. The DES was prepared by mixing 1-(carboxymethyl)pyridinium bromide ([CMPy]Br) as a hydrogen bond acceptor with maleic acid as an inexpensive and eco-friendly hydrogen bond donor [HBD]. The melting point depression enables the DES to act as a homogeneous catalyst without additional solvents. A diverse range of cyclic carbonates were synthesized in high yields from various epoxides and CO2 under atmospheric pressure at 90–110 °C temperatures. Compared to other catalytic systems, the offered DES significantly reduced reaction times of 1–3 h to achieve best quantitative conversions. The DES was recyclable for at least 5 runs without loss of activity. The high performance was attributed to the DES' ability to activate epoxides via hydrogen bonding while stabilizing reaction intermediates. This metal-free and solvent-free approach provides an efficient strategy for CO2 utilization under green conditions using readily available pyridinium-based DES.

Effect of choline amino acid ionic liquids on maize seed germination and endogenous plant hormone levels.

Prior research has established choline-based ionic liquids (ILs) as safe for various organisms. However, their impact on plants has been underexplored. To identify effective eco-friendly ILs, we synthesized seven choline amino acid ([Chl][AA]) ILs and analyzed their physiological influence on maize seed germination. In contrast to the traditionally used N-octyl pyridinium bromide IL, these seven [Chl][AA] ILs exhibited substantially lower toxicity. Moreover, within a broad treatment concentration range (10-100 mg L-1), these ILs notably enhanced maize germination indices and root and shoot growth. Specifically, treatment with 100 mg L-1 choline tryptophan resulted in a 21.2% increase in germination index compared to those of control maize. Compared to the control, the application of choline serine, choline aspartic acid, choline phenylalanine, and choline tryptophan at 100 mg L-1 led to respective increases of 23.9%, 21.5%, 22.5%, and 24.5% in maize shoot length. Analysis of endogenous hormones and free amino acid contents revealed elevated levels of growth-promoting plant hormones (gibberellic acid and zeatin) in maize shoot tips, as well as increased contents of major amino acids (glutamate, glycine, and arginine) following treatment with different [Chl][AA] ILs at 100 mg L-1. These findings indicate that [Chl][AA] holds promise for the development and application of novel low-toxicity ILs.

Unveiling the molecular interactions and antimicrobial activity of cetyl pyridinium bromide in ternary systems with short tetraalkylammonium bromide salts

Physicochemical properties of a surfactant cetyl pyridinium bromide (CPB) (0.2–2 mmol kg−1) has been investigated by the addition of greener additives, that is, aqueous tetraalkylammonium bromide (TAAB) salts at different concentrations (0.005, 0.010 and 0.015 mol kg−1) by employing techniques viz: conductivity, fluorescence and UV–visible spectra. In contrast to spectroscopic analysis, which was conducted at room temperature (298.15 K), conductivity measurements were made at various temperatures (298.15, 303.15, 308, and 313.15 K). The obtained electrical conductivity data has been used to compute the critical micelle concentration (cmc), which was also obtained from the UV–Visible and fluorescence methods. It is important to mention that the cmc values obtained from these methods are found to be in good agreement. Various thermodynamic parameters (ΔGmo, ΔHmo, and ΔSmo) have been calculated using conductivity data, the interpretation of which reveals that the interactions between CPB and TAAB are found to be both electrostatic and hydrophobic, however, hydrophobic interactions are found to be dominant in the ternary system. Additionally, the impact of TAAB on the antimicrobial activities of CPB has been evaluated by measuring the zone of inhibition, which explains why the CPB-TAAB system is more effective against gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) than gram-negative bacteria (Escherichia coli and Salmonella typhi).Communicated by Ramaswamy H. Sarma

Voltammetric Determination of Sudan I for Foodstuff Quality Control

Simple and rapid determination of Sudan I, a synthetic azo dye banned in the food industry over health concerns, is needed to ensure foodstuff safety and quality. In this study, a voltammetric approach based on Sudan I oxidation at the glassy carbon electrode (GCE) modified with manganese dioxide nanorods (MnO2 NRs) dispersed in hexadecyl pyridinium bromide was developed. The effectiveness of MnO2 NRs as a modifier was confirmed by a 7.9- and 9.2-fold increase in the electroactive surface area and the electron transfer rate, respectively, as compared to GCE. The irreversible electrooxidation of Sudan I was found to be accompanied by proton transfer and controlled by both diffusion and surface processes. Differential pulse voltammetry in phosphate buffer pH 6.5 was used for analytical purposes. The linear response of the electrode to Sudan I was shown in the ranges of 0.050–2.5 and 2.5–25 μM, with a detection limit of 13.5 nM. The developed approach was tested on dried and smoked paprika and Atlantic salmon. The obtained recovery values of 99–101% suggest that there is no matrix effect and that the method can be applied in practice.

Towards a deeper understanding of the coordination chemistry in pyridinium-based ionic liquids-iron systems: Insights from quantum chemical and semi-empirical investigations

In recent times, the utilization of ionic liquids (ILs) in mitigating corrosion has been a subject of interest, but the detailed examination of their coordination with iron remains an understudied area. This research utilizes SCC-DFTB simulations to probe the interaction profiles and coordination chemistry of six ILs—specifically, 4-(Dimethylamino)-1-(2-hydroxyethyl)pyridinium bromide (P2CH), 4-(Dimethylamino)-1-(3-hydroxypropyl)pyridinium bromide (P3CH), 4-(Dimethylamino)-1-(2-methoxyethyl)pyridinium bromide (P2CM), 4-(dimethylamino)-1-ethylpyridinium bromide (P2C), 1-butyl-4-(dimethylamino) pyridinium bromide (P4C), and 4-(dimethylamino)-1-pentylpyridinium bromide (P5C)—and their interaction with the Fe(110) iron surface. Quantum chemical calculations were conducted to understand their inherent reactivity independent of external factors. Our findings revealed comparable reactivity patterns across all ILs, with P2CM distinguishing itself through exceptional electron donating and accepting abilities, and a minimal energy gap. The study of IL-Iron coordination was carried out in three distinct interaction configurations. Molecular orientation and N-alkylation of the pyridinium component were found to be significant in controlling interaction intensities. Particularly, the ILs demonstrated maximum affinity in parallel alignment with the iron surface, and P3CH exhibited an extraordinary interaction through three Fe-C bonds. The pattern of increasing adsorption strength was identified as P2CH < P2CM < P2C < P4C < P5C < P3CH, with P2CH forming bonds consistently across configurations. Interestingly, even when ILs did not establish bonds with Fe atoms, negative interaction energies were observed, implying additional coordination mechanisms beyond mere covalent bonds. This study emphasizes the crucial role of molecular structures in determining IL-metal surface interactions and supports the design of novel ILs with enhanced corrosion resistance abilities.

Comprehensive Comparison of Bioactive N-Glycans among Seven Species of Livestock and Poultry Plasma Using a Relative Quantification Strategy.

Glycans have been proven to play special roles in keeping human health as a class of nutritional and bioactive ingredients in many food materials. However, their broad use in the food industry is hindered by the lack of comprehensive analytical methods for high-quality food glycomics studies and large-quantity raw materials for their production. This study focuses on structural identification and quantitative comparison of bioactive N-glycans in seven species of livestock and poultry plasma as potential natural glycan resources by a novel comprehensive relative quantification strategy based on stable isotope labeling with nondeuterated and deuterated 4-methyl-1-(2-hydrazino-2-oxoethyl)-pyridinium bromide (d0/d7-HMP) in combination with linkage-specific derivatization of sialic acid residues. Methodological validation of the method in terms of detection sensitivity, signal resolution, quantification linearity, precision, and accuracy on model neutral and complicated sialylated glycans demonstrated its advantages over the existing methods. Based on this method, a series of bioactive N-glycans were found in seven species of livestock and poultry plasma, and their differences in structure, abundance percentages, and relative contents of N-glycans were revealed, demonstrating their excellent applicability for comprehensive food glycomics analysis and great exploitation potential of these plasma samples as large-quantity raw materials in producing bioactive N-glycans for application in food and pharmaceutical industries.

Mechanism of defect passivation achieved by chemical interaction in inverted perovskite solar cells

A variety of defects exist in the solution-processed polycrystalline perovskites, resulting in photovoltaic output losses and degradation. Chemical interaction is a promising way to realize the passivation of defects. Herein, cetyl pyridinium bromide (CPB) containing both pyridine units and long-chain alkyl groups was introduced in the perovskite precursor solution as a passivation agent. Experimental results show that pyridine unit in CPB formed coordination with uncoordinated Pb2+, which also interact with N–H in MAPbI3. Meanwhile, long-chain alkyl groups in CPB had interaction with MAI and PbI2 in MAPbI3. Thus, trace amount of CPB in the precursor solution improved the optoelectronic properties of perovskite films and suppressed non-radiative carrier recombination in perovskite solar cell (PSC). CPB-modified perovskite films exhibit a lower trap-state density and stronger carrier migration capability. It enables the significant enhancement of PCE values of the p-i-n structured PSC from 18.27 % to 20.53 %, accompanied by the improved stability. Our work exhibits more possibility between passivating additive and PSC performance.

Synthesis of potent MDA-MB 231 breast cancer drug molecules from single step

We have prepared novel potent breast cancer drug molecules from non-toxic and inexpensive method. Column chromatography is not necessary for purification of target molecules. The value of overall atom economy, environmental factor, environmental catalyst and product mass intensity gives additional merits for this synthetic method. Synthesized flexible dimeric imidazolium bromides showed less toxicity and gives excellent anticancer response against normal mammary epithelial cells. Novel dimeric pyridinium bromides showed excellent anticancer response against tested cancer cell lines. In cell cycle, novel flexible dimeric pyridinium bromides showed significant arrest in the G2/M phase by nearly three folds, when compared with control drug. We have studied the targeting epidermal growth factor receptor for all the synthesized flexible amino substituted and methyl substituted dimeric pyridinium bromides.

Novel hydrolytic resistant antibacterial monomers for dental resin adhesive

ObjectivesTo evaluate the properties of novel hydrolytic resistant antibacterial monomers and to determine the properties of resin adhesives containing these monomers. MethodsMethacrylamide-based QAC (Quaternary Ammonium Compound) monomers, 1-(11-Methacryla-midoundecyl)pyridine-1-ium bromide (MAUPB) and 1-(12-Methacryl-amidododecyl)pyridine-1-ium bromide (MADPB), and their methacrylate-derivatives, N-(1-Methacryloylundecanyl)pyridinium bromide (MUPB) and N-(1-Methacryloyldodecanyl)pyridinium bromide (MDPB), were synthesized and characterized. The minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined against S.mutans and E.faecalis. Cytotoxicity of unpolymerized monomers were evaluated using L-929 and MDPC-23. Each monomer was incorporated into experimental resins (BisGMA/TEGDMA/CQ/EDMAB or BisGMA/HEMA/CQ/EDMAB) at 10wt%. FTIR Spectra were collected for degree of conversion (DC%) measurement. Bacterial attachment on resin disks were determined by fluorescent microscope. Mechanical properties of experimental resins were evaluated by flexural strength & modulus and shear bond strength testing. ResultsThe antibacterial activity of MDPB≥MUPB>MADPB>MAUPB. The TC50 of MAUPB> MADPB>MUPB >MDPB. Incorporation of MAUPB in BisGMA/TEGDMA-based resin, had no significant effect on DC%, while significantly increase DC% in BisGMA/HEMA-based Resin. MUPB and MAUPB containing resins showed less viable bacterial attachment than pure resins. After 3-month storage, resins containing MAUPB illustrated higher flexural strength than their corresponding resins containing MUPB. BisGMA/HEMA-based resin containing MAUPB illustrated significantly higher resin-dentin shear bond strength than that of MUPB and pure resin. ConclusionsMethacrylamide monomer containing QAC, MAUPB, possessed antibacterial properties and superior physical and mechanical properties when incorporated in resin adhesives as compared to their corresponding methacrylate monomer, MUPB. Clinical significanceMethacrylamide-based QAC monomers are potentially used to formulate antibacterial hydrolytic resistant resin adhesives and enhance resin-dentin bond strength.

Discovery of Novel Dimeric Pyridinium Bromide Analogues Inhibits Cancer Cell Growth by Activating Caspases and Downregulating Bcl-2 Protein.

Flexible dimeric substituted pyridinium bromides with primary and tertiary amines are prepared by conventional and solvent-free methods. The formation of compounds 2 and 4 is much easier than that of compounds 1 and 3 because of the benzyl carbon which is more electropositive than the primary alkyl carbon. The newly synthesized dimeric pyridinium compounds are optimized using DFT and B3LYP 6-31 g(d,p). The in vitro antiproliferative activity is studied in lung (A549) and breast cancer cell lines (MDA-MB 231). Among the four compounds, 1,1'-(1,3-phenylene bis(methylene)bis 2-aminopyridinium bromide 4 showed potent anticancer activity when compared to the standard drug 5-fluorouracil. 1,1'-(1,3-Phenylene bis(methylene)bis 2-aminopyridinium bromide 4 is not toxic to normal cell lines 3T3-L1 and MRC-5 cell lines. Also, 1,1'-(1,3-phenylene bis(methylene)bis 2-aminopyridinium bromide 4-induced apoptosis in cancer cell lines is examined using AO/EB and Hoechst staining, which is further supported by cell cycle analysis. Western blot analysis showed that 1,1'-(1,3-phenylene bis(methylene)bis 2-aminopyridinium bromide 4 induces apoptosis through the extrinsic apoptotic pathway by upregulating caspase 3 and caspase 9. This compound also downregulates intrinsic apoptotic proteins, including Bcl-2, Bcl-x, and Bad. From the present study results, it is confirmed that 1,1'-(1,3-phenylene bis(methylene)bis 2-aminopyridinium bromide 4 has potent anticancer activity when compared to other compounds.

Interaction between oxidised state of quercetin and bovine serum albumin in presence of surfactant aggregates with different charges

The present investigation focuses on the role of surfactant and its charge on the interaction of flavonoid Quercetin (QCT) and Bovine serum albumin (BSA). QCT is known to undergo autoxidation in many chemical environments which has different characteristics compared to its non-oxidised structure. In this experiment, two ionic surfactants used. They are anionic surfactant, Sodium dodecyl sulfate (SDS) and Cationic surfactants Cetyl pyridinium bromide (CPB). The characterizations employed are conductivity, FT-IR, UV–visible spectroscopy, Dynamic light scattering (DLS) and Zeta potential measurements. The critical micellar concentration (CMC) as well as the counter-ion binding constant (β) have been calculated by making use of specific conductance values, in aqueous medium at 300 K. Various thermodynamic parameters, ΔG0 m, standard free energy of micellization, ΔH0 m, standard enthalpy of micellization and ΔS0 m, standard entropy of micellization are calculated. The negative value of ΔG0 m in all systems is indicative of spontaneous binding occurring in both QCT + BSA + SDS (−23.35 kJ mol−1) and QCT + BSA + CPB (−27.18 kJ mol−1). The higher negative value infers the latter is a more stable system with greater spontaneity. The UV-visible spectroscopy study points at stronger binding of QCT and BSA in presence of surfactants and also there is stronger binding of CPB in ternary mixture with higher binding constant compared to SDS ternary mixture. Which is evident from the binding constant calculated from Benesi-Hildebrand plot (QCT + BSA + SDS, 244.46 M−1; QCT + BSA + CPB, 336.53 M−1). Further, the structural alterations occurring in the above systems has been observed by FT-IR spectroscopy. The DLS and Zeta potential measurements also support the above finding. Communicated by Ramaswamy H. Sarma

Flexible Organic Photodetectors with Mechanically Robust Zinc Oxide Nanoparticle Thin Films.

Zinc oxide nanoparticle (ZnO-NP) thin films have been intensively used as electron transport layers (ETLs) in organic optoelectronic devices, but their moderate mechanical flexibility hinders their application to flexible electronic devices. This study reveals that the multivalent interaction between ZnO-NPs and multicharged conjugated electrolytes, such as diphenylfluorene pyridinium bromide derivative (DFPBr-6), can significantly improve the mechanical flexibility of ZnO-NP thin films. Intermixing ZnO-NPs and DFPBr-6 facilitates the coordination between bromide anions (from the DFPBr-6) and zinc cations on ZnO-NP surfaces, forming Zn2+-Br- bonds. Different from a conventional electrolyte (e.g., KBr), DFPBr-6 with six pyridinium ionic side chains holds the Br--chelated ZnO-NPs adjacent to DFP+ through Zn2+-Br--N+ bonds. Consequently, ZnO-NP:DFPBr-6 thin films exhibit improved mechanical flexibility with a critical bending radius as low as 1.5 mm under tensile bending conditions. Flexible organic photodetectors with ZnO-NP:DFPBr-6 thin films as ETLs demonstrate reliable device performances with high R (0.34 A/W) and D* (3.03 × 1012 Jones) even after 1000 times repetitive bending at a bending radius of 4.0 mm, whereas devices with ZnO-NP and ZnO-NP:KBr ETLs yield >85% reduction in R and D* under the same bending condition.

Polyacetylene-based polyelectrolyte by the quaternization polymerization of 2-ethynylpyridine using (6-bromo-1-oxohexyl)ferrocene

A new polyacetylene-based polyelectrolyte with the ferrocene-containing pyridinium substituents was synthesized by the quaternization polymerization of 2-ethynylpyridine using (6-bromo-1-oxohexyl)ferrocene. The analysis results on the chemical structure of the resulting polymer revealed that it contains the conjugated polymer backbone system with the bulky N-(6-ferrocenyl-6-oxohexyl)pyridinium bromide substituents. The absorption spectrum exhibited the maximum peak of 519 nm which comes from the π → π∗ transition of the conjugated polyene group. The overall redox current shape showed irreversible results and the related values were very stable in the range of −1.5 V to 1.5 V under up to 50 cycles. The oxidation peak value was 0.5 V and 1.25 V and the reduction peak value was −1.3 V.

Synthesis, Characterization, Pharmacogenomics, and Molecular Simulation of Pyridinium Type of Ionic Liquids and Their Applications.

Substituted pyridinium bromides are prepared by conventional and solvent-free greener methods. The solvent-free solid-phase (greener) method is superior to the conventional method because of its nontoxic nature, simple reaction setup procedure, and twenty times less time consumption. Column chromatography and toxic organic solvents are avoided. Substituted pyridinium salts 1-2(a-c) show excellent catalytic response in the preparation of β-amino carbonyl derivatives using the conventional approach. Pharmacokinetics is very important in target validation and in shifting a lead compound into a drug. The physicochemical properties discussed here can be used effectively in the drug designing candidate, which is a cumbersome process in clinical research. In addition, molecular simulations are demonstrated, and compounds 1-2(a-c) possess the most potent VEGFR-2 kinase protein inhibitory activities, and most interestingly, compound 2a strongly binds and regulates the VEGFR-2 kinase activity in therapeutic approaches and cancer prevention.