Chlorine Groups Research Articles

Development of a portable SERS tool to evaluate the effectiveness of washing methods to remove pesticide residue from fruit surface

BackgroundPesticides are widely used in agriculture to control pests and enhance crop yields. However, post-harvest, there are growing concerns about the potential health risks posed by pesticide residues on produce surfaces. Analyzing these residues is challenging due to their typically low concentrations and the potential interference from the complex matrix of the produce's surface. The problem addressed in this study is the need for a sensitive, rapid, and on-site capable method to detect and quantify pesticide residues on agricultural products. ResultsWe developed a portable surface-enhanced Raman spectrometer (SERS)-based approach that offers a rapid 10-min turnaround, simplified protocol, on-site capability, and high sensitivity. Using the new analytical method, we evaluated pesticide residues on fruit surfaces after household or industrial postharvest washing, specifically the efficacy in removing the fungicide ferbam from peach surfaces. The limit of detection (LOD) for our method was determined to be 0.012 mg/kg, significantly lower than the U.S. Environmental Protection Agency's regulated limit of 7 mg/kg for ferbam on peaches. Our data shows that soaking in tap water for 1 min is the least effective method for removing ferbam, with insignificant difference from the control group. In contrast, soaking in a vinegar-water or NaHCO3-water solution for 5 min, as well as in a sodium hypochlorite solution (12 % available chlorine) for 1 or 5 min, proved to be the most effective methods. Extended soaking improved pesticide removal for tap water, vinegar, and NaHCO3, while in the chlorine groups, the effect was insignificant. SERS analysis revealed negligible penetration of ferbam into peach flesh and the inner surface of the skin. SignificanceThis study introduces an innovative method for measuring pesticide residues, significantly enhancing our understanding of pesticide removal and penetration. This new analytical approach is crucial for effectively detecting pesticides and mitigating their exposure through food sources.

Comparative, anti-infective screening and molecular docking studies of 4-amino-1, 2, 4-triazole derivatives

The rise of drug-resistant bacteria is a problem in medicine. This highlights the need to find new molecules that have anti-infective properties. In this study, thiosemicarbazone derivatives were made using a 4-amino-1,2,4-triazole structure. We have evaluated at the anti-infective activity against E. coli, S. aureus, C. albicans, & M. tuberculosis. Among the compounds tested, 4g showed activity at concentrations of 1 μg/ml & 2 μg/ml against E. coli and S. aureus. The molecule 4c had anti-infective activity at a concentration of 6.25 μg/ml against M. tuberculosis. Four compounds had nitro, anthracene, & chlorine (both mono & disubstituted) groups and were effective against all the bacteria we tested. Analysis of molecular binding was also done to see how these compounds bond with E. coli (PDB ID: 1HSK), S. aureus (PDB ID: 1HSK), C. albicans (PDB ID: 5V5Z), and M. tuberculosis (PDB ID: 4P8H).

Catalyst-Free, Zn-Mediated Decarboxylative Coupling of Chlorostibines to Access Alkylstibines with Stable C(sp3)-Sb Bonds.

Herein, decarboxylative C(sp3)-Sb coupling of aliphatic carboxylic acid derivatives with chlorostibines to access alkylstibines has been achieved. This catalyst-, ligand-, and base-free approach using zinc as a reductant affords various kinds of benzyldiarylstibines and other monoalkyldiarylstibines and tolerates various functional groups, including chlorine, bromine, hydroxyl, amide, sulfone, and cyano groups. The late-stage modification and the gram-scale experiments illustrate its potential application.

Determination of bisphosphonate properties in terms of bioavailability, bone affinity, and cytotoxicity

BackgroundThe study aimed to evaluate the therapeutic potential of fourteen newly synthesized bisphosphonates by assessing their bioavailability, bone affinity, and cytotoxicity. These bisphosphonates included a series of aminomethylenebisphosphonates and standard compounds such as risedronate and tiludronate.MethodsDrug permeability was determined using Parallel Artificial Membrane Permeability Assays (PAMPA), while bone affinity was assessed by sorption on hydroxyapatite. Bacterial cell response to the bisphosphonates was also examined using Lactobacillus paracasei cells as a model.ResultsSeveral tested compounds, including BP3 to BP8 and BP11, which feature substituents in the pyridine ring such as methyl groups, iodine, bromine, chlorine, or hydroxyl groups, demonstrated potentially more beneficial therapeutic properties than commercially used bisphosphonates. These compounds showed stronger bone affinity and higher gastrointestinal absorption with comparable or lower cytotoxic effects. Specifically, BP11 exhibited the highest bone affinity, while BP8 and BP11 showed the greatest permeability.ConclusionsThe findings suggest that BP3 BP8, and BP11 are promising candidates for further research. These results highlight the importance of comprehensively evaluating bisphosphonates' therapeutic properties to identify effective treatments for osteoporosis and other bone diseases.Graphical abstract

Detection of tetanus toxoid with iron magnetic nanobioprobe

Diagnosis of diseases with low facilities, speed, accuracy and sensitivity is an important matter in treatment. Bioprobes based on iron oxide nanoparticles are a good candidate for early detection of deadly and infectious diseases such as tetanus due to their high reactivity, biocompatibility, low production cost and sample separation under a magnetic field. In this study, silane groups were coated on surface of iron oxide nanoparticles using tetraethoxysilane (TEOS) hydrolysis. Also, NH2 groups were generated on the surface of silanized nanoparticles using 3-aminopropyl triethoxy silane (APTES). Antibody was immobilized on the surface of silanized nanoparticles using TCT trichlorothriazine as activator. Silanization and stabilized antibody were investigated by using of FT-IR, EDX, VSM, SRB technique. UV/vis spectroscopy, fluorescence, agglutination test and ELISA were used for biosensor performance and specificity. The results of FT-IR spectroscopy showed that Si–O–Si and Si-O-Fe bonds and TCT chlorine and amine groups of tetanus anti-toxoid antibodies were formed on the surface of iron oxide nanoparticles. The presence of Si, N and C elements in EDX analysis confirms the silanization of iron oxide nanoparticles. VSM results showed that the amount of magnetic nanoparticles after conjugation is sufficient for biological applications. Antibody stabilization on nanoparticles increased the adsorption intensity in the uv/vis spectrometer. The fluorescence intensity of nano bioprobe increased in the presence of 10 ng ml−1. Nanobio probes were observed as agglomerates in the presence of tetanus toxoid antigen. The presence of tetanus antigen caused the formation of antigen-nanobioprobe antigen complex. Identification of this complex by HRP-bound antibody confirmed the specificity of nanobioprobe. Tetanus magnetic nanobioprobe with a diagnostic limit of 10 ng ml−1 of tetanus antigen in a short time can be a good tool in LOC devices and microfluidic chips.

Antimicrobial Properties of Flavonoid Derivatives with Bromine, Chlorine, and Nitro Group Obtained by Chemical Synthesis and Biotransformation Studies.

The search for new substances of natural origin, such as flavonoids, is necessary in the fight against the growing number of diseases and bacterial resistance to antibiotics. In our research, we wanted to check the influence of flavonoids with chlorine or bromine atoms and a nitro group on pathogenic and probiotic bacteria. We synthesized flavonoids using Claisen-Schmidt condensation and its modifications, and through biotransformation via entomopathogenic filamentous fungi, we obtained their glycoside derivatives. Biotransformation yielded two new flavonoid glycosides: 8-amino-6-chloroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside and 6-bromo-8-nitroflavone 4'-O-β-D-(4″-O-methyl)-glucopyranoside. Subsequently, we checked the antimicrobial properties of the aforementioned aglycon flavonoid compounds against pathogenic and probiotic bacteria and yeast. Our studies revealed that flavones have superior inhibitory effects compared to chalcones and flavanones. Notably, 6-chloro-8-nitroflavone showed potent inhibitory activity against pathogenic bacteria. Conversely, flavanones 6-chloro-8-nitroflavanone and 6-bromo-8-nitroflavanone stimulated the growth of probiotic bacteria (Lactobacillus acidophilus and Pediococcus pentosaceus). Our research has shown that the presence of chlorine, bromine, and nitro groups has a significant effect on their antimicrobial properties.

Post-macrocyclization strategy to octaphenoxy-substituted zinc pyrazinoporphyrazine, its photochemical and electrochemical properties

An efficient post-macrocyclization strategy to new octaphenoxy-substituted zinc pyrazinoporphyrazine has been developed. This approach allows avoiding the template synthesis of the target compound from the phenoxy-substituted dinitrile, during which oligomerization and phenol release occur. The possibility of obtaining the initial octachloropyrazinoporphyrazine using template synthesis activated thermally and using microwave irradiation has been shown. Octaphenoxy-substituted zinc pyrazinoporphyrazine demonstrates short but intense triplet signals in triplet absorption spectrum and substantial singlet oxygen quantum yield (ΦΔ = 0.34). The fluorescent properties and fluorescence decay kinetics of target porphyrazines were studied. In contrast to the initial poorly soluble chlorinated complex, cyclic voltammetric measurements show both reduction and oxidation processes. Two waves of reduction and one wave of oxidation were observed. The electron-donating nature of phenoxy groups compared to chlorine groups is shown.

Effects of chlorine and nitro groups on the crystal structure of novel 4-quinolinone derivatives from sulfonamide chalcone

This study explores the impact of introducing chlorine and nitro groups into two novel quinolone derivatives, (E)-3-(4-nitrobenzylidene)-2-(3-nitrophenyl)-2,3-dihydro-1-(phenylsulfonyl)-quinolin-4(1H)-one (NPQ) and (E)-3-(4-chlorobenzylidene)-2-(3-nitrophenyl)-2,3-dihydro-1-(phenylsulfonyl)-quinolin-4(1H)-one (CPQ), using experimental techniques and density functional theory (DFT). The research focuses on crystalline packing, conformational changes, and intermolecular interactions. The investigation reveals that weak non-classical hydrogen interactions, hydrophobic, and CH···π interactions, predominantly stabilize the crystal structures. These interactions, quantified through a Hirshfeld surface analysis. Additionally, the Fukui function analysis indicates antioxidant potential in the crystals. NPQ and CPQ exhibit a small energy gap, implying low kinetic stability, high reactivity, and reduced resistance to charge transfer when compared. These findings provide valuable insights into the structural and electronic properties of these quinolone derivatives, aiding the design of novel compounds with desired characteristics and applications. The DFT analysis utiliazsed the M062-X functional and the 6–311++G(d,p) basis set in the Gaussian 09 package, and the result was visualized using the GaussView software.

Integrated track of nano-informatics coupling with the enrichment concept in developing a novel nanoparticle targeting ERK protein in Naegleria fowleri

Abstract Naegleria fowleri is a free-living amoeba that causes primary amoebic meningoencephalitis. Despite combination drug therapies, N. fowleri is not sensitive to current drug therapies, contributing to the pathogen’s mortality rate of 98%. To enable rational drug designing, this study has proposed an integrated track of nanotechnology coupling with the enrichment concept. In the current study, zinc oxide nanoparticles (ZNP) were screened against ERK protein, which is responsible for the production of pro-inflammatory cytokines that cause brain disturbance in N. fowleri infection. Furthermore, an enrichment analysis has been executed to increase the efficiency of the ZNP through the addition of two amines and one chlorine group. The computational prediction of zeta potential, cytotoxicity, organ toxicity, calculations of binding free energy, and ADMET analysis shows that it is stable and possesses no toxic effect. Amine + chlorine enriched ZNP resulted in a binding energy of −7.8 kcal/mol, a zeta potential reliability of −40 mV, a cytotoxicity of −0.0002, inactive against all the targeted organ models, ADMET profiling shows a molecular weight of 320.54 g/mol, a lipophilicity of −0.99, high water solubility, and good gastrointestinal tract absorption. This proposed invention represents the future work for in vitro in combating this devastating disease toward a reliable therapeutic target with drugs that specifically aimed to inhibit the infection.

The Effect of Silanes Treatments on Thermal and Mechanical Properties of Nettle Fibre/Bio Epoxy Composites

ABSTRACT Obtaining suitable reinforcement of the polymer matrix depends largely on the appropriate connection at the fiber/polymer interface. Therefore, the main aim of the research was to assess the impact of silanization treatment of Himalayan nettle fibers on the properties of bio epoxy composites. Two types of silanes with different functional groups were used: 3-chloropropylmethyldimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane at concentrations of 1 and 2%. The effectiveness of the fiber silanization process was confirmed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was found that treatment with silane with amine groups provided more effective adhesion between the fiber and the epoxy matrix than treatment with silane with chlorine groups. In addition, the thermal stability, impact strength, bending strength, impact resistance, density and water absorption of the composites were determined. It should be emphasized that silane treatment had a positive effect on the impact strength, impact resistance and flexural modulus of the tested layered composites.

Hydroxyl-terminated triazine dendrimers mediated pH-dependent solubility enhancement of glipizide across dendritic generations: A comparative investigation

A huge challenge for the pharmaceutical industry is hydrophobic compounds, which affect aqueous solubility, an important measure of a medicine’s efficacy. Several approaches have been used; dendrimers are particularly noteworthy because of their long-term viability, nanoscale size, large payload capacity, and adaptable end functional groups. The unique architecture of dendrimers allows for modified medication delivery and solubility profiles, making them a powerful tool for improving the solubility of hydrophobic drugs. This marks the beginning of a new era in pharmaceutical formulations. A new era in drug formulations has begun with this. As part of this study, we synthesized third-generation hydroxyl-terminated triazine-based dendrimers by meticulously reducing chlorine groups following Michael’s addition. We intend to methodically examine the effects of various concentrations of these dendrimers on the solubility behavior of glipizide, a pharmaceutical agent with intrinsic hydrophobicity, across the first, second, and third generations (the full generation). A stimulating tale of solubility improvement emerged from our research. Glipizide’s solubility was positively correlated with the concentration and generational progression of the dendrimers. The solubility of hydrophobic drugs in water can be dramatically altered by dendrimers based on hydroxyl-terminated triazine. This field of study benefits from adding new dendrimers with each generation.

Metal-Organic Frameworks Possessing Suitable Pores for Xe/Kr Separation.

Adsorption separation of the Xe/Kr mixture remains a tough issue since Xe and Kr have an inert nature and similar sizes. Here we present a chlorinated metal-organic framework (MOF) [JXNU-19(Cl)] and its nonchlorinated analogue (JXNU-19) for Xe/Kr separation. The two isostructural MOFs constructed from the heptanuclear cobalt-hydroxyl clusters bridged by organic ligands are three-dimensional structures. Detailed contrast of the Xe/Kr adsorption separation properties of the MOF shows that significantly enhanced Xe uptakes and Xe/Kr adsorption selectivity (17.1) are observed for JXNU-19 as compared to JXNU-19(Cl). The main binding sites for Xe in the MOF revealed by computational simulations are far away from the chlorine sites, suggesting that the introduction of the chlorine groups results in the unfavorable Xe adsorption for JXNU-19(Cl). The optimal pores, high surface area, and multiple strong Xe-framework interactions facilitate the effective Xe/Kr separation for JXNU-19.

Impact of changes in biofilm composition response following chlorine and chloramine disinfection on nitrogenous disinfection byproduct formation and toxicity risk in drinking water distribution systems

In practical drinking water treatment, chlorine and chloramine disinfection exhibit different mechanisms that affect biofilm growth. This study focused on the influence of biofilm composition changes, especially extracellular polymeric substance (EPS) fractions, on the potential formation and toxicity of nitrogenous disinfection by-products (N-DBP). Significant differences in microbial diversity and community structure were observed between the chlorine and chloramine treatments. Notably, the biofilms from the chloramine-treated group had higher microbial dominance and greater accumulation of organic precursors, as evidenced by the semi-quantitative confocal laser-scanning microscopy assay of more concentrated microbial aggregates and polysaccharide proteins in the samples. Additionally, the chloramine-treated group compared with chlorine had a higher EPS matrix content, with a 13.5 % increase in protein. Furthermore, the protein distribution within the biofilm differed; in the chlorine group, proteins were concentrated in the central region, whereas in the chloramine group, proteins were primarily located at the water–biofilm interface. Notably, functional prediction analyses of protein fractions in biofilms revealed specific functional regulation patterns and increased metabolism-related abundance of proteins in the chlorine-treated group. This increase was particularly pronounced for proteins such as dehydrogenases, reductases, transcription factors, and acyl-CoA dehydrogenases. By combining the Fukui function and density functional calculations to further analyse the effect of biofilm component changes on N-DBP production under chlorine/chloramine and by assessing the toxicity risk potential of N-DBP, it was determined that chloramine disinfection is detrimental to biofilm control and the accumulation of protein precursors has a higher formation potential of N-DBPs and toxicity risk, increasing the health risk of drinking water.

Acid treatment for enhancing Hg0 removal efficiency of chlorine-loaded biochar: mechanism and kinetic analysis.

Adsorbents modified solely with chlorine have limited effectiveness in removing mercury at high temperatures. This study aims to investigate the influence of various acid (HNO3, H2SO4, and H2O2) loadings on the removal efficiency of mercury from NH4Cl-modified adsorbents. The objective is to develop rice straw carbon adsorbents that are both more efficient and cost-effective. The experiments were conducted on a fixed bed experimental platform, with SEM and BET to observe the physical property changes of the modified char samples. XPS analysis was employed to analyze the effects of oxygen, chlorine, and sulfur functional groups. Additionally, a kinetic model was used to investigate the interaction mechanism between the adsorbent and mercury. The findings demonstrate that co-modification surpasses the use of NH4Cl alone, with the combination of NH4Cl and HNO3 yielding the best results. Co-modification enhances the development of a more refined and compact pore structure on the char surface, promoting the physical adsorption of mercury. Moreover, an increased presence of chlorine and oxygen functional groups is observed on the char surface, particularly in the NH4Cl and HNO3 co-modified samples, further enhancing the chemical adsorption capacity of the char. The results from the kinetic analysis support this conclusion. Furthermore, the adsorption process of Hg0 relies on both external mass transfer and chemical adsorption, with the chemical adsorption process playing a more significant role as the controlling factor.

Iodine(III)‐Aluminum or ‐Ammonium Salts for the Oxidative Aromatic Inorganic Functionalization

AbstractStrategies for introducing halogens and other inorganic groups in aromatic systems, usually involve non‐general and strong oxidative protocols which resulted in poor functional group compatibility. Iodine(III) reagents have emerged as an excellent alternative for the aromatic inorganic functionalization due to their low toxicity and strong oxidative character. In this context, the synergistic combination of different iodine(III) reagents and aluminum or ammonium salts including AlCl3, AlBr3, Al(NO3)3, NH4Cl, NH4Br and NH4I have recently demonstrated a great versatility for introducing the chlorine, bromine, iodine and nitro groups in aromatic systems, mainly phenols, anilines and some heterocycles. Using these common salts, their anions are softly oxidated by iodine(III) reagents, allowing the in situ formation of non‐described halogenating and nitrating species and in consequence, the introduction of these inorganic groups under an umpolung reactivity as chemical electrophilic synthons.

Lignin based water-soluble fluorescent macromolecular probes for the detection of Fe3+ ion

Lignin is an abundant biomass material in the natural world, its application value and application scope ought to be enlarged. In this work, dealkalized lignin with good water-solubility was used to combine with water-insoluble boron-dipyrromethene (BODIPY) fluorophore to obtain readily water-soluble macromolecular probes. Firstly, a small molecular fluorescent BODIPY probe with two amino groups (-NH2) and another small molecular fluorescent probe with two chlorine groups (-Cl) were synthesized. Secondly, the small-molecular fluorescent probe with two -NH2 groups reacted with carbonyl groups in the lignin by Schiff base formation reaction. Meanwhile, the small-molecular fluorescent probe with two -Cl groups reacted with hydroxyl groups in the lignin by Williamson ether formation reaction. Eventually, two lignin-based fluorescent probes were obtained. The molecular weights of the two probes reached 22.4 kDa and 20.1 kDa. Moreover, these two fluorescent probes were readily soluble in H2O and DMF. Both of the fluorescent macromolecules have good recognition ability for Fe3+, with detection limits of 2.1 × 10−7 mol/L and 1.1 × 10−7 mol/L respectively. Fe3+ interacts with the fluorescent probe, and the imine bond (-CN-) reacts with Fe3+ to cause fluorescence response. The photo-induced electron transfer effect is enhanced, and the photo-induced electron transfer (PET) mechanism causes the fluorescent quenching. This work expands the application scope of lignin as a biomass material and lays a foundation for the development of lignin materials.

Comparison of chlorine dioxide and chlorhexidine 2% antiseptic in reducing bacterial colony counts as an alternative to DUWLs cleaning: a quasi-experimental study

ABSTRACTIntroduction: The inner surfaces of dental unit waterlines (DUWLs) possess an accumulation of any bacteria. Microorganisms can enter dental unit waterlines from water reservoirs. Antiseptics are substances that inhibit the growth of bacteria. Chlorine dioxide is effective in decontaminating microbes in the DUWLs and has a beneficial effect on reducing nosocomial infections. Chlorhexidine effectively prevents the growth of Streptococcus bacteria. The addition of antiseptic agents to the water source contributed to a significant reduction of the cultivable microbial counts in the aerosol. The purpose of this study was to analyze the difference between Chlorine Dioxide 0,1% and Chlorhexidine 2% antiseptics on the number of bacterial colonies in the Dental Unit Waterline. Methods: This study was a quasi-experimental study with a total sample size of 8 dental units that have water tanks in the oral surgery clinic. The sampling technique was total sampling, where the sample was divided into 2 groups, group I using Chlorine Dioxide and group II using 2% Chlorhexidine calculation of colony counts unit using the plate count method. Results: The difference in the number of colonies before being given Chlorine Dioxide was 13,153 CFU/mL and after being given Chlorine Dioxide antiseptic was 6,070 CFU/mL, while before being given 2% Chlorhexidine antiseptic was 12,917 CFU/mL and after being given 2% Chlorhexidine antiseptic was 2,823 CFU/mL. There is a significant difference in the number of bacterial colonies before and after being given Chlorine Dioxide and Chlorhexidine 2% antiseptic with ρ=0.001; Conclusion: Chlorhexidine 2% reduces bacterial colony forming unit in DUWLs much more than using Chlorine dioxide for the alternative of DUWLs Cleaning Agents.Keywords: DUWLs, chlorine dioxide, chlorhexidine 2%, bacterial colony counts

Late-Stage C-H Activation of Drug (Derivative) Molecules with Pd(ll) Catalysis.

This review comprehensively analyses representative examples of Pd(II)-catalyzed late-stage C-H activation reactions and demonstrates their efficacy in converting C-H bonds at multiple positions within drug (derivative) molecules into diverse functional groups. These transformative reactions hold immense potential in medicinal chemistry, enabling the efficient and selective functionalization of specific sites within drug molecules, thereby enhancing their pharmacological activity and expanding the scope of potential drug candidates. Although notable articles have focused on late-stage C-H functionalization reactions of drug-like molecules using transition-metal catalysts, reviews specifically focusing on late-stage C-H functionalization reactions of drug (derivative) molecules using Pd(II) catalysts are required owing to their prominence as the most widely utilized metal catalysts for C-H activation and their ability to introduce a myriad of functional groups at specific C-H bonds. The utilization of Pd-catalyzed C-H activation methodologies demonstrates impressive success in introducing various functional groups, such as cyano (CN), fluorine (F), chlorine (Cl), aromatic rings, olefin, alkyl, alkyne, and hydroxyl groups, to drug (derivative) molecules with high regioselectivity and functional-group tolerance. These breakthroughs in late-stage C-H activation reactions serve as invaluable tools for drug discovery and development, thereby offering strategic options to optimize drug candidates and drive the exploration of innovative therapeutic solutions.

Electronic effect of substituent groups on the oxidation and reduction of bis(2,2′:6′,2″-terpyridine)ruthenium

A series of bis(tpy)ruthenium(II) (tpy = differently substituted 2,2′:6′,2″-terpyridine) were prepared. The substituents were chosen to range from electron donating (pyrrolidinyl, hydroxy, tert-butyl, methoxy, phenyl) to electron withdrawing (Cl, Br). Electrochemistry results show that the complex with the most electron donating group in the series, [Ru(4′-(N-pyrrolidinyl)-2,2′:6′,2″-terpyridine)2]2+, oxidizes at 0.363 V vs the redox couple of ferrocene (Fc/Fc+). The oxidation of [Ru(4′-chloro-2,2′:6′,2″-terpyridine)2]2+, containing the electron withdrawing chlorine group, is much higher, 0.992 V vs Fc/Fc+. Theoretical density functional theory calculations confirmed that the oxidation and reduction of bis(tpy)ruthenium(II) are metal and ligand based, respectively. Graphs comparing the experimentally measured redox potentials and theoretically calculated energies, charges, potentials and various global and local reactivity parameters, all show linear relationships associated with the donating/withdrawing nature of the substituents as quantified by Hammett constants. All these relationships may be utilized to quantify the electronic influence of substituent groups on the redox chemistry of bis(tpy)ruthenium(II) complexes. Linear relationships obtained may also be utilized in the design of bis(tpy)ruthenium(II) type of molecules with a required oxidation or reduction potential. DFT calculations also indicate the potential utilization of these complexes as dye sensitizers in dye-sensitized solar cells.

Development of Jeffamine cross-linked poly(vinyl chloride) films by sequential CuAAC click chemistry and aza-Michael addition

The objective of this study is to present a promising route to design a series of new poly(vinyl chloride) (PVC) films cross-linked with polyetheramine (PEA), namely jeffamine, by combining copper (I)-catalyzed azide-alkyne cycloaddition “click” reaction (CuAAC) and aza-Michael addition (PVC-Jeffs). In the first step, the clickable azido‐functional PVC is prepared easily by displacement reaction between chlorine groups and sodium azide (PVC-N3) and then reacted with propargyl acrylate by CuAAC (PVC-acr). The second step is aza-Michael addition of PVC-acr and Jeffamine to achieve the desired PVC-Jeffs. Transparent and uniform films are prepared by casting from dichloromethane solvent. The effect of loading ratio by weight (PVC/Jeffamine (w/w) = 9:1; 8:2 and 7:3) on the thermal properties of final PVC-Jeffs is systematically explored. The chemical structure of PVC-Jeffs and their intermediates is characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H-NMR) spectroscopies, whereas thermal characteristics of the samples are investigated by thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses. The higher Jeffamine loaded PVC-Jeff exhibit enhanced thermostability and glass transition temperature with the T g of 69.9 °C. Hence, this kind of strategy to achieve the PVC based films with good characteristics is expected to be applied in the preparation of biomedical materials.