Effects Of Different Functional Groups Research Articles

Probing resonance effects in aromatic systems by nuclear quadrupole Coupling: Investigations of 3- and 4-chlorophenol by rotational spectroscopy

Rotational transitions of the only conformer of 4-chlorophenol and the two conformers of 3-chlorophenol (syn and anti) were measured in the frequency range of 10.5–21.0 GHz using broadband pulsed-jet Fourier transform microwave spectroscopy. For the two conformers of 3-chlorophenol, the complete nuclear quadrupole coupling tensors of chlorine, χ, were obtained. Rotational, centrifugal distortion and quadrupole coupling constants were determined for each conformational species, comprising the 35Cl and 37Cl isotopologues. An extended Townes-Dailey analysis was performed on the obtained quadrupole coupling tensors and the results are discussed regarding the effects of different functional groups at different substitution positions of the benzene ring. Together with reanalyzed literature data, this analysis supplements established concepts in organic chemistry to predict and explain the reactivity of aromatic molecules.

Improved performance with molecular design of Ruthenium(II) complexes bearing diamine-based bidentate ligands as sensitizer for dye-sensitized solar cells (DSSC)

Herein, the derivatives of ruthenium (II) complexes bearing different diaminobenzene backbones were produced with the idea of molecular design and characterized. These complexes which are intended to be used as photoactive dyes in a DSSC device also contain suitable optoelectronic properties and the ligands capable of acting in accordance with the DSSC mechanism.The power conversion efficiencies (PCEs) of the first series synthesized ruthenium (II) complexes (5-8A) in DSSC tests were obtained in the range of 0.64–2.25%. Among these backbone structures, the superiority of the benzophenone structure, namely 8A, has been observed and its derivatives have been produced as a second series. The ruthenium (II) complexes produced as 8B and 8C were tested to see the effect of different functional groups on solar cell performances and although the power conversion efficiencies of these complexes were lower than the performance of 8A, they approached with 1.63% and 2.05% values. Thus, the effect of different functional and backbone group structures in the molecular structure on DSSC efficiencies was determined directly and it was emphasized that there could be significant increases in cell performances with the change of simple functional groups.

Uranium(VI) and zirconium(IV) sorption on magnetic chitosan derivatives – effect of different functional groups on separation properties

AbstractBACKGROUNDThe recovery of metal ions from aqueous solutions for environmental preservation or resource saving requires the development of new sorbents with enhanced separation properties. A new process has been designed for the functionalization of magnetic chitosan microparticles with grafting of either amidoxime (AO‐AHC) or hydrazinyl amine (HZ‐AHC). Their sorption properties have been tested for the recovery of uranium(VI) and zirconium(IV) from aqueous solutions.RESULTSA wide range of analytical tools is used for characterizing not only the chemical modifications but also the interaction mode between the sorbent and target metal ions; including elemental analysis and titration, Fourier‐transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS) characterizations, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observations, energy‐dispersive X‐ray spectroscopy (EDX) analysis and textural characterization. The optimum pH values were found in the range 4–5. The maximum sorption capacities depend on the metal and the kind of functionalization: up to 1.38 mmol U g−1 for AO‐AHC and up to 1.96 mmol Zr g−1 for HZ‐AHC. The small size of magnetic particles limits the contribution of diffusion mechanisms in the overall control of uptake kinetics and the equilibrium is reached within 40–60 min. Metal desorption is highly effective (almost quantitative over five successive cycles of sorption and desorption) using 0.3 M hydrochloric acid solutions.CONCLUSIONAO‐AHC sorbent is more selective than HZ‐AHC in terms of separation of uranium(VI) from zirconium(IV), especially at pH close to 4. The results obtained in the treatment of acidic ore leachates confirm these trends. © 2019 Society of Chemical Industry

Using Volatile Organic Compounds in Waste Streams as Fuel

Abstract To meet the environmental regulations, volatile organic compounds (VOC) in waste streams of various industries are thermally oxidized before being released to the atmosphere. This thermal oxidation process requires use of additional fuel and energy, has high operational costs and requires frequent maintenance. As an alternative, these VOCs can be considered as fuels themselves. Even without considering the energy used for the supplemental fuel such as natural gas, the enthalpy of the VOCs incinerated is not negligible. Hydrogen, a valuable energy carrier, can be produced from VOCs by reforming them. In this study, a system that can reform VOCs in the exhaust stream of paint finishing operations and use it to produce hydrogen that can be used in a fuel cell for power generation was designed. Steam reforming experiments were conducted on different VOCs using a 10 % Co/CeO2 catalyst. The effect of different functional groups and the chain length was examined. This study shows the potential of dilute VOCs in the waste stream of many industries if they can be recovered and used as a fuel effectively instead of being incinerated.

Morphology, mechanical property, and processing thermal stability of PVC/La‐OMMTs nanocomposites prepared viain situintercalative polymerization

Poly(vinyl chloride) (PVC) nanocomposites were prepared via anin situintercalative suspension polymerization of vinyl chloride with four organic carboxylic acid salts (montmorillonite [MMT] units) containing thermally stable lanthanum ions. The effects of different lanthanum organic montmorillonites (La‐OMMTs) on the particle features and molecular weight were investigated. The transmission electron microscopy data indicated the formation of partially exfoliated or intercalated PVC/La‐OMMTs nanocomposites. The effect of different functional groups on the mechanical properties and processing thermal stability of PVC/La‐OMMT nanocomposites were investigated. Tensile testing and two‐roll mill processing results showed that La‐OMMTs could enhance the dynamic thermal stability and mechanical properties versus PVC pure resin and PVC/I.30P nanocomposites (composed of PVC and I.30P). This suggested that the double bond and amidogen group in La‐OMMTs could promote the dispersion of La‐OMMTs in the PVC matrix and also improve the adhesion between the La‐OMMTs and PVC matrix. The results have potential value in the industrial development of PVC/La‐OMMTs nanocomposites. J. VINYL ADDIT. TECHNOL., 26:97–108, 2020. © 2019 Society of Plastics Engineers

Effect of Different Functional Groups on Photocatalytic Hydrogen Evolution in Covalent‐Organic Frameworks

AbstractCovalent‐organic frameworks (COFs) have been recognized as a new type of promising photocatalysts for hydrogen evolution. To investigate how different functional groups attached in the backbone of COFs affect the overall photocatalytic H2 evolution, for the first time, we selected and synthesized a series of ketoenamine‐based COFs with the same host framework as model system. It includes TpPa−COF−X (X=−H, −(CH3)2, and −NO2) with three different groups attached in the backbone of TpPa−COF. We systematically investigated the differences in morphology, light‐absorption intensity and band gap of these 2D COFs. The results of photocatalytic H2 evolution measurements indicate that the TpPa−COF−(CH3)2 shows the best activity, while the activity of TpPa−COF−NO2 is relatively low compared to that of other two COFs in the system. Moreover, the separation ability of photogenerated charge was also followed the order of TpPa−COF−(CH3)2>TpPa−COF>TpPa−COF−NO2. The best photocatalytic H2 production performance of TpPa−COF−(CH3)2 in these systems should be mainly attributed to the better electron‐donating ability of −CH3 groups compared to −H or −NO2 group, which result in more efficient charge transferring in the inner of the material. This work demonstrates that reasonably adding electron‐donating group in TpPa−COFs can lead to a better photocatalytic H2 evolution activity, and which is meaningful for further design of efficient COF‐based photocatalysts for H2 evolution.

Highly efficient electrochemiluminescence of quinoline and isoquinoline in aqueous solution

This paper reports for the first time the strong cathodic electrochemiluminescence (ECL) behavior of quinoline, isoquinoline and their derivatives in aqueous solution with K2S2O8 as coreactant. The effects of K2S2O8 concentration, pH and scan rate on the ECL intensity have been studied in detail. Calculations of the HOMO-LUMO energy gap for the ECL reaction indicated that isoquinoline is more likely to produce an excited state radical ion than quinoline. The effects of different functional groups on the ECL of isoquinoline were then compared and a possible ECL reaction mechanism was discussed. This work provides a simple and sensitive ECL method for the detection of quinoline and isoquinoline, which are important drug intermediates.

Easy, fast, and efficient removal of heavy metals from laboratory and real wastewater using electrocrystalized iron nanostructures

The effect of electrooxidation of iron on cobalt and cadmium removal was investigated. This study was initially performed on the laboratory samples and then the real wastewater of two rivers in Iran called Karun and Seimareh were studied. The effect of applied voltage (5–25 V), contact time (10 to 60 min), initial concentration of heavy metal (50–500 ppm), pH (1−13), and also different organic additives to the water sample on removal efficiency of the species were investigated. The water samples before and after treatment and also the sludge samples were characterized. The results showed that experimental parameters are affected on removal performance. Furthermore, the type of organic attached at the particles surface plays an important role on adsorption process. The atomic absorption spectroscopy results showed that the removal percentage of the species under 25 V, reaction time of 60 min, and initial concentration of cobalt 200 ppm at pH = 11 and cadmium 100 ppm at pH = 5 is about 100%. In continuation of this work, electro-crystallized magnetite nanoparticles modified with thiourea and sodium butanoate in the particle size range of ~20–95 nm were developed for the adsorption of antimony (Sb) from wastewater. The effects of different functional groups and the mean particle size on removal of antimony were also studied. The ICP-MS results confirmed the surface modification of magnetite particles by amine group provides specific functionalities that can enhance the capacity of iron oxide nanoparticles for Sb uptake in water treatment procedures.

Effects of different functional groups in graphene nanofiber on the mechanical property of polyvinyl alcohol composites by the molecular dynamic simulations

Polyvinyl alcohol (PVA) matrix composites reinforced by functional graphene nanofiber (FGF) characterized by different functional groups were investigated to identify the mechanical properties of PVA/FGF composites employing the molecular dynamic (MD) simulations. The influences of the distributions of different functional groups (-COOH, -CONH3, -O-, and -OH) on the mechanical properties of PVA/FGF and the interfacial interaction between PVA and FGF have been explored. It was found that FGF can improve the elasticity modulus, the tensile strength, and stretchability of the composites. Generally, the more oxygen-containing functional groups, the greater the influences on these properties of the composites. Meanwhile, the arrangements of the functional groups bounded to graphene also have influences on the mechanical properties of materials, i.e., the edge functional graphene nanofiber with -OH and -COOH functional groups can greatly improve the mechanical properties of materials compared to the functional groups in other positions. Moreover, the effects of the different aspect ratios of FGF on the mechanical properties of composites have been studied. It was found that the mechanical properties of composites were enhanced with the increase of the aspect ratios of FGF in a certain range. In addition, analyses of results for the radius of gyration (Rg), radial distribution function (RDF), interaction energy, and mean squared displacement (MSD) of PVA molecular chains indicate that PVA molecular chains are extended along the surface of FGF and lots of hydrogen bonds and strong interaction between PVA and FGF have been observed, suggesting that the addition of FGF limits the movement of PVA molecular chains.

Substitution Effect on Near Infrared Absorbance Based Selective Fluoride Sensing of Indole Functionalized Thiourea Molecules

A series of six new symmetrically functionalized thiourea based indole conjugated ligands (S1–S6) are synthesized in good yields and their anion recognition/sensing ability in the solution as well as in solid state is explored. Chemosensors S1–S6 show selective colorimetric sensing of fluoride by stable NIR signatures at 942 nm, 956 nm, 825 nm, 890 nm, 948 nm, and 1160 nm with corresponding spectral shifts (Δλ) of 592 nm, 588 nm, 603 nm, 485 nm, 610 nm, and 800 nm by virtue of position, conjugation and electronic effect of different functional groups attached to indole unit. To the best of our knowledge the peak shift of a chemosensor by magnitude of 800 nm (from UV to NIR region) in the presence of fluoride represents the highest of its kind. The changes in absorption spectra in the presence of various anions follow the Hofmeister series of anions. All the chemosensors show a bathochromic shift in the absorption spectra of the ligands in the presence of acetate, benzoate, dihydrogen phosphate and hydrogen pyrophosphate due to hydrogen bonding interactions with the indole and thiourea‐NH groups. The single‐crystal X‐ray structures evidence in favour of planar structures of the free sensors (S1, S4, and S5) and strong hydrogen bonding interactions between phosphate anion and indole–thiourea NH groups.

1,10‐Phenanthroline‐Based Molten Salt as a Bifunctional Sulfonic Acid Catalyst: Application to the Synthesis of N‐Heterocycle Compounds via Anomeric Based Oxidation

Abstract1,10‐phenanthroline‐based molten salt as a bifunctional sulfonic acid [Phen(SO3H)2]Cl2 was designed and synthesized. The described nano molten salt has two SO3H acid groups and a rigid structure that allows the rotation of the molecule to have a unique catalytic ability. This catalyst was applied for the synthesis of N‐heterocyclic compounds such as quinazolines, quinazolinones, acridines and dihydropyridines via multi‐component condensation reactions. These compounds are highly regarded for their medicinal and biological properties. The effect of different functional groups at the corresponding products for developing the new mechanisem entitled “anomeric based oxidation” (ABO) were studied. The major advantages of the presented methodology are mild conditions, high efficiency, short reaction times and reusability of the catalyst.

A comparison of molecular structure and de-intercalation kinetics of kaolinite/quaternary ammonium salt and alkylamine intercalation compounds

It has great significance to research the effect of intercalated molecules with the same carbon chain and different functional groups on the properties of intercalation compounds since it can reveal the effect of different functional groups on the properties of intercalated compounds without considering the difference of carbon chains. In this study, the intercalation compounds of kaolinite/dodecyl trimethyl ammonium chloride (Kaol-DTAC) and kaolinite/dodecylamine (Kaol-DA) were studied by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry and differential scanning calorimetry (TG-DSC) analysis, and Scanning electron microscope (SEM). Then the de-intercalation kinetics with different heating rates was investigated, and the optimized the mechanism function for de-intercalation process was calculated. The results showed that the basal spacings of Kaol-DTAC and Kaol-DA intercalation compounds are 3.56 and 4.08 nm, respectively. The DTAC molecules are arranged the Kaol surface in a single layer with an angle of 90° while the DA molecules are tilted towards the Kaol surface in bilayer and the inclination angle is 39.9°, which is due to the different structure between these two type molecules. The SEM showed that the ratio, nanoscrolls length to diameter, of Kaol-DA is larger than that of Kaol-DTAC, and for the yield of nanoscrolls, the former is greater than the latter. Moreover, by using KAS and Ozawa methods, the activation energy (E) of Kaol-DTAC and Kaol-DA were obtained and the average values are 102.44 kJ mol−1 and 130.80 kJ mol−1, respectively. Furthermore, The optimal mechanism function for the intercalation compounds of Kaol-DTAC and Kaol-DA are G(α) = -ln(1-α) and G(α) = [(1-α)(−1/3)−1]2, respectively.

Multiple Hydrogen Bonds Promoted ESIPT and AIE‐active Chiral Salicylaldehyde Hydrazide

AbstractThe simpler, the better! A series of simple and highly fluorescent salicylaldehyde hydrazide molecules (41 samples) have been designed and prepared. Even though these soft materials contain a very small π‐conjugated system, they can go through multiple intramolecular and intermolecular hydrogen bonds promoted excited‐state intramolecular proton‐transfer (ESIPT) to display strong blue, green, yellow, and orange aggregation‐induced emission (AIE) with large Stokes shifts (up to 184 nm) and high fluorescence quantum yields (Ф up to 0.20). Unusual mechanochromic fluorescence enhancements are also found in some solid samples. Through coordination, hydrogen and halogen bonds, these flexible molecules can be used as Mg2+ (Ф up to 0.46) probes, universal anion (Ф up to 0.14) and unprotected amino acids (Ф up to 0.16) probes, and chiral diamine (enantiomeric selectivity and Ф up to 0.36 and 0.062, respectively) receptors. Combining their advantages of AIE and biocompatibility, these low cytotoxic dyes have potential application in living cell imaging. Furthermore, the effects of different functional groups on the molecule arrangement, ESIPT, AIE, probe, and chiral recognition properties are also examined, which provide a simple and bright paradigm for the design of multiple‐stimuli‐responsive smart materials.

Meta-Analysis of Reciprocal Linkages between Temperate Seagrasses and Waterfowl with Implications for Conservation.

Multi-trophic conservation and management strategies may be necessary if reciprocal linkages between primary producers and their consumers are strong. While herbivory on aquatic plants is well-studied, direct top-down control of seagrass populations has received comparatively little attention, particularly in temperate regions. Herein, we used qualitative and meta-analytic approaches to assess the scope and consequences of avian (primarily waterfowl) herbivory on temperate seagrasses of the genus Zostera. Meta-analyses revealed widespread evidence of spatio-temporal correlations between Zostera and waterfowl abundances as well as strong top-down effects of grazing on Zostera. We also documented the identity and diversity of avian species reported to consume Zostera and qualitatively assessed their potential to exert top-down control. Our results demonstrate that Zostera and their avian herbivores are ecologically linked and we suggest that bird herbivory may influence the spatial structure, composition, and functioning of the seagrass ecosystem. Therefore, the consequences of avian herbivory should be considered in the management of seagrass populations. Of particular concern are instances of seagrass overgrazing by waterfowl which result in long-term reductions in seagrass biomass or coverage, with subsequent impacts on local populations of waterfowl and other seagrass-affiliated species. While our results showed that bird density and type may affect the magnitude of the top-down effects of avian herbivory, empirical research on the strength, context-dependency, and indirect effects of waterfowl–Zostera interactions remains limited. For example, increased efforts that explicitly measure the effects of different functional groups of birds on seagrass abundance and/or document how climate change-driven shifts in waterfowl migratory patterns impact seagrass phenology and population structure will advance research programs for both ecologists and managers concerned with the joint conservation of both seagrasses and their avian herbivores.

A Study on the Effect of Different Functional Groups in Anion Exchange Membranes for Vanadium Redox Flow Batteries

A Study on the Effect of Different Functional Groups in Anion Exchange Membranes for Vanadium Redox Flow Batteries

Evaluations of thermal and antibacterial properties of nanocomposites of functionalized poly(methyl methacrylate) with different amino containing groups

The main object of this study is to analyse the effects of different functional groups on the thermal and microbial properties of nanocomposites of poly(methyl methacrylate) (PMMA). For this, amino functionalized PMMA were synthesized by using post polymer functionalization method. In this method, PMMA was treated with four different amino compounds to obtain functionalized PMMA. To determine the structural features, functionalized PMMA was characterized with Fourier transform infrared (FTIR) spectroscopy. These functionalized PMMA were used to prepare functionalized polymer nanocomposites with addition of nanoclay and Ag nanoparticles into the polymer matrix. These nanocomposites were further studied against thermal and antibacterial properties. Sophisticated analytical techniques i.e., thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and derivative thermogravimetric curve (DTG) were used to characterize the thermal properties of nanocomposites. Antibacterial study was performed by using disc diffusion method against bacteria E. coli. The thermal results showed that, the maximum degradation temperature (T d) increases up to 85.5°C in air atmosphere in case of sample HM2. Antibacterial study showed that, the bacteria have least effect on the silver containing functionalized polymer nanocomposites.

A Porous Zn(II)-Metal–Organic Framework Constructed from Fluorinated Ligands for Gas Adsorption

A three-dimensional functional metal–organic framework (LIFM-38) has been successfully synthesized with a fluorinated bicarboxylate ligand. LIFM-38 exhibits good stability and a surface area of 803 m2 g–1. Owing to the synergistic effect of different functional groups, cocrystallized amine active sites, and suitable pore space, LIFM-38 shows good selective CO2 and C2+ hydrocarbons adsorption over CH4 and N2; in addition, LIFM-38 exhibits good selective C3 hydrocarbons adsorption over C2 hydrocarbons.

Effect of functional groups on sensitization of dye-sensitized solar cells (DSSCs) using free base porphyrins

Dye-sensitized solar cells (DSSCs) were fabricated with six meso-substituted A[Formula: see text]B and A[Formula: see text] free base porphyrin dyes having different functional groups, as sensitizers. The two step synthesis and the effect of different functional groups and their positions on the photosensitization properties of these porphyrin dyes are reported. The highest power conversion efficiencies ([Formula: see text] of 3.26%, 2.94% and 2.84% were achieved for the DSSC fabricated using 5,10,15-tris(4[Formula: see text]-pyridyl)-20-(4[Formula: see text]-carboxyphenyl)porphyrin (H[Formula: see text]TriPyMCPP), 5,10,15,20-tetrakis(4[Formula: see text]-aminophenyl)porphyrin (H[Formula: see text]TAPP) and 5-(4[Formula: see text]-pyridyl)-10,15,20-tris(4[Formula: see text]-carboxyphenyl)porphyrin (H[Formula: see text]MPyTriCPP) dyes, respectively. The electron donating amino group is shown to enhance the power conversion efficiency while pyridyl appended porphyrin sensitizers are shown to be superior sensitizers as compared to carboxyphenylporphyrins. The investigation of effect of functional group and position of functional group of porphyrin dye on DSSC can serve as an important tool to guide further selection and synthesis of potential candidates as sensitizers.

Effects of different functional groups on the optical and charge transport properties of copolymers for polymer solar cells

Three novel copolymers were designed based on BSeTT, QTT, BDT-DTBTBPz and BDT-DTBTBQx. Their properties of ground state and excited state were calculated via DFT/TDDFT methods. The charge moves from polymers to PC60BM.

Combined Effects of Functional Groups, Lattice Defects, and Edges in the Infrared Spectra of Graphene Oxide

Infrared spectroscopy in combination with density functional theory calculations has been widely used to characterize the structure of graphene oxide and its reduced forms. Yet, the synergistic effects of different functional groups, lattice defects, and edges on the vibrational spectra are not well understood. Here, we report first-principles calculations of the infrared spectra of graphene oxide performed on realistic, thermally equilibrated, structural models that incorporate lattice vacancies and edges along with various oxygen-containing functional groups. Models including adsorbed water are examined as well. Our results show that lattice vacancies lead to important blue and red shifts in the OH stretching and bending bands, respectively, whereas the presence of adsorbed water leaves these shifts largely unaffected. We also find unique infrared features for edge carboxyls resulting from interactions with both nearby functional groups and the graphene lattice. Comparison of the computed vibrational pr...