Tetrahydrofuran Research Articles

Exploring the Multifunctional PVC-DPG PolymerComplexes: Synthesis, Characterization and Evaluation of the Antibacterial Activity

Polyvinyl chloride (PVC) has attracted great attention because of its applications in different fields such as industrial and medical fields. In this work PVC has been reacted with diphenylglyoxime (DPG) in Tetrahydrofuran (THF) to form PVC–DPG polymer, then the synthesized polymer reacted with alcoholic solutions of different metal ions (Fe(II), Co(II), Ni(II), Pd(II), Pt(IV) and Cu(II) to form colored metal ion complexes. All compounds are characterized by Fourier-transform infrared (FTIR), Ultraviolet (UV-Vis) spectroscopies, magnetic susceptibility and conductivity measurements. All complexes were examined with staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), confirming the biological activity against these bacteria

Towards a greener photovoltaic industry: Enhancing efficiency, environmental sustainability and manufacturing costs through solvent optimization in organic solar cells

The energy sector is a major contributor to global greenhouse gas emissions, necessitating a transition to renewable energy sources. The photovoltaic industry plays a crucial role in this transition by harnessing solar energy, a clean and abundant resource. However, the high cost of solar panels remains a challenge. Organic solar cells (OSCs) offer a promising alternative to conventional silicon-based cells due to their low production costs and flexibility. In this study, we focus on optimizing the performance of OSCs by investigating the influence of solvent volume in the hole transport layer. By gradually increasing the volume of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and tetrahydrofuran (THF) in the PEDOT:PSS layer, we analyse the impact on power conversion efficiency (PCE) and assess the economic and environmental implications. Our results demonstrate the potential for enhancing the PCE of OSCs through solvent optimization, thereby advancing the greening of the photovoltaic industry while considering economic viability and environmental sustainability.

Understanding the effect of moderate concentration SDS on CO2 hydrates growth in the presence of THF

HypothesisAdditives like Tetrahydrofuran (THF) and Sodium Dodecylsulfate (SDS) improve Carbon Dioxide (CO2) hydrates thermal stability and growth rate when used separately. It has been hypothesised that combining them could improve the kinetics of growth and the thermodynamic stability of CO2 hydrates.Simulations and ExperimentsWe exploit atomistic molecular dynamics simulations to investigate the combined impact of THF and SDS under different temperatures and concentrations. The simulation insights are verified experimentally using pendant drop tensiometry conducted at ambient pressures and high-pressure differential scanning calorimetry.FindingsOur simulations revealed that the combination of both additives is synergistic at low temperatures but antagonistic at temperatures above 274.1 K due to the aggregation of SDS molecules induced by THF molecules. These aggregates effectively remove THF and CO2 from the hydrate-liquid interface, thereby reducing the driving force for hydrates growth. Experiments revealed that the critical micelle concentration of SDS in water decreases by 20% upon the addition of THF. Further experiments in the presence of THF showed that only small amounts of SDS are sufficient to increase the CO2 storage efficiency by over 40% compared to results obtained without promoters. Overall, our results provide microscopic insights into the mechanisms of THF and SDS promoters on CO2 hydrates, useful for determining the optimal conditions for hydrate growth.

Interaction of mitoxantrone with abasic sites - DNA strand cleavage and inhibition of apurinic/apyrimidinic endonuclease 1, APE1

Mitoxantrone (1,4-dihydroxy-5,8-bis[2-(2-hydroxyethylamino)ethylamino]-anthracene-9,10-dione) is a clinically-relevant synthetic anthracenedione that functions as a topoisomerase II poison by trapping DNA double-strand break intermediates. Mitoxantrone binds to DNA via both stacking interactions with DNA bases and hydrogen bonding with the sugar-phosphate backbone. It has been shown that mitoxantrone inhibits apurinic/apyrimidinic (AP) endonuclease 1 (APE1)-catalyzed incision of DNA containing a tetrahydrofuran (THF) moiety and more recently, that mitoxantrone forms Schiff base conjugates at AP sites in DNA. In this study, mitoxantrone-mediated inhibition of APE1 at THF sites was shown to be consistent with preferential binding to, and thermal stabilization of DNA containing a THF site as compared to non-damaged DNA. Investigations into the properties of mitoxantrone at AP and 3′ α,β-unsaturated aldehyde sites demonstrated that in addition to being a potent inhibitor of APE1 at these biologically-relevant substrates (∼ 0.5 μM IC50 on AP site-containing DNA), mitoxantrone also incised AP site-containing DNA by catalyzing β- and β/δ-elimination reactions. The efficiency of these reactions to generate the 3′ α,β-unsaturated aldehyde and 3′ phosphate products was modulated by DNA structure. Although these cell-free reactions revealed that mitoxantrone can generate 3′ phosphates, cells lacking polynucleotide kinase phosphatase did not show increased sensitivity to mitoxantrone treatment. Consistent with its ability to inhibit APE1 activity on DNAs containing either an AP site or a 3′ α,β-unsaturated aldehyde, combined exposures to clinically-relevant concentrations of mitoxantrone and a small molecule APE1 inhibitor revealed additive cytotoxicity. These data suggest that in a cellular context, mitoxantrone may interfere with APE1 DNA repair functions.

Probing the instability of surface structure on solid Hydrates: A microscopic perspective through experiment and simulation

The surface structural characteristics of clathrate hydrates play a significant role in mass transfer, interfacial properties, and mechanical stability during the hydrate growth process. However, the microstructure of hydrate surfaces remains unclear and controversial. In this study, a modified Atomic Force Microscopy (AFM) system was employed to confirm the presence of a quasi–liquid layer (QLL) on the solid tetrahydrofuran (THF) hydrate surface. Subsequently, sensitivity analyses were conducted on factors affecting the instability (fluidity) of QLL, including relative position, inclination angle, environmental temperature, and surface morphology. The results indicate that higher temperatures enhance the instability of the QLL surface, and altering the slope of the hydrate surface leads to an increase in the average thickness of the QLL due to the driving forces of gravity and surface tension, resulting in increased fluidity. Additionally, the surface morphological structure formed by Oswald ripening in polycrystalline THF hydrates affects the thickness of QLL. Furthermore, molecular dynamics simulations reveal that water molecules on the hydrate surface exhibit a multilayered structure, with the QLL region near the gas phase showing greater instability, while the region closer to the hydrate exhibits solid–phase characteristics, consistent with experimental findings.

Steam reforming of n-butanol and tetrahydrofuran: Influence of aliphatic carbon chain and furan ring on coking behaviors

Almost all small organics, in theory, could be potential feedstock for production of hydrogen via steam reforming (SR). Nevertheless, not all organics contain a linear carbon chain like ethanol or acetone. How do ring structure of an organic substrate impacted coking behaviors in SR were explored herein with n-butanol and tetrahydrofuran (THF) as the research objects over Ni/SiO2 catalyst, due to the same carbon number but distinct carbon chains in these two molecules. The results indicated that furan ring in THF lowered reactivity towards SR, as its adsorption on metallic sites was more difficult than n-butanol. The in-situ IR analysis for measuring reaction intermediates suggested that n-butanol and THF involved generation of intermediates with CO formed via dehydrogenation, CxHy formed via cracking and CC species that can be further gasified or aggregate to coke. However, more oxygenated intermediates generated in SR of n-butanol than in THF, rendering n-butanol more reactive towards SR. This, however, also formed substantially more coke of aliphatic nature in amorphous form, which led to the coke of thermally unstable and had higher tendency being oxidized. In converse, coke formed from SR of THF was more aromatic, showing less impact on catalytic activity, higher thermal stability, and larger crystal size with more carbon nanotube form of coke. This was closely connected with the ring structures that could dehydrogenated to form the unsaturated ring with capability to involve in Diels-Alder reactions, forming coke of aromatic nature.

Localized Anion‐Cation Aggregated Aqueous Electrolytes with Accelerated Kinetics for Low‐Temperature Zinc Metal Batteries

AbstractAqueous zinc metal batteries hold great promise for large‐scale energy storage because of their high safety, rich material resources and low cost. However, the freeze of aqueous electrolytes hinders low‐temperature operation of the batteries. Here, aqueous localized anion‐cation aggregated electrolytes composed of Zn(BF4)2 as the salt and tetrahydrofuran (THF) as the diluent, are developed to improve the low‐temperature performance of the Zn anode. THF promotes the inclusion of BF4− in the solvation sheath of Zn2+, facilitating the formation of ZnF2‐rich solid‐electrolyte‐interphase. THF also affects the hydrogen bonding between neighboring H2O molecules, effectively lowering the freezing point. Therefore, the full cells of Zn||polyaniline (PANI) exhibit an ultralong cycle life of 8000 cycles with an average Coulombic efficiency of 99.99 % at −40 °C. Impressively, the pouch cells display a high capacity retention of 86.2 % after 500 cycles at −40 °C, which demonstrates the great prospect of such electrolytes in cold regions. This work provides new insights for the design of low‐temperature aqueous electrolytes.

Localized Anion-Cation Aggregated Aqueous Electrolytes with Accelerated Kinetics for Low-Temperature Zinc Metal Batteries.

Aqueous zinc metal batteries hold great promise for large-scale energy storage because of their high safety, rich material resources and low cost. However, the freeze of aqueous electrolytes hinders low-temperature operation of the batteries. Here, aqueous localized anion-cation aggregated electrolytes composed of Zn(BF4 )2 as the salt and tetrahydrofuran (THF) as the diluent, are developed to improve the low-temperature performance of the Zn anode. THF promotes the inclusion of BF4 - in the solvation sheath of Zn2+ , facilitating the formation of ZnF2 -rich solid-electrolyte-interphase. THF also affects the hydrogen bonding between neighboring H2 O molecules, effectively lowering the freezing point. Therefore, the full cells of Zn||polyaniline (PANI) exhibit an ultralong cycle life of 8000 cycles with an average Coulombic efficiency of 99.99 % at -40 °C. Impressively, the pouch cells display a high capacity retention of 86.2 % after 500 cycles at -40 °C, which demonstrates the great prospect of such electrolytes in cold regions. This work provides new insights for the design of low-temperature aqueous electrolytes.

Preparation and characterization of ball milled hexagonal‑boron nitride (BMBN) and fluorescein (FL) decorated reduced graphene oxide (RGO) nanocomposite towards toxic heavy metal ion detection

In the present work, a novel hybrid fluorescent nanocomposite (RBF) based on ball milled hexagonal-Boron Nitride (BMBN) and Fluorescein (FL) decorated reduced Graphene Oxide (RGO) was synthesized for the effective detection and removal of hazardous heavy metal ions present in effluents. Where two different textile effluents namely, reaction outlet and factory outlet collected at the river Noyyel, Tamilnadu were considered. The prepared RBF was subjected to XRD, FTIR, SEM, EDX, TEM, PSA, BET, UV–vis, PL and XPS studies which strongly confirm the decoration of FL and BMBN at the surface of RGO sheets. The selectivity of RBF was examined by considering various toxic heavy metal ions. Where the RBF exhibits remarkable sensing towards Zn2+ (10.7 nM) via enhanced fluorescence and for Fe3+ (15.6 nM), Sn4+ (60.7 nM) and Hg2+ (465.4 nM) ions by “Turn-off” fluorescence only at neutral pH. In addition, the RBF was highly efficient to remove Hg (81.3 %) than Zn (63.7 %), Fe (38.2 %) and Sn (62.9 %) in real-time samples. Moreover, the prepared RBF could also serve as water sensor for the water contaminated organic solvents of Acetonitrile (ACN) and Tetrahydrofuran (THF). Hence the prepared RBF might be a potential choice for the effective detection and removal of heavy metal ions during wastewater treatment.

Mo-based bio-derived carbon catalyst enables a tandem dehydration reaction for the direct synthesis of fuel precursors from fructose

In the pursuit of sustainable alternatives for petroleum fuels, bio-based hydrocarbons emerge as a promising choice. To explore this, a molybdenum catalyst supported on bio-derived carbon was developed, enabling the direct synthesis of fuel precursors from fructose. The catalyst was synthesized by varying the wt.% of molybdenum loading through hydrothermal treatment and carbonization. The NH3-TPD analysis revealed the presence of 1 mmol/g of acidic sites on best the catalyst. HRTEM and XPS analysis reveals that the majority of molybdenum is present as Mo6+. The synthesized catalyst effectively facilitated the dehydration of fructose to 5-hydroxymethylfurfural (5-HMF), followed by hydroxyalkylation/alkylation (DHAA) of 5-HMF with 2-methylfuran. Furthermore, compared to commercial Brønsted acid catalysts, the synthesized catalyst demonstrated remarkable performance, achieving complete fructose conversion with 36% selectivity towards the DHAA product. Moreover, an innovative approach was developed for the separation of 5,5′-((5-((5-methylfuran-2-yl)methyl)furan-2-yl)methylene)bis(2-methylfuran) and 5-HMF from dimethyl sulphoxide (DMSO) using a saturated aqueous sodium chloride (NaCl) solution in tetrahydrofuran (THF). This developed method, utilizing the bio-derived catalyst with efficient catalytic performance and effective product separation from DMSO, shows great promise for directly synthesizing fuel precursors from fructose and advancing sustainable fuel production.

Evaluating the gas storage capacity of 1,3-dioxolane–hydrogen binary hydrates via molecular simulations

H2 is a green fuel with high energy density, but its efficient storage and transportation remain challenging. Clathrate hydrates are promising materials for H2 storage. In this study, molecular simulations are conducted to evaluate the gas storage capacity of 1,3-Dioxolane (DIOX)–H2 hydrate under various thermodynamic conditions. Results reveal that the growth rates of DIOX–H2 and tetrahydrofuran (THF)–H2 hydrates exhibit similar trends to those of pure DIOX and THF hydrates with temperature, indicating that the growth processes of the binary hydrates are dominated by DIOX and THF. However, their growth rates are almost constant with pressure of 10–110 MPa at 250 K. H2 can significantly improve the growth rate of hydrates due to its small size and high mobility. Furthermore, temperature has little effect on the gas storage capacity of the binary hydrates, but an increase of pressure significantly enhances it. Although DIOX is more efficient than THF in promoting the growth of hydrates, the gas storage capacity of DIOX–H2 hydrate is weaker. The gas occupancy of 512 cages is the key factor determining the gas storage capacity of the binary hydrates. Multiple H2 occupancies can be found in 51264 cages at high pressures. This study provides molecular-level insights into the hydrate growth process, which can serve as a guide for improving the gas storage capacity of hydrates.

Two-stage reaction rates in transesterification of palm oil with methanol catalysed by anion-exchange resin with tetrahydrofuran as a co-solvent

Several heterogeneous catalysts have been proposed as recoverable catalysts for transesterification in place of homogeneous hydroxide or methoxide. Anion-exchange resin is a potential recoverable and reusable catalyst but its industrial use is still barred by its low catalytic activity. Transesterification of refined palm oil with methanol catalysed by anion-exchange resin was studied. A phenomenon limiting the reaction rates was discovered and is presented. Two types of anion-exchange resins were used as the catalysts: dense IRA402 and macroporous A26. With IRA402, an oil conversion of only 6.1 % was obtained from 4 h transesterification at 60 °C with a methanol-to-oil molar ratio of 9.5:1 and 4 cm3 resin per 42 cm3 reaction mixture. Severe mass transfer resistance in this three-phase system appeared to be the limiting factor. Addition of tetrahydrofuran (THF) as a co-solvent helped form a single liquid phase. The oil conversion was improved to 19.3 %. The reaction between oil and adsorbed methoxide at resin’s ion-exchange sites seemed to be the rate-determining step. When A26 was used, the rate of FAME production was boosted due to the porous nature of the resin. Nevertheless, the reaction rate fell sharply after a while into a slower second stage. The formation of a secondary liquid phae in resin pores triggered by glycerol generation was proposed as the cause of this drop in the reaction rate. A higher oil conversion of 63.4 % was obtained. Diluting the reaction mixture with more THF eliminated the slower second stage and sustained the firststage’s faster reaction rate. An oil conversion of 84.7 % was achieved from 3 h transesterification. A finite-volume model was developed to simulate the reaction and internal mass transport in A26 resin beads. The proposed secondary liquid phase formation and a branching pore structure in resin beads were required in the model to reproduce experimental data. The findings suggested improvement directions for anion-exchange resin as a catalyst for transesterification.

A simple AIE probe to pesticide trifluralin residues in aqueous phase: Ultra-fast response, high sensitivity, and quantitative detection utilizing a portable platform

The threat from pesticide trifluralin residues to ecological environment and public health is becoming a growing problem. Thus, rapid and sensitive detection, particularly a simple and portable detected platform for trifluralin residues, are highly desired. Here, a small organic aggregation-induced emission (AIE) molecule (TPETPy) is facilely synthesized and applied to detect trifluralin both in lab and in actual water systems. Based on the photo-induced electron transfer (PET) mechanism, the emissive peak of TPETPy located at 475 nm in tetrahydrofuran (THF)/water mixture (ƒw = 90 %) under the excitation of 340 nm, decreases dramatically upon trace trifluralin addition and exhibits ultra-fast response (3 s), high sensitivity and selectivity, and good anti-interference ability. The fluorescence sensing correlation with the concentration of trifluralin shows good linearity in the range of 20–90 μg L−1 with the limit of detection of 6.28 μg L−1. Moreover, a portable smartphone-integrated detected platform based on fluorescent pattern Red/Green/Blue (RGB) values is first employed to realize the real-time and on-site quantitative fluorescent detection of trifluralin in actual water sources, featuring good accuracy and reproducibility. Hereby, this work provides not only a highly efficient trifluralin residues fluorescent probe but also a portable and straightforward operating platform to detect trifluralin pesticides quantitatively.

Gradient high-performance thin-layer chromatography for characterizing complex hydrocarbon-containing products

Classic saturates, aromatics, resins, and asphaltenes (SARA) analysis has long enabled the chromatographic separation of complex hydrocarbon-containing products into these four families. This simplification often does not provide sufficient or correct information on the relationship between the composition of the products and the process variables studied. The obtention of profiles by gradient automated multiple development (AMD) is an interesting alternative to obtain extended SARA separations with increasing level of complexity for heavy petroleum products that adequately represent the entirety of the sample. An optimized 20-step gradient based on tetrahydrofuran (THF)‒dichloromethane‒n-heptane over a total migration distance of 83 mm is proposed here to characterize all types of heavy oil products. The combination of ultraviolet (UV)–densitometry (at 201, 228, and 273 nm), fluorescence detection by intensity changes using berberine cation, together with on-plate recording of UV spectra of separated peaks and the comparison with those of standards, allow for a deep characterization of chemical families. In the apolar zone of the chromatogram saturates, naphthenes, naphteno-aromatics, alkyl-aromatics, and aromatics with different degrees of condensation are detected. The use of THF, both in the plate precleaning stage and in the first stages of the gradient, is responsible for the satisfactory resolution of the resins in the polar zone. AMD chromatographic zones can be related to peaks from hydrocarbon groups in classical SARA. The application of this gradient to different types of products allowed for the relation of the profiles of bitumen to their origin, differentiation of the resin part trapped in asphaltenes, control performance of deasphalting in hydrorefining products, and the control of the composition of base oils.

The influence of extraction of various solvents on chemical properties on Chang 7 shale, Ordos Basin, China

Abstract. To explore the effect of various solvents extraction on the chemical property of shale, several lacustrine shale samples from the Chang 7 member of the Upper Triassic Yanchang Formation, Ordos Basin, with maturities, from marginally mature (Tmax=439∘) to late mature (Tmax=456∘), were extracted by using acetone, tetrahydrofuran (THF), carbon disulfide (CS2), and benzene, respectively. Fourier transform infrared spectroscopy (FTIR) was employed to examine the functional groups of the samples before and after extraction with different solvents. The results showed that the extraction yield from shale with THF is significantly higher than that of other solvents, which may be related to the properties of the THF, including the aromatic structure, high boiling point, excellent Hansen solubility parameters, and strong polarity. The total organic carbon (TOC)-normalized yield of the mature sample J1 is significantly higher than that of other samples, which may be related to the fact that the J1 sample is at the peak of hydrocarbon generation; thus, a large number of kerogens were cracked into oil and bitumen. The aromaticity of organic matter (OM) increases with the increase in the maturity. The length of the aliphatic chains of the OM first increased with the increase in the maturity before late maturity stage and then decreased in late maturity stage. The extraction of shale samples with solvents hardly changes the length of aliphatic chains. Higher aromaticity is observed in shale residues after THF extractions than for other solvents (i.e., acetone, CS2, and benzene).

Defect-free asymmetric Matrimid® gas separation membranes using dihydrolevoglucosenone (Cyrene™) as a greener polar aprotic solvent than traditional solvents

Industrial membrane manufacturing via nonsolvent-induced phase separation (NIPS) generates large volumes of solvent-contaminated wastewater. An effective solution is to reduce the inherent toxicity of NIPS casting solutions, or dopes, by substituting traditional polar aprotic solvents with potentially benign alternatives such as dihydrolevoglucosenone (Cyrene™). This study demonstrates the reproducible preparation of high-flux defect-free asymmetric Matrimid® gas separation membranes via dry/wet NIPS using Cyrene™ as a majority dope formulation component. Defect-free membrane performance, as benchmarked for pure gas H2/N2 and O2/N2 separations, is maximized with high loadings of Cyrene™ relative to the volatile co-solvent tetrahydrofuran (THF) in casting solutions (volume ratios up to 3.20:1), which exceed the value of 1.68:1 used for Udel® polysulfone in our previous study. Cyrene™'s poor thermodynamic compatibility with the water coagulant and ability to produce highly viscous dopes ensure minimization and/or elimination of sublayer macrovoids while enabling defect-free membrane preparation at low (i.e., 12–14 wt %) Matrimid® and THF concentrations. Defect-free H2 permeance values up to 164 ± 14 GPU were achieved with a combination of high Cyrene™:THF volume ratios, low Matrimid® concentrations, and short dry step times (i.e., <15 s). Membrane performance achieved in this study matches or exceeds other literature reports of defect-free asymmetric Matrimid® membranes prepared with traditional NIPS solvents.

Deep eutectic solvent liquid phase microextraction, powered by ultrasonic system, for determination of β-carotene in food samples

The research work is mainly concerned with the extraction of β-carotene, which is a terpenoid compound, from food and fruit samples using deep eutectic solvent based liquid phase extraction. Deep eutectic solvent liquid phase microextraction method, powered by ultrasonic mixing, (DES-UP-LPME) was carried out with deep eutectic solvent (DES) consisting of tetrabutylammoniumbromide (TBAB) and decanoic acid (DA). Key parameters such as pH, sample volume, tetrahydrofuran (THF) volume, DES type and volume, matrix effect, ultrasonication/centrifugation time were optimized to increase the extraction efficiency of β-carotene. Quantitative recoveries were obtained when pH, TBAB:DA ratio and sample volume were 3, 1:3 and 30, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.005 µg/mL and 0.015 µg/mL, respectively. Various food samples were analyzed spectrophotometrically by using the developed DES-UP-LPME at 450 nm. The addition/recovery studies were also performed on water samples to evaluate the accuracy of the method.

Novel hybrid reactive-extractive distillation for separation of tetrahydrofuran, ethanol, and water azeotropic system with rigorous side reactions consideration

This study builds upon our previous research work (Ind. Eng. Chem. Res. 2023, 62, 27, 10,601–10,610), which investigated the impact of considering the side reactions in the hybrid reactive-extractive distillation (RED). Our prior investigation revealed a significant challenge, as the inclusion of side reactions led to staggering spikes in energy consumption and total annual cost (TAC), seemingly rendering the performance of RED impractical. In this study, we present another possible scenario for considering side reactions in RED and highlight that RED with side reactions can still be a superior alternative to conventional distillation methods, even when side reactions are considered. This work was exemplified by using the recovering tetrahydrofuran (THF) and ethanol (EtOH) from waste effluent. We explore two different cases: Case 1 involves a side-reaction-free RED configuration reproduced as the base case, while the introduction of side reactions resulted in an increase in TAC by about 79.2% and a rise in total energy consumption by about 69%. Implementing a vacuum system (Case 2) substantially reduced the TAC by about 39% and energy consumption by about 20.5%. Although Case 2 outperformed Case 1 economically, it fell short of the base case due to additional capital costs. In contrast, Case 2 exhibited a lower TAC by 58% relative to the conventional pressure swing distillation.

Nanoparticles of poly(3-hexylthiophene): Toward a solvent-independent performance of electrochromic films

Nanoparticles of poly(3-hexylthiophene), P3HT(NP), uniquely enable the preparation of stable dispersions in environmentally-friendly media and thus offer a sustainable liquid phase fabrication of electrochromic device structures. In this work, we assess the electrochromic performance of P3HT(NP) films spray-coated from either tetrahydrofuran (THF)-water or chloroform (CHCl3)-ethanol dispersions on ITO substrates. The nanoparticle films exhibit consistent and reproducible high optical contrast values of around 50 %, t90-switching speeds of about 0.45 s and a cycling stability of approximately 200 cycles for a 20 % performance retention, independent of the solvent being used. Conversely, non-nanostructured P3HT films spray-coated from THF or CHCl3 reveal a strong solvent dependent variability in their electrochromic behavior presenting low optical contrast, high switching speeds and fast degradation rates in the case of CHCl3. The solvent independent electrochromic characteristics of P3HT nanoparticle films is related to a consistent availability of accessible electroactive sites provided by a homogeneous porous P3HT network structure formed on the underlying substrate, as probed by SEM and profilometric studies. Our findings reveal that the use of nanoparticles of P3HT and its environmentally benign liquid phase processing, a concept which is extendable to other electrochromic polymers, opens a sustainable pathway toward the large-area fabrication of electrochromic device structures with favorable and consistent performance parameters.

Carbon-Nitrogen Bond Formation Using Sodium Hexamethyldisilazide: Solvent-Dependent Reactivities and Mechanisms.

The solvent-dependent reactivity of sodium hexamethyldisilazide (NaHMDS) toward carbon-centered electrophiles reveals reactions that are poorly represented or unrepresented in the literature, including direct aminolysis of aromatic methyl esters to give carboxamides, nitriles, or amidines, depending on the choice of solvent. SNAr substitutions of aryl halides and opening of terminal epoxides are also examined. A combination of 1H and 29Si nuclear magnetic resonance (NMR) spectroscopic studies using [15N]NaHMDS, kinetic studies, and computational studies reveals the complex mechanistic basis of the preferences for simple aryl carboxamides in toluene and dimethylethylamine and arylnitriles or amidines in tetrahydrofuran (THF). A prevalence of dimer- and mixed dimer-based chemistry even starting from the observable NaHMDS monomer in THF solution is notable.