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Three types of 9,9-bis(4-hydroxyphenyl)fluorene-based diols reacted with 4,4′-difluorobenzophenone via nucleophilic substitution polymerization to afford the corresponding aromatic poly(ether ketone)s. The resulting polyketones have excellent solubility in typical organic solvents, such as THF, CHCl3, and NMP. They also have good thermal stability above 400 °C (Td10). In particular, the surface tension of the polyketone, which has four C4F9 groups per repeating unit, is 18.7 mN/m, which is equal to that of PTFE. The introduction of propylene linkers and many C4F9 groups per repeating unit was effective at improving water/oil repellency. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs), as a new class of crystalline, well‐ordered, and porous materials with intermittent constructions, are formed via organic structural parts connected through covalent bonds. These materials have been employed in several fields comprising pollutant adsorption and separation, catalysis, electrical conductivity, gas storage, etc. The preparation of COFs is mainly applied in tubes with high temperatures and degassing treatment. Furthermore, the reaction medium is involved in toxic organic solvents like toluene, dioxane, mesitylene, acetonitrile, and so on. Hence, discovering clean medium and green approaches has attracted wide attention. Recently, facile, less dangerous, and greener methods have been developed for COFs synthesis in diverse applications like performing the reaction at ambient temperature or employing aqueous solvents, ionic liquids, and a mixture of organic solvents/water. This review article summarizes the eco‐friendly production approaches of COFs for diverse applications. [ABSTRACT FROM AUTHOR]

A trimer‐cyclisation reaction of propiolate esters yielded 1,3,5‐benzenetricarboxylate tri‐esters in water. The reaction proceeded selectively in the presence of secondary or tertiary amine salts in pure water solvent. Other organic solvents, such as dimethyl formamide, tetrahydrofuran, and ethanol, afforded a 1 : 1 adduct of propiolate and amine. The hydrogen bonding characteristics of water stabilised the proposed intermediate in a conformation that promoted the final cyclisation. The synthesis can be successfully conducted in water–a universal and an eco‐friendly solvent. [ABSTRACT FROM AUTHOR]

In this work, we reported two nitrogen doped carbon quantum dot fluorescence sensors (Y‐CDs and R‐CDs) with good stability and luminescence efficiency, which can be quickly, sensitively and low‐cost for the determination of trace water content in organic solvents. Using o‐phenylenediamine and p‐phenylenediamine as nitrogen sources and terephthalic acid as carbon sources, the preparation was carried out through simple solvothermal synthesis and heteroatom doping. The luminescence characteristics and interaction mechanism with the target were discussed. The results indicate that the two carbon dots can effectively quench the water content in acetone, ethanol, and DMF, as well as physical interactions such as hydrogen bonding and dynamic quenching, which are the reasons for the observed quenching effect. Based on this, a new method for determining water content in organic solvents using carbon quantum dot fluorescence probes has been established. The linear relationship between the fluorescence quenching efficiency F0/F of two carbon quantum dots and the water content in different organic solvents was studied. The detection limits (LOD) of water in acetone, ethanol and N,N‐dimethylformamide (DMF) were 0.17 %, 2.35 %, 0.26 %, respectively, determined by Y‐CDs. The LOQ of acetone, ethanol, and DMF were 0.554 %, 7.83 %, 0.855 %, respectively. The LOD of water in acetone, ethanol and DMF determined by R‐CDs were 0.056 %, 0.69 %, 0.27 % and the LOQ was 0.187 %, 2.290 %, 0.909 %, respectively. Good recovery rates and precision were achieved in practical applications. [ABSTRACT FROM AUTHOR]

A straightforward, rapid, green, and efficient synthetic procedure has been introduced for easy access to the synthetically highly substituted arylideneisoxazol-5-(4H)-one products. A wide scope of the heterocyclic products was obtained via the three-component cyclocondensation of various aryl aldehydes, NH2OH·HCl, and β-dicarbonyls by zinc oxide nanoparticles (ZnO NPs) as the catalyst. Optimizing the reaction conditions indicated that a relatively small amount of catalyst was required and arylideneisoxazol-5-(4H)-ones were obtained in very short reaction times. Purification of synthesized heterocyclic molecules was carried out with the help of simple filtration and crystallization from ethanol. In this method, exhausting and expensive chromatography methods were not used to purify the products, and the use of organic solvents was also avoided. In addition, this method is important from the point of view of green chemistry. The simplicity of the method, cost-effective catalyst, less time-consuming, mild reaction conditions, conducting experiments at room temperature, as well as recyclability and reusability of ZnO nano-catalyst are among other advantages of this powerful process. [ABSTRACT FROM AUTHOR]

Reversible addition‐fragmentation chain transfer (RAFT) polymerization has proven itself as a powerful polymerization technique affording facile control of molecular weight, molecular weight distribution, architecture, and chain end groups ‐ while maintaining a high level of tolerance for solvent and monomer functional groups. RAFT is highly suited to water as a polymerization solvent, with aqueous RAFT now utilized for applications such as controlled synthesis of ultra‐high molecular weight polymers, polymerization induced self‐assembly, and biocompatible polymerizations, among others. Water as a solvent represents a non‐toxic, cheap, and environmentally friendly alternative to organic solvents traditionally utilized for polymerizations. This, coupled with the benefits of RAFT polymerization, makes for a powerful combination in polymer science. This perspective provides a historical account of the initial developments of aqueous RAFT polymerization at the University of Southern Mississippi from the McCormick Research Group, details practical considerations for conducting aqueous RAFT polymerizations, and highlights some of the recent advances aqueous RAFT polymerization can provide. Finally, some of the future opportunities that this versatile polymerization technique in an aqueous environment can offer are discussed, and it is anticipated that the aqueous RAFT polymerization field will continue to realize these, and other exciting opportunities into the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyclic polymer with amphiphilic nature is first investigated as fluorescence sensor. • The probe displays the vast potential for sensing of water in 10 organic solvents. • The broadest concentration range of water in N,N-dimethyl acetamide was achieved. • The mechanism was explored by theory and experimental investigation. A sensor capable of sensing of water in various organic solvents ranging from water-soluble to water-miscible solvents is still a challenging task. In this research, a cyclic polymer fluorescence chemosensor (CPFC) has been developed for sensing of water by turn-on model in 9 organic solvents and turn-off model in DMA, where the broadest concentration range and the lowest detection limit was obtained for water in DMA (10 %–90 %) and dioxane (0.011 %), respectively. The sensing mechanism is explored by theory calculation and experimental investigation. The amphiphilic nature endows the polymer probe with great potential for measuring various contaminants from aqueous and nonaqueous mediums. Furthermore, the present search highlights the potential applications of cyclic polymer as fluorescence probes in the field of sensing. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enthalpies of L- carnosine dissolution have been measured in some water-organic mixtures. • Dependence of L- carnosine solvation on the mixture composition is established. • Results are compared with similar for β-alanyl-β-alanine. • The enthalpic contribution of L- carnosine and β-alanyl-β-alanine side-chains to h xy were determined. • The enthalpy of L -carnosine solvation depends on the polarity and donor–acceptor properties of solvents. Isothermal calorimetry was used to measure the enthalpies of L -carnosine digestion in aqueous solutions of acetonitrile (AN) 1,4-dioxane (DO), acetone (AC), dimethyl sulfoxide (DMSO), ethanol EtOH), 1-propanol (1-PrOH), and 2-propanol (2-PrOH). The values of Δ sol H ° obtained were combined with the standard enthalpies of L -carnosine sublimation to obtain the corresponding enthalpies of solvation Δ solv H °. In addition, the enthalpic coefficients of pairwise interactions (h xy) of L -carnosine with organic solvent molecules and the enthalpy of transfer (Δ tr H °) from water in their mixture with the latter were calculated. It is established that the solvation of L -carnosine is weakened in a series of (H 2 O + EtOH) > (H 2 O + 1-PrOH) > (H 2 O + 2-PrOH). This may be due to an increase in the hydrophobicity of alcohols of the same order as well as the presence of CH 3 -groups within the alcohol molecule. The weakening of the solvation energy of L -carnosine by co-solvent molecules in a series of mixed solvents: (H 2 O + AN) < (H 2 O + AC) < (H 2 O + DO) < (H 2 O + DMSO) is associated both with an increase in the hydration energy of co-solvents in the same order and with their physicochemical properties. The enthalpic coefficients of water-organic solvent pairwise interactions were discovered to be linearly related to the corresponding coefficients of L -carnosine-organic solvent interactions. An increase in the polarity and acidity of an organic solvent increases the energy of pairwise interactions between L -carnosine and the organic solvent. Increasing the cohesion energy density, molar volume, and basicity of the organic solvent reduces the energy of the pairwise interactions between L -carnosine and the organic solvent. [ABSTRACT FROM AUTHOR]

Three new derivatives of (4-methoxyphenyl) ethynyl-naphthalimide were synthesized by Sonogashira coupling reaction. These compounds showed robust and strong fluorescent signals, which shift from blue to orange as the solvent polarity increases. Computational calculations revealed that in low-polarity solvents, the molecules preferred a 90° rotation between the naphthalimide and ethynyl benzene fragments. In high-polarity solvents, where the energy barrier for rotation of the alkyne bond was higher, the molecules favored the 0° conformer, leading to longer emission wavelengths. The compound with a 2-methoxyethyl group tethered to the naphthalimide nitrogen demonstrated sensitivity to water presence in the ranges of 0–30 % (v/v) in THF, 0–15 % (v/v) in DMSO, 0–30 % (v/v) in MeCN, 0–15 % (v/v) in acetone, and 0–40 % (v/v) in EtOH. The detection limits for water were determined to be 0.0523 %, 0.1365 %, 0.0337 %, 0.0570 %, and 0.1170 % (v/v) in THF, DMSO, MeCN, acetone, and EtOH, respectively. The effectiveness of this compound in quantifying ethanol content in spirit samples was successfully demonstrated. [Display omitted] • Three new naphthalimides exhibited strong fluorescence transitioning from blue to orange based on solvent polarity. • Computational calculations identified conformational preferences influencing emission wavelengths. • One of these compounds was effective for quantifying ethanol in spirit samples. [ABSTRACT FROM AUTHOR]

Using biomass-derived solvents in various organic reactions is challenging for the fine chemicals industry. We herein report a Pd/C catalyzed Suzuki–Miyaura reaction in water extract of suaeda salsa (WES) without using external phosphine ligand, base, and organic solvent. The cross-coupling reactions were carried out in a basic WES medium with a broad substrate scope and wide functional group tolerance. Furthermore, the high purity of solid biaryl products can be obtained by column chromatography or filtration. [ABSTRACT FROM AUTHOR]

A water‐promoted synthesis methodology for constructing 3‐sulfone propionic acids from sulfonyl hydrazides and α, β‐unsaturated propionic acids with excellent yields were reported. The green synthesis methodology was promoted by water without any catalyst, ligand and organic solvent. The D2O control experiment sufficiently proved that the 2‐hydrogen atom of 3‐sulfone propionic acid come from water. Moreover, the 3‐sulfone propionic acid derivates could be directly purified by crystallization without column chromatography. [ABSTRACT FROM AUTHOR]

Molecular recognition processes in water differ from those in organic solvents in that they are mediated to a much greater extent by solvent effects. The hydrophobic effect, for example, causes molecules that only weakly interact in organic solvents to stay together in water. Such water‐mediated interactions can be very efficient as demonstrated by many of the synthetic receptors discussed in this review, some of which have substrate affinities matching or even surpassing those of natural binders. However, in spite of considerable success in designing such receptors, not all factors determining their binding properties in water are fully understood. Existing concepts still provide plausible explanations why the reorganization of water molecules often causes receptor‐substrate interactions in water to be strongly exothermic rather than entropically favored as predicted by the classical view of the hydrophobic effect. [ABSTRACT FROM AUTHOR]

Seeking a more environmentally balanced method of peptide synthesis, we are focusing on developing organic solvent-free synthetic methods using water, an environmentally friendly solvent. In current peptide synthesis, the most common building blocks are Boc- and Fmoc-protected amino acids, which are highly soluble in organic solvents. We previously reported a technique for solid-phase peptide synthesis in water that utilizes Fmoc-amino acids converted to water-dispersible nanoparticles. The Boc strategy is well-known to be suitable for the industrial chemistry and green chemistry, because only gases are generated without any other by-products in the deprotection step of Boc group. Here we summarize in-water both liquid and solid-phase method using Boc-amino acids based on MW-assisted coupling reaction of nanosized reactants, nanoparticles and nanomicelles. [ABSTRACT FROM AUTHOR]

The first example of the sulfinylation of indoles with arylsulfinamides in water in the presence of trifluoroacetic acid as a promoter is described. The reaction occurs smoothly at room temperature under environmentally benign conditions without any catalyst, additive, ligand, or organic solvent. The developed sulfoxide synthetic protocol is attractive due to the use of water as the solvent and provides a novel and efficient route to a wide range of functionalized diaryl sulfoxides. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-emission fluorescent MOF has been synthesized based on the introduction of Eu3+ ions, into aluminum metal − organic frameworks. • The dual-emission Eu/Al-MOF is used to design the sensor for the quantitative detection of histidine and water by changing the independent fluorescence signals. • The Eu/Al-MOF has been successfully applied to the detection of histidine in urine samples. • The solid-state fluorescence of Eu/Al-MOF proves instrumental in visualizing and identifying fingerprints. Ratiometric fluorescent sensors possess inherent self-calibration features that enable the mitigation of interference from factors unrelated to the analysis. This characteristic results in heightened sensitivity and more pronounced visual detection during qualitative and quantitative analytical processes. A ratiometric fluorescence probe Eu/Al-MOF has been successfully prepared via Eu3+ doped aluminum metal − organic frameworks. Upon introducing histidine, the fluorescence intensity of Eu3+ showed a noteworthy increase, whereas the intensity originating from the ligand decreased owing to enhancing energy transfer from the ligand to Eu3+ ions in the probe. Eu/Al-MOF could detect histidine over a wider linear range of 0.1–400 μM and a lower detection limit of 0.04 μM. Besides, in the presence of water in organic solvents, the excited state of Eu3+ in the probe could be coupled with the O-H oscillation of water molecules, and the excited state energy from Eu3+ would be transferred to the water molecules so that only the fluorescence intensity of Eu3+ gradually decreased. Thus, the proportional detection of trace water could be realized. In ethanol and DMF, the detection range for water was 0.1–20 % and 0.5–20 %, respectively. Moreover, it was found that Eu/Al-MOF could efficiently achieve the visualization identification of fingerprints, providing the possibilities for applying the nano-sensor as a promising multifunctional fluorescence probe. [ABSTRACT FROM AUTHOR]

Imidazolium-based ionic liquids (ILs) represent a well-studied class of ILs. These compounds are characterized by many fascinating properties such as non-flammability, low vapor pressure, wide electrochemical window, and thermodynamic and kinetic stability. This review paper aims to provide an insight into some experimental methods of investigations and applications of these ILs. Additionally, some results on the topic of imidazolium-based ILs in various solvents are presented. [ABSTRACT FROM AUTHOR]

Molecular machines are ubiquitous in nature and function away from equilibrium by consuming fuels to produce appropriate work. Chemists have recently excelled at mimicking the fantastic job performed by natural molecular machines with synthetic systems soluble in organic solvents. In efforts toward analogous systems working in water, we show that guest molecules can be exchanged in the synthetic macrocycle cucurbit[7]uril by involving kinetic traps, and in such a way as modulating energy wells and kinetic barriers using pH, light, and redox stimuli. Ditolyl‐viologen can also be exchanged using the best kinetic trap and interfaced with alginate, thus affording pH‐responsive blue, fluorescent hydrogels. With tunable rate and binding constants toward relevant guests, cucurbiturils may become excellent ring molecules for the construction of advanced molecular machines working in water. [ABSTRACT FROM AUTHOR]

To develop highly efficient synthetic reactions is quite important in organic chemistry. Cross dehydrogenative couplings (CDC) utilize C−H bonds of substrates to construct new C−X (X=C, S, O, N, P) bonds. For CDC, the pre‐functionalization of reaction substrates can be avoided and the C−X (X=C, S, O, N, P) bonds can be newly formed by simple and efficient synthesis routes. Meanwhile, water is increasingly used as a substitute for organic solvents in cross‐dehydrogenative coupling because of its rich content, non‐toxicity, and non‐ flammability. In recent years, organic chemists are devoted their efforts to explore the cross dehydrogenative couplings (CDC) in aqueous phase which feature high atom utilization rate and environmental friendliness. Herein, we summarized the recent advances in the construction of C−C, C−S, C−O, C−N, and C−P bonds through CDC reactions of C−H bonds in water. [ABSTRACT FROM AUTHOR]

Self‐assembly by imine condensation in aqueous media is a formidable task because of the labile nature of imines in the presence of water. Here, by taking advantage of multivalence and ligand preorganization, basket‐shaped triscationic cage molecules are self‐assembled in high yields in both water and organic solvent, by condensing a hexaformyl and bisamine. These cages, especially the chiral ones, are stable or inert in aqueous solution, that is, no decomposition was observed upon dilution, precipitation, or exposure to competitive amines or aldehydes. Such water‐compatibility allows the hosts to take advantage of the hydrophobic effect to accommodate hydrophobic guests. The chiral cage S‐23+ selectively binds and distinguishes one of two enantiomers, opening up opportunities for applications such as chiral compound separation. Chiral narcissistic self‐sorting and sergeants‐and‐soldiers effects occur during cage formation when two amino precursors are involved in self‐assembly. [ABSTRACT FROM AUTHOR]

Metal‐bound water molecules have recently been recognized as a new facet of soft Lewis acid catalysis. Herein, a chiral palladium aqua complex was constructed that enables carbon–hydrogen bonds of indoles to be functionalized efficiently. We embraced a chiral 2,2′‐bipyridine as both ligand and hydrogen‐bond donor to configure a robust, yet highly Lewis acidic, chiral aqua complex in water. Whereas the enantioselectivity could not be controlled in organic solvents or under solvent‐free conditions, the use of aqueous environments allowed the σ‐indolylpalladium intermediates to react efficiently in a highly enantioselective manner. This work thus describes a potentially powerful new approach to the transformation of organometallic intermediates in a highly enantioselective manner under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Metal‐bound water molecules have recently been recognized as a new facet of soft Lewis acid catalysis. Herein, a chiral palladium aqua complex was constructed that enables carbon–hydrogen bonds of indoles to be functionalized efficiently. We embraced a chiral 2,2′‐bipyridine as both ligand and hydrogen‐bond donor to configure a robust, yet highly Lewis acidic, chiral aqua complex in water. Whereas the enantioselectivity could not be controlled in organic solvents or under solvent‐free conditions, the use of aqueous environments allowed the σ‐indolylpalladium intermediates to react efficiently in a highly enantioselective manner. This work thus describes a potentially powerful new approach to the transformation of organometallic intermediates in a highly enantioselective manner under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Reducing or eliminating organic solvent use in pharmaceutical manufacturing is perhaps the most effective way to reduce the environmental, health, and safety impacts of drug substance manufacturing. With this in mind, we have developed a process to manufacture an investigational 5-HT4 receptor agonist that is conducted almost entirely in water, including multiple controlled isolations. Key transformations carried out in aqueous media include a benzimidazole cyclization, amide bond formation, reductive amination, and a selective oxidation of an aliphatic alcohol. Compared to the first-generation manufacturing process using organic solvents, the aqueous process described here uses 77% less material inputs, 94% less organic solvent, and, surprisingly, 48% less water, while improving overall yield from 35% to 56%. [ABSTRACT FROM AUTHOR]

Nitroaromatic compounds were massively used in the formulation of explosives during both world wars. Even several decades after the end of these wars, their residues are suspected to be widely present in the environment. Their occurrence and effect on ecosystems and human health are still not fully determined. This paper describes the development of a method for the determination of 28 nitroaromatic compounds in water, including isomers of nitrotoluene (NT), dinitrotoluene (DNT), trinitrotoluene (TNT), nitrobenzene (NB), dinitrobenzene (DNB), chloronitrobenzene (ClNB), chlorodinitrobenzene (DNCB), nitronaphthalene (NN), dinitronaphthalene (DNN), nitroaniline (NA), dinitroanisole (DNAN), diphenylamine (DPA), and nitrodiphenylamine (nitro-DPA). In order to separate and individually quantify all the analytes with the best possible sensitivity, stir bar sorptive extraction (SBSE) was chosen as the extraction and pre-concentration step prior to gas chromatography (GC) separation and tandem mass spectrometry detection (MS/MS). Our SBSE optimization efforts focused on parameters such as the type of stir bar, ionic strength, addition of organic solvent, and extraction and desorption times. After these optimizations, the analytical method enabled us to reach limits of quantification (LOQs) between 1 and 50 ng/L in tap water, groundwater, and surface water. The method was applied to the determination of targeted nitroaromatic explosive residues in spring and groundwater samples collected in an area where mine warfare had raged during World War I. Up to 16 different nitroaromatic compounds were detected in the same sample. The highest concentrations were recorded for 2,4-DNT and 1,3-DNB (1700 and 2690 ng/L respectively). [ABSTRACT FROM AUTHOR]

Eco-friendly and practical methods for the complementary regioselective synthesis of 3-(1-substituted pyrazol-3-yl) indoles and 3-(1-substituted pyrazol-5-yl) indoles, from DBSA-mediated regioselective cyclocondensation reaction of β-ethyltho-β-indolyl-α, β-unsaturated ketones and monosubstituted hydrazines in water through simply varying the appropriate reaction way, had been developed. The methods not only efficiently avoided the use of organic solvent but also exhibited attractive characteristics such as operational simplicity, broad substrate scope, easy separation of products and ease of scale-up. [ABSTRACT FROM AUTHOR]

Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol/acetonitrile/acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials. [ABSTRACT FROM AUTHOR]

A smartphone-based ratiometric fluorescence device was designed to monitor the reaction kinetic process under vigorous mixing conditions, demonstrated by the hydrolysis of Cs4PbBr6 nanocrystals (NCs). In the presence of trace water, part of Cs4PbBr6 NCs (non-fluorescent) was converted to CsPbBr3 NCs (strong fluorescent). Using anthracene as the reference fluorophore, the brightness ratio of the green (from CsPbBr3 NCs) to blue (from anthracene) components in the fluorescence image which was recorded in situ by the smartphone camera was measured as the signal for kinetic analysis. It was shown that the water-triggered conversion reaction from Cs4PbBr6 NCs to CsPbBr3 NCs follows the pseudo-second-order kinetic model in the early rapid hydrolysis stage (up to 4 min). With increasing water content, the hydrolysis of Cs4PbBr6 NCs is promoted to yield more CsPbBr3 NCs, which was used to determine trace water in n-hexane, dichloromethane, and toluene with detection limits of 0.031, 0.043, and 0.057 μL mL−1, respectively. The device offers the advantages of portability and low cost for rapid field determination of trace water in hydrophobic organic solvents. [ABSTRACT FROM AUTHOR]

Graphene has attracted much attention and holds great promise in various applications due to its extraordinary properties. To realize applications of graphene in large scale, developing a facile, green and cost-effective method for mass production of high-quality graphene is highly desired. Relative to expensive and complicated bottom-up approaches, top-down methods for graphene production are promising owing to their low cost and simplicity. Specifically, exfoliation of graphene nanosheets in liquid phase is favorable for their dispersion, functionalization and processing. Instead of highly toxic organic solvents, using water as the liquid medium makes exfoliation process eco-friendly and sustainable. In this review, recent progress on exfoliation of graphene nanosheets in water is discussed, with a particular focus on exfoliation and stabilizing mechanism in various aqueous media. Different water-based exfoliation methods, such as liquid-phase exfoliation and electrochemical exfoliation, are surveyed. [ABSTRACT FROM AUTHOR]

An environmental-friendly and mild method has been successfully developed for the synthesis of 3-aryl-2-nitro-2,3-dihydrobenzofurans through domino Friedel–Crafts/substitution reaction of (Z)-bromonitrostyrenes with sesamol. A variety of substrates performed well in this reaction, and the corresponding 3-aryl-2-nitro-2,3-dihydrobenzofurans were obtained in excellent yields (up to 99%). Significantly, water served as the sole green solvent. Remarkably, the crude products were purified by simple filtration, washing with water and drying in oven without any organic solvents or silica gel. [ABSTRACT FROM AUTHOR]

Effective extraction is an essential step in the sensitive and accurate analysis of sulfonamides (SAs) in complex samples. In this study, based on the chemical properties of SAs, a novel monolith-based adsorbent using 4-vinylbenzoic acid and 4-vinylphenylboronic acid as dual-functional monomers was tailored and employed as efficient extraction phase of solid-phase microextraction. Various characterized techniques were applied to investigate the structure and morphology of the obtained adsorbent. Due to the abundant functional groups, the synthetic adsorbent displayed satisfying extraction performance for target SAs through multiple interactions including ion-exchange, B–N coordination, π-π and hydrophobic interactions. Following elution with the desorption solution of methanol/formic acid (98.5/1.5, v/v), the extractive SAs were measured by HPLC-MS/MS. Under the optimized conditions, the proposed approach exhibited wide linear ranges (0.005–10.0 μg/L for most of analytes), low limits of detection (in the range of 0.31–2.3 ng/L) and good precision (RSDs were lower than 8.0%). In the analysis of target SAs in environment waters and honey samples, the recoveries at low, medium and high spiked concentrations were in the range of 83.5–119%, and the RSDs (n = 3) varied from 0.6% to 9.6%. Compared with existing approaches, the current method presents some merits such as high sensitivity, good reproducibility, low consumptions of sample and organic solvent. Image 1 • A novel porous monolith-based adsorbent for MMF-SPME was prepared. • Multiply interactions contributed to the effective extraction of SAs. • Various parameters affecting the extraction performance were optimized. • Highly sensitive method for the quantification of trace SAs was developed. [ABSTRACT FROM AUTHOR]

Lignocellulosic material is an abundant renewable resource with the potential to replace petroleum as a feedstock for the production of fuels and chemicals. The large scale deployment of biomass saccharification is, however, hampered by the necessity to use aggressive reagents and conditions, formation of side-products, and the difficulty to reach elevated monosaccharide concentrations in the crude product. Herein we report the high efficacy of Reactive Aging (or Raging, a technique where enzymatic reaction mixtures, without any bulk aqueous or organic solvent, are treated to multiple cycles of milling and aging) for gram-scale saccharification of raw lignocellulosic biomass samples from different agricultural sources (corn stover, wheat straw, and sugarcane bagasse). The solvent-free enzymatic conversion of lignocellulosic biomass was found to proceed in excellent yields (ca. 90%) at protein loadings as low as 2% w/w, without the need for any prior chemical pre-treatment or high temperatures, to produce highly concentrated (molar) monosaccharides. This crude product of mechanoenzymatic depolymerization is non-toxic to bacteria and can be used as a carbon source for bacterial growth. [ABSTRACT FROM AUTHOR]

Two new families of lanthanide antennas are described. 8-Methoxy-4,5-dihydrocyclopenta[de]quinolin-2(1H)-one phosphonates or carboxylates behave as selective antennas exhibiting Eu3+ luminescence in organic solvents, while quinolin-2(1H)-one analogues selectively sensitize the Tb3+ emission. These emissions are quenched by H2O addition. Based on this behaviour, the new lanthanide antennas can be used as highly sensitive water sensors. [ABSTRACT FROM AUTHOR]

A highly crystalline covalent organic frameworks (COFs) formed by condensation reaction between 1, 3, 5-tris (4-aminophenyl) benzene and 4, 4′-biphenyldicarboxaldehyde is utilized as a sensing platform for water in organic solvent over a broad concentration range. The resulting COFs exhibits brilliant fluorescence in various organic solvents such as methanol, DMF, acetonitrile and ethanol, moreover its fluorescence intensity has a significant and rapid response to the content of water in organic solvent over a broad concentration range. The broadest sensing range is achieved over 7%–70% (v/v) for water in DMF, and the lowest limit of detection is 0.042% (v/v) for water in methanol among the investigated organic solvents. The superior properties of the sensing platform expand the application ranges of COFs and endow the resulting COFs with a great prospect in practical applications for highly efficient detecting water in organic solvent. A fluorescence sensor for detecting water in organic solvent has been constructed based on an emerging material (COFs) over a broad range from 7% to 70% (v/v) for water in DMF. The sensing platform proposes a potential approach for monitoring water in organic solvent. Image 1 • The highly crystalline COFs has been synthesized successfully. • The COFs could serve as a sensing platform for water in organic solvent. • A broad concentration range and high sensitivity revealed the advantages of the platform. • The platform showed potential application in monitoring contaminant in environment and chemical industry. [ABSTRACT FROM AUTHOR]

Two new hydroxyl-containing polyimides (PIs) with excellent comprehensive performances were designed and synthesized. After PIs react with fluoride ion (F−), the resulting polyimide-fluoride complexes (PI-1 ·F and PI-2 ·F) are exploited as ratiometric and colorimetric sensors for detecting trace water in DMSO/DMF with high sensitivity. Both sensors PI-1 ·F and PI-2 ·F exhibit a good naked-eye visual detection as well as an excellent linear relationship between the UV– vis absorbance ratio and the low water content in DMSO/DMF, which constitutes a quantitative method for determining water content in DMSO/DMF. The limits of detection (LOD) of sensor PI-1 ·F for water in DMSO and DMF are as low as 0.0035% and 0.0031% (v/v), respectively. The sensor PI-2 ·F shows the higher sensitivity for water detection with extremely low detection limits of 0.00084% and 0.0015% in DMSO and DMF, respectively. Furthermore, PI films have been directly used for the visual sensing of water in acetonitrile, acetone and ethanol, which provides an effective way for fabricating high-performance film-based water sensor devices. Image 1 • Two hydroxyl-containing polyimides are successfully synthesized. • Polyimide-fluoride complexes are applied for detecting trace water in organic solvents. • The sensors show high sensitivity toward a trace amount of water in DMSO and DMF. • The sensors exhibit a good naked-eye visual water detection. • PI films are directly used for visual detection of water in organic solvents. [ABSTRACT FROM AUTHOR]

Multiple‐stimuli‐responsive photoluminescence films based on a ZnII–organic framework, {[Zn2(Htpim)(3,4‐pydc)2]⋅4 DMF⋅4 H2O}n (1, Htpim=2,4,5‐tri(4‐pyridyl)imidazole, 3,4‐H2pydc=3,4‐pyridinedicarboxylic acid), were fabricated. This compound consisted of a 2D corrugated layer, {Zn(3,4‐pydc)}n, which was further pillared using a Y‐shaped pillar N‐donor ligand (Htpim) to form a 3D‐pillared‐layer framework with 1D open channels. The rectangular channels in the as‐synthesized compound are fully occupied by guest DMF and H2O molecules. The framework exhibits instant and reversible thermochromic properties corresponding to the removal of different H2O and DMF guest molecules as temperature increases. The pale‐yellow crystal undergoes significant redshifting to a greenish emission centered at 530 nm. Compound 1 also showed remarkable solvatochromic effects in the presence of various organic solvents without affecting its structural integrity. In addition, polycrystalline MOF films were grown on an α‐Al2O3 support for switchable and fast‐response thermochromic and solvatochromic sensors. [ABSTRACT FROM AUTHOR]

In the present investigation, a green aqua‐mediated protocol for the synthesis of novel 2‐arylidene indanone derivatives from 1,2,6,7‐tetrahydro‐8H‐indeno[5,4‐b]furan‐8‐one was unveiled. The application of water in organic reactions as a solvent is one of the incredible tools of green chemistry as reactions can be carried out under benign conditions minimizing environmental hazard and chemical waste. A library of novel 2‐arylidene indanone derivatives are synthesized in good to excellent yield by utilizing the green potential of water as a solvent. The structures of all novel 2‐arylidene indanone derivatives reported herein are confirmed using Fourier‐transform infrared spectroscopy (FTIR), 1H NMR, 13C NMR, 19F NMR, distortionless enhancement by polarization transfer (DEPT), and High Resolution Mass Spectrometry (HRMS) techniques. [ABSTRACT FROM AUTHOR]

A novel liquid-based Janus porous membrane system was developed through the simple infusion of water and oil within different surfaces. This generates a stable liquid-infusion interface that repels immiscible organic solvents and water, and itself floats at the oil/water interface as a separator. The developed membrane successfully acts as a simple alternative for high-performance liquid separation. [ABSTRACT FROM AUTHOR]

The current industrial approach to sonidegib utilizes wasteful organic solvents and relies on high loadings of endangered Pd. This anticancer drug can now be synthesized in 5 steps using only 3 pots, along with ppm levels of a Pd catalyst, all done in water at ambient temperatures. [ABSTRACT FROM AUTHOR]

A highly efficient stereoselective synthesis of CF3-oxazinoquinolines was elaborated using the reaction of CF3-ynones with quinolines in water. It was demonstrated that under these green conditions, the reaction proceeds up to 20 times faster to provide target compounds in almost quantitative yields. Moreover, this method is devoid of any chromatographic purification to give CF3-oxazinoquinolines with complete diastereoselectivity. The presented eco-friendly approach was found much more efficient than standard reactions in organic solvents. The synthetic utility of the prepared CF3-oxazinoquinolines was demonstrated. [ABSTRACT FROM AUTHOR]

Dissipative particle dynamics simulations were used to study the effects of mixing time, solute solubility, solute and diblock copolymer concentrations, and copolymer block length on the rapid coprecipitation of polymer-protected nanoparticles. The simulations were aimed at modeling Flash NanoPrecipitation, a process in which hydrophobic solutes and amphiphilic block copolymers are dissolved in a water-miscible organic solvent and then rapidly mixed with water to produce composite nanoparticles. A previously developed model by Spaeth et al. [J. Chem. Phys. 134, 164902 (2011)] was used. The model was parameterized to reproduce equilibrium and transport properties of the solvent, hydrophobic solute, and diblock copolymer. Anti-solvent mixing was modeled using time-dependent solvent-solute and solvent-copolymer interactions. We find that particle size increases with mixing time, due to the difference in solute and polymer solubilities. Increasing the solubility of the solute leads to larger nanoparticles for unfavorable solute-polymer interactions and to smaller nanoparticles for favorable solute-polymer interactions. A decrease in overall solute and polymer concentration produces smaller nanoparticles, because the difference in the diffusion coefficients of a single polymer and of larger clusters becomes more important to their relative rates of collisions under more dilute conditions. An increase in the solute-polymer ratio produces larger nanoparticles, since a collection of large particles has less surface area than a collection of small particles with the same total volume. An increase in the hydrophilic block length of the polymer leads to smaller nanoparticles, due to an enhanced ability of each polymer to shield the nanoparticle core. For unfavorable solute-polymer interactions, the nanoparticle size increases with hydrophobic block length. However, for favorable solute-polymer interactions, nanoparticle size exhibits a local minimum with respect to the hydrophobic block length. Our results provide insights on ways in which experimentally controllable parameters of the Flash NanoPrecipitation process can be used to influence aggregate size and composition during self-assembly. [ABSTRACT FROM AUTHOR]

A combination of the polarizable continuum model (PCM) and the hybrid quantum mechanics/molecular mechanics (QM/MM) methodology, PCM-MM/QM, is used to include the solute electronic polarization and then study the solvent effects on the low-lying n→π* excitation energy and the 15N nuclear magnetic shielding of pyrazine and pyridazine in aqueous environment. The results obtained with PCM-MM/QM are compared with two other procedures, i.e., the conventional PCM and the iterative and sequential QM/MM (I-QM/MM). The QM calculations are made using density functional theory in the three procedures. For the excitation energies, the time-dependent B3LYP/6-311+G(d) model is used. For the magnetic shielding, the B3LYP/aug-pcS2(N)/pcS2(C,O,H) is used with the gauge-including atomic orbitals. In both cases, i.e., PCM-MM/QM and I-QM/MM, that use a discrete model of the solvent, the solute is surrounded by a first shell of explicit water molecules embedded by an electrostatic field of point charges for the outer shells. The best results are obtained including 28 explicit water molecules for the spectral calculations and 9 explicit water molecules for the magnetic shielding. Using the PCM-MM/QM methodology the results for the n→π* excitation energies of pyridazine and pyrazine are 32 070 ± 80 cm-1 and 32 675 ± 60 cm-1, respectively, in good agreement with the corresponding I-MM/QM results of 32 540 ± 80 cm-1 and 32 710 ± 60 cm-1 and the experimental results of 33 450-33 580 cm-1 and 32 700-33 300 cm-1. For the 15N magnetic shielding, the corresponding numbers for the gas-water shifts obtained with PCM-MM/QM are 47.4 ± 1.3 ppm for pyridazine and 19.7 ± 1.1 ppm for pyrazine, compared with the I-QM/MM values of 53.4 ± 1.3 ppm and 19.5 ± 1.2 ppm and the experimental results of 42-54 ppm and 17-22 ppm, respectively. The agreement between the two procedures is found to be very good and both are in agreement with the experimental values. PCM-MM/QM approach gives a good solute polarization and could be considered in obtaining reliable results within the expected QM/MM accuracy. With this electronic polarization, the solvent effects on the electronic absorption spectra and the 15N magnetic shielding of the diazines in water are well described by using only an electrostatic approximation. Finally, it is remarked that the experimental and theoretical results suggest that the 15N nuclear magnetic shielding of any diazine has a clear dependence with the solvent polarity but not directly with the solute-solvent hydrogen bonds. [ABSTRACT FROM AUTHOR]

The self-diffusion coefficients D for water, benzene, and cyclohexane are determined by using the pulsed-field-gradient spin echo method in high-temperature conditions along the liquid branch of the coexistence curve: 30–350 °C (1.0–0.58 g cm-3), 30–250 °C (0.87–0.56 g cm-3), and 30–250 °C (0.77–0.48 g cm-3) for water, benzene, and cyclohexane, respectively. The temperature and density effects are separated and their origins are discussed by examining the diffusion data over a wide range of thermodynamic states. The temperature dependence of the self-diffusion coefficient for water is larger than that for organic solvents due to the large contribution of the attractive hydrogen-bonding interaction in water. The density dependence is larger for organic solvents than for water. The difference is explained in terms of the van der Waals picture that the structure of nonpolar organic solvents is determined by the packing effect due to the repulsion or exclusion volumes. The dynamic solvation shell scheme [K. Yoshida et al., J. Chem. Phys. 127, 174509 (2007)] is applied for the molecular interpretation of the translational dynamics with the aid of molecular dynamics simulation. In water at high temperatures, the velocity relaxation is not completed before the relaxation of the solvation shell (mobile-shell type) as a result of the breakdown of the hydrogen-bonding network. In contrast, the velocity relaxation of benzene is rather confined within the solvation shell (in-shell type). [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) have become a promising alternative to molecular organic solvents and ionic liquids in a variety of scientific applications. Their customizable physicochemical properties make them attractive for extraction, catalysis, electrochemistry and drug delivery. Recently, the study of not so much DES themselves, as their mixtures with water, has attracted particular interest. In this study, six widely used DESs based on choline chloride and carboxylic acids (citric, tartaric, malic, glycolic, malonic and lactic) with a water content of 0–50 wt% were analyzed. Properties such as density, viscosity, conductivity and spectral properties of DES (IR spectroscopy and refractive index) were studied. The results show that in the entire range of water content under study, there are no abrupt changes in properties for all the studied parameters, which allows us to conclude that water is gradually incorporated into the DES structure without its destruction. However, within this class of eutectic solvents, subclasses can be distinguished, due to various changes in the studied properties. These results provide important information for optimizing the performance of DES in practical applications and highlight their potential as sustainable green solvents in modern science and technology. [Display omitted] • Density, viscosity, conductivity of DESs based choline chloride and carboxyl acids and water were investigated. • The water is gradually incorporated into the DES structure without its decomposition. • DESs can be divided into two subclasses: Newtonian and non-Newtonian, based on their rheological properties. • Two subclasses of eutectic solvents can be identified based on the number of functional groups in the original acids. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solubility and solvation thermodynamics of L-phenylalanine in aqueous-EG/DMF/DMSO/ACN were investigated. • Solvents parameters are calculated and used to explain solvation parameters. • Explained weak force interactions between solute and solvent, including cavity formation and solvent–solute interactions. • Transfer chemical transfer Gibbs energies and entropies were discussed. • L-phenylalanine solubility was shown in comparative way in complex solvent environments. This research elucidates comprehensive insights into the dissolution nature and solvation energetics of L-phenylalanine across distinct solvent environments. Specifically, the investigation encompasses saturated solubility measurements and the subsequent derivation of overall transfer free energies (Δ G t 0 (i)) and entropies (Δ S t 0 (i)) at 298.15 K, of L-phenylalanine from an aqueous medium to aqueous solutions comprising protic ethylene glycol (EG), dipolar aprotic N,N -dimethylformamide (DMF), acetonitrile (ACN), and dimethyl sulfoxide (DMSO). In this study the 'gravimetric method' was used to find the saturated solubilities of L-phenylalanine at five equidistant temperatures (288.15 K to 308.15 K). These experimental solubility measurements serve as the foundational dataset for the subsequent determination of transfer energies. The investigated drenched or equilibrium solubility data was applied to ascertain the solvation energies. In case of pure solvent, we get the solubility trend of L-phenylalanine as follows: ACN < DMSO < DMF < EG < water, at any temperature. At 298.15 K, we found the solubilities of L- phenylalanine in pure solvents like water, EG, DMF, DMSO and ACN are 0.1675, 0.0911, 0.0888, 0.0850 and 0.0811 mol·kg−1 respectively. A pivotal facet of this study involves the examination of the correlation between the saturated solubility of L-phenylalanine and the intricate characteristics of its solvation energetics across diverse aqueous organic solvent systems. [ABSTRACT FROM AUTHOR]

A novel aptamer-based adsorbent was prepared for the magnetic solid-phase extraction of tetracycline. The Fe3O4/aptamer adsorbent was fabricated by immobilizing an aptamer on the surface of Fe3O4 magnetic nanoparticles by the reaction between avidin and biotin. The parameters affecting the isolation efficiency such as the pH, extraction time, extraction temperature, eluent, and elution time were investigated in detail. Under the optimal conditions, a linear relationship between the peak area and the concentration of tetracycline was observed in the range from 10.0 to 3000.0 µg L−1 with a correlation coefficient of 0.9985 and a limit of detection of 2.5 µg L−1. The developed method was successfully employed for the determination of tetracycline in honey and water samples with recovery values from 82.9 to 107.3% and relative standard deviations less than 7.6%. Compared with previously reported methods for the determination of tetracycline, the proposed protocol provides improvements in the limit of detection and specificity with reduced consumption of adsorbent and organic solvents. [ABSTRACT FROM AUTHOR]

Novel nanoscale lanthanide and mixed lanthanide metal-organic frameworks with thermo-sensitive polymer as organic links were successfully prepared. They were obtained through biomimetic mineralization approach. This is the first report of fabrication of polymer-metal-organic frameworks via biomimetic mineralization. The particle size was in the range from 200 to 500 nm. The photoluminescent properties of the materials have also been studied. The fluorescence intensity changed in different solvent (N, N -dimethylformamide, tetrahydrofuran, ethanol, acetone, dichloromethane, water), so solvent recognition can be achieved by using the polymer-metal-organic frameworks. The materials are also very sensitive to water (even trace water) in the mixed solutions composed of water and organic solvents. Especially the mixed lanthanide polymer-metal-organic frameworks can be designed to a ratiometric fluorescent nanosensor. The novel fluorescence detection materials have very important potential applications in the field of chemical industry. Image 1 • Novel nanoscale poly-LnMOFs were successfully obtained within several seconds. • The poly-LnMOFs were prepared via biomimetic mineralization approach. • The poly-LnMOFs can be used for solvent recognition and water detection. [ABSTRACT FROM AUTHOR]

In this paper, a biocatalytic route is described wherein PPL, lipase from porcine pancreas, in conjunction with water on reaction with different thiophenols and styrene oxides undergo thiolysis with C-S bond formation without the use of any metal catalysts, oxidants, bases, additives or organic solvents towards formation of β-hydroxysulfides in good to excellent yields with high regioselectivity at room temperature. Furthermore, PPL also facilitates thiophenols to undergo hydrothiolation with styrenes or phenylacetylenes in sole water and thus forming linear thioethers or vinylsulfides respectively via C–S bond formation. In addition to the straightforward and atom-efficient protocol, a gram-scale synthesis of β-hydroxysulfide and recyclability for three consecutive cycles without decrease in efficiency of PPL make our biocatalytic protocol for constructing C–S bond highly valuable from both environmental and economic viewpoints than traditional chemical practices. [ABSTRACT FROM AUTHOR]

Although graphene oxide (GO) lamellar membranes have emerged as attractive candidate of membrane technology for advanced molecular separation in water treatment, their organic solvent nanofiltration performance is significantly limited by almost impermeability of organic solvents through GO membranes. Here, we present a two-dimensional (2D) GO/MXene (GM) composite lamellar membrane fabricated by facile vacuum filtration method for ultrafast water and organic solvent permeation and molecular separation. Benefiting from the similar 2D structure and hydrophilic property of MXene nanosheets with GO, the resultant GM membranes possessed typical lamellar structure with increased interlayer spacing compared to GO membranes and excellent surface wettability to water and organic solvents. The effects of MXene content on the structure, solvent permeation and molecular separation performance of GM membranes were systematically investigated. The GM membranes exhibited ultrahigh flux for pure solvents (21.02, 48.32, 25.03, 10.76, 6.18 L/m2h for water, acetone, methanol, ethanol and IPA) and outstanding dyes molecular separation performance (over 90%) in both aqueous and organic solutions. The relationship between solvent viscosity, dyes solubility and separation performance of GM membranes was further demonstrated. Moreover, long-term operation studies also revealed the stability of GM membranes with the different solvents and indicated their potential for practical applications. Image 1 • GM composite membranes have been successfully fabricated by a facile vacuum filtration method. • GM membranes possess lamellar structure excellent surface wettability to water and organic solvents. • GM membranes exhibit excellent balanced separation performance for both aqueous and organic solution. • GM membranes show good long term operation stability and are applicable for a series of dyes. [ABSTRACT FROM AUTHOR]

The enthalpies of l -glutamine dissolution in an aqueous solution of acetamide, N -methylacetamide, and N, N -dimethylacetamide were determined by the calorimetric method at T = 298.15 K and organic solvent mole fractions up to x 2 ~ 0.25. The standard enthalpies of solution (Δ sol H °) and transfer (Δ tr H °) of l -glutamine from water to a mixed solvent as well as the enthalpy coefficients of pairwise interactions (h xy) were calculated. The interrelation between enthalpic characteristics of l -glutamine dissolution (transfer) and the composition of water-organic mixtures was determined. The received thermochemical characteristics of intermolecular interactions of l -glutamine with the molecules of acetamides were compared with the analogous characteristics interactions of l -glutamine with the molecules of formamides (formamide, N -methyformamide, and N , N -dimethylformamide). Unlabelled Image • Enthalpies of l - glutamine dissolution have been measured in aqueous acetamides. • Dependence of Δ sol H ° of l - glutamine dissolution on the mixture composition is established. • Results are compared with similar for formamides. • The enthalpic contribution of l - glutamine side chain to h xy was determined. [ABSTRACT FROM AUTHOR]

Here we report a new sensor Tb97.11Eu2.89-L1 that enables ratiometric detection of trace water in CH3CN. As the water content increases from 0% to 2.5% (v/v%), Tb97.11Eu2.89-L1 exhibits an excellent linear relationship between the water content and I543/I615, as well as variable emissive light colors visible to the naked eye. [ABSTRACT FROM AUTHOR]

The time‐dependent emission enhancement (TDEE) phenomena of the 1‐(o‐carboran‐1‐yl)ethynylpyrene dyad were reported. It was found that the emission intensity from the dyad increased in tetrahydrofuran (THF), acetone and dichloromethane with increasing incubation time. From the mechanistic studies, it was suggested that agglomeration of the dyad gradually proceeded in these media, followed by expression of excimer luminescence. Additionally, it was shown that the rates of TDEE of the dyad were sensitively accelerated in the presence of a trace amount of water. Based on this fact, a detection system for water contents in acetone was constructed. Before and after incubation for 96 h at room temperature, time courses of changes in optical properties were monitored. Finally, water contents in acetone can be estimated by the degrees of TDEE and emission color changes in the range from 0.1 wt % to 2.0 wt % and from 2.0 wt % to 20 wt %, respectively. [ABSTRACT FROM AUTHOR]