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Deep Eutectic Solvents (DESs) are a class of solvents that are increasing their relevance in the research activity thanks to their environmental-friendly features as well as to their structural characteristics and catalytic properties. Formed by no-solvent mixing of two substances, namely a hydrogen bond donor and a hydrogen bond acceptor, DESs are finding fruitful applications in many different topics as alternatives to common organic compounds. In this work the realization, the characterization and the solubility applications of a novel water- based class of DESs are proposed. These innovative liquids, called aquo-DESs, are binary mixtures of water with glycolic acid (GA) and with trimethylglycine (TMG): GA/H2O (1/4 molar ratio) and TMG/H2O (1/5 molar ratio). The DES identity of these mixtures was demonstrated by: shifts both in terms of the molar fraction and of the melting points in the experimental melting point curves from the theoretical ones; amounts of components over their reported maximum solubility in water; thermogravimetric profiles compared to the pure substances. The aquo-DESs were characterized in their viscosity and ionic conductivity in the temperature range 20-55 C, showing really low viscosity and low ionic conductivity, with a peculiar behavior of the ionic conductivity of GA/H2O DES. The solubilizing properties of aminoacids, phenols and carboxylic acids showed peculiar really high values whenever the solute can participate to the DES as DES component itself.

Development of a simple method to efficiently immobilize lipase ensuring its stability and activity in water even at high temperatures.

One aspect of heritage science is to examine and, if possible, reduce the chemical and physical interactions between the restoration products and artworks’ constituent materials. This research aims to identify an alternative process to minimize the impact on materials and health risk for users when hypochlorite is used as biocide on stone materials. In this study, we tested a hydrogel comprised of sodium alginate as an inert matrix and hypochlorite ions as biocide agents for the removal of biological patinas from calcarenite Lecce samples. These biofilms resulted formed mainly by filamentous cyanobacteria and green microalgae. We carried out 1H-NMR T2 relaxation measurements to check the hydrogel’s cleaning efficacy on artificially bio-deteriorated samples through a portable NMR equipment. Simultaneously, optical microscopy and colorimetric measurements allowed the establishment of color differences induced by treatments. Our biocide hydrogel proved to be effective in removing microbial colonization from the surface of Lecce stone specimens and from a section of an altar rail in the rupestrian Church of San Pietro Barisano, located in the “Sassi of Matera”.

Deep Eutectic Solvents (DESs) are increasing their relevance thanks to their ecologically favourable properties, their interesting structural features and their catalytic properties. In this paper we present three novel hydrophobic DESs mixtures prepared by mixing thymol with water, with urea and with phenylacetic acid. These natural DESs represent important advances in the development of green DESs liquids: Thymol/Water mixture is the first binary, water-based DES with hydrophobic properties; in Thymol/Urea DES, urea and its chelating properties were put in a water-separable phase; finally, Thymol/Phenylacetic acid DES is a mixture of two hydrogen-bond donor molecules showing hydrophobic and slightly acidic properties. The hydrogen bond properties within the different mixtures were investigated via DFT, while ab initio molecular dynamics results showed a substantial interaction between thymol and water in the Thymol/Water DES. Moreover, the investigated DESs show excellent extraction properties of heavy metal salts and phenols from aqueous phases.

Two symmetric quadrupolar cationic push-pull compounds with a central electron-acceptor (N+-methylpyrydinium, A+) and different lateral electron-donors, (N,N-dimethylamino and N,N-diphenylamino, D) in a D-π-A+-π-D arrangement, were investigated together with their dipolar counterparts (D-π-A+) for their excited-state dynamics and NLO properties. As for the quadrupolar compounds, attention was focused on excited-state symmetry breaking (ESSB), which leads to a relaxed dipolar excited state. Both electron charge displacements and structural rearrangements were recognized in the excited-state dynamics of these molecules by resorting to femtosecond-resolved broadband fluorescence up-conversion experiments and advanced data analysis, used as a valuable alternative approach for fluorescent molecules compared to time-resolved IR spectroscopy, only suitable for compounds bearing IR markers. Specifically, intramolecular charge transfer (ICT) was found to be guided by ultrafast inertial solvation, while diffusive solvation can drive the twisting of lateral groups to originate twisted-ICT (TICT) states on a picosecond time scale. Yet still, only the bis-N,N-diphenylamino-substituted compound undergoes ESSB, in both highly and sparingly polar solvents, provided that it can experience large amplitude motions to a fully symmetry-broken TICT state. Besides well-known solvation effects, this structural requirement proved to be a necessary condition for these quadrupolar cations to undergo ESSB. In fact, a more efficient uncoupling between the out-of-plane D and A+ groups in the TICT state allows a greater stabilization gained through solvation, relative to the bis-N,N-dimethylamino-substituted derivative, which instead maintains its symmetry. This different behavior parallels the two-photon absorption (TPA) ability, which is greatly enhanced in the case of the bis-N,N-diphenylamino-substituted compound, paving the way for cutting-edge bio-imaging applications.

Deoxydehydration (DODH) reaction of glycerol (GL) and 1,2-propanediol (1,2-PD), in ionic liquids (ILs), catalyzed by methyltrioxorhenium (MTO) and Re

The synergistic catalytic effect of surfactants is highlighted in the photodegradation of Orange G and Eosin Y by TiO2 at alkaline pH.

Photochromic compounds are employed in implementing neuron surrogates. They will boost the development of neuromorphic engineering in wetware. In this work, the photochromic behaviours of (E)-3,4,6-trichloro-2-(p-diazenil)-phenol (t-DZH) and its conjugated phenoxide base (t-DZ) have been investigated experimentally in three different media: (1) pure acetonitrile, (2) in water and acetonitrile mixed in a 1/1 volume ratio, and (3) in an aqueous micellar solution of 3-(N,N-Dimethylmyristylammonio)propanesulfonate (SB3-14). The analysis of the spectral and kinetic features of t-DZH and t-DZ has been supported by quantum-mechanical DFT calculations, the maximum entropy method, and the determination of their colourability (C). The versatility of t-DZH and t-DZ makes them promising molecular probes of micro-environments and potential ingredients of photochemical oscillators required for implementing pacemaker neurons capable of communicating through optical signals in wetware.

Deep Eutectic Solvents (DESs) are experiencing growing interest as substitutes of polluting organic solvents for their low or absent toxicity and volatility. Moreover, they can be formed with natural bioavailable and biodegradable molecules, they are synthesized in absence of hazardous solvents. DESs are, inter alia, successfully used for the extraction/preconcentration of biofunctional molecules from complex vegetal matrices. Onion skin is a highly abundant waste material which represents a reservoir of molecules endowed with valuable biological properties such as quercetin and its glycosylated forms. An efficient extraction of these molecules from dry onion skin from “Dorata di Parma” cultivar was obtained with water dilution of acid-based DESs. Glycolic acid (with betaine 2/1 molar ratio and L-Proline 3/1 molar ratio as counterparts) and of p-toluensulphonic acid (with benzyltrimethylammonium methanesulfonate 1/1 molar ratio)-based DESs exhibited more than 3-fold higher extraction efficiency than methanol (14.79 µg/mL, 18.56 µg/mL, 14.83 µg/mL vs. 5.84 µg/mL, respectively). The extracted quercetin was also recovered efficaciously (81% of recovery) from the original extraction mixture. The proposed extraction protocol revealed to be green, efficacious and selective for the extraction of quercetin from onion skin and it could be useful for the development of other extraction procedures from other biological matrixes.

The environmental impact of chemical applications can be reduced by using novel solvents with green properties. In this field, Deep Eutectic Solvents (DESs) are promising liquids thanks to their low toxicity, high eco-compatibility and high easiness and “greenness” of preparation. DESs are mixtures of a hydrogen bond donor molecule (HBD) and a hydrogen bond acceptor molecule (HBA) at the proper molar ratio. In this paper, we present the preparation of novel hydrophobic deep eutectic solvents and the studies of their properties: density, eutectic profiles, ranges of water separation, contamination of the separated phases, extraction capabilities of phenol model polluting molecules, capabilities of extraction at acidic and basic conditions. Interesting results emerged about the role of the components of the DESs because of the use of a properly-chosen set of liquids. Their capabilities were dependent on the nature of the HBD molecule, and in particular on its hydrophobicity. Even the DESs with highly water-soluble HBA showed to be easily separable from water and really efficacious as extracting agents when prepared with hydrophobic HBDs. The results of the extractions of pollutants in acid and basic conditions showed the capability of water separation and extraction efficiency of these mixtures even with water at pH = 2 and pH = 9; therefore, the phenols could interact with these liquids without involvement of any acid/base-type of interactions.

The hydrogel obtained by a zwitterionic N-oxide surfactant is proposed as the core of a pH-responsive artificial gland model. The viscosity and pH variations, induced by pulse additions of acid and...

The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis.

To address the problem of the biodeterioration of stone monuments by developing innovative methodologies, two new alginate hydrogels were obtained by using titanium dioxide as photoactivatable biocide and sodium dichloroisocyanurate as reservoir of hypochlorous acid. The effectiveness of both hydrogels in removing the biological patina on artificially colonized Lecce stones without altering the properties of the treated substrates was demonstrated by measurements of light microscopy, colorimetry, SEM/EDS analyses and 1H-NMR relaxometry. The biocidal activity of the new developed hydrogels has been also tested on natural cyanobacterial biofilms collected in Roman Catacombs and grown on agar medium and on calcareous stones. The results are very promising with the complete inhibition of cyanobacterial photosynthesis and without any side effects on the substrates tested.

The role of tetraalkylammonium bromide surfactants on the TiO2 photocatalyzed degradation of Alizarin, Purpurin and Bromothymol Blue has been studied in air-equilibrated aqueous medium under UV light irradiation. Alizarin has also been investigated by carrying out the photodegradation in TiO2/surfactant dispersions irradiated by natural solar light. Absorption spectral analysis showed that the photodegradation efficiency of the dyes was significantly enhanced by the addition of the cationic surfactants. The effect of pre-micellar, micellar and post-micellar concentrations of the surfactants was analyzed to gain insight into the mechanism of the surfactant-assisted TiO2-photocatalytic degradation of the three dyes. The findings revealed that various parameters, such as initial pH, dye pK’s, type of water and light source exerted their influence on the photocatalytic degradation. The results were explained on the basis of hydrophobic and electrostatic interactions between dye and surfactant/TiO2 in the various forms of aggregation. Density functional theory (DFT) calculations of charge distribution and Gibbs free energy changes of solvation of the species involved were used as a support in rationalizing the surfactant effect on the photodegradation process.

The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs. In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes. The appraisal of a different local heterogeneity, depending on either the nature of the DES or the amount of added water, was also supported by the maximum entropy method (MEM) applied to the fluorescence decay kinetics, which gave clear indications about the different micro-heterogeneity of the DES systems.

To improve the loadability and antioxidant properties of wool impregnated with onion skin extract, the introduction of SB3-14 surfactant in the dyeing process was evaluated. A preliminary investigation on the surfactant&ndash, quercetin interaction indicated that the optimal conditions for dye solubility, stability, and surfactant affinity require double-distilled water (pH = 5.5) as a medium and SB3-14 in a concentration above the c.m.c. (2.5 &times, 10&minus, 3 M). The absorption profile of textiles showed the flavonoid absorption band (390 nm) and a bathochromic feature (510 nm), suggesting flavonoid aggregates. The higher absorbance for the sample dyed with SB3-14 indicated greater dye uptake, which was further confirmed by HPLC analysis. The Folin&ndash, Ciocalteu method was applied to evaluate the total phenol content (TPC) released from the treated wool, while the assays FRAP, DPPH, ABTS, and ORAC were applied to evaluate the corresponding total antioxidant activity (TAC). Higher TPCs (about 20%) and TACs (5&ndash, 55%) were measured with SB3-14, highlighting textiles with improved biofunctional properties. Spectrophotometric analyses were also performed with an artificial sweat. The potential cytotoxic effect of SB3-14 in both monomeric and aggregated forms, cell viability, and induction of apoptosis were evaluated in RAW 264.7 cells. These analyses revealed that SB3-14 is safe at concentrations below the c.m.c.

To improve the loadability and antioxidant properties of wool impregnated with onion skin extract, the introduction of SB3-14 surfactant in the dyeing process was evaluated. A preliminary investigation on the surfactant–quercetin interaction indicated that the optimal conditions for dye solubility, stability, and surfactant affinity require double-distilled water (pH = 5.5) as a medium and SB3-14 in a concentration above the c.m.c. (2.5 × 10−3 M). The absorption profile of textiles showed the flavonoid absorption band (390 nm) and a bathochromic feature (510 nm), suggesting flavonoid aggregates. The higher absorbance for the sample dyed with SB3-14 indicated greater dye uptake, which was further confirmed by HPLC analysis. The Folin–Ciocalteu method was applied to evaluate the total phenol content (TPC) released from the treated wool, while the assays FRAP, DPPH, ABTS, and ORAC were applied to evaluate the corresponding total antioxidant activity (TAC). Higher TPCs (about 20%) and TACs (5–55%) were measured with SB3-14, highlighting textiles with improved biofunctional properties. Spectrophotometric analyses were also performed with an artificial sweat. The potential cytotoxic effect of SB3-14 in both monomeric and aggregated forms, cell viability, and induction of apoptosis were evaluated in RAW 264.7 cells. These analyses revealed that SB3-14 is safe at concentrations below the c.m.c.

In this work, chitosan-succinic acid membranes were prepared by casting method and the physicochemical and mechanical properties of non-neutralized and neutralized with NaOH films were compared. Mechanical strength, flexibility, thermal stability and water-vapor permeability of chitosan membranes are significantly improved after neutralization. These improvements could be partly ascribed to the use of a dicarboxylic acid, which decreases the spacing between chitosan chains as a consequence of ionic crosslinking. Moreover, the addition of the strong base to the hydrogel promotes the formation of amide bonds, as suggested by FTIR analysis and demonstrated by acid-base titration. The favorable features of chitosan-succinic acid films as well as the possibility to easily incorporate drugs, enzymes, essential oils or other additives in the hydrogel, make such membranes suitable for many applications.

The impact on the environment of polluting and volatile organic solvents represents nowadays a severe problem. In order to reduce the incidence on the environment of chemical applications, Deep Eutectic Solvents (DESs) represent a step ahead in this field thanks to their green properties. These novel liquids are formed by inter- and intra-molecular weak interactions between two species and they are synthesized by simply heating and mixing them without any solvent. These solvents also show interesting catalytic capabilities, since their properties are truly tuneable. In this paper, l-Proline-based Chiral Deep Eutectic Solvents (CDESs) were prepared and used as green and organocatalytic reaction media in a probe asymmetric Michael addition; in this reaction the l-Proline acts as solvent component as well as chiral organocatalyst. The results were analysed with NMR studies taking in account the availability of the l-Proline, considering the strength of the association of it with the counterpart of the liquids. With DFT studies, the geometry and energy of the adducts are shown and a qualitative rationale to the reaction stereoisomers distribution is given. This work was supported by the University of Pisa through the PRA_2018_36 grant, and by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN, PGC2018-096616-B-I00) and the University of Alicante (VIGROB-173).

The self-assembling of the 10-methylacridinium perchlorate fluorophore and azathiocrown ether derivative receptor through sodium dodecyl sulfate (SDS) or sodium 4-octylbenzenesulfonate (SOBS) aggregates in water has allowed the realization of a new effective sensing system for Hg2+ ions. In the absence of metal ions, occurrence of the fluorophore-receptor interaction was signaled through the fluorescence quenching of acridinium. Upon addition of increasing quantities of Hg2+, fluorescence experiments pointed out an unusual further quenching of the acridinium fluorescence, followed by an emission enhancement with a switching point around 1 × 10−7 and 1 × 10−8 M in SDS and SOBS, respectively. Such a behavior was attributed to the formation of mercury-receptor complexes with different coordination number and accordingly with distinct redox activity. The stoichiometry of the mercury complexes was assessed by spectrophotometric titration, while insights into their structures were obtained with density functional theory (DFT) calculation. Hg2+ ions can be selectively detected in SDS solutions, and its concentration in the nanomolar range can be linearly determined. Altogether, this modular approach allows quick variation of the components, which makes the optimal tuning of the process up to its maximum efficiency level very easy.

A new OFF-ON fluorescent chemosensor for ions Hg2+ in water has been designed by associating fluorophore 10-methylacridinium perchlorate (MA+ClO4−) with a selective lipophilic sulfur-containing ligand, such as N,N-bis (2-hydroxyethylthio-1-ethyl)dodecyl amine (DBSO). The communication between the two subunits is only due to their spatial closeness, ensured by sodium dodecyl sulfate (SDS) micellar aggregates. The quenching of MA+ fluorescence is ascribed to a photoinduced electron-transfer from the ligand to the excited fluorophore, still the emission is quickly restored by addition of Hg2+ (as chloride salt) due to the complex formation between ligand and metal. The sensitivity of the system improves by decreasing the ligand concentration, as well as by changing the stoichiometry of the ligand-Hg2+ complex from 1:1 to 2:1. DFT calculations give interesting insights into the structures of the complexes and provide useful information on the sensorial activity experimentally observed. The replacement of MA+ClO4− with 9-cyanoanthracene, a fluorophore differently localized on the micellar aggregate, highlights the effect of Cl− coordination to the complexed Hg2+ on the operating mechanism of the sensor. These results demonstrate as the micellar aggregates provide for a straightforward means to regulate the response of the sensorial system without altering the recognition or reporter unit.

A number of quaternary ammonium salts with bulky hydrophobic moieties are known to provoke the superactivation of α-chymotrypsin (α-CT) in aqueous solution. In particular, benzyl-substituted ammonium and dicationic ammonium-based salts have recently emerged as promising classes of compounds to induce α-CT superactivation and stabilization. Preliminary in silico modelling suggested the α-CT residue tryptophan 215 to be the major anchor point of these additives. In order to achieve a broader knowledge of the enzyme–additive interactions and to validate the modelling studies, new ammonium-based additives were designed and tested. The hydrophobic interaction resulted in being critical to improving superactivation, with [(2,3,5,6-tetramethyl-p-phenylene)dimethylene]bis[triethylammonium bromide] (bisEDuEAB) resulting as the most effective quaternary ammonium superactivating agent studied so far. Finally, a general agreement between in silico outcomes and kinetic parameters was observed, and data interpretation is discussed based on the proposed α-CT/additive binding modes.

The search for innovative and green reaction media is a prominent topic in the recent research in chemistry. Deep Eutectic Solvents (DESs) are currently gaining relevance in this field thanks to their unique properties in terms of their “greenness” as well as in terms of their catalytic properties. In this work we developed an efficient protocol for the conjugate aza-Michael addition of amines to 2-vinylpyridine using 14 differently structured acid DESs as both reaction media and catalysts, so preventing the use of other acid additives. The results are influenced by the acidity of the components of the DESs, showing the best results with weak acids in the DESs components, with isolated yields up to 86%. The aza-Michael reaction is a widely used synthetic route for the C–N bond formation in organic synthesis. In particular, the addition of amines to 2-vinylpyridine is used for the realization of pharmaceutically relevant compounds with anticancer, antiarrhythmic, and analgesic properties. Comparing the results with the ones observed in literature for the same reaction, this procedure revealed to be a convenient and efficient method for this relevant transformation.

This work is an important contribution to the development of neuromorphic engineering based on solutions of nonlinear chemical systems. It reports the results of experiments and simulations regarding the optical communication between the Belousov-Zhabotinsky reaction and photochromic and luminescent materials. It demonstrates that thermally reversible photochromic and luminescent compounds are dynamic models of phasic photo-excitable neurons. Moreover, it shows that photo-reversible photochromic compounds can be used for the implementation of optical synapsis and memory effects. Finally, it reports the first example of transmission of a chaotic signal between a Hydrodynamic Photochemical Oscillator based on a photochromic naphthopyran and a luminescent acridinium salt.

We have measured the diffusion coefficients, D, of aqueous micelles formed by cetyltriethyl-, cetyltripropyl- and cetyltributyl-ammonium bromides (CTEABr, CTPABr and CTBABr, respectively) and cetyltriethyl- and cetyltripropyl-ammonium hydroxides (CTEAOH and CTPAOH, respectively) by dynamic light scattering (DLS) at several temperatures from 15 to 55 °C and a range of surfactant (0.01–0.05 M) and salt (0.02–0.06 M NaBr; 0.05–0.3 M NaOH) concentrations. From values of D, we derived the respective fractional ionization values of micellar surfaces. For surfactants with bromide counterion we obtained fits of the diffusivity data using the linear interaction/DLVO approach, thus yielding estimates of the micellar hydrodynamic radius, Rh, and the micellar fractional ionization, α, which ranged from 0.26 to 0.35. For CTEAOH and CTPAOH, the fits appeared to be poorly sensitive to changes in the London-Van der Waals interactions, as expressed by the Hamaker constant, and only a large fractional ionization could account for the observed diffusivities.

Hypothesis Clathrate hydrates of hydrogen form at relatively low pressures (e.g., ca. 10 MPa) when a co-former compound is added. In that case, however, the gravimetric amount of stored hydrogen drops to less than 1 wt% from ca. 5.6 wt% without a co-former. Another factor hindering the entrapment of hydrogen into a clathrate matrix appears to be of a kinetic origin, in that the mass transfer of hydrogen into clathrates is limited by the macroscopic scale of the gas–water interfaces involved in their formation. Thus, the enhanced formation of binary (hydrogen + co-former) hydrates would represent a major achievement in the attempt to exploit those materials as a convenient means for storing hydrogen. Experiments Here, we present a simple process for the enhanced formation of binary hydrates of hydrogen and several co-formers, which is based on the use of reverse micelles for reducing the size of hydrate-forming gas–water interfaces down to tens of nanometers. This reduction of particle size allowed us to reduce the kinetic hindrance to hydrate formation. Findings The present process was able to (i) enhance the kinetics of the formation process; and (ii) assist clathrate formation when using water-insoluble coformers (e.g., cyclopentane, tetrahydrothiophene).

Introduction For the determination of harpagoside and the wide phenolic pattern in Harpagophytum procumbens root and its commercial food supplements, dispersive liquid–liquid microextraction (DLLME), ultrasound-assisted DLLME (UA-DLLME), and sugaring-out liquid–liquid extraction (SULLE) were tested and compared. Objectives In order to optimise the extraction efficiency, DLLME and UA-DLLME were performed in different solvents (water and aqueous solutions of glucose, β-cyclodextrin, (2-hydroxypropyl)-β-cyclodextrin, sodium chloride, natural deep eutectic solvent, and ionic liquid). Material and Methods The plant material was ground and sieved to obtain a uniform granulometry before extraction. Commercial food supplements, containing H. procumbens are commercially available in Italy. Results The most effective sodium chloride-aided-DLLME was then optimised and applied for analyses followed by HPLC-PDA. For comparison, microwave-assisted extraction was performed using the same solvents and the best results were obtained using 1% of β-cyclodextrin or 15% of sodium chloride. Conclusion All commercial samples respected the European Pharmacopoeia monograph for this plant material, showing a harpagoside content ≥ 1.2%. Copyright © 2017 John Wiley & Sons, Ltd.

Four novel Deep Eutectic Solvents (DESs) were prepared by mixing phenylacetic acid (which is a natural molecule present in honey) with amine N-oxides, which are molecules easily biodegradable in nature. Three of these N-oxides are amphiphilic. The novel DESs have very low freezing points (from − 34 °C to 20 °C) and they have very low viscosity, much lower than the most common and used DES in literature so far (choline chloride/urea mixture). The conductivity values resulted low and the ionicity analysis showed these DESs to be “super ionic”. Their polarity resulted high enough and it can be compared with other commonly used solvents or ionic liquids.

The TiO 2 photocatalyzed degradation of a hazardous texile dye, 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt (Alizarin Red-S, ARS), has been assisted by various cationic surfactants and examined in air-equilibrated aqueous medium under UV light irradiation. Absorption spectral analysis showed that ARS degrades slowly via a pH-dependent process in TiO 2 dispersions containing no surfactant. The photodegradation efficiency of the dye was significantly enhanced, especially in alkaline media, by the addition of surfactants such as cetyltrialkylammonium salts (CTRAX). Since both ARS and the TiO 2 surface are negatively charged in basic conditions, the addition of cationic surfactants has effectively allowed the mutual interaction among the dye, CTRAX and TiO 2 . The cooperation between the inorganic and organic components, which is very likely realized through the formation of cationic surfactant bilayers on the TiO 2 particles, permitted an improvement in the coadsorption of ARS onto the TiO 2 particles and thus rendering ARS more available to the action of the photo-yielded oxidative species formed on the semiconductor surface. The crucial influence of the surfactant adsorption was clearly pointed out by the investigation of the counterion effect on the degree of ARS photodecomposition as a function of the cetyltrimethylammonium salt (CTAX) concentration. Two particularly significant aspects have emerged from this investigation: the almost complete degradation of ARS was achieved, for all surfactants used, at a concentration close to 1 mM (value well above the cmc in the experimental conditions); also, by increasing the surfactant concentration, the photocatalytic reaction became less and less efficient and significantly dependent on the counterion nature. These results have allowed to gain insight and a better understanding of the surfactant-assisted photocatalytic degradation mechanism of the dye.

Background: Galium is a plant rich in iridoid glycosides, flavonoids, anthraquinones, and small amounts of essential oils and vitamin C. Recent works showed the antibacterial, antifungal, antiparasitic, and antioxidant activity of this plant genus. Methods: For the determination of the multicomponent phenolic pattern, liquid phase microextraction procedures were applied, combined with HPLC-PDA instrument configuration in five Galium species aerial parts (G. verum, G. album, G. rivale, G. pseudoaristatum, and G. purpureum). Dispersive Liquid&ndash, Liquid MicroExtraction (DLLME) with NaCl and NAtural Deep Eutectic Solvent (NADES) medium and Ultrasound-Assisted (UA)-DLLME with &beta, cyclodextrin medium were optimized. Results: The optimal DLLME conditions were found to be: 10 mg of the sample, 10% NaCl, 15% NADES or 1% &beta, cyclodextrin as extraction solvent&mdash, 400 &mu, L of ethyl acetate as dispersive solvent&mdash, 300 &mu, L of ethanol, vortex time&mdash, 30 s, extraction time&mdash, 1 min, centrifugation at 12000&times, g for 5 min. Conclusions: These results were compared with microwave-assisted extraction procedures. G. purpureum and G. verum extracts showed the highest total phenolic and flavonoid content, respectively. The most potent extract in terms of antioxidant capacity was obtained from G. purpureum, whereas the extract obtained from G. album exhibited the strongest inhibitory effect against tyrosinase.

The monocarbonyl analogue of curcumin (1E,4E)-1,5-Bis(2-methoxyphenyl)penta-1,4-dien-3-one (C1) has been used as a specific activator of the master gene transcription factor EB (TFEB) to correlate the activation of this nuclear factor with the increased activity of lysosomal glycohydrolases and their recruitment to the cell surface. The presence of active lysosomal glycohydrolases associated with the lipid microdomains has been extensively demonstrated, and their role in glycosphingolipid (GSL) remodeling in both physiological and pathological conditions, such as neurodegenerative disorders, has been suggested. Here, we demonstrate that Jurkat cell stimulation elicits TFEB nuclear translocation and an increase of both the expression of hexosaminidase subunit beta (HEXB), hexosaminidase subunit alpha (HEXA), and galactosidase beta 1 (GLB1) genes, and the recruitment of &beta, hexosaminidase (Hex, EC 3.2.1.52) and &beta, galactosidase (Gal, EC 3.2.1.23) on lipid microdomains. Treatment of Jurkat cells with the curcumin analogue C1 also resulted in an increase of both lysosomal glycohydrolase activity and their targeting to the cell surface. Similar effects of C1 on lysosomal glycohydrolase expression and their recruitment to lipid microdomains was observed by treating the SH-SY5Y neuroblastoma cell line, the effects of C1 treatment were abolished by TFEB silencing. Together, these results clearly demonstrate the existence of a direct link between TFEB nuclear translocation and the transport of Hex and Gal from lysosomes to the plasma membrane.

As previously reported, quaternary ammonium salts with bulky hydrophobic portions provoke a superactivation of α-chymotrypsin in aqueous solution: this is the case of the surfactant cetyltributylammonium bromide (CTBABr) and the corresponding salt tetrabutylammonium bromide (TBABr). In order to achieve a broader knowledge of the enzyme–additive interactions, in this paper the activity and stability of α-chymotrypsin were tested in the presence of additives with slightly modified bulky ammonium groups. The effect of three additives with a benzylic group as substituent (benzyltrimethylammonium bromide (BzTMABr), benzyltributylammonium bromide (BzTBABr) and benzyldodecyldimethylammonium bromide (BzDDABr)) was investigated. A significant increase in instantaneous activity, but a deactivation of enzyme, faster than in pure buffer, was observed. Moreover, two novel dicationic salts, (1,8-bis(tributylammonium)octane dibromide (bisBOAB) and 1,4-bis(tributylammonium)xylene dibromide (bisBAB)) were designed and synthesized in order to evaluate the effect of two tributylammonium head groups with a different spacer. BisBOAB provoked superactivation and stabilization effects in a way similar to the “homologue” TBABr, but at lower concentration. In contrast, when the benzyl group was constrained within the spacer structure, the obtained superactivity was lower than in the presence of a more flexible hydrocarbon chain spacer, and enzyme deactivation was faster. Molecular modelling studies allowed us to rationalize the hypotheses derived from kinetic evidence. The results confirmed that the improvement in the catalytic properties observed in the presence of additives with a bulky, hydrophobic ammonium head group could be addressed to an increase in the overall hydrophobicity of the α-chymotrypsin catalytic site.

In this work, we present the effects of ionic and zwitterionic surfactants on the hydrolytic activity of Candida rugosa lipase (CRL), one of the most important and widely used microbial lipases. A series of amine N-oxide surfactants was studied to explore the relationship between their molecular structures and their effect on catalytic properties of CRL. These zwitterionic amphiphiles are known for their ability to form aggregates that can increase their size, thanks to a sphere–rod transition, without any additive. Enzyme activity seemed to be improved by morphological changes of micelles from spherical to rod-like, and the structure of the monomers played a crucial role in this transition. In fact, all the amine oxides investigated provoked superactivation, but the CRL activity increased by lengthening the alkyl chain of N-oxide surfactants, whereas it decreased in the presence of bulky head groups. Superactivity was mainly because of an increase in kcat (0.57 s–1 in buffer, 0.80–1.99 s–1 in surfactant ...

The potential application of some novel zwitterionic Natural Deep Eutectic Solvents, NADESs, based on betaine N,N,N-trimethylglycine and carboxylic acids (glycolic, phenylacetic and oxalic acid), has been evaluated in the synthesis of gold nanoparticles (AuNPs). AuNPs have been successfully obtained by reduction of gold(III) chloride trihydrate by ascorbic acid or sodium borohydride as reducing agents, without the use of any surfactant or capping agent. The effect of the different experimental conditions (nature of the reducing agent, temperature) has been discussed. In the NADES composed of trimethylglycine and oxalic acid, no addition of a reductant was needed because AuNPs start to form immediately after the dissolution of the precursor salt. This result may open new perspectives in fine-tuning smart solvent characteristics and developing the most appropriate NADES for an environmentally friendly metal nanoparticle synthesis without using auxiliary chemicals.

A simple ratiometric optical method for mercuric ion sensing has been developed using an ensemble of an indicator, such as 7-hydroxy-4-methylcoumarin (7H4MC) and bromothymol blue (BTB), and a receptor, such as N,N-bis(p-methoxybenzyl)-3,6-dioxaoctane-1,8-diamines (bis-pMDODA) and cryptand [2.2.2] (C222), in aqueous solution. The equilibrium between indicator and receptor is perturbed by adding Hg2+ ions (0.8–80 μM), due to the formation of a receptor-metal complex, resulting in a change of the UV/Vis spectra. Both sensitivity and selectivity are explained in terms of association constants between receptor and metal ions and equilibrium constants of the reaction between indicator and receptor. Indicator bromothymol blue has also presented a color variation from light blue to yellow upon coordination of Hg2+ to the receptor, which allows a metal naked-eye detection. The detection limit of the system was found to be about 3 μM and the relative standard deviation for five measurements of 20 μM concentration was 5.6%. BTB/7H4MC arrangement showed a particular selectivity over different interfering cations, suffering only interference from Cu2+ ions for Hg2+ sensing.

We present the realization, the use as reaction media/chiral organocatalysts/acid catalysts and the structural properties of novel chiral Deep Eutectic Solvents. These liquids are formed by mixtures of chiral HBD and HBA molecules that are common, relatively cheap and commercially available (the two enantiomers of camphorsulfonic acid as HBD) or easily one-step synthesized molecules from commercially available compounds ((S)- and (R)-N,N,N-trimethyl-(1-phenylethyl)ammonium methanesulfonate as HBA). These liquids proved to be highly-structured as showed by different yields and enantiomeric excesses observed in a probe reaction, suggesting these liquids to form diastereoisomerically different liquids by changing one of the two enantiomers. Their structural features were analyzed via 1H Pulsed Field gradient Spin Echo (PGSE) NMR, NMR titration, 1H NMR analyses of formation and differences in the chemical shifts of the peaks of the liquids. Density Functional Theory (DFT) optimization helped to define the structures of these liquids. The methanesulfonate counterion of HBA molecule showed to be relevant in order to obtain these highly-structured liquids as it interacts specifically with the HBD. These chiral Deep Eutectic Solvents revealed to be promising novel high-structured media for enantioselective reactions.

Photophysical properties of some azinium iodides in aqueous solution of nanostructured systems as DNA and nonionic micelles were investigated using steady-state and ultrafast time-resolved spectroscopy. Spectrophotometric and fluorimetric titrations of the investigated compounds with salmon testes DNA supplied evidence of a good interaction between the salts and DNA with binding constants of 10(4)-10(6) M(-1), making them interesting for pharmaceutical applications. The interaction with DNA also changes the photobehavior of the compounds, increasing the radiative deactivation pathway to the detriment of internal conversion and slowing down the excited state dynamics. The interaction of the azinium salts with the nonionic surfactant Triton X-100 from premicellar to postmicellar concentration was studied by spectrophotometric and fluorimetric titrations evidencing the ability of the micelles to associate the studied salts in their hydrophobic portion and to release them in the presence of DNA, acting as promising drug carriers. Also transient absorption spectroscopy with femtosecond resolution demonstrated the insertion of the investigated compounds into micellar aggregates. Preliminary measurements by confocal fluorescence microscopy on MCF-7 cells in the presence of the studied azinium salts showed that they are able to cross the cellular membrane and that their cytotoxicity can be expressed through interaction with DNA (RNA). In fact, they showed a significant fluorescence signal in all cell compartments, particularly (for 2 and 3) into punctuate structures within the nuclei compatible with a localization into the nucleoli.

A green dispersive liquid-liquid microextraction (DLLME) using deep eutectic solvent (DES) as the extracting solvent has been developed and applied for the simultaneous quantification of ferulic acid, umbelliferone, boropinic acid, 7-isopentenyloxycoumarin, 4'-geranyloxyferulic acid (GOFA), and auraptene in some vegetable oils using ultra high performance liquid chromatography (UHPLC) with photodiode array detection (PDA). All parameters in the extraction step, including selection and loading of both extracting and dispersing solvents, amount of both extractant and disperser solvent were investigated and optimized. PhAA/TMG DES achieved higher recovery and enrichment factor compared to other DESs. The validated method showed good linearity with correlation coefficients, r2>0.9990 for all the analytes. Furthermore, this is the first time that eco-friendly solvents are used for the extraction of oxyprenylated phenylpropanoids and the corresponding extract analyzed with ultra high performance liquid chromatography with photodiode array detection.

Neuromorphic engineering promises to have a revolutionary impact in our societies. A strategy to develop artificial neurons (ANs) is to use oscillatory and excitable chemical systems. Herein, we use UV and visible radiation as both excitatory and inhibitory signals for the communication among oscillatory reactions, such as the Belousov–Zhabotinsky and the chemiluminescent Orban transformations, and photo-excitable photochromic and fluorescent species. We present the experimental results and the simulations regarding pairs of ANs communicating by either one or two optical signals, and triads of ANs arranged in both feed-forward and recurrent networks. We find that the ANs, powered chemically and/or by the energy of electromagnetic radiation, can give rise to the emergent properties of in-phase, out-of-phase, anti-phase synchronizations and phase-locking, dynamically mimicking the communication among real neurons.

A novel off-on fluorescent sensing system for Hg2+ ions was prepared through self-assembly, by anionic surfactant micelles, of different combinations of 10-alkylacridinium perchlorates (as fluorophores, with a methyl or an n-octyl chain) and N,N-bis(p-alkyloxybenzyl)-3,6-dioxaoctane-1,8-diamines (as receptors, with a methyl or an n-dodecyl chain) in water solution. The fluorescence quenching observed in the absence of metal ions (“off” state), likely due to a photoinduced electron transfer (PET) mechanism from diamine to acridinium moiety, has demonstrated that a communication between the binding site and the signaling unit actually occurs. The addition of Hg2+ resulted in its incorporation in the micelle with the formation of a receptor-metal complex in competition with the PET process, accordingly the fluorescence emission of acridinium was restored (“on” state). The experimental data suggested that compartmentalization effects in the different micellar microenvironments, due to the different hydrophobic degree of the components, can affect the fluorescence response of the sensor and therefore its sensitivity. These systems showed good sensitivity in Hg2+ sensing and its concentration can be linearly determined according to the fluorescence quenching.

The role of surfactants such as single- and double-tailed tetraalkylammonium bromide and various non-amphiphilic tetraalkylammonium salts was investigated on the TiO2 photocatalyzed degradation of 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt (Alizarin Red-S, ARS) in an air-equilibrated alkaline medium under UV light irradiation. Absorption spectral analysis showed that the photodegradation efficiency of the dye was significantly enhanced by the addition of cationic surfactants. Two interesting findings emerged from this study: ARS was almost completely degraded at surfactant concentrations close to 1 mM (values well above the cmc in the experimental conditions); moreover, on increasing the surfactant concentration, the photocatalytic reaction became less and less efficient and significantly dependent on the surfactant headgroup size. The presence of a maximum of efficiency depending on the surfactant concentration was due to the combination of catalytic and inhibiting processes. The first one likely depended on the ability of the surfactant to improve the ARS approach to the semiconductor through the formation of cationic bilayers on the TiO2 particles; this effect made the ARS more easily oxidized by TiO2. This catalytic action of the surfactant was opposed by the increase of the micellar aggregate number in the aqueous bulk, which competes with the TiO2 sites in associating to the dye. This was supported by the results obtained with the non-amphiphilic alkylammonium bromide. In this case a higher amount of salt must be added to reach the same maximum efficiency of ARS photooxidation. This is due to the lower capability of neutralization of these salts for both the ARS and the TiO2 surface; the inhibiting effect was not evidenced anymore.

We report the preparation and the study of the properties of novel deep eutectic solvents (DESs) formed by zwitterionic trimethylglicine and high melting point carboxylic acids. These zwitterionic DESs are liquid at room temperature or at temperatures lower than 70 °C and do not have chloride or any metal ions in their composition. These media were characterized in terms of their viscosity, conductivity, density, ionicity (via Walden plots), surface tension and thermal stability. The values observed are similar to other typical DESs, and the mixtures resulted in “poor ionic liquids” in the Walden plot. The values obtained could be correlated to the carboxylic acids' structures. The toxicity of the pure mixtures was evaluated via an FTIR-bioassay on Saccharomyces cerevisiae cells. This method allowed us to define the action of these media as dehydrating agents on eukaryotic model cells, with a mechanism highly correlated with CaCl2, a well-known dehydrating agent. The Glycolic acid/Trimethylglicine eutectic system can be considered a NADES (Natural Deep Eutectic Solvent) and resulted as the best in our set for many reasons. It is formed by natural, renewable, eco-compatible and cheap compounds (both the molecules can be derived from sugar beet) and it can be used in many applications because it has a low melting point (−36 °C) and it is colorless, and therefore suitable for spectroscopic measurements. For these reasons, the solubility of some α-L-amino acids was investigated in this DES, showing a good solubility for aromatic amino acids, which are normally scarcely soluble in water.

Starting from previous evidence on the crucial role of imidazolium ions, long alkyl chains, and aromatic rings in favoring the adsorption of surfactants onto carbon nanotube (CNT) walls, we have synthesized novel gemini surfactants with the aim to optimize and identify a reference structure for CNT dispersants. The efficiency of 1 the novel surfactants has been evaluated, discussed, and compared with already well-investigated dispersants. The good affinity of the surfactants for the CNT sidewalls is highlighted by the presence of resonant van Hove absorption and highly resolved Raman and fluorescence spectra, while the strong hydrophobic interactions and favorable packing between the two alkyl chains of the investigated gemini surfactants and the CNT sidewalls ensure good CNT dispersion. Our results show no selectivity toward specific diameters/chiralities, confirming the twin heads of imidazolium surfactants are pointed toward the bulk water, while the alkyl chains are arranged on the CNT walls, improving water solubility at the expense of potential selectivity.