Triphenylamine-Containing Benzoic Acids: Synthesis, Liquid Crystalline and Redox Properties.

The synthesis, characterization and liquid crystalline and electrochemical properties of novel triarylamines, in which the triphenylamine platform is non-symmetrically modified with a 4-(6-oxyhexyloxy)benzoic acid group, are reported. Compounds show columnar liquid crystalline behavior, as confirmed through the use of polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. Electrochemical properties were measured using cyclic voltammperometry, obtaining low oxidation potentials and HOMO values that were optimum for consideration as organic semiconductors in hole transport layers. In addition, the photoredox activity of one of these derivatives in dichloromethane was studied under light irradiation. A photooxidation/assembly process under white light irradiation occurs without the assistance of hydrogen bonding amide functional groups.

Crop year, harvest date and clone effects on fruit characteristics, chemical composition and olive oil stability from an Empeltre clonal selection grown in Aragon.

BACKGROUND: In this study, the effects of crop year, harvest date and clone on the fruit characteristics and chemical composition of Empeltre olive oils were evaluated. For this purpose, the weight and oil content of fruit and the fatty acid composition, polyphenol content and oxidative stability of the olive oil was analysed throughout ripening during three successive seasons. RESULTS: The weight and moisture in the fruit, as well as the fatty acids and polyphenol content in the olive oil, were mainly affected by crop year. In contrast, the stability was strongly influenced by the harvest date. Both factors had an influence on the fruit's oil content. The clone was not a substantial component in terms of variability, although the interaction with crop year was notable for some of the characteristics. The oil content increased significantly along with the harvest date and reached maximum values in the last period (44.9%). Conversely, stability and polyphenols decreased significantly (depending on the year, by 30-70%) from October to December, reaching the highest mean values between 1 October and 10 November (15.5 h; 500 mg caffeic acid kg-1 ). Oleic acid and monounsaturated/polyunsaturated fatty acids (MUFA/PUFA) did not show significant differences depending on the harvest date, but between years, with 2018 having the highest percentage of oleic acid (72.72%) and MUFA/PUFA (8.38). CONCLUSION: Early harvesting of Empeltre olives would provide considerably more stable olive oils, regardless of the clone selected, with higher phenolic content. It would not affect the MUFA/PUFA ratio, mainly influenced by the crop year. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Functional analysis of ß-ketoacyl-CoA synthase from biofuel feedstock Thlaspi arvense reveals differences in the triacylglycerol biosynthetic pathway among Brassicaceae.

KEY MESSAGE: Differences in FAE1 enzyme affinity for the acyl-CoA substrates, as well as the balance between the different pathways involved in their incorporation to triacylglycerol might be determinant of the different composition of the seed oil in Brassicaceae. Brassicaceae present a great heterogeneity of seed oil and fatty acid composition, accumulating Very Long Chain Fatty Acids with industrial applications. However, the molecular determinants of these differences remain elusive. We have studied the ß-ketoacyl-CoA synthase from the high erucic feedstock Thlaspi arvense (Pennycress). Functional characterization of the Pennycress FAE1 enzyme was performed in two Arabidopsis backgrounds; Col-0, with less than 2.5% of erucic acid in its seed oil and the fae1-1 mutant, deficient in FAE1 activity, that did not accumulate erucic acid. Seed-specific expression of the Pennycress FAE1 gene in Col-0 resulted in a 3 to fourfold increase of erucic acid content in the seed oil. This increase was concomitant with a decrease of eicosenoic acid levels without changes in oleic ones. Interestingly, only small changes in eicosenoic and erucic acid levels occurred when the Pennycress FAE1 gene was expressed in the fae1-1 mutant, with high levels of oleic acid available for elongation, suggesting that the Pennycress FAE1 enzyme showed higher affinity for eicosenoic acid substrates, than for oleic ones in Arabidopsis. Erucic acid was incorporated to triacylglycerol in the transgenic lines without significant changes in their levels in the diacylglycerol fraction, suggesting that erucic acid was preferentially incorporated to triacylglycerol via DGAT1. Expression analysis of FAE1, AtDGAT1, AtLPCAT1 and AtPDAT1 genes in the transgenic lines further supported this conclusion. Differences in FAE1 affinity for the oleic and eicosenoic substrates among Brassicaceae, as well as their incorporation to triacylglycerol might explain the differences in composition of their seed oil.

On the Structure and Chiral Aggregation of Liquid Crystalline Star-Shaped Triazines H-Bonded to Benzoic Acids.

The ability of a star-shaped tris(triazolyl)triazine derivative to hierarchically build supramolecular chiral columnar organizations through the formation of H-bonded complexes with benzoic acids was studied from a theoretical and experimental point of view. The combined study has been done at three different levels including the study of the structure of the triazine core, the association with benzoic acids in stoichiometry 1:3, and the assembly of 1:3 complexes in helical aggregates. Although the star-shaped triazine core crystallizes in a non-C3 conformation, the C3 -symmetric conformation is theoretically predicted to be more stable and gives rise to a favorable C3 supramolecular 1:3 complex upon the interaction with three benzoic acids in their voids. In addition, calculations at different levels (DFT, PM7, and MM3) for the 1:3 host-guest complex predict the formation of large stable columnar helical aggregates stabilized by the compact packing of the interstitial acids by π-π and CH⋅⋅⋅π interactions. The acids restrict the movement of the the star-shaped triazine cores along the stacking axis causing a template effect in the self-assembly of the complex. Theoretical predictions correlate with experimental results, since the interaction with achiral or chiral 3,4,5-(4-alkoxybenzyloxy)benzoic acids gives rise to supramolecular complexes that organize in bulk hexagonal columnar mesophases stable at room temperature with intracolumnar order. The existence of supramolecular chirality in the mesophase was determined for complexes formed by acids derived from (S)-2-octanol. Chiral aggregation was also evidenced for complexes formed in dodecane.

Manipulation of Supramolecular Columnar Structures of H-Bonded Donor-Acceptor Units through Geometrical Nanoconfinement.

Ambipolar organic semiconductors are considered promising for organic electronics because of their interesting electric properties. Many hurdles remain yet to be overcome before they can be used for practical applications, especially because their orientation is hard to control. We demonstrate a method to control the orientation of columnar structures based on a hydrogen (H)-bonded donor-acceptor complex between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acid, using physicochemical nanoconfinement. The molecular configuration and supramolecular columnar assemblies in a one-dimensional porous anodic aluminium oxide (AAO) film were dramatically modulated by controlling the pore-size and by chemical modification of the inner surface of the porous AAO film. In situ experiments using grazing-incidence X-ray diffraction (GIXRD) were carried out to investigate the structural evolution produced at the nanometer scale by varying physicochemical conditions. The resulting highly ordered nanostructures may open a new pathway to effectively control the alignment of liquid crystal ambipolar semiconductors.

On-Surface Crystallization Behaviors of H-Bond Donor-Acceptor Complexes at Liquid/Solid Interfaces.

Two-dimensional (2D) crystallization behaviors of A-TPC n ( n = 4, 6, 10), T3C4, and hydrogen-bonded complexes T3C4@TPC n ( n = 4, 6, 10) are investigated by means of scanning tunneling microscope (STM) observations and density functional theory (DFT) calculations. The STM observations reveal that A-TPC4, A-TPC10, and T3C4 self-organize into dumbbell-shaped structures, well-ordered bright arrays, and zigzag structures, respectively. Interestingly, T3C4@TPC10 fails to form the cage-ball structure, whereas T3C4@TPC4 and T3C4@TPC6 co-assemble into cage-ball structures with the same lattice parameters. The filling rates of the balls of these two kinds of cage-ball structures depend heavily on the deposition sequence. As a result, the filling rates of the cages in T3C4/A-TPC n ( n = 4, 6) with deposition of T3C4 anterior to A-TPC n are higher than those in A-TPC n/T3C4 ( n = 4, 6) with the opposite deposition sequence. Furthermore, lattice defects formed by T3C4 coexist with the cage-ball structures. Moreover, the similar energy per unit area of lattice defects (-0.101 kcal mol-1 Å-2) and the two cage-ball networks (-0.194 and -0.208 kcal mol-1 Å-2, respectively), illustrating the similar stabilities of lattice defects and cage-ball networks, demonstrates the rationality of lattice defects. Combining STM investigations and DFT calculations, this work could provide a useful approach to investigate the 2D crystallization mechanisms of supramolecular liquid crystals on surfaces.

Inspecting the Electronic Architecture and Semiconducting Properties of a Rosette-Like Supramolecular Columnar Liquid Crystal.

Computational and experimental studies unravel the structural and electronic properties of a novel supramolecular liquid crystal built through a hierarchical assembly process resulting in an H-bonded melamine rosette decorated with peripheral triphenylenes. The six-fold symmetry of the mesogen facilitates the formation of a highly organized hexagonal columnar mesophase stable at room temperature. X-ray diffraction and electron density maps confirm additional intra- and intercolumn segregation of functional subunits, and this paves the way for 1D charge transport. Indeed, hole mobility has been measured and found to be higher than for related mesogens. DFT calculations of HOMO and LUMO levels and parameters such as reorganization energy and transfer integral of the rosette structure have been achieved, and not only validate the columnar organization but also establish the way it translates into a favorable electronic architecture and molecular orbital interactions to promote charge carrier mobility.

Decisive Influence of the Metal in Multifunctional Gold, Silver, and Copper Metallacycles: High Quantum Yield Phosphorescence, Color Switching, and Liquid Crystalline Behavior.

Three cyclic trinuclear pyrazolate complexes with Au(I), Ag(I), or Cu(I) have been studied. These complexes have interesting and distinct optical and thermal properties depending on the metal, namely, liquid crystalline behavior, red or deep-red phosphorescence at room temperature, thermoluminochromism, and response to silver ions. The selected ligand, 4-hexyl-3,5-dimethylpyrazolate, maximizes the effect that the nature of the metals has on the properties of the complexes, thus allowing the intermolecular metallophilic interactions to be responsible for the optical properties. Moreover, the gold and silver complexes show columnar liquid crystal phases at high temperature. All of the complexes have good solubility properties for processing as poly(methyl methacrylate) (PMMA) doped films. Films of the gold, silver, and copper complexes show interesting optical behavior such as wide-range color switching or phosphorescence turn-on upon cooling. In addition, films of the gold complex show a bright color switching (red to blue) in the presence of silver ions. The gold and copper complexes are bright phosphors with phosphorescent quantum yields of 90% in PMMA films, the highest values reported for this class of compounds at room temperature.

Review and update on non-suicidal self-injury: who, how and why?

Non-suicidal self-injury (NSSI) is defined as the direct and deliberate destruction of one’s own body tissue in the absence of lethal intent. Following decades of progressive increase in the incidence of NSSI among adolescents and young adults, as well as growing scientific interest, the disorder was listed as a condition for further study in the Diagnostic and Statistical Manual of Mental Disorders (fifth edition). In this review we provide updated information on this phenomenon, focusing on: prevalence, course and prognosis; associated factors; its relationship with psychopathology; and the role of the mass media, social networks, and the internet. Finally, we discuss some conclusions and future proposals, emphasizing the need for collaborative work to better understand NSSI in Spain, and to improve prevention and treatment strategies.

H-Bonded Donor-Acceptor Units Segregated in Coaxial Columnar Assemblies: Toward High Mobility Ambipolar Organic Semiconductors.

A novel approach to ambipolar semiconductors based on hydrogen-bonded complexes between a star-shaped tris(triazolyl)triazine and triphenylene-containing benzoic acids is described. The formation of 1:3 supramolecular complexes was evidenced by different techniques. Mesogenic driving forces played a decisive role in the formation of the hydrogen-bonded complexes in the bulk. All of the complexes formed by nonmesogenic components gave rise to hexagonal columnar (Colh) liquid crystal phases, which are stable at room temperature. In all cases, X-ray diffraction experiments supported by electron density distribution maps confirmed triphenylene/tris(triazolyl)triazine segregation into hexagonal sublattices and lattices, respectively, as well as remarkable intracolumnar order. These highly ordered nanostructures, obtained by the combined supramolecular H-bond/columnar liquid crystal approach, yielded donor/acceptor coaxial organization that is promising for the formation of ambipolar organic semiconductors with high mobilities, as indicated by charge transport measurements.

Supramolecular Columnar Liquid Crystals with Tapered-Shape Simple Pyrazoles Obtained by Efficient Henry/Michael Reactions.

A straightforward synthesis of mesogenic pyrazoles starting from benzaldehydes by a combination of efficient Henry and Michael reactions led to novel supramolecular liquid crystals. The mesogens are fluorescent 3,5-dimethyl-4-(di or trialkoxyphenyl)pyrazoles and, in spite of the tapered shape of these molecules and their structural simplicity (only one phenyl ring), columnar liquid-crystal phases were formed that are stable at room temperature. The self-assembled structure was studied by XRD and the columnar cross section contains two molecules on average with an antiparallel arrangement of pyrazoles interacting through hydrogen bonds. In contrast, the single-crystal structure of a trimethoxy analog did not show hydrogen-bonded pyrazoles but chains of head-to-tail arranged molecules.

Supramolecular columnar liquid crystals formed by hydrogen bonding between a clicked star-shaped s-triazine and benzoic acids.

A star-shaped tris(triazolyl)triazine is shown to establish hydrogen-bond interactions with polycatenar benzoic acids. The formation of hydrogen-bonded triazine/acid complexes has been demonstrated both in solution and in bulk by different techniques. The complexes, mainly formed by nonmesogenic components, all show enantiotropic hexagonal columnar mesomorphism, which relies on the formation of hydrogen-bond complexes in a triazine/acid ratio of 1:3. This approach combines the straightforward synthesis of a nonmesomorphic triazine core by click chemistry, and the preparation of a supramolecular complex, providing a much more convenient route than covalent synthesis to modify the periphery of triazine discotics and thus to modulate their functionality.

Bent-core liquid crystalline cyanostilbenes: fluorescence switching and thermochromism.

Fluorescent bent-core molecules, bearing one or two cyanostilbene units in the lateral structure and different positions of the cyano group (α- or ß-isomers), are described with the aim of modulating the molecular packing and fluorescence properties. These compounds give rise to a variety of crystal polymorphs and bent-core liquid crystalline phases (SmCP, Colr and B6), offering the unique chance to study the fluorescence properties of the cyanostilbene structure in different phases. Experimental and computational studies elucidate geometrical and electronic properties of these bent-core structures but especially the fluorescence properties (spectral positions, quantum yields and decay curves), in a detailed comparison between diluted solutions, in dichloromethane (DCM) or poly(methylmethacrylate) (PMMA), and condensed phases. Quantum yields as high as 70% have been obtained in some diluted solutions (PMMA) and condensed phases. Remarkably, the quantum yield values depend on the position of the cyano group, being higher for ß- than for the α-isomers due to the higher radiative rates and lower non-radiative rates of the former. The photophysical characterization in the condensed phase focuses on RT studies with solid samples and different processing, and show that, upon aggregation, interactions between the cyanostilbene groups result in changes of the emission spectra and dynamics compared to the diluted systems in DCM and PMMA, giving rise to H-aggregations of varying strength. Furthermore, the compounds exhibit thermochromism, showing a green-yellow fluorescence in the pristine crystalline phase that changes to blue on heating to the liquid crystal phase.

Multifunctional supramolecular dendrimers with an s-triazine ring as the central core: liquid crystalline, fluorescence and photoconductive properties.

Novel liquid crystal (LC) dendrimers have been synthesised by hydrogen bonding between an s-triazine as the central core and three peripheral dendrons derived from bis(hydroxymethyl)propionic acid. Symmetric acid dendrons bearing achiral promesogenic units have been synthesised to obtain 3:1 complexes with triazine that exhibit LC properties. Asymmetric dendrons that combine the achiral promesogenic unit and an active moiety derived from coumarin or pyrene structures have been synthesised in order to obtain dendrimers with photophysical and electrochemical properties. The formation of the complexes was confirmed by IR and NMR spectroscopy data. The liquid crystalline properties were investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffractometry. All complexes displayed mesogenic properties, which were smectic in the case of symmetric dendrons and their complexes and nematic in the case of asymmetric dendrons and their dendrimers. A supramolecular model for the lamellar mesophase, based mainly on X-ray diffraction studies, is proposed. The electrochemical behaviour of dendritic complexes was investigated by cyclic voltammetry. The UV/Vis absorption and emission properties of the compounds and the photoconductive properties of the dendrons and dendrimers were also investigated.

Silver Dendritic Gels with Luminescence and Aggregation-Induced Emission Effect.

This work reports on a novel family of silver metallogels based on discrete coordination complexes. Structurally, they consist of dendrimers containing a trinuclear silver metallacycle at the core, with the general formula [M(µ-pz)]3, and poly(benzyl)ether branched structures with different numbers or terminal alkoxy chains at the periphery. These silver metallodendrimers are able to gel low-polarity solvents such as dodecane or cyclohexane, giving rise to luminescent organogels at room temperature with the property of aggregation-induced emission (AIE). This property means that in solution or the sol state, they are weak emitters, but in the gel state, luminescence is considerably increased. In this particular case, they exhibit blue luminescence. Two different dendritic scaffolds have been studied, finding significant differences in solubility, gel formation and dependence of luminescence on temperature. The results show that properly tailored silver gelators can show luminescence in the gel state.

Effect of Hydrogen Bonding and Chirality in Star-Shaped Molecules with Peripheral Triphenylamines: Liquid Crystal Semiconductors and Gels.

Organic semiconductors with well-defined architectures pose a suitable alternative to amorphous silicon-based inorganic semiconductors. Encouraged by the development of organic semiconductors based on columnar liquid crystals, herein, we report on a family of C3-symmetric star-shaped mesogens based on triphenylamine (TPA), a functional unit with strong electron donor character. Highly stable columnar phases with high hole mobility values were obtained out of this nonplanar functional unit, and this was achieved by using flexible amide spacers to join the TPA units to a tris(triazolyl)triazine (T) star-shaped core, allowing the formation of intermolecular hydrogen bonds. The presence of hydrogen bonds results in a stabilization of the columnar architectures either in bulk or in the presence of solvents by reinforcing π-stacking and van der Waals interactions, as deduced by Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) studies. Furthermore, the introduction of a stereogenic center in the flexible spacer prompts the formation of chiral aggregates in the liquid crystal state and in the organogel formed in 1-octanol, as demonstrated by circular dichroism spectroscopy.

Chemometric and Physico-Chemical Characterization of Fruit and Olive Oils from Autochthonous Cultivars Grown in Aragon (Spain).

Olive tree crops and the olive oil market are becoming less and less diverse due to the rise of intensive growth varieties, with the consequent loss of varietal richness provided by oils from minority and autochthonous cultivars. "Royal de Calatayud" and "Negral de Sabiñán" are two local minority cultivars in Aragon (Spain). Fruit parameters such as ripening, fresh weight, and oil yield were evaluated, as well as physico-chemical and chemical composition parameters in olive oil in comparison with "Arbequina", a cultivar widespread in Spain and other countries. Fruits were harvested from October to December in 2017 and 2019. Chemometric analysis revealed significant varietal differences among the three cultivars. In comparison with "Arbequina", higher oil yields were obtained in the two local cultivars. "Royal de Calatayud" has a higher oleic acid content and a greater quantity of phenolic compounds. It thus displays a better nutritional profile than "Arbequina". This preliminary study shows that "Royal de Calatayud" could be regarded as an excellent alternative to the "Arbequina" cultivar in the parameters analyzed.

Recent Advances in MXene/Epoxy Composites: Trends and Prospects.

Epoxy resins are thermosets with interesting physicochemical properties for numerous engineering applications, and considerable efforts have been made to improve their performance by adding nanofillers to their formulations. MXenes are one of the most promising functional materials to use as nanofillers. They have attracted great interest due to their high electrical and thermal conductivity, hydrophilicity, high specific surface area and aspect ratio, and chemically active surface, compatible with a wide range of polymers. The use of MXenes as nanofillers in epoxy resins is incipient; nevertheless, the literature indicates a growing interest due to their good chemical compatibility and outstanding properties as composites, which widen the potential applications of epoxy resins. In this review, we report an overview of the recent progress in the development of MXene/epoxy nanocomposites and the contribution of nanofillers to the enhancement of properties. Particularly, their application for protective coatings (i.e., anticorrosive and friction and wear), electromagnetic-interference shielding, and composites is discussed. Finally, a discussion of the challenges in this topic is presented.

Authenticity in Olive Oils from an Empeltre Clonal Selection in Aragon (Spain): How Environmental, Agronomic, and Genetic Factors Affect Sterol Composition.

Sterol composition is used as a "fingerprint" to demonstrate the authenticity of olive oils. Our study's objective was to exhaustively characterize the sterol composition of Empeltre olive oils from clonal selection during the ripening period in 2017, 2018, and 2019. We likewise assessed the influence of crop year, fruit ripening, and clonal selection on the oils' regulatory compliance in terms of sterol composition. Empeltre olive oils were shown to have medium-range ß-sitosterol and Δ5-avenasterol content, along with elevated amounts of campesterol and Δ7-stigmastenol. A total of 26% and 12% of the samples were non-compliant in terms of apparent ß-sitosterol and Δ7-stigmastenol, respectively. Crop year was the most influential factor in the case of most sterols. Clone type was the least influential factor, except in the case of campesterol. Olive maturity was only significant for Δ7-sterols. We likewise applied a discriminant analysis, with "crop year" as the grouping variable: 94.9% of the oils were thereby classified correctly.

Structural Diversity of Hydrogen-Bonded 4-Aryl-3,5-Dimethylpyrazoles for Supramolecular Materials.

The 1H-pyrazoles have high versatility and ability to form hydrogen-bonded supramolecular materials. In this study, the thermal stability, fluorescence, and H-bonding ability of the studied 3,5-dimethyl-4-(4-X-phenyl)-1H-pyrazoles showed large differences depending on the terminal substituent. Supramolecular structures were analyzed using X-ray diffraction and Hirshfeld surface calculations. Compounds were found to arrange in different hydrogen-bonded structures, depending on the substitution at the para position of the phenyl ring (X = OCH3, NO2, NH2). The methoxy-substituted compounds arranged in dimers through methanol bridges, the nitro-substituted compound formed supramolecular polymers or catemers, and the amino-substituted compound gave rise to a new structure based on a 2D hydrogen-bonded network.