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Organic phosphorothioates are a class of organic compounds containing the C–S–P structural motif, known for their unique physical and chemical properties. These compounds hold significant value in various fields, including agriculture, pharmaceuticals, and materials science, particularly playing a crucial role in agrochemicals and nucleotide modification. Traditionally, phosphorothioates have been synthesized primarily through the formation of P–S bonds or direct phosphorothioation reactions from organic phosphorus sources such as P(O)H and P(O)SH. In recent years, new strategies utilizing inorganic phosphorus sources, such as P4S10 and white phosphorus (P4), have emerged as a dynamic area of research. This review highlights the latest advancements in the synthesis of phosphorothioates and phosphoropolythioates from inorganic phosphorus sources, focusing on their applicability, mechanisms, current limitations, and potential future directions. [ABSTRACT FROM AUTHOR]

Despite the important role of the dark 1nπ* state in the photostability of thymidine in aqueous solution, no detailed ultraviolet (UV) wavelength-dependent investigation of the 1nπ* quantum yield (QY) in aqueous thymidine has been experimentally performed. Here, we investigate the wavelength-dependent photoemission spectra of aqueous thymidine from 266.7 to 240 nm using liquid-microjet photoelectron spectroscopy. Two observed ionization channels are assigned to resonant ionizations from 1ππ* to the cationic ground state D0 (π−1) and 1nπ* to the cationic excited state D1 (n−1). The weak 1nπ* → D1 ionization channel appears due to ultrafast 1ππ* → 1nπ* internal conversion within the pulse duration of ∼180 fs. The obtained 1nπ* quantum yields exhibit a strong wavelength dependence, ranging from 0 to 0.27 ± 0.01, suggesting a hitherto uncharacterized 1nπ* feature. The corresponding vertical ionization energies (VIEs) of D0 and D1 of aqueous thymidine are experimentally determined to be 8.47 ± 0.12 eV and 9.22 ± 0.29 eV, respectively. Our UV wavelength-dependent QYs might indicate that different structural critical points to connect the multidimensional 1ππ*/1nπ* conical intersection seam onto the multidimensional potential energy surface of the 1ππ* state might exist and determine the relaxation processes of aqueous thymidine upon UV excitation. [ABSTRACT FROM AUTHOR]

We report a structure–property relationship in sulfur-based chemical structures for thermotropic ferroelectric nematic (NF) materials. We synthesized a wide variety of sulfur-containing thioether-, thioester-, and thiophene-based analogs and their oxygen-based counterparts of an archetypal ferroelectric nematogen RM734. Compound 2, having the 4-terminal methylthio (SMe) group instead of the methoxy (OMe) group of RM734, shows the nematic (N), unknown N (NX), and NF phases upon cooling. In contrast, 6 with SMe at the inner lateral 2-position only exhibts a monotropic N phase. A thioester analog 7 exhibits the N and NF phases. Without the 4-terminal OMe, 10 having SMe at the lateral 3-position shows the enantiotropic N and monotropic NX phases, whereas 12 and 13 with SMe and OMe, respectively, at the 2-position form the monotropic NF phase directly from the isotropic (Iso) phase. In addition, thiophene-besed compounds (14, 15, 18, and 19) exhibit the NF phase (and NX phase for 14 and 15) regardless of the presence of the terminal chain groups. The NF phases of 18 and 19 with OMe at the inner 3-position and no chain group, respectively, directly appear from the Iso phase. Compounds 20 and 21 with the ester direction opposite from RM734 only show enantiotropic N phases. The ferroelectric nature is characterized by dielectric measurement, second harmonic generation, and spontaneous polarization analysis. [ABSTRACT FROM AUTHOR]

Cataluminescence (CTL) has emerged as a sensing transduction principle of gas–solid interface for constructing gas sensors that present fast response, high sensitivity, and online monitoring. It has thus been widely associated with the field of chemical analysis and catalytic science. Herein, the latest developments in CTL sensors are reviewed, and the status quo of CTL-based gas sensing systems is discussed. In particular, the basic principles and sensing systems of CTL are outlined, including performance enhancement strategies for specific targets and recognition methods for multiple targets. Moreover, the important applications of CTL sensors are listed and classified, including environmental pollutant monitoring, product quality control, clinical diagnosis, and evaluation of catalyst performance. Finally, based on abundant case reports, the current conundrums of CTL sensors are summarized and their future development trends are also put forward. [ABSTRACT FROM AUTHOR]

Resveratrol is well-known for promoting health benefits due to its antioxidant, anti-aging, anticarcinogenic, and other beneficial activities. Understanding the photophysics of resveratrol is essential for determining its applicability to pharmaceutical innovations. In the present work, we used an explore then-assess strategy to map the internal conversion pathways of trans-resveratrol. This strategy consists of exploring the multidimensional configurational space with nonadiabatic dynamics simulations based on a semi-empirical multireference method, followed by a feasibility assessment of reduced dimensionality pathways at a high ab initio theoretical level. The exploration step revealed that internal conversion to the ground state may occur near five distinct conical intersections. The assessment step showed that the main photoisomerization pathway involves a twisted-pyramidalized S1/S0 conical intersection, yielding either trans or cis isomers. However, a secondary path was identified, where cis-trans isomerization happens in the excited state and internal conversion occurs at a cyclic conical intersection, yielding a closed-ring resveratrol derivative. This derivative, which can be formed through this direct path or an indirect photoexcitation, may be connected to the production of oxygen-reactive species previously reported and have implications in photodynamic therapy. [ABSTRACT FROM AUTHOR]

The recent discovery of a new ferroelectric nematic (NF) liquid crystalline phase has become of utmost interest for the liquid crystal (LC) and the whole soft and condensed matter fields. Contrary to the previously known ferroelectric LC materials, whose ferroelectric characteristics were much weaker, new polar nematics exhibit properties comparable to solid ferroelectrics. This discovery brought about tremendous efforts to further explore compounds showing these phases, and fascinating physical properties have been reported. Herein, we present the first synthesized compounds with the enantiotropic ferro-(NF) and antiferroelectric (NX) nematic phases. The enantiotropic nature and an unprecedentedly broad temperature range of NF and NX phases are confirmed by various experimental techniques: polarized-light optical microscopy (POM) observations, different scanning calorimetry (DSC), dielectric spectroscopy, second harmonic generation (SHG), and molecular modeling. The presented achievements in designing achiral compounds that exhibit enantiotropic polar nematic phases with ferro- and antiferroelectric properties significantly contribute to the development of multicomponent mixtures with a broad temperature range of NF and NX phases down to room temperature. Furthermore, this accomplishment considerably enhances the general understanding of the structural correlations that promote polar nematic liquid crystal phases with high thermodynamic stability. Finally, this work may benefit various applications in photonic devices. [ABSTRACT FROM AUTHOR]

Time-resolved photoelectron spectroscopy using an extreme-ultraviolet (XUV) probe pulse was used to investigate the UV photoinduced dynamics of adenine (Ade), adenosine (Ado), and adenosine-5-monophosphate (AMP) in a liquid water jet. In contrast to previous studies using UV probe pulses, the XUV pulse at 21.7 eV can photoionize all excited states of a molecule, allowing for full relaxation pathways to be addressed after excitation at 4.66 eV. This work was carried out using a gas-dynamic flat liquid jet, resulting in considerably enhanced signal compared to a cylindrical jet. All three species decay on multiple time scales that are assigned based on their decay associated spectra; the fastest decay of B100 fs is assigned to pp* decay to the ground state, while a smaller component with a lifetime of B500 fs is attributed to the np* state. An additional slower channel in Ade is assigned to the 7H Ade conformer, as seen previously. This work demonstrates the capability of XUV-TRPES to disentangle nonadiabatic dynamics in an aqueous solution in a state-specific manner and represents the first identification of the np* state in the relaxation dynamics of adenine and its derivatives. [ABSTRACT FROM AUTHOR]

The +5 state is an unusual oxidation state of uranium due to its instability in the aqueous phase. As a result, gaining information about its aqueous speciation is extremely difficult. The present work is an attempt in that direction and it provides insight into the existence of a new pentavalent species in the presence of hetero-bifunctional phosphonocarboxylate (PC) chelators, other than the carbonate ion, in the aqueous medium. The aqueous chemistry of pentavalent uranium species with three environmentally relevant PCs was probed using electrochemical and DFT methods to understand the redox energy and kinetics of conversion of the U(VI)/U(V) couple, stability, structure, stoichiometry, binding modes, etc. Interestingly, pentavalent uranium complexes with PCs are quite persistent over a wide range of pH starting from acidic to alkaline conditions. The PC chelators block the cation-cation interaction (CCI) of U(V) through strong hetero-bidentate chelation and intermolecular hydrogen bonding (IMHB) interactions which stabilize the pentavalent metal ion against disproportionation. For uranyl species in the presence of PCs, acting as chelators, CV plots were obtained at varying pH values from 2 to 8. The obtained results indicate an irreversible single redox peak involving U(VI) to U(V) conversion and association of a coupled chemical reaction with the electron transfer step. ESI-MS studies were performed to understand the speciation effect on the U(VI)/U(V) redox couple with varying pH. Speciation modelling of U(V) with the PC ligands was carried out, which indicated that the U(V) is redox stable in nearly 47% of the pH region in the presence of the PCs as compared to the carboxylate-based chelators. The free energy and reduction potential of the U(V) complexes and the reduction free energy and disproportionation free energy for the U(VI)/U(V) couple were determined by DFT computations in the presence of the PCs. In situ spectroelectrochemical spectra were recorded to provide evidence for the existence of U(V) species with PCs in the aqueous medium and to acquire its absorption spectra. The present study is highly significant for understanding the coordination chemistry of pentavalent uranium species, accurate modelling of uranium, and isolation of U(V). [ABSTRACT FROM AUTHOR]

The ionotropic γ-aminobutyric acid (GABA) receptor (iGABAR) is an important target of agricultural insecticides. Our previous studies indicated that competitive antagonists (CAs) of iGABARs have potential to be insecticides with a novel mechanism of action, and 3-isothiazolol might be used as a basic scaffold of iGABAR CA for further structural modification. Here, we designed and synthesized a novel series of 4-(3-pyrrolidinyl/4-piperidinyl)-3-isothiazolol (5-SPI) analogs with various aromatic substituents at the 5-position of the isothiazole ring. These target 5-SPIs exhibited good insecticidal activity against Drosophila melanogaster and Spodoptera litura, especially 9j and 15g, with 100% and 485% mortality against D. Melanogaster at 100 mg L-1 and with nearly 95% and 480% mortality against S. litura at 100 mg kg-1 diet, respectively. Pesticide-likeness and toxicity predictions revealed that compounds 9j and 15g were well within the reasonable range of pesticide-likeness properties and may be non-toxic to honey bees and humans. Molecular docking studies indicated that the hydroxyl group of the isothiazole ring of 9j and 15g could form hydrogen bonds with R53 and S118 of the D. Melanogaster iGABAR model, respectively, and the amino group of the nitrogen heterocyclic substituent could form a hydrogen bond with E146. These interactions might be significant for the binding of target 5-SPIs with insect iGABARs. The findings of the present study might provide useful information for further designing and developing novel iGABAR-targeting insecticides. [ABSTRACT FROM AUTHOR]

Aqueous nanodiamonds illuminated by UV light produce free solvated electrons, which may drive high-energy reduction reactions in water. However, the influence of water conformations on the excited-state electron-transfer mechanism are still under debate. In this work, we offer a theoretical study of charge-transfer states in adamantane-water structures obtained by linear-response time-dependent density-functional theory. Small water clusters with broken hydrogen bonds are found to efficiently bind the electron from adamantane. A distinction is made with respect to the nature of the water clusters: some bind the electron in a water cavity, others along a strong permanent total dipole. These two types of bound states are more strongly binding, the higher their electron affinity and their positive electrostatic potential, the latter being dominated by the energy of the lowest unoccupied molecular orbital of the isolated water clusters. Structural sampling in a thermal equilibrium at room temperature via molecular dynamics snapshots confirms under which conditions the underlying waters clusters can occur and verifies that broken hydrogen bonds in the water network close to adamantane can create traps for the solvated electron. [ABSTRACT FROM AUTHOR]

During the physiological activities of the human body, a variety of rich electrophysiological signals are generated, and these signals are mainly acquired through electrodes. Therefore, the performance of electrodes directly determines the quality and stability of electrophysiological signals. Among the electrodes, electrodes based on conductive hydrogels show great potential in the field of electrophysiological signal acquisition due to their excellent conductivity, stability, biocompatibility and low Young's modulus. This review first introduces representative strategies for the preparation of conductive hydrogels, discusses the possible problems of introducing conductive materials into hydrogels and offers solutions. Subsequently, the mechanism of electrophysiological signal generation is introduced, and the recent research progress of conductive hydrogels in the field of electrophysiological signal acquisition is discussed. Finally, the opportunities and challenges faced by conductive hydrogels for electrophysiological signal acquisition are summarized and outlooked. [ABSTRACT FROM AUTHOR]

Coordination polymers containing a sulfur coordination atom (S-CPs) are an emerging class of materials with unique optoelectronic properties resulting from their inorganic metal–sulfur (–M–S–)n networks. Although the structural dimensionalities of (–M–S–)n networks govern the semiconductive properties of S-CPs, few systematic investigations have examined the impact of these dimensionalities on their semiconductive nature. In this study, we explored the relationship between the (–Pb–S–)n dimensionality and photoconductivity. We systematically synthesized Pb(II) S-CPs with the formula [Pb(x-SPhOMe)2] (x = ortho (KGF-32), meta (KGF-33), and para (KGF-34); HSPhOMe = methoxybenzenthiol). Single-crystal X-ray diffraction showed that KGF-32 and KGF-34 featured holodirected coordination spheres, but 1D (–Pb–S–)n chains with [PbO2S4] octahedra and 2D (–Pb–S–)n layers with [PbS6] octahedra, respectively. In contrast, KGF-33 features a 1D (–Pb–S–)n chain comprising a hemidirected [PbS5] coordination sphere. Notably, time-resolved microwave conductivity measurements and first-principles calculations revealed that the 2D-extended (–Pb–S–)n layer with the holodirected [PbS6] octahedron observed in KGF-34 served as a pathway for electron mobility. The findings of this study provide further design strategies for fabricating highly photoconductive Pb(II) S-CPs. [ABSTRACT FROM AUTHOR]

Urea, an important derivative of ammonia, has become an integral part of modern agriculture to meet the increasing global food demand. However, its reliance on depleting fossil fuels impedes efforts toward sustainable agriculture and a low-carbon economy. The synthesis of green urea presents a promising opportunity for carbon fixation and improving sustainability. To materialize this concept and leverage the benefits of the hydrogen economy and carbon capture, this study proposes a strategy to fuel urea production through green ammonia and captured carbon dioxide. To achieve this, a comprehensive process for producing 460 ktons per year of green urea was designed in Aspen Plus V14. The simulated process results were validated against the industrial process, demonstrating a high level of agreement. Subsequently, discounted cash flow analysis and cradle-to-gate life cycle analysis were performed to examine the economic and environmental benefits. The analysis concluded that the design has a minimum urea selling price of USD 0.71 per kg. Electrolysis (64%) and ammonia synthesis (63%) are identified as the most energy- and cost-intensive processes, respectively. Between conventional and green urea synthesis, the latter exhibited a more favorable environmental profile, showcasing a 38% reduction in abiotic fossil fuel depletion and a 16% reduction in global warming potentials. Finally, a sensitivity analysis was conducted, identifying the hydrogen price as a key economic driver. The results indicate that by varying the hydrogen price between USD 3.04 and USD 3.19 per kg, green urea can generate a net present value ranging from 25 million to 75 million USD over a 30-year project lifespan. Overall, the results of this study highlight both the positive and critical aspects of green urea production, providing a quantitative basis for the scientific community and policymakers to guide future research and development necessary for the success of this industry. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) Cd(II) coordination polymers [Cd(x-SPhOMe)2]n (x = ortho, meta, and para; HSPhOMe = methoxybenzenethiol) containing inorganic 1D (–Cd–S–)n chains were synthesized. Among these, the KGF-31 polymer bearing para-SPhOMe featured a three-strand chain structure assembled via interchain S⋯S interactions and exhibited high photoconductivity and longevity. [ABSTRACT FROM AUTHOR]

With the rise of two-dimensional (2D) materials, unique properties that are completely distinct from bulk counterparts continue to emerge at low-dimensional scales, presenting numerous opportunities and challenges. It also provides a new perspective for the study of transition metal systems. Here, based on density functional theory (DFT), the physical properties of 2D monolayer LiV2S4 have been studied. Remarkable changes have been observed, i.e., vanadium dimerization, ferromagnetism, charge distribution and metal–insulator transition (MIT). It is argued that the electronic instability leads to the V dimerization, which further lifts the degeneracy of charge distribution and stabilizes the charge and spin ordering state. [ABSTRACT FROM AUTHOR]

The ferroelectric nematic phase became the centre of interest of scientists because of its unique physical properties. The uniqueness of this particular phase results in its monotropic character in all known NF materials. Here we present the very first example of a compound with an enantiotropic ferroelectric nematic phase. Compound 3JK is complementary with already well known NF materials, i.e. RM734 and DIO and is characterized by moderately high dielectric anisotropy. [ABSTRACT FROM AUTHOR]

We report a novel and simplified synthetic procedure for making analogues of the widely studied ferroelectric nematogen RM734. Our new procedure focuses on building materials starting from the nitro-terminus and eschewing protecting groups, in contrast to previously reported syntheses. This new synthetic approach confers two principal advantages: firstly, the synthesis of the variants described herein is expedient, being a single step as opposed to three or more via the classical route. Secondly, by forgoing the use of benzyl groups as utilised in the original synthesis we can include functionality that is incompatible with hydrogenolysis conditions (e.g. olefins, late halogens, unsaturated heterocycles). Several of the RM734-like materials we report exhibit ferroelectric nematic phases, and we rationalise the behaviour of these materials with aid of electronic structure calculations, potential energy surface scans and atomistic molecular dynamics simulations. [ABSTRACT FROM AUTHOR]

Interfaces of ferromagnetic/organic material hybrid structures refer to the spin interface that governs physical properties for achieving high spin polarization, low impedance mismatch, and long spin relaxation. Spintronics can add new functionalities to electronic devices by taking advantage of the spin degree of freedom of electrons, which makes understanding the dynamic magnetic properties of magnetic films important for spintronic device applications. Our knowledge regarding the magnetic dynamics and magnetic anisotropy of combining ferromagnetic layer and organic semiconductor by microwave-dependent magnetic measurements remains limited. Herein, we report the impact of an organic layer on the dynamic magnetic behavior of nickel/rubrene bilayers deposited on a Si(100) substrate. From magnetic dynamic measurements, opposite signs of effective magnetic fields between the in-plane (IP) and out-of-plane (OP) configurations suggest that the magnetization of Ni(x)/rubrene/Si prefers to coexist. A shift in OP resonance fields to higher values can mainly be attributed to the enhanced second-order anisotropy parameter K2 value. Based on IP measurements, a two-magnon scattering mechanism is dominant for thin Ni(x)/rubrene/Si bilayers. By adding a rubrene layer, the highly stable IP combined with the tunable OP ferromagnetic resonance spectra for Ni(x)/rubrene/Si bilayers make them promising materials for use in microwave magnetic devices and spintronics with controllable perpendicular magnetic anisotropy. [ABSTRACT FROM AUTHOR]

Difficult-to-measure radionuclides (DTMRs), defined by an absence of high energy gamma emissions during decay, are problematic in groundwaters at nuclear sites. DTMRs are common contaminants at many nuclear facilities, with (often) long half-lives and high radiotoxicities within the human body. Effective remediation is, therefore, essential if nuclear site end-state targets are to be met. However, due to a lack of techniques for in situ DTMR detection, technologies designed to remediate these nuclides are underdeveloped and tend to be environmentally invasive. With a growing agenda for sustainable remediation and reduction in nuclear decommissioning costs, there is renewed international focus on the development of less invasive technologies for DTMR clean-up. Here, we review recent developments for remediation of selected problem DTMRs (129I, 99Tc, 90Sr and 3H), with a focus on industrial and site-scale applications. We find that pump and treat (P&T) is the most used technique despite efficacy issues for 129I and 3H. Permeable reactive barriers (PRBs) are a less invasive alternative but have only been demonstrated for removal of 99Tc and 90Sr at scale. Phytoremediation shows promise for site-scale removal of 3H but is unsuitable for 129I and 99Tc due to biotoxicity and bioavailability hazards, respectively. No single technique can remediate all DTMRs of focus. Likewise, there has been no successful site-applied technology with high removal efficiencies for iodine species typically present in groundwaters (iodide/I−, iodate/IO3− and organoiodine). Further work is needed to adapt and improve current techniques to field scales, as well as further research into targeted application of emerging technologies. [ABSTRACT FROM AUTHOR]

Metal phthalocyanines, which are examples of one-dimensional semiconductors, are widely used as active layers of chemiresistive sensors for detecting various gases, in particular ammonia. Despite the high interest in such sensors, there have been few systematic studies on the effect of the type of substituent and structural features of films on their chemiresistive response to gases. In this work, films of zinc phthalocyanine (ZnPc-1, 2, 3 and 4) bearing alkylthio (–S(CH2)5CH3) and polyoxo (–O(CH2CH2O)3CH3 and –S(CH2CH2O)3CH3) substituents, which exhibit liquid crystalline properties and, as a consequence, are capable of forming ordered films, were tested as active layers of chemiresistive sensors for the detection of low concentrations of ammonia (0.1–50 ppm). The effect of the type of substituent on the films' alignment and sensor response to ammonia was studied for the first time. It was shown that the films of all investigated zinc phthalocyanines demonstrated a reversible chemiresistive sensor response to gaseous ammonia. The sensor response of the as-deposited films of ZnPc-1 and ZnPc-2 with polyoxo-substituents, which are liquid crystalline at room temperature, was noticeably higher than that of ZnPc-3 and ZnPc-4, which form polycrystalline disordered films. The limit of ammonia detection was 17 ppb for ZnPc-1 and ZnPc-2 films. Heat treatment of ZnPc-1 and ZnPc-2 films did not cause any changes in their structure and sensor properties, while ZnPc-3 and ZnPc-4 films became more ordered after heating, and their sensor response increased several times. This led to a reduction in the detection limit of ammonia to 10 ppb in the case of the ZnPc-3 film. All investigated films have high selectivity to ammonia in the presence of carbon dioxide and vapors of some volatile organic compounds. [ABSTRACT FROM AUTHOR]

The local ordering of particles is considered an important process in glass transition. Ordering is usually observed in simulation and micrometer-sized colloid. However, clear information on local ordering at the molecular level is difficult to obtain experimentally. In this study, we prepared an easily glass-forming fluorophore with a color change owing to the intermolecular arrangement in the liquid, glass, and crystal states. The bathochromic shifts of the photoluminescence spectra indicated a change in the intermolecular orientation upon immediate cooling of the melt. The recovery of the spectra by successive heating indicated that rotation contributed to the change in the intermolecular orientation. The orientation in the glass was distinct from that during crystal growth, which was observed as a slow bathochromic shift by maintaining the temperature between the melting points of the blue- and green-luminescent crystals obtained from dichloromethane/ethanol and dichloromethane/hexane, respectively. Our results demonstrate that the anisotropic interaction between glass-forming luminophores is useful for uncovering molecular-level events in the glassy state. [ABSTRACT FROM AUTHOR]

We herein report two Zn(II)–terpyridine coordination polymers for photoredox reactions. One coordination polymer bearing the pyridinium unit is able to activate molecular O2 in air for photooxidation of organic substrates without external additives. Various kinds of organic compounds including sulfides, amines, alcohols, and N-heterocycles are oxidized into corresponding products under mild conditions. Moreover, this coordination polymer is also able to activate CO2 for photoreduction of CO2 with selective CO evolution. In contrast, the other coordination polymer exhibits no catalytic reactivity in aerobic photooxidation of organic substrates and displays a lower CO yield in photoreduction of CO2. Spectroscopic studies and photoelectrochemical measurements reveal that the former coordination polymer has a longer-lived photoexcited state, more efficient separation of photogenerated electrons and holes, and more stable active sites in photocatalysis. These findings provide key insights on photocatalytic performances of coordination polymers, and pave the way to rationally design multifunctional coordination polymers for both photooxidation and photoreduction reactions. [ABSTRACT FROM AUTHOR]

The direct CO2 hydrogenation to formic acid is appealing since it is a potential hydrogen storage material and can be a precursor of higher value-added products. Due to thermodynamic limitations, developing an efficient catalyst system for this process is quite a challenge. Herein, a Ni-based N-modified TiO2-supported catalyst that showed exemplary activity and selectivity toward formic acid synthesis (757 TON), which was reported to be the highest over noble metal-free catalyst system, is designed. The combined impact of Ni and N over TiO2 as a support was thoroughly investigated in this research for improved activity in the selective conversion of CO2 to formic acid. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy investigations showed direct coordination between Ni and N, which emphasizes the metal support interaction for significantly higher catalytic activity. In-depth characterization of Ni/N-TiO2 reveals that CO2 undergoes insertion reaction with H2 to yield formic acid on Ni0 as an active surface via the formate intermediate. Complementary DFT studies elucidate the pivotal effect of nitrogen doping on the TiO2 surface, which provides a more feasible pathway than pure TiO2 by lowering the activation barriers. More significantly, the catalyst demonstrated a steady performance in experiments involving continuous recycling and long-term study. [ABSTRACT FROM AUTHOR]

Recently, ferroelectric fluid, such as ferroelectric nematic liquid crystals (NFLCs) and ferroelectric smectic A LCs (SmAFLCs), has been of great fundamental and practical interest owing to its excellent polarization properties (e.g., dielectric permittivity, polarization, and nonlinear optical coefficient). To deeply understand the physical underpinning of such emergent ferroelectric phases and develop state-of-the-art device applications, effective preparation of various NF molecules is essential. Herein, to expand the NFLC molecular library, we implemented a mechanochemical (MC) technique for the production of LCs, demonstrating its high synthetic compatibility with NF/SmAFLCs. Chemical building blocks with high polarity can be bonded one by one through various ball-milling MC reactions, resulting in rapid access to NFLC molecules, a series of DIO, RM734, UUZU, and BIOTN, with high yield within 2.7–7 h for 4–8 steps. For a new DIO variant, in which a terminal alkyl chain was completely removed, for the first time, we discovered the direct phase transition from the isotropic liquid to the SmAF phase. Furthermore, the highly bistable polarization memory (∼5.2 μC cm−2) in the SmAF phases was evaluated using the positive–up–negative–down (PUND) method. [ABSTRACT FROM AUTHOR]

Oxidative chemical vapor deposition (oCVD) has developed progressively in the last two decades as a solvent-free (or dry) methodology for synthesis and thin film deposition of conjugated polymers. This method has offered new opportunities beyond traditional solution processing methods in the research of these materials. It is crucial to have a clear understanding of the differences between the solvent-free vs. solvent-based methodologies for synthesis and thin film deposition of conjugated polymers. Herein, the strengths and limitations of each procedure are compared in order to provide guidelines for future research and development. This review systematically approaches this comparison by first characterizing the thin films in terms of their chemical and physical properties. Then, the interfacial properties of a conjugated polymer thin film with the underlying substrate are critically compared when two different processing methods are exploited. Finally, the effect of the substrate on the coating properties and performance is reviewed. [ABSTRACT FROM AUTHOR]

The second-order nonlinear optical effect is the foundation of realizing optical wavelength regulation and conversion technology. Improved organic nonlinear optical materials have been shown in recent decades to deliver performances as good as those of inorganic materials, and are hence attracting a revisit by researchers with regards to applying their excellent nonlinear optical properties and processability toward modern flexible devices. Traditional high-performance organic nonlinear optical materials rely on D–π–A chromophores dispersed in apolar polymer systems. A strong electric field has usually been utilized for poling the D–π–A chromophore, which requires complicated processing and faces severe polarization relaxation issues. Here we provided a mechanism for an unprecedented enhancement of nonlinear properties. We employed fluidic ferroelectric nematics as a spontaneous polarization background acting as an internal electric field to polarize doped D–π–A chromophores. We revealed a synergetic effect of polarization enhancement results in a dramatic increase in second-harmonic generation, by about two orders of magnitude, compared to those of the corresponding undoped materials. [ABSTRACT FROM AUTHOR]