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The design and development of organic solid-state luminescent materials stand as crucial pillars within the realm of contemporary photofunctional materials. Overcoming challenges such as concentration quenching and achieving tailored luminescent properties necessitates a judicious approach to molecular structure design and the strategic utilization of diverse stimuli to modulate molecular packing patterns. Among the myriad candidates, α-cyanodiarylethenes (CAEs) emerge with distinctive solid-state luminescent attributes, capable of forming self-assembled packing structures with varying degrees of π–π stacking. This characteristic endows them with potential in the field of intelligent molecular responsive materials and optoelectronic devices. This tutorial review embarks on an exploration of design strategies geared towards attaining tunable solid-state emission through customized packing of CAEs. It explores the utilization of stimuli responses, including such as mechanical forces, light irradiation, solvent interactions, thermal influences, as well as the utilization of co-assembly methodologies. The overarching aim of this review is to provide a widely applicable platform fostering the flourishing development of modern organic photofunctional materials through integrating principles of molecular engineering, organic optoelectronics, and materials science. [ABSTRACT FROM AUTHOR]

The electrocatalytic CO2 reduction reaction (CO2RR) offers a fascinating approach to converting CO2 into valuable chemical feedstocks. Up to now, the development of highly efficient electrocatalysts has been a significant bottleneck in this field. In this study, employing density functional theory (DFT) calculations, we design a range of stable two-dimensional (2D) metalloporphyrin organic frameworks (TM-PMOFs, TM = Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, and Ag, respectively) built by copper clusters and metalloporphyrin (TM-TCPP), whose CO2RR performance is studied in detail. Among them, the 2D cobaltporphyrin-based organic framework (Co-PMOF) is identified to be the best CO2RR electrocatalyst on account of its low limiting potential (−0.53 V), whose enhanced electrocatalytic performance can be attributed to the presence of numerous active sites on both sides of its 2D framework, as well as the synergistic effect between copper clusters and cobaltporphyrins in facilitating CO2 reduction. These findings provide valuable insights and encourage further experimental research on metallic 2D PMOF materials for CO2 electrochemical reduction. [ABSTRACT FROM AUTHOR]

Organic molecular framework materials are an emerging type of porous material formed by discrete molecules through weak supramolecular interactions. They have unique flexibility, solution processability and potential applications in gas adsorption and separation, molecular transport and so on. The frameworks with aggregation-induced emission properties, represented by tetraphenylethylene and other fluorophores, provide an expansion property for the fluorescence visualization of molecular organic frameworks. In this review, we feature organic framework materials based on tetraphenylethylene in the last ten years, focusing on the formation of frameworks, fluorescent properties and corresponding applications, and further discuss their development. This article will provide a reference for those who pay attention to the materials that combine molecular frameworks and fluorescence. [ABSTRACT FROM AUTHOR]

Imidazole is an important heterocyclic motif and its derivatives are widely used in many fields such as catalysis, medicine, and smart sensors. Here we report the synthesis of four imidazole derivatives (M1, M2, M3, and M4) with different fused aromatics as fluorescent sensors for picric acid (PA) detection. The four compounds with modifications of triphenylamine or tetraphenylethylene at the N1 and C2 positions of the imidazole ring exhibit typical aggregation-induced emission (AIE) properties. The single crystallography results indicate that the bright luminescence is ascribed to the rigidified molecular conformation by multiple weak interactions. As PA probes, M1–M4 show high selectivity and sensitivity in the tetrahydrofuran/water mixture (fw = 99%). The detection limits are as low as 10−9 M. Mechanism study suggests that photoinduced electron transfer (PET) is responsible for PA detection. These AIE-active imidazole derivatives have been demonstrated to be convenient and easily operating sensors for PA detection. [ABSTRACT FROM AUTHOR]

A novel palladium polyaniline complex (Pd@PANI) was synthesized via a one-pot method using a low concentration of hydrogen peroxide (3 wt%) as a mild oxidant. Pd@PANI was employed to catalyze Suzuki–Miyaura cross-couplings with 0.11 ppm levels of palladium and high turnover numbers (up to 6.1 × 104). Various aromatic halides and aromatic boric acids were used as reaction partners to prepare the biaryl compounds in high yields. Application of the method in the synthesis of D -fructose derivatives was also performed. Furthermore, the catalyst was evaluated under a flow process to provide the corresponding products in good yields with shorter residence times and lower temperatures in more convenient operations compared with the batch conditions. [ABSTRACT FROM AUTHOR]

There is an urgent demand for the rapid and sensitive analysis of uranyl ions and uranyl compounds in environmental monitoring and nuclear emergency fields. However, most of the current analytical techniques do not provide both the content of uranyl ions and the structural information of uranyl compounds in trace level. Comparatively, surface-enhanced Raman scattering (SERS) can achieve the single molecule detection and provide the structural information of molecules as well. Hence, SERS has become a suitable solution for the in situ analysis of trace uranyl species, especially when coupled with a portable Raman spectrometer. This review systematically introduces the SERS studies of uranyl ions and uranyl compounds in recent years, including the fabrication of silver and gold substrates with a high density of "hotspots" and excellent stability, the performances of different substrates in the quantitative detection of uranyl ions and structural analysis of uranyl compounds, and the explanations for the Raman enhancement mechanisms of uranyl ions. Additionally, the developments about the field assay of uranyl ions are also elaborated to further evaluate the practical application prospect of the SERS technique. Finally, we dissect the current problems existing in this field and thus provide a valuable reference for the trend and future direction. [ABSTRACT FROM AUTHOR]

An efficient hydrophobic condensation surface was developed and used as an ultrasensitive surface-enhanced Raman scattering (SERS) sensor. The sensors were based on ZnO–Ag hybrid mesoporous nanosheets (MNSs) grafted on ordered Si micropillar arrays for detection of explosives. The hybrid SERS substrates were prepared via three steps: first, the ZnO seeds were precoated onto highly ordered Si micropillar arrays through atomic layer deposition; second, porous ZnO nanosheet arrays were grown based on ZnO seeds via chemical bath deposition by a secondary solvent addition method. Finally, ion-sputtering of Ag-nanoparticles (NPs) onto the ZnO MNSs was performed. Because the ordered Si micropillar arrays with a high aspect ratio provided 3D framework structures, the 3D ZnO MNSs of the Si pillar also generated three types of SERS active "hot spots". And the excellent SERS effect induced by the three different "hot spots" from 3D structures was further theoretically confirmed by simulating the electromagnetic field distributions. What's really interesting was that the prepared substrates showed superhydrophobicity. Based on the hydrophobic condensation strategy, hazardous explosives of NTO, FOX-7 were label-free detected in real samples like tap water and river water. And these samples, which were spiked with nitrophenylamine explosive TNT, were also selectively detected by secondary solvent addition under the 4-aminothiophenol (4-ATP)-modified superhydrophobic surface. Because the electronic transfer compensation effect of the hybrids ensured the stability of substrates, ZnO–Ag MNS hybrid substrates could be used for ultrasensitive detection of explosives after being stored for 49 days. Therefore, these effective SERS substrates demonstrated a promising application in forensic science and homeland security. [ABSTRACT FROM AUTHOR]

The construction of a nano-heterojunction photoanode is an attractive strategy for accelerated charge separation. Here, α-Fe2O3 nanorod arrays (Fe2O3 NAs) top-decorated with an MIL-101 layer are achieved via the CVD method for constructing one intimate contact between two layers. The systematical analysis in time-dependent deposition shows that the photoelectric response capability can be modulated by controlling the thickness of the MIL-101 layer as a function of CVD duration. An optimized thickness of 4–6 nm MIL-101 in the Fe2O3/MIL-101 photoanode presents the best PEC performance with the IPCE of 25% and a photocurrent density of 1 mA cm−2 at 1.3 V vs. RHE, about 2.5 times higher than that of pristine Fe2O3 NAs. The exciton lifetime and the electrochemical active surface area of the composited electrode are greatly improved by 14 and 1.3 times respectively compared to that of pristine Fe2O3. The notable advancement can be attributed to the fact that the top-decorated MOF layer can promote charge separation efficiency led by the built-in electric field and form a tight interface between Fe2O3 and MIL-101 with a favorable diffusion length for holes, as well as the fact that it can reduce surface defects and provide more reaction sites. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) is one of the most promising methods in detecting trace amounts of molecules owing to its high sensitivity, fast response, and high molecular specificity. One of the key issues for SERS applications is to fabricate highly sensitive and homogeneous SERS substrates. Here, we present a template-assisted synthetic approach to fabricate urchin-like Ag-nanoparticle (Ag-NP) decorated ZnO-nanorods grafted on hexagonally ordered polyacrylonitrile (PAN) nanopillar arrays as flexible and reliable surface-enhanced Raman scattering (SERS) substrates, which are achieved by a combined process of molding highly ordered PAN-nanopillar array films, electrochemical depositing ZnO nanorods onto molded PAN nanopillar arrays, then sputtering Ag-NPs onto the surface of ZnO nanorods. The resultant hetero-hierarchical nanostructure exhibits not only much stronger SERS activity but also uniform SERS signals over the whole arrays based on the high density of nanogaps (hot spots) between the neighboring Ag-NPs on both the same ZnO-nanorods and adjacent ZnO-nanorods and the highly ordered PAN-nanopillar arrays. Using the Ag-NP assembled ZnO-nanorod arrays as SERS-substrates, not only 10−13 M Rhodamine 6G has been identified, but also 10−8 M parathion-methyl has been recognized, showing great potential in detection of trace organic pollutants in the environment. Furthermore, the Ag-NPs@ZnO-nanorods could achieve self-cleaning and reactivation of SERS-activity by simple UV light irradiation and retain stable SERS sensitivity even after five cycles, demonstrating the high reusability of the hybrid substrates. [ABSTRACT FROM AUTHOR]

3D biomimetic superhydrophobic Ag micro/nano-pillar array (AMA) surfaces as SERS substrates were prepared for ultrasensitive and reproducible detection of explosives such as picric acid (PA) and 3-nitro-1,2,4-triazol-5-one (NTO) by a simple, efficient, and inexpensive hydrophobic condensation strategy. We took advantage of different kinds of Si pillar arrays (biomimetic structure based on cicada wing topography) as templates for electrochemical deposition generation of 3D AMA. We studied the effects of biomimetic superhydrophobicity and different AMA micro-morphology on SERS performance from a macro and micro perspective, respectively. For the first time, simple hydrophilic organic synthesis process was also conducted to improve poor water-solubility of toxins to aid detection. Such SERS sensors exhibited high sensitivity to rhodamine 6G (R6G) in a low concentration of 10−15 mol L−1, PA in a low concentration of 10−12 mol L−1, and NTO in concentration as low as 10−13 mol L−1 after hydrophilic synthesis. This method of hydrophobic condensation of substrates resolved the problems for extremely low concentration of organic solutions of toxins in difficulty to SERS detection. Furthermore, it was found to be very useful to improve practical application of portable Raman detection devices to detect low-solubility protonic toxins. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymer hollow spheres (MIHSs) were produced by using hexanitrohexaazaisowurtzitane (HNIW or CL-20) as a template, silica nanospheres as a sacrificial matrix, acrylamide as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and acetonitrile as a porogen at 4 °C under UV irradiation. This sorbent was applied to the selective solid-phase extraction (SPE) of several explosives simultaneously by using a newly-developed SPE procedure. For the first time, 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX) and CL-20 were selectively extracted and determined simultaneously from simulated post-blast samples prepared from motor oil and vacuum pump oil. The matrix effects were successfully eliminated and accurate quantization was achieved. When the loading amounts of HMX, RDX, TNT and CL-20 were, respectively, below 10, 2, 5 and 20 nmol for 100 mg of MIHS, these explosives were almost retrieved completely (above 98%). For the MIHSs and non-imprinted polymer hollow spheres (NIHSs), in acetonitrile and methanol, the imprinting factors (IFs) of CL-20 and tetraacetyldibenzylhexaazaisowurtzitane (TADB, a structural analogue of CL-20) changed dramatically, from 7.75 to 1.57 and 0.88 to 2.39, respectively. It highlighted the significant effect of solvents on imprinted sites. [ABSTRACT FROM AUTHOR]

An efficient and green approach was used to fabricate novel and low-cost surface-enhanced Raman scattering (SERS) spectroscopy sensors based on 4-aminothiophenol (4-ATP) functionalized ZnO–Ag hybrid nanoflowers for the detection of explosives. Such SERS sensors exhibited high sensitivity to rhodamine 6G (R6G) at a low concentration of 10−12 M and an enhancement factor of over 4.12 × 106 was achieved. Moreover, the Raman-inactive trinitrotoluene (TNT) initiated the high Raman scattering of non-resonated 4-ATP through the formation of a π-donor–π-acceptor interaction between the π-acceptor, TNT, and the π-donor, the 4-ATP–Ag–ZnO complex, on the flower-like hybrids. Because this π-donor–π-acceptor interaction could effectively induce the “hot spots” for SERS, TNT concentrations as low as 5 × 10−9 M could be detected. Furthermore, other derivatives of TNT were also explored, and this sensor exhibited better selectivity for TNT than other similarly structured explosives. The low-cost hybrid SERS substrates presented good sensitivity and reproducibility for the analytes employed, demonstrating promising application in forensic science and homeland security. [ABSTRACT FROM AUTHOR]

A chiral N,N′-dioxide–Ni(ii) complex was found to exhibit highly enantioselective fluorescent recognition of chiral amines and amino alcohols. It can be used to determine their concentration and ee value. Using a 96-well plate, high-throughput screening for enantiomer discrimination was accomplished. [ABSTRACT FROM AUTHOR]

Oxygen vacancy sites on a catalyst surface have been extensively studied and been proved to promote the adsorption and activation of carbon dioxide. We use Sn-doped ZrO 2 to prepare a Zr/Sn catalyst rich in oxygen vacancies (OVs) by co-precipitation. The yield of dimethyl carbonate is 5 times that of ZrO 2 . Compared with the original ZrO 2 , Zr/Sn exhibits a higher specific surface area, number of acid-base sites and a lower band gap, which improves the conductivity of electrons and creates more surface. The number of reaction sites greatly enhances the adsorption and activation capacity of CO 2 molecules on the catalyst surface. In situ infrared spectroscopy shows that CO 2 adsorbs on oxygen vacancies to form monomethyl carbonate, and participates in the reaction as an intermediate species. This work provides new clues for the preparation of ZrO 2 -based catalysts rich in oxygen vacancies to directly catalyze the synthesis of dimethyl carbonate from methanol and CO 2 ., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)