Semiorganic Nonlinear Optical Material: Preparation and Properties of (NH₄)·Sr[l-(+)-C₄H₂O₆·B(OH)₂]·4H₂O

The synthesis, crystal structure, and characterization of the noncentrosymmetric semiorganic material (NH4)·Sr[l-(+)-C4H2O6·B(OH)2]·4H2O were reported. Crystals were synthesized through slow evaporation at room temperature, utilizing SrCl2·6H2O, C4H4O6, H3BO3, and NH3·H2O as reagents, and its structure was determined by single-crystal X-ray diffraction. It crystallizes in the triclinic space group P1 (No. 1) with a = 6.4633(10) Å, b = 7.0452(13) Å, c = 7.0745(12) Å, α = 85.351(5)°, β = 77.678(5)°, γ = 73.276(4)°, and Z = 1. It exhibits a two-dimensional layered structure along the c axis, consisting of SrO9 polyhedra, BO4 tetrahedra, tartrate molecules, NH4+ cations, and H2O molecules. IR spectroscopy, UV−vis diffuse-reflectance spectroscopy, thermal analysis, and second-harmonic generation (SHG) were also performed on the reported material. Nonlinear optical measurements, using 1064 nm radiation, indicate that the material has SHG properties, with an efficiency of approximately 1.5 times that of KH2PO4

Reversible Transition between SDS@2β-CD Microtubes and Vesicles Triggered by Temperature

Switching between association and dissociation is the well-known strategy for constructing responsive materials based on the host–guest complexes of cyclodextrins (CDs). In this work, we report that temperature may also trigger self-assembly transition in the supramolecular system composed of sodium dodecyl sulfate (SDS) and β-cyclodextrin (β-CD) at a molar ratio of 1:2. We reported previously that, at this ratio, SDS and β-CD form a channel-type SDS@2β-CD supramolecular unit, which further self-assembles into non-amphiphilic vesicles and microtubes driven by hydrogen bonding. Here, we report that the vesicles and microtubes can be reversibly switched between each other upon decreasing and increasing temperature. Control experiments in heavy water suggest that water molecules play a dominating role in the hydrogen bonding between SDS@2β-CD supramolecular units at lower concentration and higher temperature. Under opposite conditions, the hydrogen bonding between CDs is dominating. Therefore, for the 5% system, we observed a vesicle to microtube transition with a decreasing temperature, whereas for the 10% system, we observed the reverse process. Both processes are reversible. This is not only an example of temperature-triggered responsiveness in non-amphiphilic self-assemblies but also a new mode of responsiveness for the host–guest inclusion systems based on CDs. This temperature-responsive process is anticipated to shed light on the design and development of novel advanced materials

Adsorption Behavior of Diclofenac on Polystyrene and Poly(butylene adipate-<i>co</i>-terephthalate) Microplastics: Influencing Factors and Adsorption Mechanism

To unveil the intricacies surrounding the interaction between microplastics (MPs) and pollutants, diligent investigation is warranted to mitigate the environmental perils they pose. This exposition delves into the sorption behavior and mechanism of diclofenac sodium (DCF), a contaminant, upon two distinct materials: polystyrene (PS) and poly(butylene adipate-co-terephthalate) (PBAT). Experimental adsorption endeavors solidify the observation that the adsorption capacity of DCF onto the designated MPs amounts to Q(PBAT) = 9.26 mg g–1 and Q(PS) = 9.03 mg g–1, respectively. An exploration of the factors governing these discrepant adsorption phenomena elucidates the influence of MPs and DCF properties, environmental factors, as well as surfactants. Fitting procedures underscore the suitability of the pseudo-second-order kinetic and Freundlich models in capturing the intricacies of the DCF adsorption process onto MPs, corroborating the notion that the mentioned process is characterized by non-homogeneous chemisorption. Moreover, this inquiry unveils that the primary adsorption mechanisms of DCF upon MPs encompass electrostatic interaction, hydrogen bonding, and halo hydrogen bonding. An additional investigation concerns the impact of commonly encountered surfactants in aqueous environments on the adsorption of DCF onto MPs. The presence of surfactants elicits modifications in the surface charge properties of MPs, consequently influencing their adsorption efficacy vis-à-vis DCF

Semiorganic Nonlinear Optical Material: Preparation and Properties of (NH₄)·Sr[l-(+)-C₄H₂O₆·B(OH)₂]·4H₂O

The synthesis, crystal structure, and characterization of the noncentrosymmetric semiorganic material (NH4)·Sr[l-(+)-C4H2O6·B(OH)2]·4H2O were reported. Crystals were synthesized through slow evaporation at room temperature, utilizing SrCl2·6H2O, C4H4O6, H3BO3, and NH3·H2O as reagents, and its structure was determined by single-crystal X-ray diffraction. It crystallizes in the triclinic space group P1 (No. 1) with a = 6.4633(10) Å, b = 7.0452(13) Å, c = 7.0745(12) Å, α = 85.351(5)°, β = 77.678(5)°, γ = 73.276(4)°, and Z = 1. It exhibits a two-dimensional layered structure along the c axis, consisting of SrO9 polyhedra, BO4 tetrahedra, tartrate molecules, NH4+ cations, and H2O molecules. IR spectroscopy, UV−vis diffuse-reflectance spectroscopy, thermal analysis, and second-harmonic generation (SHG) were also performed on the reported material. Nonlinear optical measurements, using 1064 nm radiation, indicate that the material has SHG properties, with an efficiency of approximately 1.5 times that of KH2PO4

Co@Co₃O₄ Prepared in Situ from Metallic Co as an Efficient Semiconductor Catalyst for Photocatalytic Water Oxidation

This paper reported the first attempt of using Co@Co₃O₄ core–shell nanoparticles obtained in situ from a metallic Co precursor as a highly active and stable catalyst for the photocatalytic water oxidation. Co nanoparticle precursor was prepared through a hydrothermal process. The components of precursor and catalyst were confirmed by multiple measurements (X-ray diffraction, field emission scanning electron microscopy, scanning transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, line scanning analysis, UV–vis diffuse reflectance spectroscopy, Mott–Schottky curve). The Co@Co₃O₄ semiconductor catalyst exhibited excellent activity for the photocatalytic water oxidation without any addition of photosensitizer or cocatalyst, with an average O₂ evolution rate of 2778 μmol h^–1 g^–1, and the Co@Co₃O₄ maintained 90% of the initial activity even after the sixth run; its oxygen evolution reaction performance under λ = 600 and 765 nm still remained 16% and 7.2% of λ ≥ 420 nm, respectively. The high activity of this photocatalyst was strongly dependent on the generation of Co₃O₄ nanoclusters on the surface of metallic Co. The synergistic effect between Co₃O₄ and metallic Co was helpful for electron transfer and separation and catalytic performance improvement, because metallic Co played a crucial role during the water oxidation process

High-Efficiency Bimetallic Catalyst Prepared in Situ from Prussian Blue Analogues for Catalytic Water Oxidation

The synergistic catalysis of bimetallic catalysts is one of the important ways to improve the catalytic performance; therefore, the development of efficient bimetallic water oxidation catalysts (WOCs) has received extensive attention. This work proposed a bimetallic Fe3O4/CuO catalyst prepared in situ from the Cu–Fe Prussian blue analogues precursor, promoting Fe3O4-modified CuO as a highly efficient and stable bimetallic WOC. The Fe3O4/CuO exhibits superior and robust catalytic activity for the oxidation of water. Compared with the reported results, it has a higher O2 evolution rate of about 4406 μmol·h–1·g–1 and a maximum value for the yield of O2 as 83.2%, mainly because of the synergetic effect between Fe3O4 and CuO in the complicated water oxidation reaction (WOR) process. We hope this work will be useful for other researchers to design new transition metal bimetallic catalysts for WOR

Construction of Zn_<i>x</i>Cd_<i>y</i>S with a 3D Hierarchical Structure for Enhanced Photocatalytic Hydrogen Production from Water Splitting

The ZnxCdyS has been proven to have unique photoelectric properties, but its synthesis method and photocatalytic water cracking performance need to be further improved. In this paper, Cd-MOF@ZIF-8 with a MOF-on-MOF (MOF = metal–organic framework) structure was prepared by a simple ion adsorption method. Then, a CdS/ZnxCdyS heterojunction with a 3D hierarchical structure was formed by solvothermal sulfidation. The prepared catalysts with different Zn/Cd ratios show an improved hydrogen production performance for photocatalytic water splitting, and the hydrogen evolution rate of Zn1Cd1S can reach up to 29.2 mmol·g–1·h–1. The excellent photocatalytic activity not only benefits from ZnxCdyS strong light conversion ability but also is closely related to the hierarchical structure and large specific surface area. A type II heterojunction also plays an important role in the spatial separation of photogenerated carriers. This paper provides a simple and feasible idea for the synthesis of a photocatalyst with a large specific surface area using a MOF-on-MOF synthesis strategy

Intersystem Crossing in Acceptor–Donor–Acceptor Type Organic Photovoltaic Molecules Promoted by Symmetry Breaking in Polar Environments

The intramolecular electron push–pulling effect has been widely applied to manipulate the excited states in organic photovoltaic (OPV) molecules toward efficient photocurrent generation in working devices with bias fields. However, the effect of field induced polar environments on the excited-state dynamics remains largely unexplored. Here, we investigate the polar environment effect on excited dynamics in acceptor–donor–acceptor type OPV molecules dissolved in solvents with different polarities. By combining ultrafast transient absorption spectroscopy and quantum chemical computation, we observe the stabilization of excited states induced by symmetry breaking in the polar solvent in the molecules exhibiting strong electron push–pulling effects. The stabilized excited states undergo faster intersystem crossing processes with reduced singlet–triplet energy gaps. The findings suggest that the dynamics of charge generation and recombination may be controlled by manipulating the polar environment and electron push–pulling effect to improve the device performance

Coordinating Self-Assembly of Copper Perylenetetracarboxylate Nanorods: Selectively Lighting up Normal Cells around Cancerous Ones for Better Cancer Diagnosis

Specific imaging of cancer cells has been well-accepted in cancer diagnosis although it cannot precisely mark the boundary between the normal and cancerous cells and report their mutual influence. We report a nanorod fluorescent probe of copper perylenetetracarbonate (PTC-Cu) that can specifically light up normal cells. In combination with cancer cell imaging, the cocultured normal and cancer cells can be lit up with different colors, offering a clear contrast between the normal and cancer cells when they coexist. Because cancerous cells are only 20–30% in cancer area, this provides a possibility to visibly detect the mutual influence between the cancer and normal cells during therapy. We expect this method is beneficial to better cancer diagnosis and therapy

Synthesis, Structure, and Properties of the Noncentrosymmetric Hydrated Borate Na₂B₅O₈(OH)·2H₂O

Single crystal of hydrated sodium borate Na2B5O8(OH)·2H2O has been grown with sizes up to 5 × 5 × 3 mm3 under mild hydrothermal conditions at 180 °C. The structure is determined by single-crystal X-ray diffraction and further characterized by IR and TG analyses. It crystallizes in the orthorhombic space group Pna21, with a = 11.967(2) Å, b = 6.5320(13) Å, c = 11.126(2) Å, Z = 4, R1 = 0.0183, and wR2 = 0.0483. The crystal structure of Na2B5O8(OH)·2H2O is made up of Na−O polyhedra, and [B5O8(OH)]2− polyborate anions. Transmittance spectrum is performed on the Na2B5O8(OH)·2H2O crystal, which shows an absorption edge less than 190 nm in the UV region. The powder second-harmonic generation intensity measured by the Kurtz−Perry method indicates that Na2B5O8(OH)·2H2O is about half that of KH2PO4 (KDP)