ROS-responsive thermosensitive polypeptide hydrogels for localized drug delivery and improved tumor chemoimmunotherapy.

In this study, we developed a ROS-responsive thermosensitive poly(ethylene glycol)-polypeptide hydrogel loaded with a chemotherapeutic drug, doxorubicin (Dox), an antiviral imidazoquinoline, resiquimod (R848), and antibody targeting programmed cell death protein 1 (aPD-1) for local chemoimmunotherapy. The hydrogel demonstrated controllable degradation and sustained drug release behavior according to the concentration of ROS in vitro. Following intratumoral injection into mice bearing B16F10 melanoma, the Dox/R848/aPD-1 co-loaded hydrogel effectively inhibited tumor growth, prolonged animal survival time and promoted anti-tumor immune responses with low systemic toxicity. In the postoperative model, the Dox/R848/aPD-1 co-loaded hydrogel exhibited enhanced tumor recurrence prevention and long-term immune memory effects. Thus, the hydrogel-based local chemoimmunotherapy system demonstrates potential for effective anti-tumor treatment and suppression of tumor recurrence.

Injectable, Adhesive Albumin Nanoparticle-Incorporated Hydrogel for Sustained Localized Drug Delivery and Efficient Tumor Treatment.

Injectable hydrogels are receiving increasing attention as local depots for sustained anticancer drug delivery. However, most current hydrogel-based carriers lack tissue-adhesive ability, a property that is important for the immobilization of drug-loaded systems at tumor sites to increase local drug concentration. In this study, we developed a paclitaxel (PTX)-loaded injectable hydrogel with firm tissue adhesion for localized tumor therapy. PTX-loaded bovine serum albumin (BSA) nanoparticles (PTX@BN) were prepared, and the drug-loaded hydrogel was then fabricated by cross-linking PTX@BN with o-phthalaldehyde (OPA)-terminated 4-armed poly(ethylene glycol) (4aPEG-OPA) via a condensation reaction between OPA and the amines in BSA. The hydrogel showed firm adhesion to various organs and tumor tissues ex vivo due to the condensation reaction of unreacted OPA groups and amines in the tissues. The PTX-loaded nanocomposite hydrogels sustained PTX release over 30 days following the Korsmeyer-Peppas model and exhibited notable inhibition activities against mouse C26 colon and 4T1 breast cancer cells in vitro. Following peritumoral injection into mice with C26 or 4T1 tumors, the PTX@BN-loaded hydrogel significantly enhanced the antitumor efficacy and prolonged animal survival time compared to free PTX solutions with low systemic toxicity. Therefore, the adhesive, PTX-loaded nanocomposite hydrogels have the potential for efficient localized tumor therapy.

[Mechanism of Gegen Qinlian Decoction in improving glucose metabolism in vitro and in vivo by alleviating hepatic endoplasmic reticulum stress].

This study investigated the mechanism of Gegen Qinlian Decoction(GQD) in improving glucose metabolism in vitro and in vivo by alleviating endoplasmic reticulum stress(ERS). Molecular docking was used to predict the binding affinity between the main effective plasma components of GQD and ERS-related targets. Liver tissue samples were obtained from normal rats, high-fat-induced diabetic rats, rats treated with metformin, and rats treated with GQD. RNA and protein were extracted. qPCR was used to measure the mRNA expression of ERS marker glucose-regulated protein 78(GRP78), and unfolded protein response(UPR) genes inositol requiring enzyme 1(Ire1), activating transcription factor 6(Atf6), Atf4, C/EBP-homologous protein(Chop), and caspase-12. Western blot was used to detect the protein expression of GRP78, IRE1, protein kinase R-like ER kinase(PERK), ATF6, X-box binding protein 1(XBP1), ATF4, CHOP, caspase-12, caspase-9, and caspase-3. The calcium ion content in liver tissues was determined by the colorimetric assay. The ERS-HepG2 cell model was established in vitro by inducing with tunicamycin for 6 hours, and 2.5%, 5%, and 10% GQD-containing serum were administered for 9 hours. The glucose oxidase method was used to measure extracellular glucose levels, flow cytometry to detect cell apoptosis, glycogen staining to measure cellular glycogen content, and immunofluorescence to detect the expression of GRP78. The intracellular calcium ion content was measured by the colorimetric assay. Whereas Western blot was used to detect GRP78 and ERS-induced IRE1, PERK, ATF6, and eukaryotic translation initiation factor 2α(eIF2α) phosphorylation. Additionally, the phosphorylation levels of insulin receptor substrate 1(IRS1), phosphatidylinositol 3-kinase regulatory subunit p85(PI3Kp85), and protein kinase B(Akt), which were involved in the insulin signaling pathway, were also measured. In addition, the phosphorylation levels of c-Jun N-terminal kinases(JNKs), which were involved in both the ERS and insulin signaling pathways, were measured by Western blot. Molecular docking results showed that GRP78, IRE1, PERK, ATF4, and various compounds such as baicalein, berberine, daidzein, jateorhizine, liquiritin, palmatine, puerarin and wogonoside had strong binding affinities, indicating that GQD might interfere with ERS-induced UPR. In vivo results showed that GQD down-regulated the mRNA transcription of Ire1, Atf6, Atf4, Grp78, caspase-12, and Chop in diabetic rats, and down-regulated GRP78, IRE1, PERK, as well as ERS-induced apoptotic factors ATF4 and CHOP, caspase-12, caspase-9, and caspase-3, while up-regulating XBP1 to enhance adaptive UPR. In addition, GQD increased the calcium ion content in liver tissues, which facilitated correct protein folding. In vitro results showed that GQD increased glucose consumption in ERS-induced HepG2 cells without significantly affecting cell viability, increased liver glycogen synthesis, down-regulated ATF6 and p-eIF2α(Ser51), and down-regulated IRE1, PERK, and GRP78, as well as p-IRS1(Ser312) and p-JNKs(Thr183/Tyr185), while up-regulating p-PI3Kp85(Tyr607) and p-Akt(Ser473). These findings suggested that GQD alleviates excessive ERS in the liver, reduces insulin resistance, and improves hepatic glucose metabolism in vivo and in vitro.

Internal reference self-powered aptasensor for on-site detection of MC-RR used sunlight as light source and CoMoS4 hollow nanospheres as photocathode.

As a liver toxin, long-term exposure of microcystin-arginine-arginine (MC-RR) is harmful to the ecological environment and human health, so it is necessary to realize on-site detection of MC-RR. The self-powered sensor has enormous potential for on-site detection in battery-free devices. However, due to the low photoelectric conversion efficiency and poor anti-interference ability to environmental fluctuation, the field detection of self-powered sensor is limited. Herein, we tackled above problems according to the following two aspects. For one hand, CoMoS4 hollow nanospheres modified internal reference electrode was arranged in the self-powered sensor, which effectively avoided the influence of unstable sunlight caused by different space, time, weather and other factors. For the other hand, dual-photoelectrode could absorb and convert sunlight, so as to improve the solar capture and energy utilization, and realized the sunlight instead of traditional external light source (Xenon lamp or LED, etc.). This method effectively simplified the sensing device and solved the interference of environment in on-site detection. In addition, multimeter was used to measure the output voltage instead of electrochemical workstation, achieving the purpose of portability. This work established a sunlight-driven internal reference self-powered sensor with miniaturization, portability and anti-interference to realize MC-RR on-site monitoring in lake water.

pH- and Temperature-responsive Hydrogels Based on Tertiary Amine-modified Polypeptides for Stimuli-responsive Drug Delivery.

pH- and temperature-responsive hydrogels have attracted considerable attention due to their responsiveness to dual physiologically-relevant stimuli. In this study, we developed stimuli-responsive hydrogels based on monomethoxy poly(ethylene glycol) (mPEG)-polypeptide block copolymers containing various tertiary amine pendants (EEP-TAs). The EEP-TAs were synthesized via ring-opening copolymerization of α-amino acid N-carboxyanhydrides, and further modified post-polymerization with click chemistry. The EEP-TAs exhibited an α-helix-to-ß-sheet transition when the pH was increased from 4.0 to 7.4. At elevated polymer concentrations, aqueous solutions of the EEP-TAs underwent thermo-induced sol-gel phase transitions, which were dependent on the pH. The hydrogels almost fully degraded within 3 weeks in the subcutaneous layer of mice and exhibited good histocompatibility in vivo. Additionally, doxorubicin (DOX)-loaded hydrogels exhibited pH-responsive drug release profiles in vitro, which were composed of rapid release at acidic pH and more sustained release at neutral pH. Thus, these polypeptide hydrogels hold potential as depots for environment-responsive delivery of therapeutic agents.

Pressure-Induced Structural Phase Transition and Enhanced Interlayer Coupling in Two-Dimensional Ferromagnet CrSiTe3.

The two-dimensional van der Waals ferromagnetic semiconductor CrSiTe3 has attracted growing interest as an intrinsic topological magnet. Both superconductivity and enhancement of ferromagnetism, usually competing for orders, have been observed in CrSiTe3 at high pressure. However, the high-pressure structure of CrSiTe3 is still unclear, setting obstacles in understanding pressure-induced novel physics. Here, combining the Raman spectra and first-principles calculations, the structure of CrSiTe3 at high pressure has been clarified. The interlayer breathing mode located at ∼42.1 cm-1 has been observed for the first time in CrSiTe3 by ultralow-frequency Raman spectroscopy at high pressure. Theoretical calculations confirm a phase transition from the R3̅ phase to the R3 phase accompanying noticeable enhancement of the Curie temperature. Our results highlight ultralow-frequency Raman spectroscopy combined with high pressure for detecting and modulating the structure and interlayer coupling of two-dimensional materials.

Injectable Polypeptide Hydrogel Depots Containing Dual Immune Checkpoint Inhibitors and Doxorubicin for Improved Tumor Immunotherapy and Post-Surgical Tumor Treatment.

In this work, we developed a strategy for local chemo-immunotherapy through simultaneous incorporation of dual immune checkpoint blockade (ICB) antibodies, anti-cytotoxic T-lymphocyte-associated protein 4 (aCTLA-4) and anti-programmed cell death protein 1 (aPD-1), and a chemotherapy drug, doxorubicin (Dox), into a thermo-gelling polypeptide hydrogel. The hydrogel encapsulating Dox or IgG model antibody showed sustained release profiles for more than 12 days in vitro, and the drug release and hydrogel degradation were accelerated in the presence of enzymes. In comparison to free drug solutions or hydrogels containing Dox or antibodies only, the Dox/aCTLA-4/aPD-1 co-loaded hydrogel achieved improved tumor suppression efficiency, strengthened antitumor immune response, and prolonged animal survival time after peritumoral injection into mice bearing B16F10 melanoma. Additionally, after injection of Dox/aCTLA-4/aPD-1 co-loaded hydrogel into the surgical site following tumor resection, a significantly enhanced inhibition on tumor reoccurrence was demonstrated. Thus, the polypeptide hydrogel-based chemo-immunotherapy strategy has potential in anti-tumor therapy and the prevention of tumor reoccurrence.

Coherent Control and Magnetic Detection of Divacancy Spins in Silicon Carbide at High Pressures.

Spin defects in silicon carbide appear to be a promising tool for various quantum technologies, especially for quantum sensing. However, this technique has been used only at ambient pressure until now. Here, by combining this technique with diamond anvil cell, we systematically study the optical and spin properties of divacancy defects created at the surface of SiC at pressures up to 40 GPa. The zero-field-splitting of the divacancy spins increases linearly with pressure with a slope of 25.1 MHz/GPa, which is almost two-times larger than that of nitrogen-vacancy centers in diamond. The corresponding pressure sensing sensitivity is about 0.28 MPa/Hz-1/2. The coherent control of divacancy demonstrates that coherence time decreases as pressure increases. Based on these, the pressure-induced magnetic phase transition of Nd2Fe14B sample at high pressures was detected. These experiments pave the way to use divacancy in quantum technologies such as pressure sensing and magnetic detection at high pressures.

[Anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol against H_2O_2-induced oxidative damage in pancreatic ß cells (INS-1 cells)].

The present study investigated the anti-oxidative and anti-apoptotic effects and molecular mechanisms of catalpol on the H_2O_2-induced pancreatic ß-cells(INS-1 cells).The oxidative damage model of INS-1 cells was induced and optimized by the stimulation of H_2O_2 of different concentrations for different time.CCK-8 assay was used to detect cell viability after catalpol intervention(1, 5, 10, 20, 40, 80, and 160 µmol·L~(-1)) for 24 h.Intracellular reactive oxygen species(ROS), superoxide dismutase(SOD), and lipid peroxide malondialdehyde(MDA) were measured by DCFH-DA fluorescent probe, WST-1, and TBA respectively.Moreover, the apo-ptotic effect was detected by AO-EB and Annexin V-FITC/PI staining.In addition, the protein expression levels were detected by Wes-tern blot, and intracellular insulin concentration was measured by ELISA.The results showed that the oxidative damage model of INS-1 cells was stably induced by 50 µmol·L~(-1) H_2O_2 treatment for 2 h, and catalpol at 1-80 µmol·L~(-1) did not affect cell viability of INS-1 cells.Compared with the conditions in the model group, 1, 5, and 10 µmol·L~(-1) catalpol intervention for 2 h could protect INS-1 cells from oxidative damage(P<0.001), reduce ROS and MDA, increase SOD, and inhibit excessive cell apoptosis.Moreover, 1, 5, and 10 µmol·L~(-1) catalpol could also up-regulate the phosphorylation of nuclear transcription factor NF-E2 related factors, negatively regulate Kelch-like ECH-associated protein 1(Keap1), phosphorylation of extracellular signal-regulated kinase(ERK), and heme oxyge-nase 1(HO-1), and promote the protein expression of pancreatic-duodenal homeobox factor-1(PDX-1) and glucose transporter 2(GLUT2).In addition, 1, 5, and 10 µmol·L~(-1) catalpol increased insulin secretion of INS-1 cells under oxidative damage in the high-glucose culture medium, indicating function recovery of pancreatic ß cells.PDX-1 is a key nuclear transcription factor of pancreatic ß cell function that directly regulates GLUT2 and insulin synthesis, and affects glucose homeostasis.In conclusion, catalpol can reduce the oxidative damage and apoptosis of INS-1 cells, activate antioxidant pathway, protect the function of pancreatic ß cells, and improve insulin synthesis and secretion.

Pressure-Induced Bifurcation in the Photoluminescence of Red Carbon Quantum Dots: Coexistence of Emissions from Surface Groups and Nitrogen-Doped Cores.

Carbon quantum dots (CDs) with favorable fluorescent properties have stimulated considerable effort to modulate their photoluminescence (PL) for bioimaging and sensing. However, the fluorescent mechanisms are still only partially understood due to the diverse physicochemical properties of CDs prepared by various synthesis methods and postpreparation processes. In this report, pressure-induced bifurcation of PL is reported in red carbon quantum dots (R-CDs) for the first time. The splitting of PL into an irreversible blue-shifted peak and a reversible red-shifted peak under pressure suggests the coexistence of multiple fluorescent mechanisms in R-CDs, i.e., emissions from surface groups and nitrogen-doped cores. The concentration and excitation laser energy dependencies of pressure-induced bifurcation, as well as the time-resolved PL, further support the coexistence of multiple emitters. Our results provide a method for distinguishing between the different fluorescent mechanisms related to surface groups and carbon cores in CDs.

Effect of Polymer Topology and Residue Chirality on Biodegradability of Polypeptide Hydrogels.

Polypeptide-based injectable hydrogels have attracted the attention of biomedical researchers due to their unique biocompatibility and biodegradability, tunable residue chirality, and secondary conformation of polypeptide chains. In the present study, four types of poly(ethylene glycol)-block-poly(glutamic acid)s with different topological structures and residue chirality of polypeptide segments were developed, which were grafted with tyramine side groups for further cross-linking. The results demonstrated that the covalent conjugation between the tyramine groups in the presence of horseradish peroxidase and hydrogen peroxide could form porous hydrogels rapidly. Additionally, the gelation time and mechanical strength of the hydrogels were measured. All the polymer precursors and hydrogels exhibited good cytocompatibility in vitro. Further assessment of the enzymatic degradability of the hydrogels and copolymers in vitro revealed that the degradation rate was influenced by the adjustment of polymer topology or residue chirality of polypeptide copolymers. Subsequently, the effect of copolymer topology and polypeptide chirality on in vivo biodegradability and biocompatibility was assessed. This study will provide insights into the relationship between copolymer structures and hydrogel properties and benefit future polypeptide-based hydrogel studies in biomedical applications.

[Molecular mechanism of Gegen Qinlian Decoction in promoting differentiation of brown adipose tissue to improve glucose and lipid metabolism disorders in diabetic rats].

This study explored the molecular mechanism underlying the Gegen Qinlian Decoction(GQD) promoting the differentiation of brown adipose tissue(BAT) to improve glucose and lipid metabolism disorders in diabetic rats. After the hypoglycemic effect of GQD on diabetic rats induced by high-fat diet combined with a low dose of streptozotocin was confirmed, the total RNA of rat BAT around scapula was extracted. Nuclear transcription genes Prdm16, Pparγc1α, Pparα, Pparγ and Sirt1, BAT marker genes Ucp1, Cidea and Dio2, energy expenditure gene Ampkα2 as well as BAT secretion factors Adpn, Fndc5, Angptl8, IL-6 and Rbp4 were detected by qPCR, then were analyzed by IPA software. Afterward, the total protein from rat BAT was extracted, and PRDM16, PGC1α, PPARγ, PPARα, SIRT1, ChREBP, AMPKα, UCP1, ADPN, NRG4, GLUT1 and GLUT4 were detected by Western blot. The mRNA expression levels of Pparγc1α, Pparα, Pparγ, Ucp1, Cidea, Ampkα2, Dio2, Fndc5, Rbp4 and Angptl8 were significantly increased(P<0.05) and those of Adpn and IL-6 were significantly decreased(P<0.05) in the GQD group compared with the diabetic group. In addition, Sirt1 showed a downward trend(P=0.104), whereas Prdm16 tended to be up-regulated(P=0.182) in the GQD group. IPA canonical pathway analysis and diseases-and-functions analysis suggested that GQD activated PPARα/RXRα and SIRT1 signaling pathways to promote the differentiation of BAT and reduce the excessive lipid accumulation. Moreover, the protein expression levels of PRDM16, PGC1α, PPARα, PPARγ, SIRT1, ChREBP, AMPKα, UCP1, GLUT1, GLUT4 and NRG4 were significantly decreased in the diabetic group(P<0.01), which were elevated after GQD intervention(P<0.05). Unexpectedly, the expression of ADPN protein in the diabetic group was up-regulated(P<0.01) as compared with the control group, which was down-regulated after the administration with GQD(P<0.01). This study indicated that GQD promoted BAT differentiation and maturity to increase energy consumption, which reduced the glucose and lipid metabolism disorders and thereby improved diabetes symptoms.

Two-Dimensional Electron Gas at the Spinel/Perovskite Interface: Suppression of Polar Catastrophe by an Ultrathin Layer of Interfacial Defects.

Two-dimensional electron gas (2DEG) at the interface between two insulating perovskite oxides has attracted much interest for both fundamental physics and potential applications. Here, we report the discovery of a new 2DEG formed at the interface between spinel MgAl2O4 and perovskite SrTiO3. Transport measurements, electron microscopy imaging, and first-principles calculations reveal that the interfacial 2DEG is closely related to the symmetry breaking at the MgAl2O4/SrTiO3 interface. The critical film thickness for the insulator-to-metal transition is approximately 32 Å, which is twice as thick as that reported on the widely studied LaAlO3/SrTiO3 system. Scanning transmission electron microscopy imaging indicates the formation of interfacial Ti-Al antisite defects with a thickness of ∼4 Å. First-principles density functional theory calculations indicate that the coexistence of the antisite defects and surface oxygen vacancies may explain the formation of interfacial 2DEG as well as the observed critical film thickness. The discovery of 2DEG at the spinel/perovskite interface introduces a new material platform for designing oxide interfaces with desired characteristics.

Light-Enhanced Spin Diffusion in Hybrid Perovskite Thin Films and Single Crystals.

Organolead trihalide perovskites have attracted substantial interest with regard to applications in charge-based photovoltaic and optoelectronic devices because of their low processing costs and remarkable light absorption and charge transport properties. Although spin is an intrinsic quantum descriptor of a particle and spintronics has been a central research theme in condensed matter physics, few studies have explored the spin degree of freedom in the emerging hybrid perovskites. Here, we report the characterization of a spin valve that uses hybrid perovskite films as the spin-transporting medium between two ferromagnetic electrodes. Because of the light-responsive nature of the hybrid perovskite, a high magnetoresistance of 97% and a large spin-diffusion length of 81 nm were achieved at 10 K under light illumination in polycrystalline films. Furthermore, by using thin perovskite single crystals, we discovered that the spin-diffusion length was able to reach 1 µm at low temperatures. Our results indicate that the spin relaxation is not significant as previously expected in such lead-containing materials and demonstrate the potential of low-temperature-processed hybrid perovskites as new active materials in spintronic devices.

ZnO Nanorods on a LaAlO3 -SrTiO3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties.

Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials.

Anisotropic imprint of amorphization and phase separation in manganite thin films via laser interference irradiation.

Materials with mesoscopic structural and electronic phase separation, either inherent from synthesis or created via external means, are known to exhibit functionalities absent in the homogeneous counterparts. One of the most notable examples is the colossal magnetoresistance discovered in mixed-valence manganites, where the coexistence of nano- to micrometer-sized phase-separated domains dictates the magnetotransport. However, it remains challenging to pattern and process such materials into predesigned structures and devices. In this work, a direct laser interference irradiation (LII) method is employed to produce periodic stripes in thin films of a prototypical phase-separated manganite Pr0.65 (Ca0.75 Sr0.25 )0.35 MnO3 (PCSMO). LII induces selective structural amorphization within the crystalline PCSMO matrix, forming arrays with dimensions commensurate with the laser wavelength. Furthermore, because the length scale of LII modification is compatible to that of phase separation in PCSMO, three orders of magnitude of increase in magnetoresistance and significant in-plane transport anisotropy are observed in treated PCSMO thin films. Our results show that LII is a rapid, cost-effective and contamination-free technique to tailor and improve the physical properties of manganite thin films, and it is promising to be generalized to other functional materials.

Surfactant-thermal syntheses, structures, and magnetic properties of Mn-Ge-sulfides/selenides.

Although either surfactants or amines have been investigated to direct the crystal growth of metal chalcogenides, the synergic effect of organic amines and surfactants to control the crystal growth has not been explored. In this report, several organic bases (hydrazine monohydrate, ethylenediamine (en), 1,2-propanediamine (1,2-dap), and 1,3-propanediamine (1,3-dap)) have been employed as structure-directing agents (SDAs) to prepare four novel chalcogenides (Mn3Ge2S7(NH3)4 (1), [Mn(en)2(H2O)][Mn(en)2MnGe3Se9] (2), (1,2-dapH)2{[Mn(1,2-dap)2]Ge2Se7} (3), and (1,3-dapH)(puH)MnGeSe4(4) (pu = propyleneurea) under surfactant media (PEG-400). These as-prepared new crystalline materials provide diverse metal coordination geometries, including MnS3N tetrahedra, MnGe2Se7 trimer, and MnGe3Se10 T2 cluster. Compounds 1-3 have been fully characterized by single-crystal X-ray diffraction (XRD), powder XRD, UV-vis spectra, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Moreover, magnetic measurements for compound 1 showed an obvious antiferromagnetic transition at ~9 K. Our research not only enriches the structural chemistry of the transitional-metal/14/16 chalcogenides but also allows us to better understand the synergic effect of organic amines and surfactants on the crystallization of metal chalcogenides.

Surfactant media to grow new crystalline cobalt 1,3,5-benzenetricarboxylate metal-organic frameworks.

In this report, three new metal-organic frameworks (MOFs), [Co3(µ3-OH)(HBTC)(BTC)2Co(HBTC)]·(HTEA)3·H2O (NTU-Z30), [Co(BTC)]·HTEA·H2O (NTU-Z31), [Co3(BTC)4]·(HTEA)4 (NTU-Z32), where H3BTC = 1,3,5-benzenetricarboxylic acid, TEA = triethylamine, and NTU = Nanyang Technological University, have been successfully synthesized under surfactant media and have been carefully characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and IR spectromtry. NTU-Z30 has an unusual trimeric [Co3(µ3-OH)(COO)7] secondary building unit (SBU), which is different from the well-known trimeric [Co3O(COO)6] SBU. The topology studies indicate that NTU-Z30 and NTU-Z32 possess two new topologies, 3,3,6,7-c net and 2,8-c net, respectively, while NTU-Z31 has a known topology rtl type (3,6-c net). Magnetic analyses show that all three materials have weak antiferromagnetic behavior. Furthermore, NTU-Z30 has been selected as the heterogeneous catalyst for the aerobic epoxidation of alkene, and our results show that this material exhibits excellent catalytic activity as well as good stability. Our success in growing new crystalline cobalt 1,3,5-benzenetricarboxylate MOFs under surfactant media could pave a new road to preparing new diverse crystalline inorganic materials through a surfactant-thermal method.

Growing crystalline chalcogenidoarsenates in surfactants: from zero-dimensional cluster to three-dimensional framework.

Although surfactants have been widely used to tailor the size, shape, and surface properties of nanocrystals and control the pore size and phases of mesoporous frameworks, the use of surfactants as reaction media to grow chalcogenide crystals is unprecedented. In addition, compared with ionic liquids, surfactants are much cheaper and can have multifunctional properties such as acidic, basic, neutral, cationic, anionic, or even block. These features suggest that surfactants could be promising reaction platforms for the development of novel chalcogenide crystals. In this work, we used chalcogenidoarsenates as a model system to demonstrate our strategy. By using three different surfactants as reaction media, we obtained a series of novel thioarsenates ranging from a zero-dimensional (0D) cluster to a three-dimensional (3D) framework, namely, [NH(4)](8)[Mn(2)As(4)S(16)] (1), [Mn(NH(3))(6)][Mn(2)As(2)S(8)(N(2)H(4))(2)] (2), [enH][Cu(3)As(2)S(5)] (3), and [NH(4)][MnAs(3)S(6)] (4). The band gaps (estimated from the steep absorption edges) were found to be 2.31 eV for 1 (0D), 2.46 eV for 2 (1D), 1.91 eV for 3 (2D), and 2.08 eV for 4 (3D). The magnetic study of 4 indicated weak antiferromagnetic behavior. Our strategy of growing crystalline materials in surfactants could offer exciting opportunities for preparing novel crystalline materials with diverse structures and interesting properties.