Post‐synthetic modification (PSM) is an effective approach for the tailored functionalization of metal‐organic architectures, but its generalizability remains challenging. Herein we report a general ...covalent PSM strategy to functionalize PdnL2n metal‐organic cages (MOCs, n=2, 12) through an efficient Diels–Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd12L24 in common solvents can be greatly improved. Interestingly, concentration‐dependent circular dichroism and aggregation‐induced emission are achieved with chiral binaphthol (BINOL)‐ and tetraphenylethylene‐modified Pd12L24, respectively. Furthermore, Pd12L24 can be introduced with two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step‐by‐step PSM route to obtain chirality‐induced circularly polarized luminescence. Moreover, similar results are readily observed with a smaller Pd2L4 system.
Two PdnL2n (n=2, 12) type metal‐organic cages (MOCs) decorated with anthracene groups have been successfully functionalized by a covalent post‐synthetic modification (PSM) approach. This has led to the modified MOCs having new functions compared to the parent MOCs (e.g., concentration‐dependent chirality, aggregation‐induced emission, and chirality‐induced circularly polarized luminescence).
Post‐synthetic modification (PSM) is an effective approach for the tailored functionalization of metal‐organic architectures, but its generalizability remains challenging. Herein we report a general ...covalent PSM strategy to functionalize PdnL2n metal‐organic cages (MOCs, n=2, 12) through an efficient Diels–Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd12L24 in common solvents can be greatly improved. Interestingly, concentration‐dependent circular dichroism and aggregation‐induced emission are achieved with chiral binaphthol (BINOL)‐ and tetraphenylethylene‐modified Pd12L24, respectively. Furthermore, Pd12L24 can be introduced with two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step‐by‐step PSM route to obtain chirality‐induced circularly polarized luminescence. Moreover, similar results are readily observed with a smaller Pd2L4 system.
Two PdnL2n (n=2, 12) type metal‐organic cages (MOCs) decorated with anthracene groups have been successfully functionalized by a covalent post‐synthetic modification (PSM) approach. This has led to the modified MOCs having new functions compared to the parent MOCs (e.g., concentration‐dependent chirality, aggregation‐induced emission, and chirality‐induced circularly polarized luminescence).
When compared to industrially stable zeolites, the instability of metal–organic frameworks (MOFs) has been denounced by researchers. Boosting the stability of existing MOFs is highly important for ...practical applications. In this report, we develop a new strategy to prepare MOFs/poly(tetrafluoroethylene) (PTFE) composites, which can highly improve the chemical, pressure, and photostabilities of zeolitic imidazolate framework (ZIF)-8. Composite materials were prepared by a physical blending of ZIF-8 and PTFE emulsion with different ratios and annealing at 370 °C. Transmission electron microscopy (TEM) studies reveal that the nanoparticles of ZIF-8 are coated by PTFE to form the composite materials. Upon mixing with 20 or 50 wt % PTFE, the ZIF-8/PTFE materials show a superhydrophobic property with water contact angles of around 156°. Pristine ZIF-8 is not stable in water with stirring under acidic, basic, and irradiation conditions, while the ZIF-8/PTFE materials are stable under the same conditions. The ZIF-8/PTFE materials can also maintain their crystalline structure after being compressed with a 10 MPa pressure, while pristine ZIF-8 changes to an amorphous solid after the same pressure treatment. Using water as a solvent, ZIF-8/PTFE can be used as a highly efficient and recyclable catalyst for Knoevenagel reaction at room temperature. The successful preparation of stable ZIF-8/PTFE composite materials provides a useful method to enhance the chemical, pressure, and photostabilities of MOFs.
Abstract
Post‐synthetic modification (PSM) is an effective approach for the tailored functionalization of metal‐organic architectures, but its generalizability remains challenging. Herein we report a ...general covalent PSM strategy to functionalize Pd
n
L
2
n
metal‐organic cages (MOCs,
n
=2, 12) through an efficient Diels–Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd
12
L
24
in common solvents can be greatly improved. Interestingly, concentration‐dependent circular dichroism and aggregation‐induced emission are achieved with chiral binaphthol (BINOL)‐ and tetraphenylethylene‐modified Pd
12
L
24
, respectively. Furthermore, Pd
12
L
24
can be introduced with two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step‐by‐step PSM route to obtain chirality‐induced circularly polarized luminescence. Moreover, similar results are readily observed with a smaller Pd
2
L
4
system.
Abstract
Post‐synthetic modification (PSM) is an effective approach for the tailored functionalization of metal‐organic architectures, but its generalizability remains challenging. Herein we report a ...general covalent PSM strategy to functionalize Pd
n
L
2
n
metal‐organic cages (MOCs,
n
=2, 12) through an efficient Diels–Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd
12
L
24
in common solvents can be greatly improved. Interestingly, concentration‐dependent circular dichroism and aggregation‐induced emission are achieved with chiral binaphthol (BINOL)‐ and tetraphenylethylene‐modified Pd
12
L
24
, respectively. Furthermore, Pd
12
L
24
can be introduced with two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step‐by‐step PSM route to obtain chirality‐induced circularly polarized luminescence. Moreover, similar results are readily observed with a smaller Pd
2
L
4
system.
Post-synthetic modification (PSM) is an effective approach for the tailored functionalization of metal-organic architectures, but its generalizability remains challenging. Herein we report a general ...covalent PSM strategy to functionalize Pd
L
metal-organic cages (MOCs, n=2, 12) through an efficient Diels-Alder cycloaddition between peripheral anthracene substituents and various functional motifs bearing a maleimide group. As expected, the solubility of functionalized Pd
L
in common solvents can be greatly improved. Interestingly, concentration-dependent circular dichroism and aggregation-induced emission are achieved with chiral binaphthol (BINOL)- and tetraphenylethylene-modified Pd
L
, respectively. Furthermore, Pd
L
can be introduced with two different functional groups (e.g., chiral BINOL and achiral pyrene) through a step-by-step PSM route to obtain chirality-induced circularly polarized luminescence. Moreover, similar results are readily observed with a smaller Pd
L
system.
AIM： To observe the therapeutic effects of dexamethasone on rats with severe acute pancreatitis （SAP） and investigate the influences of dexamethasone on the inflammatory mediators and NF-κB ...expression in multiple organs of SAP rats as well as the mechanisms involved.
METHODS： Ninety Sprague-Dawley （SD） rats with SAP were randomly divided into the model group （n = 45） and dexamethasone treatment group （n = 45）, and another 45 rats were selected for the sham operation group. All groups were randomly subdivided into the 3 h, 6 h and 12 h groups, each group containing 15 rats. The survival of all groups and pathological changes of multiple organs （liver, kidney and lung） were observed at different time points after the operation. The pathological score of multiple organs was carried out, followed by the determination of amylase, endotoxin and TNF-α contents in blood. The tissue microarray was used to detect the expression levels of NF-κB p65 protein in multiple organs. RESULTS： There was no marked difference between the model group and treatment group in the survival rate. The amylase content,of the treatment group was significantly lower compared to the model group at 12 h （P 〈 0.01, 7791.00 vs 9195.00）. Moreover, the endotoxin and TNF-α levels of the treatment group were significantly lower than that of the model group at 6 h and 12 h （P 〈 0.01, 0.040 vs 0.055, 0.042 vs 0.059 and P 〈 0.05, 58.30 vs 77.54, 38.70 vs 67.30, respectively）. Regarding the changes in liver NF-κB expression, the model group significantly exceeded the sham operation group at 3 h （P 〈 0.01, 1.00 vs 0.00）, and the treatment group significantly exceeded the sham operation group at 12 h （P 〈 0.01, 1.00 vs 0.00）, whereas no marked difference was observed between the model group and treatment group at all time points. The kidney NF-κB expression level in the treatment group significantly exceeded the model group （P 〈 0.05, 2.00 vs 0.00） and the sham operation group （P 〈 0.01, 2.00 vs 0.00） at 12 h. No NF-κB expression in the lung was found in any group.
CONCLUSION： Dexamethasone can lower the amylase, endotoxin and TNF-α levels as well as mortality of SAP rats. NF-κB plays an important role in multiple organ injury. Further studies should be conducted to determine whether dexamethasone can ameliorate the pathological changes of multiple organs by reducing the NF-κB expression in the liver and kidney. The advantages of tissue microarrays in pancreatitis pathological examination include time- and energy- saving, and are highly efficient and representative. The restriction of tissue microarrays on the representation of tissues to various extents due to small diameter may lead to the deviation of analysis.
The PEBP family of proteins, which encode a phosphatidyl ethanolamine-binding protein （PEBP） domain, serve as a hub in the network of integrating environmental and developmental signals to regulate ...flowering in all angiosperms. To understand how PEBP duplication genes arose and evolved during plant evolution, we identified 259 genes involved in the PEBP domain from 25 species, including angiosperms, 8ymnosperms, and embryophytes. We found that plant PEBP genes could be divided into three monophyletic groups, including F-T-like, TFL-like and MFT-like subgroups. Based on the phylogeny, FT-like and TFL-like subgroups split before the angiosperm divergence. The likelihood ratio test indicates that the F-r-like clade is significantly different in/（JKs with TFL-like and MFT-like clades. We found this shift in mutation might be attributed to the positive selection imposed on the fourth exon of recent FT duplications. Divergent expression patterns of FT paralogs indicated that they had undergone subfunctionalization after duplication. In addition, some of the FT-like genes have been targets of selection during domestication in rice and maize, for which the flowering time is an important agronomic trait. These results imply potential recent positive selection on FT-like genes with potential to increase the prevalence of novel functional alleles leading to extensive plant flowering time diversity and adaptation to environmental changes.
AIM： To study effects of recombinant human growth hormone （rhGH） on growth of a human gastric carcinoma cell in vivo. METHODS： Experimental mice were divided into control group, rhGH group, ...oxaliplatin （L-OHP） group and rhGH＋L-OHP group. Cultured human gastric carcinoma cells BGC823 were inoculated into right axilla of nude mice and carcinoma xenograft model was established successfully. Inhibitory rate of xenograft tumor growth was estimated by measuring tumor volume; expression of proliferating cell nuclear antigen （PCNA）, Bax and Bcl-2 proteins of xenograft tumor was detected using immunohistochemical S-P method. RESULTS： Tumor growth inhibitory rate, the positive expression rate of PCNA, Bax and Bcl-2 were 49.3%, 58.2%, 65.2% and 59.2% in rhGH＋L-OHP group respectively; 46.6%, 62.5%, 59.7% and 64.7% in L-OHP group; 5.0%, 82.7%, 23.2% and 82.2% in rhGH group and 0, 77.8%, 23.5% and 80.3% in control group. There was significant difference between rhGH＋L-OHP group （or L-OHP group ） and control group or rhGH group （P 〈 0.05）, whereas there were no significant differences （P 〉 0.05） between L-OHP group and rhGH＋L-OHP group and between rhGH group and control group. CONCLUSION： rhGH does not accelerate the proliferation of human gastric cancer cell in vivo.
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