Conversion of Propargylic Amines with CO2 Catalyzed by a Highly Stable Copper(I) Iodide Thorium-Based Heterometal-Organic Framework.

The conversion of CO2 to generate high-value-added chemicals has become one of the hot research topics in green synthesis. Thereinto, the cyclization reaction of propargylic amines with CO2 is highly attractive because the resultant oxazolidinones are widely found in pharmaceutical chemistry. Cu(I)-based metal-organic frameworks (MOFs) as catalysts exhibit promising application prospects for CO2 conversion. However, their practical application was greatly limited due to Cu(I) being liable to disproportionation or oxidization. Herein, the solid copper(I) iodide thorium-based porous framework {[Cu5I6Th6(µ3-O)4(µ3-OH)4(H2O)10(L)10]·OH·4DMF·H2O}n (1) (HL = 2-methylpyridine-4-carboxylic acid) constructed by [Th6] clusters and [CuxIy] subunits was successfully prepared and structurally characterized. To our knowledge, this is the first copper(I) iodide-based actinide organic framework. Catalytic investigations indicate that 1 can effectively catalyze the cyclization of propargylic amines with CO2 under ambient conditions, which can be reused at least five times without a remarkable decline of catalytic activity. Importantly, 1 exhibits excellent chemical stability and the oxidation state of Cu(I) in it can remain stable under various conditions. This work can provide a valuable strategy for the synthesis of stable Cu(I)-MOF materials.

Silver Metal-Organic Framework Derived N-Doped Carbon Nanofibers for CO2 Conversion into ß-Oxopropylcarbamates.

Developing efficient heterogeneous catalysts for chemical fixation of CO2 to produce high-value-added chemicals under mild conditions is highly desired but still challenging. Herein, we first reported an approach to prepare a novel catalyst (Ag@NCNFs), featuring Ag nanoparticles (NPs) embedded within porous nitrogen-doped carbon nanofibers (NCNFs), via growing a Ag metal-organic framework on one-dimensional electrospun nanofibers followed by pyrolysis. Benefiting from the abundant nitrogen species and porous structure, Ag NPs is well dispersed in the obtained Ag@NCNFs. Catalytic studies indicated that Ag@NCNFs exhibited excellent catalytic activity for the three-component coupling reaction of CO2, secondary amines, and propargylic alcohols to generate ß-oxopropylcarbamates under mild conditions with a turnover number (TON) of 16.2, and it can be recycled and reused at least 5 times without an obvious decline in catalytic activity. The reaction mechanism was clearly clarified by FTIR, NMR, 13C isotope labeling, control experiments, and density functional theory calculations. The results suggest that Ag@NCNFs and 1,8-diazabicyclo[5.4.0]undec-7-ene can synergistically activate propargylic alcohol to react with CO2, and then the generated α-alkylidene cyclic carbonate was invaded by secondary amine to produce ß-oxopropylcarbamate. Importantly, to the best of our knowledge, this is the first experimental and theoretical investigation on this reaction.

[The trend of stomach neoplasms mortality in Zhaoyuan County, from 1970 to 2004].

OBJECTIVE: To understand the trend of gastric cancer mortality based on the exploration of the death data from 1970 to 2004 in Zhaoyuan County. METHODS: The death data of 1970-1974 were collected from the first malignant tumor death survey of China, and the data of 1985-2004 were derived from the cancer registration network of Zhaoyuan. The appreciation indexes were crude mortality rate and standardized mortality rates by the percentages of Chinese population in 1982 and the percentages of world population in 1966. RESULTS: The crude mortality rates in the five periods of 1970-1974, 1985-1989, 1990-994, 1995-1999, and 2000-2004 were 34.94, 44.34, 40.05, 48.73, and 40.18 per 100,000, respectively; the standardized mortality rates by Chinese population were 30.82, 30.35, 27.78, 31.63, and 20.10 per 100,000, respectively. The gastric cancer mortality remained stability from 1970 to 1999, however, the standardized mortality rate of gastric cancer in 2000-2004 declined by 34.8% compared with that in 1970-1974. The study also observed that the highest age-specific gastric cancer mortality, in the past 35 years, has been postponed by 10 years. And, the gastric cancer mortality ranked from top first to top three. CONCLUSION: There is a decreasing trend for the incidence of stomach cancer and this might be associated with the changes of dietary consumption and pattern.