Privileged strategies for direct transformations of inert aliphatic C–H bonds

<正>Functional group transformations are central to organic synthesis.Traditionally,the functionalities used in such transformations are highly active organic groups such as halogens,ester groups and hydroxyl groups.Carbon–hydrogen bonds are ubiquitous structural motifs in organic compounds,but they are not considered to be functionalgroups because(1)in general,the bond dissociation energy of a C–H bond is high,and therefore,such bonds     

A Fundamental Study and Applied Exploration of Some Novel Photo-functional Materials

This project focuses on fundamental problems in the interdisciplinary research of chemistry and materials, covering main achievements on fundamental study and applied exploration of novel photo-functional materials.Significant progress was made in the design and con- struction of special photo-functional molecules and complexes by implementation of this project. (1) Organic nanomaterials were investigated sys- tematically in this project, extending the particularity of nanomaterials from metal…     

Piezotronics and piezo-phototronics: fundamentals and applications

Technology advancement that can provide new solutions and enable augmented capabilities to complementary metal–oxide–semiconductor(CMOS)-based technology,such as active and adaptive interaction between machine and human/ambient,is highly desired.Piezotronic nanodevices and integrated systems exhibit potential in achieving these application goals.Utilizing the gating efect of piezopotential over carrier behaviors in piezoelectric semiconductor materials under externally applied deformation,the piezoelectric and semiconducting properties together with optoelectronic excitation processes can be coupled in these materials for the investigation of novel fundamental physics and the implementation of unprecedented applications.Piezopotential is created by the strain-induced ionic polarization in the piezoelectric semiconducting crystal.Piezotronics deal with the devices fabricated using the piezopotential as a‘gate’voltage to tune/control charge-carrier transport across the metal–semiconductor contact or the p–n junction.Piezo-phototronics is to use the piezopotential for controlling the carrier generation,transport,separation and/or recombination for improving the performance of optoelectronic devices.his review intends to provide an overview of the rapid progress in the emerging ields of piezotronics and piezo-phototronics.he concepts and results presented in this review show promises for implementing novel nano-electromechanical devices and integrating with micro/nano-electromechanical system technology to achieve augmented functionalities to the state-of-the-art CMOS technology that may ind applications in the human–machine interfacing,active lexible/stretchable electronics,sensing,energy harvesting,biomedical diagnosis/therapy,and prosthetics.     

Morphed Graphene of BCO-C_(16):A Novel Topological Node-Line Semimetal

正Carbon is extremely versatile in its ability to form a rich variety of allotropes with a wide range of fascinating properties.At ambient conditions graphite is the thermodynamically most stable carbon allotrope,and many structural transformations and modifications of carbon structures in various sp~2 and sp~3 bonding networks can be produced under various pressure and temperature conditions.For example,under high     

Synthesizing Our Future

Chemistry has a central role in science,and synthesis plays an essential role in chemistry. Synthetic substances and materials have demonstrated a significant impact in determining the quality of our life in the last century. Although chemical synthesis has now reached an extraordinary level of sophistication,there is still vast room for improvement. In this century,to be more tightly merged with other fields such as material and life sciences,to generate more interdisciplinary areas,is an inevitable trend in synthetic chemistry. Nowadays,synthetic chemistry should pursue "GREEN" process. In this context,the atom economy,the E-factor and 3Rs (reduction,recycling and reuse) of resources must be taken into account in synthetic industry. The greatest challenge of synthetic chemistry,not only,will be immense responsibility to tackle a range of existing or predicted social and global issues associated with resources,energy,materials,the environment,food and health,but also the redeeming the negative impression of synthetic chemistry in public.     

Aromatic chloroosmacyclopentatrienes

Aromatic metallacycles are of considerable current interest.Reported aromatic metallacycles are mainly those with carbon,nitrogen,oxygen and sulfur.In this work,we report the synthesis and characterization of aromatic chloroosmacyclopentatrienes,which represent the first structurally confirmed metallaaromatic with a chlorine atom in its framework.Single-crystal X-ray diffraction studies show that these planar chloroosmacyclopentatrienes possess a very short Os-CIC distance suggesting M=CIC bond ...     

A case where BO Approximation breaks down

The Bom-Oppenheimer (BO)Approximation is ubiquitous in molecular physics,quantum physics and quantum chemistry. However, CAS researchers recently observed a breakdown of the Approximation in the reaction of fluorine with deuterium atoms.The result has been published in the August 24 issue of Science.     

科学家成功把二氧化碳变成石头(英文)

正The researchers report an experiment in Iceland where they have pumped CO_2 and water underground into volcanic rock.Reactions with the minerals in the deep basalts convert the carbon dioxide to a stable,immobile chalky solid.Even more encouraging,the team writes in Science magazine,is the speed at which this process occurs:on the order of months.     

The Need for More Women Scientists and Young Scientists To Be Engaged in Chemistry- A Central Science

This year, 2011 is a very important and meaningful year for chemists.The United Nations has declared 2011 as the International Year of Chemistry (IYC 2011), which is the year for the worldwide celebration of the achievements of Chemistry and its contributions to the well-being of mankind.The goals of IYC 2011 are to increase the public appreciation of chemistry in meeting world needs, to encourage interest in chemistry amongst young people, and to generate enthusiasm for the creative future of chemistry.The year 2011 also coincides with the 100th anniversary of the International Women's Day on March 8 as well as the 100th anniversary of the Nobel Prize awarded to Madame Marie Curie -a great opportunity to celebrate and to highlight the contributions and achievements of women in science.     

Graphene Network Structure of BCT-C_(40): A New Topological Nodal-Net Semimetal

正The valence electrons of a carbon atom can form sp~3-,sp~2-,and sp-hybridized states that support single,double,triple,and aromatic carboncarbon bonds,which profoundly impact a wide range of properties of carbon-based materials.At ambient conditions,graphite is the most stable carbon phase;its honeycomb lattice can be viewed as a planar molecule     

Neopolarographic Study On Vitamin D

Vitamin D_2 and vitamin D_3 give a clear polarographic oxidation-wave,respectively,by neopolarography,with a 0.25M solution oflithium perehlorate in ethanol-dimethylformamide(1:1)as the supportingelectrolyte.Peak potentials are both+1.27V(vs.pure Ag plate).Thewave-height is proportional to the concentration in the range from 2.6×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(420μg/ml)for vitamin D_3 and from2.5×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(435μg/ml)for vitamin D_2,respe-ctively.The detection limits are both 1.3×10~(-6)M(0.5μg/ml).Themethod can be satisfactorily applied to the determination of vitamin D_3in injcction.Through various experiments,it is shown that the electrodeprocess of vitamin D at glassy carbon electrode is an irreversible oxida-tion process controlled by diffusion.The value of an is 0.84(α is thetransfer coefficient and n is the number of cleclron in the kineticprocess).n=2.The electrode reaction mechanism has been inferred.Besides,the choices of base solution and of experiment conditions aswell as the stability of vitamin D etc.are also discussed.     

A Janus heteroatom-doped carbon electrocatalyst for hydrazine oxidation

The trade-off between the intrinsic activity and electronic conductivity of carbon materials is a major barrier for electrocatalysis.We report a Janus-type carbon material combining electrically conductive nitrogen-doped carbon(NC) and catalytically active boron,nitrogen co-doped carbon(BNC).The integration of NC with BNC can not only ensure high electronic conductivity of the hybrid,but also achieve an enhancement in the intrinsic activity of the BNC side due to the electron redistribution on t...     

How does Mei-yu precipitation respond to climate change?

Mei-yu is an important weather phenomenon in the middle-lower Yangtze River valley(YRV) region.This study investigates the changes in the characteristics of Mei-yu under global warming and the potential reasons based on observation and reanalysis data during 1961–2022. Notable increasing long-term trends are detected in the number of days without rainfall(NDWOR), the intensity of rainfall events, and the frequency and intensity of extreme precipitation events(EPEs) in the YRV region during the M...     

Chemists Honored with National Top S&T Award

XU Guangxian, chemist, was born in Shaoxing, Zhejiang Province in November 1920.In 1951, he received his Ph.D.from Columbia University in US.He was elected a CAS Member in 1980.He serves as a vice editor-chief of Science in China and Chinese Science Bulletin.He has long been engaged in teaching and research in physical chemistry and inorganic chemistry which involves the fields of quantum chemistry, chemical bond theory, coordination chemistry, extraction chemistry, nuclear fuel chemistry and rare-earth science, etc.     

N-heterocyclic carbene-stabilized metal nanoparticles within porous organic cages for catalytic applicationOA

Tuning the surface-embellishing ligands of metal nanoparticles(NPs) is a powerful strategy to modulate their morphology and surface electronic and functional features, impacting their catalytic activity and selectivity. In this work, we report the design and synthesis of a polytriazolium organic cage PIC-T, capable of stabilizing Pd NPs within its discrete cavity. The obtained material(denoted Pd@PCC-T) is highly durable and monodispersed with narrow particle-size distribution of 2.06 ± 0.02 nm,...     

A unified superatomic-molecule theory for local aromaticity in π-conjugated systems

Aromaticity is one of the most important concepts in chemistry.However,there is still no unified chemical insight for various systems with conjugated sp² carbon.Herein,we proposed a superatomic-molecule theory to build a generalized electron rule for polycyclic conjugated hydrocarbons,fullerenes and 2D periodic materials.Taking benzenoid units as 2D superatoms,polycyclic conjugated hydrocarbons and C₆₀can be seen as superatomic molecules consisting of bonded superatoms,resu...     

Microbial Carbon Sequestration in the Ocean: The Big Role of Small Bugs in Mitigating Global Climate Change——An Interview with Prof. JIAO Nianzhi

Ocean is the largest carbon reservoir on Earth. By taking up about one-third of all human carbon emissions, it has effectively reduced atmospheric carbon dioxide and eased global climate change. Scientists have studied extensively on the mechanisms of C02 absorption in the ocean, or the so-called ＂carbon pumps＂, from physical to chemical and biological pumps. Microbes, traditionally regarded as organic matter decomposers, had been long neglected until a few years ago Prof. JIAO Nianzhi from Xiamen University proposed the concept ＂microbial carbon pump （MCP）＂ illustrating that these tiny marine inhabitants are also producers of refractory dissolved organic carbon, a persistent form of matter which can be stored in the ocean for thousands of years and thus constitute an ideal carbon pool. Today, the MCP concept has been widely accepted as a promising sequestration strategy, and Prof. JIAO is working hand in hand with scientists from all over the world under the Scientific Committee on Oceanic Research （SCOR） Working Group 134 to better understand how to use these magic creatures for preserving carbon in the deep blue.     

MPS／CAS Partner Group on Nanotechnology in Catalysis

The first contact between Bao Xinhe and the Fritz Haber Institute (FHI) of the Max Planck Society goes back to 1989, when he was a Humboldt Scholarship holder in Germany. He worked at the FHI with Gerard Ertl on the surface and catalytic properties of Ag-cluster until 1995, when he returned to China and joined the Dalian Institute of Chemical Physics (DICP) under the Chinese Academy of Sciences. The cooperation with the FHI continued in 2000, when a Partner Group was established under the leadership of Robert SchlogI and Bao Xinhe. The group is devoted to the application of nano-related technologies in catalysis, with emphasis on controlled fabrication and dynamic characterization of nano-structured metallic particles and porous materials. In the past years, the cooperation has focused on various carbon nanotubes with special aligned structure and well-defined silver nano-particles in mesoporous materials. The nanostructured catalysts show high performance in methane activation at low temperature and in     

Long-term cycles in the carbon reservoir of the Quaternary ocean: a perspective from the South China Sea

In recent years,long-term,high-resolution records from the deep sea and ice-cores have ofered new research opportunities for Quaternary science.Paleoclimate studies are no longer restricted to individual glacial cycles,but extend to long-term(≥105 yr)processes across those cycles.Ocean Drilling Program Leg 184 of the South China Sea in 1999 uncovered well-preserved sediment sections,in which three long-term cycles in Pleistocene carbon isotope(δ13C)sequence have been found and demonstrated to be common in the global ocean.Subsequent discoveries conirm the existence of long-term processes of 105yr in both the hydrologic(ice-sheet changes)and carbon(biogeochemical changes)cycles,posing the question whether the two processes are related.he present review shows that the long-eccentricity cycles prevail throughout theδ13C and other biogeochemical records in geologic history,and 400-kyr cycles in the oceanicδ13C sequence before the Quaternary can be hypothetically explained by changes in ratio between particulate and dissolved organic carbon(POC/DOC)in the ocean,depending on the monsoon-controlled nutrient supply.his is a‘DOC hypothesis’.However,ocean restructuring at 1.6 Ma marked by the isolation of a sluggish abyss under the Southern Ocean has obscured the long-eccentricity 400-kyr signal in oceanicδ13C.he last million-year period has experienced two major changes in the climate regime,namely the mid-Pleistocene transition(MPT)centered at 0.9 Ma and the mid-Brunhes event(MBE)around 0.4 Ma.he MPT and MBE were preluded byδ13C maxima-III(δ13Cmax-III)～1.0 Ma andδ13Cmax-II～0.5 Ma,respectively.Together with similar hydroclimatic phenomena over corresponding glacial cycles,the two groups of hydrologic and biogeochemical events appear to have been driven largely by oceanographic changes in the Southern Ocean.herefore,we interpret that the long-term biogeochemical processes originating from the Southern Ocean must have played a crucial role in Quaternary ice-sheet waxing and waning.     

Rhesus monkeys exhibiting spontaneous ritualistic behaviors resembling obsessive-compulsive disorder

Obsessive-compulsive disorder(OCD) is a chronic and debilitating psychiatric disorder that affects ～2%–3% of the population globally. Studying spontaneous OCD-like behaviors in non-human primates may improve our understanding of the disorder. In large rhesus monkey colonies, we found 10 monkeys spontaneously exhibiting persistent sequential motor behaviors(SMBs) in individual-specific sequences that were repetitive, time-consuming and stable over prolonged periods. Genetic analysis revealed seve...