Isolable oxysulfuranes in organic chemistry

The development of synthetic methods for oxysulfuranes has made a wide range of isolable compounds of hypervalent sulfur available for study. Structure-reactivity correlations are now becoming evident as a result of such study. The fact that oxygen is dicoordinate makes it possible to synthesize cyclic oxysulfuranes and to use the pronounced changes of reactivity which accompany cyclization to design new, potentially useful sulfurane reagents stable enough to allow isolation.     

Sculpting horizons in organic chemistry

Organic chemistry as a discipline derives from and impacts on the biological and abiological world in which we live. Its challenges lie in the areas of structure, reactivity, techniques, and concepts. Powerful structural tools reveal structures from biology that range from control of insect development and behavior to whole new metabolic pathways in humans. Unnatural products create beautiful new molecular shapes whose properties cannot be predicted as well as catalysts that function with enzyme-like control. From structure flows reactivity. Exploration of known reactions points to new directions, and development of new reactions offers the opportunity of streamlined synthetic design. Emerging new techniques offer new dimensions for performing and studying reactions as well as the hope for developing new ones. Merging disparate facts into unified concepts increases predictive capabilities. The extraordinary difficulty of finding the resultant of many small effects may obscure the presence of general theories, creates the art in the practice of the science, and challenges the practitioner. From these general themes derives the quest for selectivity--chemo-, regio-, diastereo-, and enantio-. An examination of the fundamental underpinnings of the applications of organic chemistry reveals that, while impressive strides have been made, the science is best described as being between infancy and childhood. The cross-fertilization between organic chemistry and molecular biology vividly illustrates a merging of chemistry and biology.     

含三唑基酰基硫脲类除草剂的结构与生物活性的量子化学研究

利用量子化学方法,对14种含三唑基酰基硫脲类化合物的结构与除草活性关系进行了研究.采用HF方法和6-31G基组,对14种化合物进行全参数优化,得到了它们的稳定构型.并对化合物中原子的净电荷分布、前线分子轨道能级及轨道组成等性质进行了分析,把它们与试验得到的生物活性数据对照,通过研究发现,三唑基酰基硫脲类化合物的除草活性与分子的前线轨道(HOMO、LUMO)能级存在一定的关系.     

Quantum phase transition in organic charge-transfer complexes

A phase transition in an organic charge-transfer complex, which originates from the neutral-ionic valence instability, can be tuned toward zero kelvin with use of external pressure or chemical modification as a control parameter. The phase diagram and observed dielectric behaviors are typical of quantum paraelectricity, yet this zero-kelvin transition point namely, the quantum critical point, accompanies large quantum fluctuation of the molecular charge, as demonstrated by the molecular vibrational mode spectra. The result indicates that the pi-electron transfer between donor and acceptor molecules is coupled with the zero-point lattice dynamics around the quantum critical point.     

利用多媒体技术优化有机化学教学效能研究

计算机辅助教学(CAI)是现代教学手段的一个重要体现,有机化学教学中运用多媒体技术,可将不同的有机化学内容进行模拟仿真、创设情景,化不可见为可见,化静态为动态,化抽象为直观,化复杂多变为简洁明了。利用多媒体技术优化有机化学教学,极大地增强了有机化学课堂教学的表现力,提高了有机化学教学的效率,促进了有机化学考试方法的改革。     

Irreversible organic crystalline chemistry monitored in real time

Because multiple laser shots are typically required to monitor ultrafast photochemical reaction dynamics, sample depletion and product accumulation have greatly restricted the range of substrates and structural environments amenable to study. By implementing a two-dimensional spatial delay gradient across the profile of a femtosecond probe pulse, we can monitor in a single laser shot organic crystalline reaction dynamics despite the formation of permanent photoproducts that cannot be conveniently removed. We monitored the photolysis of the triiodide anion, I3-, and subsequent recombination or relaxation of its reaction products, in three very different pure organic molecular crystals. The experimental results and associated molecular dynamics simulations illustrate the intimate connection between lattice structure and reaction dynamics, highlighting the role of lattice constraints in directing phase-coherent geminate recombination of photofragments within a crystalline reaction cage.     

《有机化学》课程教学改革的尝试

编写并正式出版了适用于农业院校的《有机化学》教科书及教学参考书，对《有机化学》课堂教学、教学方式和教学手段等进行了改革，并提出了今后要尽快研制出形式多样的有机化学多媒体软件，使教学水平再上一个新台阶。     

多媒体在有机化学教学中的应用

多媒体应用在有机化学教学中能模拟物质微观结构、反应历程,动态地展示图表内容、模拟实验过程,增加教学容量和教学信息量。但是,教师在教学过程中存在过分依赖课件、使用统一的课件制作,缺乏个性、动画过多过滥等问题。为提高教学效果,教师应独立制作课件,使用课件时适当加入板书,适时讲解,精选动画,将传统教学方法与现代教学手段结合使用,激发学生兴趣,创造良好的教学氛围。     

Interstellar chemistry recorded in organic matter from primitive meteorites

Organic matter in extraterrestrial materials has isotopic anomalies in hydrogen and nitrogen that suggest an origin in the presolar molecular cloud or perhaps in the protoplanetary disk. Interplanetary dust particles are generally regarded as the most primitive solar system matter available, in part because until recently they exhibited the most extreme isotope anomalies. However, we show that hydrogen and nitrogen isotopic compositions in carbonaceous chondrite organic matter reach and even exceed those found in interplanetary dust particles. Hence, both meteorites (originating from the asteroid belt) and interplanetary dust particles (possibly from comets) preserve primitive organics that were a component of the original building blocks of the solar system.     

壳聚糖衍生物阻垢缓蚀的量子化学研究

针对线型高分子具有重复单元的结构特点,提出一种优化算法.以壳聚糖(CTS)和羧甲基壳聚糖(CM-CTS)为例,利用GaussView 6.0软件对两种分子进行了量子化学计算,对其分子结构、前线轨道能级、电子云密度、原子电荷分布、作用基团空间密度和链柔性进行分析,初步探讨了它们的阻垢缓蚀性能.计算结果表明,CTS和CM-...     

Quantum confinement and host/guest chemistry: probing a new dimension

Nanoparticulate metals and semiconductors that have atomic arrangements at the interface of molecular clusters and "infinite" solid-state arrays of atoms have distinctive properties determined by the extent of confinement of highly delocalized valence electrons. At this interface, the total number of atoms and the geometrical disposition of each atom can be used to significantly modify the electronic and photonic response of the medium. In addition to teh novel inherent physical properties of the quantum-confined moieties, their "packaging" into nanocomposite bulk materials can be used to define the confinement surface states and environment, intercluster interactions, the quantum-confinement geometry, and the effective charge-carrier density of the bulk. Current approaches for generating nanostructures of conducting materials are briefly reviewed, especially the use of three-dimensional crystalline superlattices as hosts for quantum-confined semiconductor atom arrays (such as quantum wires and dots) with controlled inter-quantum-structure tunneling.     

生物专业的有机化学在独立学院的教学探讨

针对独立学院生物专业的有机化学理论教学学时较少且学生学习基础相对薄弱的教 学实际情况,通过采用多样化的教学方法,同时应用网络信息技术教学手段,优化和整合有机化 学的教学内容,与科研相结合等几个方面进行有机化学的教学改革,提高了学生的学习积极性, 使有机化学的教学效果得到提升,为学院的应用型人才培养目标奠定坚实的知识基础。