Current Organic Chemistry - Volume 15, Issue 21, 2011

Conventional organic chemistry treated low molecular weight compounds. Nano-organic chemistry is a new organic chemistry that treats nanoscale reactions and nano-sized compounds with the molecular weight of more than several thousands. Nano-organic chemistry is a rapidly developing area of research because of its importance in syntheses and functionalization of organic, inorganic and hybrid organic/inorganic nanomaterials dealing with organic systems. This special Hot Topic issue highlights the substantial progresses on syntheses of nanomaterials by organic molecules, functionalization of nanomaterials by organic syntheses, nanocatalyst-based organic reactions, preparation of porous films by the method of breath figure and switching properties and dynamic functions of supramolecular systems. In current nanomaterials syntheses, choice of appropriate organic precursors is becoming more and more important to control the shape and size of nanomaterials. The first review came from G. M. Huang and J. Weng, Department of Biomaterials, College of Materials, Xiamen University, China. They focus mainly on preparation of carbon nanomaterials with different shapes made by ferrocene. In recent years, “click” chemistry has emerged as an attractive and promising synthesis approach to functionalize nanomaterials. H. K. He and C. Gao, College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University and Department of Polymer Science and Engineering, Zhejiang University, China, focuses on the click chemistry on the hard and soft nano-surfaces in the second review. In current organic synthesis, choice of appropriate catalysts is becoming more and more important. Among those catalysts, noble metal nanoparticles catalyst is one type of the most important catalysts and has been successfully applied in organic synthesis reactions. In the third review, provided by W. Q. Sheng, Q. Yang and J. Weng, Department of Biomaterials, College of Materials, Xiamen University, China, focuses on applications of noble metal nanoparticles with different sizes and structures in hydrogenation, dehydrogenation, selective oxidation, alkylation and other reactions. The fourth review was contributed by X. P. Xiong, M. F. Lin, W. W. Zou and Y. Jin, Department of Materials Science and Engineering, College of Materials, Xiamen University and Unilever R&D Shanghai, China. The review highlights history and development of honeycomb structured porous films prepared by the method of breath figure. In current nanotechnology, bottom-up approaches where supramolecular chemistry plays a crucial role are gradually gaining in importance relative to the top-down approaches. A key process of the bottom-up approaches is self-assembly of component materials where supramolecular chemistry plays a crucial role. Well-designed structures formed through self-assembly particularly make excellent prototypes for functioning man-made devices. K. Ariga, S. Ishihara, J. Labuta and J. P. Hill, World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Japan, contribute to the last review, which deals with supramolecular approaches in nanotechnology for developing switching properties and dynamic functions that are summarized and classified into three categories: (i) molecular functions in solution; (ii) hard supramolecular systems; (iii) soft supramolecular systems. Finally, I, as a guest editor for this special issue, would like to thank all of the authors for their valuable and excellent contributions. I also sincerely thank all the reviewers for their valuable comments.

Ferrocene, an organometallic chemical compound consisting of two cyclopentadienyl rings bound on opposite sides of a central iron atom, has been widely used to synthesize carbon nanomaterials with different shapes. It can not only serve as a catalyst but also act as a carbon or iron source because it contains both a transition metal and two hydrocarbon fragments. In this review, we summarize the information generated in the literature on carbon nanomaterials with different shapes made by ferrocene. We have classified the review content into: (i) syntheses of carbon nanotubes by ferrocene; (ii) syntheses of carbon nanospheres by ferrocene; (iii) syntheses of iron/carbon composites by ferrocene; and (iv) syntheses of other shaped carbon nanostructures by ferrocene.

In recent years, “click” chemistry, especially the Cu(I)-catalyzed azide/alkyne 1,3-dipolar cycloaddition “click” reaction, has emerged as an attractive and promising synthesis approach due to its prominent virtues such as high specificity, quantitative yields, compatibility with various solvents (including water), and mild reaction conditions. Since there are already many reviews concerning click chemistry itself or its applications in some fields, the present review focuses only on the click chemistry on the nano-surfaces that mainly include hard (e.g., Au, γ-Fe2O3, Fe3O4, Si/SiO2, CNTs, CdSe, TiO2 nanoparticles) and soft nanosurfaces (e.g., polymeric nanoparticles and biomacromolecules). The “click” surface modification strategies of various nano-objects are summarized comprehensively, providing a valuable repository of knowledge for the interested researchers to further dive into click chemistry, surface chemistry, and biochemistry.

In current organic synthesis, choice of appropriate catalysts is becoming more and more important. Among these catalysts, noble metal nanoparticles catalyst is one of the most important catalysts which has been successfully applied in hydrogenation, dehydrogenation, selective oxidation, alkylation and other reactions. At the same time, recent advances in nanotechnology allow the researchers to prepare noble metal nanoparticles with appropriate size and shape, and interestingly, properties of nano-sized noble metals are different from those of bulk metals. Therefore, noble metal nanoclusters or colloids have been attracting much attention in catalytic reactions due to their special physical and chemical properties. In this review, the applications of noble metal nanoparticles with different sizes and structures in organic reactions are described; and all the sections in this review have been subdivided according to the reaction types. Besides, the mechanism will be also briefly mentioned.

Solvent evaporation induced cooling of a solution surface will result in condensation of water vapor, which is known as breath figure. The condensed water droplets arrange normally into hexagonal packing to template the solution surface. After complete evaporation of solvent and water, hexagonally ordered porous array (breath figure array, BFA) can be left on the solute matrix by the imprints of the water droplets. An optimal BFA can be obtained by adjusting the controlling factors in a breath figure fabrication such as solvent, water vapor and material. The solvent is usually volatile organic solvent, and the water vapor can be dynamic or static; the solute can be homopolymer, block copolymer, polymer blend, polymer/additive mixture, polymer/inorganic hybrid or even pure nano particles. At the same time, hierarchically ordered structural patterns can be fabricated with such materials as building blocks by combining breath figure method with other microfabrication strategies. Moreover, specific fabrication procedures different from typical breath figure condition can be used for particular preparations. Progress in this field is summarized and discussed. Especially, some applications and post treatments of BFAs are introduced too.

In current nanotechnology, bottom-up approaches where supramolecular chemistry plays a crucial role are gradually gaining in importance relative to the top-down approaches. A key process of the bottom-up approaches is self-assembly of component materials where supramolecular chemistry plays a crucial role. Well-designed structures formed through self-assembly particularly make excellent prototypes for functioning man-made devices. Recent advances in organic chemistry allow us to construct attractive units that can be assembled into further advanced micro-factories, leading to switchable properties and dynamic functions. In this review, supramolecular approaches in nanotechnology for developing switching properties and dynamic functions are summarized and classified into three categories: (i) molecular functions in solution; (ii) hard supramolecular systems; (iii) soft supramolecular systems.

The general concepts, features and applications of ambient ionization mass spectrometry for studying the heterogeneous/homogeneous ion-molecule reactions are reviewed. Important ambient ionization mass spectrometric methods and their applications in organic chemistry are summarized, focusing on SESI (secondary electrospray ionization), DESI (desorption electrospray ionization-mass spectrometry), ESSI (electrosonic spray ionization), EESI (extractive electrospray ionization-mass spectrometry), ELDI (electrospray-assisted laser desorption/ionization), LTP (low-temperature plasma probe) and APTDI (atmospheric-pressure thermal desorption ionization) technologies. At the same time, the advantages of ambient ionization mass spectrometry in studying organic reactions allow chemists to explore new type of organic reactions, probe reaction mechanisms and to intercept/characterize transient reactive intermediates in ambient condition.