The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

Magnetic nanoparticles: Synthesis, protection, functionalization, and application

Reduced transition metal colloids: a novel family of reusable catalysts

Inorganic colloidal nanoparticles are very small, nanoscale objects with inorganic cores that are dispersed in a solvent. Depending on the material they consist of, nanoparticles can possess a number of different properties such as high electron density and strong optical absorption (e.g. metal particles, in particular Au), photoluminescence in the form of fluorescence (semiconductor quantum dots, e.g. CdSe or CdTe) or phosphorescence (doped oxide materials, e.g. Y(2)O(3)), or magnetic moment (e.g. iron oxide or cobalt nanoparticles). Prerequisite for every possible application is the proper surface functionalization of such nanoparticles, which determines their interaction with the environment. These interactions ultimately affect the colloidal stability of the particles, and may yield to a controlled assembly or to the delivery of nanoparticles to a target, e.g. by appropriate functional molecules on the particle surface. This work aims to review different strategies of surface modification and functionalization of inorganic colloidal nanoparticles with a special focus on the material systems gold and semiconductor nanoparticles, such as CdSe/ZnS. However, the discussed strategies are often of general nature and apply in the same way to nanoparticles of other materials.

https://faculty.washington.edu/mzhang/mse599/Surface-modification.full.pdf

Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

Chiral nitrogen-containing compounds are widely distributed in nature and include many biologically important molecules (Chart 1). In these compounds, the nitrogen-containing units are known to play important roles for their bioactivities. For the synthesis of these chiral nitrogen-containing building blocks, use of imines as electrophiles is the most promising and convenient route.1 While many approaches using chiral imines or chiral nucleophiles have been reported,1 these diastereoselective reactions have some disadvantages. First, the procedures to introduce chiral auxiliaries to substrates and to remove them after the diastereoselective reactions are often tedious. Second, more than stoichiometric amounts of chiral sources are needed to obtain chiral compounds according to these reactions. On the other hand, catalytic enantioselective reactions provide the most efficient methods for the synthesis of chiral compounds,2 because large quantities of chiral compounds are expected to be prepared using small amounts of chiral sources. While much progress has been made recently in catalytic enantioselective reactions of aldehydes and ketones such as aldol,3 allylation,4 Diels-Alder,5 cyanation reactions,6 reduction,1b,2b etc., progress in catalytic enantioselective reactions of imines is rather slow. There are some difficulties in performing catalytic enantioselective reactions of imines. For example, in the cases of chiral Lewis acid promoted asymmetric Shū Kobayashi was born in 1959 in Tokyo, Japan. He studied chemistry at the University of Tokyo and received his Ph.D. in 1988 (Professor T. Mukaiyama). After spending 11 years at Science University of Tokyo (SUT), he moved to Graduate School of Pharmaceutical Sciences, University of Tokyo, in 1998. His research interests include development of new synthetic methods, development of novel catalysts (especially chiral catalysts), organic synthesis in water, solid-phase organic synthesis, total synthesis of biologically interesting compounds, and organometallic chemistry. He received the first Springer Award in Organometallic Chemistry in 1997.

https://chemistry.mdma.ch/hiveboard/picproxie_docs/000499541-cr980414z.pdf

Catalytic enantioselective addition to imines.

The coordination chemistry of the amidine ligand

Studies of the double surfactant layer stabilization of water-based magnetic fluids

Reaction of ethene with CO in CH3OD in the presence of a catalyst prepared in situ from [Pd(DBPMB)(DBA)] (DBPMB = 1,2-bis[(di-tert-butyl)phosphinomethyl]benzene, DBA = dibenzylideneacetone) and methanesulfonic acid under conditions of good gas mixing gives a 1 ∶ 1 mixture of CH2DCH2CO2Me and CH3CHDCO2Me with no H incorporated into the CH3OD. If the gas mixing is less efficient, the methyl propanoate has 0–5 D atoms incorporated in the ethyl group, CH3OD exchanges to give increasing amounts of CH3OH throughout the reaction and there is a slight increase in the less deuteriated products with reaction time. Significant D incorporation into unreacted ethene is also observed. These results are interpreted in terms of a hydride mechanism with the rates of the individual steps under conditions of good mixing being: reversible H migration
to coordinated ethene > CO coordination ≫ C2H4 exchange > H/D exchange.

Deuterium labelling evidence for a hydride mechanism in the formation of methyl propanoate from carbon monoxide, ethene and methanol catalysed by a palladium complex

A comparison of catalytic activity for imine hydrogenation using Ru ditertiary phosphine complexes, including chiral systems

The double surfactant layer principle for colloidal stability is applied to the design of magnetite particles having primary and secondary surfactant layers composed of different fatty acids. Concentrated aqueous dispersions, containing up to 32% by weight Fe3O4, are prepared, which are stable to dilution (60 fold). Specific magnetizations of up to 28 J T−1 kg−1 (28 emu/g) are recorded. Particles are initially stripped of surfactant which is surplus to the primary layer, in a treatment prior to the addition of the secondary surfactant layer. The particles having solely a primary surfactant layer, disperse readily in nonpolar solvents to give fluids containing up to 33% by weight Fe3O4. Differences occur for some fatty acids between the use of NH+4 and CH3NH+3 salts for the formation of the secondary surfactant layer, and are ascribed to the ready decomposition of NH4 salts at 90°C. Oleic acid and Sarkosyl-“O,” having unsaturation in their hydrocarbon chains, are found to be suitable for the primary surfactant layer when straight chain fatty acids are used as the second surfactant, but not for use as the secondary surfactant layer. Redispersion of double surfactant layer coated particles, separated from aqueous media at pH

Melvyn Kilner

Papers

The coordination chemistry of the amidine ligand

Studies of the double surfactant layer stabilization of water-based magnetic fluids

Deuterium labelling evidence for a hydride mechanism in the formation of methyl propanoate from carbon monoxide, ethene and methanol catalysed by a palladium complex

A comparison of catalytic activity for imine hydrogenation using Ru ditertiary phosphine complexes, including chiral systems

“Stripped” magnetic particles. Applications of the double surfactant layer principle in the preparation of water-based magnetic fluids