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The utilization of nanoparticles for a variety of applications has raised much interest in recent years as new knowledge has emerged in nanochemistry. New and diverse methods for synthesis, characterization, and application of these particles have been discovered with differing degrees of ease and reproducibility. Post-synthetic modification of nanoparticles is often a required step to facilitate their use in applications. The reaction conditions and chemical environment for the nanoparticle synthesis may not support or may conflict with further reactions. For this reason, it is beneficial to have phase transfer methods for nanoparticles to allow for their dispersion in a variety of solvents. Phase transfer methods are often limited in the types and sizes of particles that can be effectively dispersed in an immiscible solvent. Currently, general transfer methods for a wide variety of nanoparticles have not been identified. New routes for phase transfer allow for utilization of a larger range of particles in applications which were previously limited by solubility and reactivity issues. In this work, we will describe the fundamental methods for the phase transfer of metallic nanoparticles. We will look at the major problems and pitfalls of these methods. The applications of phase transfer will also be reviewed, mainly focusing on catalysis and drug delivery.

In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

A mild, selective and facile synthesis of vinylsilanes via a recyclable platinum nanoparticle catalysed hydrosilylation of alkynes is reported. Various functionalized alkynes are selectively hydrosilylated to furnish functional β-E vinylsilanes in high yields. The catalytic effectiveness, ease of catalyst recovery and recyclability of the polysiloxane stabilized Pt-nanoparticle catalyst are the major achievements of this work. Detailed in situ characterization using Electron Microscopy and controlled poisoning experiments supports the participation of Pt-nanoparticles as active catalysts.

A simple one pot, highly efficient method to produce self-assembled arrays of functional silver nanoparticles is presented. In this strategy, a combination of tris[3-(trimethoxysilyl)propyl] isocyanurate (TTPI) and trioctylamine (TOA) play the dual role of reducing and stabilizing agents. In situ self-polymerization of TTPI, after attachment with self-assembled nanoparticles provides unique silicon nucleated soluble nanocomposites.

The direct production of silver nanoparticles in organic media is achieved via a simple one pot protocol using long chain hydrosilanes both as reducing and stabilizing agents. This synthetic strategy leads to highly efficient production of stable yet reactive silver nanoparticles. This synthesis is unique in terms of stabilization mechanism, where a very weak passivation is used to produce dispersible but highly active nanoparticles. The effect of hydrosilane alkyl chain length on the growth mechanism, reactivity, dispersibility and stability of the nanoparticles are also investigated.

Amino-bridged gel polymer P1 was discovered to catalyze alkyne halo-functionalization in excellent yields, regioselectivity, functional group compatibility, and recyclability. We have observed that both aromatic and aliphatic alkynes can be converted to α,α-dihalogenated ketones in the presence of polymer P1 under metal-free conditions at room temperature within a short reaction time.

Recently, metal nanoparticles have found applications in various fields, which have necessitated exploration of new avenues to obtain such materials. In this publication, a hydrosilane-based reduction and characterization of resulting palladium nanoparticles is achieved using palladium acetate as nanoparticle precursor and octadecylsilane as a reducing agent. The influence of phosphine and amine ligands in the stabilization of nanoparticles is also investigated. In addition, a brief mechanistic proposal of the reduction process is also discussed. Copyright © 2009 John Wiley & Sons, Ltd.

Selective hydrolytic oxidation of organohydrosilanes was achieved with water in the presence of Pt-nanoparticle catalyst. The selectivity of the process was established by NMR analysis. In addition, various Pt-based catalysts were screened to compare the activity and selectivity with Pt-nanoparticles catalysis. The method was equally applicable to hydrosilanes bearing unsaturated functional groups, which led to corresponding silanols under mild reaction conditions without formation of any side products. Pt-nanoparticle catalysis was studied in details using UV–vis, TEM and mercury poisoning experiments during the transformation. Copyright © 2009 John Wiley & Sons, Ltd.

‘Palladium-polysiloxane’ nanocomposites were synthesized as stable and isolable powder by reduction of Pd(OAc)2 with polymethylhydrosiloxane, which functions as a reducing agent and as a capping agent for the generation and stabilization of ‘palladium’-nanoclusters. Redispersion of ‘palladium-polysiloxane’ nanocomposite in common organic solvents, in the presence of polymethylhydrosiloxane, yielded catalytically active polysiloxane-wrapped soluble ‘palladium’-nanoclusters. Polysiloxane-encapsulated ‘palladium’-nanoclusters were used as recyclable catalyst for macromolecular grafting via alcoholysis of polyhydrosiloxane. Selective alcoholysis of polyhydrosiloxane took place in fair to excellent yields under moderate reaction conditions with a variety of alcohols (primary, secondary, tertiary/sterically bulky and functional alcohols). ‘In situ’ electron microscopy studies of the reaction mixtures in conjunction with controlled poisoning experiments revealed catalytic participation of ‘palladium’-nanoclusters during substitution reactions. Copyright © 2005 John Wiley & Sons, Ltd.

Ferrocene grafted siloxanes were prepared in high yields (∼79–97%) via Rh-catalyzed dehydrogenative coupling of a series of monomeric, polymeric, and cyclic hydrosiloxanes with ferrocenemethanol. Wilkinson’s catalyst was the most efficient of those surveyed (Karstedt’s catalyst, H 2 PtCl 6 , Co 2 (CO) 8 , 10% Pd/C, 10% Pt/C, 5% Rh/C) with respect to yield and selectivity. Benzene and toluene were better solvents than tetrahydrofuran and methylene chloride.

Polysiloxane-encapsulated "Pd"-nanoclusters were generated by reduction of Pd(OAc)(2) with polymethylhydrosiloxane, which functions as a reducing agent as well as a capping material for production and stabilization of catalytically active "Pd"-nanoparticles. Chemoselective hydrogenation of functional conjugated alkenes was achieved by in-situ- or ex-situ-generated polysiloxane-stabilized "Pd"-nanoclusters under mild reaction conditions in high yields. Electron microscopy, UV-vis, and NMR studies of the reaction mixture during the catalytic transformation were performed and, in conjunction with catalyst poisoning experiments, demonstrated unequivocally the role of polysiloxane-encapsulated "Pd"-nanoclusters as the real catalytic species. The recyclability of the "Pd"-nanoclusters was established by reusing the solid left after the reaction.

We have conducted Monte Carlo simulations to investigate a greatly simplified model for a blend composed of templated materials (polymers or monomers), smaller reacting particles and solvents on a two-dimensional lattice. In the simulations, we compute the mean chain conformation of flexible templated polymers, and the distribution of the number of adjacent reacting particles aligned along the same axis to rationalize how templated materials affect the physical aggregation of smaller particles in a blend. We first examine the effects of the effective interactions between templated materials and smaller reacting particles. For repulsive interactions, flexible templated polymers tend to contract to reduce repulsions arising from smaller reacting particles, but for attractive interactions, mean chain dimension increases to maximize attraction. When templated material composition is increased, the conformational deformation of templated polymers becomes more pronounced. Moreover, in the presence of attractive interactions, reacting particles are more dispersed in the blend. In contrast, repulsive interactions increase the probability of aggregation of reacting particles. Also, our findings show that templated monomers (without chain connectivity) interact with reacting particles more effectively than with templated polymers due to the greater interacting area per monomer, which enhances the dispersion and segregation of reacting particles in the blend due to the attractive and repulsive interaction, respectively. In addition, as templated material composition is increased, the probability of forming a larger aggregate decreases. This simple model allows us to elucidate the role of templated materials on the physical aggregation of smaller particles in a blend.

This account reports the new directions in the synthesis and characterization of polysiloxane-encapsulated metal nanoparticles and their applications to catalysis. These materials are prepared by sequestering metal ions with hydropolysiloxanes followed by chemical reduction to yield the corresponding zerovalent metal nanoparticles. The size and processability of such particles depends on the metal to polysiloxane ratios. Our method enables routine formation of stable nanometallic reservoirs in organic solvents avoiding particle aggregation during the storage as well as nucleation and growth process. Catalytic activity of nanoparticles vs metal complexes compares favorably for silaesterification reactions. We also demonstrate the utility of such reservoirs in grafting the surface properties of nanosized silver particles by ligand exchange reactions with thiols and phosphine oxide surfactants.

Twelve new linear polysiloxanes were prepared in high yields by catalytic (RhCl(PPh3)3) alcoholysis of poly(methylhydrosiloxane). The reaction conditions preserve the backbone and are tolerant of a variety of functional groups.

Linear and cyclic polysiloxanes with pendant amine moieties have been synthesized via the [(C 6 H 5 ) 3 P] 3 RbCl-catalyzed dehydrogenative alcoholysis of poly(methylhydrosiloxane) (PMHS) or cyclotetra(methylthydrosiloxane) (D4H) with hydroxyalkylamines.

Dehydrocoupling of polyhydrosiloxanes with thiols proceeded smoothly in the presence of Wilkinson's catalyst to furnish polythioethers in high yields under mild conditions. The process is free of rearrangement and cross-linking reactions.

A facile one step synthesis of poly(methylalkoxy-crownether)siloxanes has been achieved by dehydrogenative alkoholysis of PMHS (polymethylhydrosiloxane) catalyzed by a Rh(I) complex.

Chapter 1. Thermosensitive Core-Shell Microgel Particles as Carrier System for Catalytic Metal Nanoparticles (Professor Matthias Ballauff). Chapter 2. Metal and Metal Oxide Nanostructures on Resin Support (Professor Tarasankar Pal). Chapter 3. Nanocluster Catalysts and Their Practical Utility in Generation of Functionalized Organo-Silicon Polymers (Professor Bhanu P. S. Chauhan). Chapter 4. Design and Synthesis of Nano-Hybrid Systems Based on Silicon-Oxygen Bond (Professor Yusuke Kawakami). Chapter 5. Nanocrystalline Magnesium Oxide for Asymmetric Organic Reactions (Dr. M. Lakshmi Kantam). Chapter 6. Boron-Based Hybrid Nanostructures: Novel Applications of Modern Materials (Professor Narayan S. Hosmane). Chapter 7. The Exploration of Biomedical Multimodality in Small Solid Core Nanoparticles (Professor Marc Walters). Chapter 8. A Survey of Interactions of Gold Nanoparticles with Common Human Blood Plasma Proteins (Professor Alamgir Karim). Chapter 9. Genetically Modified Collagen-Like Triple Helix Peptide as Biomimetric Template (Professor Hiroshi Matsui). Chapter 10. Polydiacetylene-Containing Liposomes as Sensory Materials (Professor Sanku Mallik). Chapter 11. Block-Copolymer-Templated Synthesis of Ordered Silicas with Closed Mesopores (Professor Michal Kruk). Chapter 12. Organic Inorganic Hybrid Nanomaterials: Organization, Functionalization and Potential Applications in Environmental Domain (Professor Ahmad Mehdi).

Acrylonitrile and 2-chloroacrylonitrile react with trichlorosilane in the presence of cobalt chloride and an amine to give the β-adduct in 75–95% yields under mild conditions.

Dehydrocoupling of polyhydrosiloxanes with thiols proceeded smoothly in the presence of Wilkinson's catalyst to furnish polythioethers in high yields under mild conditions. The process is free of rearrangement and cross-linking reactions.

A one-step, highly selective catalytic route to silyl esters is reported. Commercially available silanes with Si-H functionality were converted to silyl or siloxy esters in the presence of Pd(OAc)2 under mild reaction conditions. This protocol was found to be equally applicable for the modification of multiple silicon centers in one framework and lead to the corresponding polysilyl esters in high yields. A comparison of catalytic efficiency of Pd(OAc)2 versus Pd on carbon was also undertaken.

[formula: see text] A one-step, highly selective catalytic route to silyl esters is reported. Commercially available silanes with Si-H functionality were converted to silyl or siloxy esters in the presence of Pd(OAc)2 under mild reaction conditions. This protocol was found to be equally applicable for the modification of multiple silicon centers in one framework and lead to the corresponding polysilyl esters in high yields. A comparison of catalytic efficiency of Pd(OAc)2 versus Pd on carbon was also undertaken.

In this chapter, nanocluster catalyzed modifications of organic and silicon based polymers are described. The tailoring of the polymeric templates was carried out under mild conditions and led to hybrid polymers in quantitative yields. Detailed characterization studies indicated that the integrity of the polymeric templates was not compromised during the functionalization process. The nanoparticle catalysis was found to be quite effective and highly selective. In most cases exclusive β-hydrosilylation products were obtained without any rearrangement or isomerization reactions. Detailed characterization and property profiling of the new hybrid polymers is also presented.

The role of "Pd" colloids in Pd(OAc)2 -catalyzed silaesterification reactions was investigated. The first example of the generation and utilizations of recyclable polysiloxane network stabilized palladium nanoparticles is described. We also provide the evidence that the silicon polymers play the role of stabilizing agents, preventing the generation of bulk palladium without compromising the activity of the catalyst.

The first example of "Pt"-nanocluster-catalyzed regioselective generation of hybrid polymers via attachment of organic functionalities to evenly distributed Si-H bonds of poly(methylhydro)siloxane is described. In addition, participation of Pt-nanoclusters as an active catalyst was evidenced by various spectroscopic techniques during the catalytic transformations.

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

Drug delivery and targeting on the molecular level comprises a fast growing branch of the biomaterials and bioengineering fields. A requirement for success is the proper choice of biomaterial used. Currently, there are several polymers used as biomaterials, many of which can cause long-term side effects and complications. Collagen is a natural, inert biomaterial found suitable for drug delivery. It is valued for its superior biocompatibility, biodegradability, and weak antigenicity relative to other polymers used as biomaterials. It has been used in resorbable surgical sutures, hemostatic agents, and wound dressings for many years and shows promise for future development in the drug delivery field. Collagen has been rarely implicated in adverse reactions and can be molded into a variety of drug delivery systems.

Acrylonitrile and 2-chloroacrylonitrile react with trichlorosilane in the presence of cobalt chloride and an amine to give the β-adduct in 75–95% yields under mild conditions.

Pt(cod)2 catalyzed dehydrocoupling of acyclic and cyclic secondary silanes R1R2SiH2[R1, R2 = alkyl group; R1 + R2 = (CH2)n(n = 3,4,5); R1 + R2 = o-biphenylene] to afford polysilanes while a (CH3)2Pt(cod)-catalyzed reaction of silacyclobutane (n = 3) resulted in selective ring-opening polymerization.