http://www.mdpi.com/journal/molecules/special_issues/nano-catalysits/ Dear Colleagues, Transition-metal nanoparticles are attracting a great deal of attention in almost any scientific and technological field. An increasing interest is nowadays devoted to the high activity and selectivity of nanocatalysts which allow to develop greener and waste-minimized processes. In addition, nanoparticles are suitable catalysts for processes carried out in neoteric eco-friendly solvents (viz. ionic liquids, supercritical fluids, fluorous phases, water etc.). For these reasons, green chemistry can play a prominent role in guiding the development of nanotechnology to provide the maximum benefit of these products for society and the environment. This Special Issue of Molecules has the objective to present articles dealing with the use of nanocatalysts and/or nanotechnologies in a wide range of catalytic organic reactions, ranging from the traditional carbon-carbon or carbon-heteroatom bond forming reactions (e.g. Heck, Suzuki, Stille, Sonogashira, Ullmann, Glodberg and so on) to the more innovative synthetic approaches based on the green chemistry principles (atom-economy, dematerialization, energy saving, raw material diversification, green solvents etc.) such as for example detoxification of PCBs, fixation of CO2 and so on. Multidisciplinary studies providing a bird-view of the nanocatalyst features, including its development/synthesis and its analytical chemical & morphological characterization, as well as organic synthesis application and structure-performance level correlations, are strongly encouraged. Nicola Cioffi, Ph. D. Prof. Dr. Angelo Nacci Guest Editors Submission All manuscripts should be submitted to molecules@mdpi.com with a copy to the Guest Editor. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed Open Access monthly journal published by MDPI. Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this Open Access journal is 1400 CHF per accepted paper. http://www.mdpi.com/1420-3049/16/1/348/ In the present work, a microchannel reactor for autothermal reforming of methanol using a synthesized catalyst porous alumina support-CuO/ZnO mixed with ZrO2 sol washcoat has been developed and its fine structure and inner surface characterized. Experimentally, CuO/ZnO and alumina support with ZrO2 sol washcoat catalyst (catalyst slurries) nanoparticles is the catalytically active component of the microreactor. Catalyst slurries have been dried at 298 K for 5 h and then calcined at 623 K for 2 h to increase the surface area and specific pore structures of the washcoat catalyst. The surface area of BET N2 adsorption isotherms for the as-synthesized catalyst and catalyst/ZrO2 sol washcoat samples are 62 and 108 ± 2 m2g−1, respectively. The intensities of Cu content from XRD and XPS data indicate that Al2O3 with Cu species to form CuAl2O4. The EXAFS data reveals that the Cu species in washcoat samples have Cu-O bonding with a bond distance of 1.88 ± 0.02 Å and the coordination number is 3.46 ± 0.05, respectively. Moreover, a hydrogen production rate of 2.16 L h−1 is obtained and the corresponding methanol conversion is 98% at 543 K using the CuO/ZnO with ZrO2 sol washcoat catalyst. http://www.mdpi.com/1420-3049/16/1/348/ Fri, 07 Jan 2011 00:00:00 CET Molecules 2011-01-07 16 1 Article 348 366 1420-3049 Hydrogen Generation Using a CuO/ZnO-ZrO2 Nanocatalyst for Autothermal Reforming of Methanol in a Microchannel Reactor 2011-01-07 doi: 10.3390/molecules16010348 Kuen-Song Lin Cheng-Yu Pan Sujan Chowdhury Mu-Ting Tu Wan-Ting Hong Chuin-Tih Yeh http://www.mdpi.com/1420-3049/15/7/4947/ This article is an account of the work carried out in the authors’ laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The “click” synthesis of dendrimers constructed generation by generation by 1à3 C connectivity, introduces 1,2,3-triazolyl ligands insides the dendrimers at each generation. Complexation of the ligands by PdII followed by reduction to Pd0 forms dendrimer-stabilized Pd nanoparticles (PdNPs) that are extremely reactive in the catalysis of olefin hydrogenation and C-C bond coupling reactions. The stabilization can be outer-dendritic for the small zeroth-generation dendrimer or intra-dendritic for the larger first- and second-generation dendrimers. The example of the Miyaura-Suzuki reaction that can be catalyzed by down to 1 ppm of PdNPs with a “homeopathic” mechanism (the less, the better) is illustrated here, including catalysis in aqueous solvents. http://www.mdpi.com/1420-3049/15/7/4947/ Tue, 20 Jul 2010 00:00:00 CEST Molecules 2010-07-20 15 7 Review 4947 4960 1420-3049 Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles 2010-07-20 doi: 10.3390/molecules15074947 Didier Astruc Cátia Ornelas Abdou K. Diallo Jaime Ruiz http://www.mdpi.com/1420-3049/15/7/4792/ Modern chemical synthesis makes heavy use of different types of catalytic systems: homogeneous, heterogeneous and nano-sized. The latter – nano-sized catalysts – have given rise in the 21st century to a rapidly developing area of research encompassing several prospects and opportunities for new technologies. Catalytic reactions ensure high regio- and stereoselectivity of chemical transformations, as well as better yields and milder reaction conditions. In recent years several novel catalytic systems were developed for selective formation of carbon-heteroatom and carbon-carbon bonds. This review presents the achievements of our team in our studies on various types of catalysts containing metal nanoparticles: palladium-containing diblock copolymer micelles; soluble palladium-containing polymers; metallides on a support; polymeric metal salts and oxides; and, in addition, metal-free organic catalysts based on soluble polymers acting as nanoreactors. Representative examples are given and discussed in light of possible applications to solve important problems in modern organic synthesis. http://www.mdpi.com/1420-3049/15/7/4792/ Thu, 08 Jul 2010 00:00:00 CEST Molecules 2010-07-08 15 7 Review 4792 4814 1420-3049 Recyclable Nanostructured Catalytic Systems in Modern Environmentally Friendly Organic Synthesis 2010-07-08 doi: 10.3390/molecules15074792 Beletskaya Tyurin http://www.mdpi.com/1420-3049/15/7/4679/ The preparation of carbon nanotube (CNT)/PdO nanoparticles and graphene oxide (GO)/PdO nanoparticle hybrids via a general aqueous solution strategy is reported. The PdO nanoparticles are generated in situ on the CNTs and GO by a one-step “green” synthetic approach in aqueous Pd(NO3)2 solution under ambient conditions without adding any additional chemicals. The production of PdO is confirmed by energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The morphologies of the resulting CNT/PdO and GO/PdO nanohybrids are characterized by transmission and/or scanning transmission electron microscopy. PdO nanoparticles with an average size of 2–3 nm in diameter are decorated evenly along the surfaces of CNTs and GO. This synthesis strategy is demonstrated to be compatible for 1) CNTs with different modifications, including pristine, oxidized, and polymer-functionalized CNTs; 2) different types of CNTs, including single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and multiwalled carbon nanotubes (MWCNTs); and 3) different shapes of carbon materials, including tubular CNTs and planar GO. The as-prepared CNT/PdO and GO/PdO nanohybrids can be transformed into CNT/Pd and GO/Pd nanohybrids by reduction with NaBH4, and can then be used as a heterogeneous catalyst in the catalytic reduction of 4-nitrophenol. http://www.mdpi.com/1420-3049/15/7/4679/ Fri, 02 Jul 2010 00:00:00 CEST Molecules 2010-07-02 15 7 Article 4679 4694 1420-3049 A General Strategy for the Preparation of Carbon Nanotubes and Graphene Oxide Decorated with PdO Nanoparticles in Water 2010-07-02 doi: 10.3390/molecules15074679 He Gao http://www.mdpi.com/1420-3049/15/7/4511/ Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO2 nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl halides in water. The catalyst efficiency is attributed to the stabilization of Pd nanophases provided by tetra(alkyl)- ammonium hydroxide, which behaves both as base and PTC (phase transfer catalyst) agent. http://www.mdpi.com/1420-3049/15/7/4511/ Thu, 24 Jun 2010 00:00:00 CEST Molecules 2010-06-24 15 7 Article 4511 4525 1420-3049 Palladium/Zirconium Oxide Nanocomposite as a Highly Recyclable Catalyst for C-C Coupling Reactions in Water 2010-06-24 doi: 10.3390/molecules15074511 Monopoli Nacci Calò Ciminale Cotugno Mangone Giannossa Azzone Cioffi http://www.mdpi.com/1420-3049/15/6/3863/ The one-pot acid-catalysed conversion of mono/di/polysaccharides (inulin, xylan, cellobiose, sucrose, glucose, fructose, xylose) into 2-furfuraldehyde (FUR) or 5-hydroxymethylfurfural (HMF) in the presence of aluminium-containing mesoporous TUD-1 (denoted as Al-TUD-1, Si/Al = 21), at 170 ºC was investigated. Xylose gave 60% FUR yield after 6 h reaction; hexose-based mono/disaccharides gave less than 20% HMF yield; polysaccharides gave less than 20 wt % FUR or HMF yields after 6 h. For four consecutive 6 h batches of the xylose reaction in the presence of Al-TUD-1, the FUR yields achieved were similar, without significant changes in Si/Al ratio. http://www.mdpi.com/1420-3049/15/6/3863/ Fri, 28 May 2010 00:00:00 CEST Molecules 2010-05-28 15 6 Article 3863 3877 1420-3049 Acid-Catalysed Conversion of Saccharides into Furanic Aldehydes in the Presence of Three-Dimensional Mesoporous Al-TUD-1 2010-05-28 doi: 10.3390/molecules15063863 Lima Antunes Fernandes Pillinger Ribeiro Valente http://www.mdpi.com/1420-3049/15/5/3441/ A brief summary of selected pioneering and mechanistic contributions in the field of carbon-carbon cross-coupling reactions with palladium nanoparticles (Pd-NPs) in ionic liquids (ILs) is presented. Five exemplary model systems using the Pd-NPs/ILs approach are presented: Heck, Suzuki, Stille, Sonogashira and Ullmann reactions which all have in common the use of ionic liquids as reaction media and the use of palladium nanoparticles as reservoir for the catalytically active palladium species. http://www.mdpi.com/1420-3049/15/5/3441/ Wed, 12 May 2010 00:00:00 CEST Molecules 2010-05-12 15 5 Article 3441 3461 1420-3049 Carbon-Carbon Cross Coupling Reactions in Ionic Liquids Catalysed by Palladium Metal Nanoparticles 2010-05-12 doi: 10.3390/molecules15053441 Prechtl Scholten Dupont http://www.mdpi.com/1420-3049/15/5/3311/ Catalytic hydrogenation under mild conditions of olefins, unsaturated aldeydes and ketones, nitriles and nitroarenes was investigated, using a supported rhodium complex obtained by copolymerization of Rh(cod)(aaema) [cod: 1,5-cyclooctadiene, aaema–: deprotonated form of 2-(acetoacetoxy)ethyl methacrylate] with acrylamides. In particular, the hydrogenation reaction of halonitroarenes was carried out under 20 bar hydrogen pressure with ethanol as solvent at room temperature, in order to minimize hydro-dehalogenation. The yields in haloanilines ranged from 85% (bromoaniline) to 98% (chloroaniline). http://www.mdpi.com/1420-3049/15/5/3311/ Wed, 05 May 2010 00:00:00 CEST Molecules 2010-05-05 15 5 Article 3311 3318 1420-3049 A Recyclable Nanoparticle-Supported Rhodium Catalyst for Hydrogenation Reactions 2010-05-05 doi: 10.3390/molecules15053311 Dell’Anna Gallo Mastrorilli Romanazzi http://www.mdpi.com/1420-3049/15/4/2124/ Since metal nanoparticles have a high surface-to-volume ratio and very active surface atoms, they are very attractive catalysts for a wide variety of organic and inorganic reactions, compared to bulk catalysts. Metal nanoparticles suspended in colloidal solutions and those adsorbed onto bulk supports have been used as catalysts for a wide variety of carbon-carbon bond formation reactions such as the Suzuki and Heck cross-coupling reactions. This review article highlights some of the latest advances in the application of noble metal nanoparticles as catalysts for these two industrially important classes of cross-coupling reactions. We will discuss several important advances in using metal nanocatalysts in Suzuki and Heck cross-coupling reactions such as investigations on the nanoparticle shape dependence on the catalytic activity, novel types of supported metal nanoparticles as nanocatalysts, and the use of bi-metallic, tri-metallic and multi-metallic nanoparticles as catalysts for the Suzuki and Heck cross-coupling reactions. http://www.mdpi.com/1420-3049/15/4/2124/ Thu, 25 Mar 2010 00:00:00 CET Molecules 2010-03-25 15 4 Review 2124 2138 1420-3049 Recent Advances in Noble Metal Nanocatalysts for Suzuki and Heck Cross-Coupling Reactions 2010-03-25 doi: 10.3390/molecules15042124 Narayanan http://www.mdpi.com/1420-3049/15/2/747/ The CeO2 nanorods (CeNR) promote the oxidation of ethylbenzene (PhEt) and cyclohexene with t-BuOOH, at temperatures as low as 55 ºC. For both substrates the saturated C-H bonds are preferentially activated over the unsaturated ones. The catalyst seems fairly stable towards leaching phenomena. The liquid-phase oxidation catalysis may be associated with the Ce3+/Ce4+ inter-conversion in the one-electron redox processes mediating the formation of tert-butyl-(per)oxy radicals. CeNR is very effective in H2O2 disproportionation. Pre-treatment of CeNR with H2O2 or t-BuOOH prior to the catalytic reaction enhances the reaction rate of PhEt with t-BuOOH in comparison to CeNR. Textural characterization and spectroscopic studies suggest that catalytic activation is associated to defect sites. http://www.mdpi.com/1420-3049/15/2/747/ Tue, 02 Feb 2010 00:00:00 CET Molecules 2010-02-02 15 2 Article 747 765 1420-3049 Catalytic Performance of Ceria Nanorods in Liquid-Phase Oxidations of Hydrocarbons with tert-Butyl Hydroperoxide 2010-02-02 doi: 10.3390/molecules15020747 Andreia G. Macedo Sílvia E. M. Fernandes Anabela A. Valente Rute. A. S. Ferreira Luís D. Carlos João Rocha