http://www.mdpi.com/journal/molecules/special_issues/click-chemistry/ Dear Colleagues, Click-chemistry is a new way of thinking molecular construction that emerges at the turn of this century. This concept, introduced by K. B. Sharpless, is based on the use of fast and efficient reactions between building blocks that opens the way to quasi-illimited variations in chemical architecture. Click-chemistry permits the construction of highly diversified structures through the use of reactive subunits, that can be joined using nucleophilic and electrophilic substitutions, ring opening reactions, cycloadditions reactions such as the copper (I)-modified Huisgen reaction and the Diels-Alder one, additions to unsaturated bonds, carbonyl chemistry, and so on. The scope of this new way of thinking molecular construction is large and has found many applications in classical organic synthesis, polymers and material sciences, as well as at the biological interface, with biocompatible conditions. This Special Issue of Molecules has the objective to present articles that cover the use of click-chemistry to generate molecular diversity by organic synthesis (molecular libraries, chemical architecture, complexe structures, etc.), as well as its application at the frontier with other sciences. Prof. Dr. Christian Girard Guest Editor {snippet name="submission_info"} http://www.mdpi.com/1420-3049/15/8/5768/ Boronic acids have been widely used in a wide range of organic reactions, in the preparation of sensors for carbohydrates, and as potential pharmaceutical agents. With the growing importance of click reactions, inevitably they are also applied to the synthesis of compounds containing the boronic acid moiety. However, such applications have unique problems. Chief among them is the issue of copper-mediated boronic acid degradation in copper-assisted [2,3]-cycloadditions involving an alkyne and an azido compound as the starting materials. This review summarizes recent developments, analyzes potential issues, and discusses known as well as possible solutions. http://www.mdpi.com/1420-3049/15/8/5768/ Mon, 23 Aug 2010 00:00:00 CEST Molecules 2010-08-23 15 8 Review 5768 5781 1420-3049 Click Reactions and Boronic Acids: Applications, Issues, and Potential Solutions 2010-08-23 doi: 10.3390/molecules15085768 Chaofeng Dai Yunfeng Cheng Jianmei Cui Binghe Wang http://www.mdpi.com/1420-3049/15/5/3087/ This article deal with the parallel synthesis of a 96 product-sized library using a polymer-based copper catalyst that we developed which can be easily separated from the products by simple filtration. This gave us the opportunity to use this catalyst in an automated chemical synthesis station (Chemspeed ASW-2000). Studies and results about the preparation of the catalyst, its use in different solvent systems, its recycling capabilities and its scope and limitations in the synthesis of this library will be addressed. The synthesis of the triazole library and the very good results obtained will finally be discussed. http://www.mdpi.com/1420-3049/15/5/3087/ Wed, 28 Apr 2010 00:00:00 CEST Molecules 2010-04-28 15 5 Article 3087 3120 1420-3049 Automated Synthesis of a 96 Product-Sized Library of Triazole Derivatives Using a Solid Phase Supported Copper Catalyst 2010-04-28 doi: 10.3390/molecules15053087 Jlalia Beauvineau Beauvière Önen Aufort Beauvineau Khaba Herscovici Meganem Girard http://www.mdpi.com/1420-3049/15/3/2039/ Novel heteroleptic iridium complexes containing the 1-substituted-4-phenyl-1H-1,2,3-triazole (phtl) cyclometalating ligand have been synthesized. The 3+2 Huisgen dipolar cycloaddition method (‘click’ chemistry) was utilized to prepare a class of bidentate ligands (phtl) bearing different substituents on the triazole moiety. By using various ligands (phtl-R1 and pytl-R2) (R1=adamantane, methyl and R2=adamantane, methyl, β-cyclodextrin, ursodeoxycholic acid), we prepared a small library of new luminescent ionic iridium complexes [Ir(phtr-R1)2(pytl-R2)]Cl and report on their photophysical properties. The flexibility of the clicking approach allows a straightforward control on the chemical-physical properties of the complexes by varying the nature of the substituent on the ligand. http://www.mdpi.com/1420-3049/15/3/2039/ Tue, 23 Mar 2010 00:00:00 CET Molecules 2010-03-23 15 3 Article 2039 2059 1420-3049 Cationic Heteroleptic Cyclometalated IridiumIII Complexes Containing Phenyl-Triazole and Triazole-Pyridine Clicked Ligands 2010-03-23 doi: 10.3390/molecules15032039 Felici Contreras-Carballada Smits Nolte Williams De Cola Feiters http://www.mdpi.com/1420-3049/15/1/178/ In the last few years click chemistry reactions, and in particular coppercatalyzed cycloadditions, have been used intensively for the preparation of new bioconjugate molecules and materials applicable to biomedical and pharmaceutical areas. This review will be focused on conjugates of the tripeptide Arg-Gly-Asp formed by means of click chemistry reactions. This sequence is a well known binding motif for specific transmembrane proteins and is involved in cellular adhesion to the extracellular matrix, allowing the selective recognition of the biomolecule or polymer in which it is incorporated. http://www.mdpi.com/1420-3049/15/1/178/ Wed, 06 Jan 2010 00:00:00 CET Molecules 2010-01-06 15 1 Review 178 197 1420-3049 Click Chemistry for the Synthesis of RGD-Containing Integrin Ligands 2010-01-06 doi: 10.3390/molecules15010178 Matteo Colombo Aldo Bianchi