This unique thesis discusses the development of conceptually novel and synthetically valuable methods that use visible light photocatalysis. Each chapter addresses a different topic in the emerging field of photocatalysis, which has become an indispensable tool for organic synthesis. Photocatalysis employs environmentally harmless and abundant visible light in the presence of a photosensitizer, and as such offers an attractive alternative to harmful UV light in photo-mediated reactions. This book introduces the novel concept of merging gold catalysis with visible light photocatalysis in a dual catalytic fashion, which demonstrates their compatibility with each other for first time and has inspired the development of various reactions. Moreover, a novel trifluoromethylation method, which combines radical addition chemistry with a polar rearrangement to synthesize valuable fluorinated compounds, is presented, since compounds featuring fluorinated functionality are the subject of increasing attention in pharmaceutical, agrochemical and material research. It also develops an external photocatalyst-free photochemical method for the synthesis of valuable indolizine heterocycles, where the product mediates its own formation. Lastly, it describes the synthesis and characterization of two novel highly porous metal-organic frameworks (MOFs). The comprehensive text is rounded out with illustrations and color figures.

Advances in Heterocyclic Chemistry, Volume 129 is the definitive series in the field—one of great importance to organic chemists, polymer chemists and many biological scientists. Because biology and organic chemistry increasingly intersect, the associated nomenclature also is being used more frequently in explanations. Written by established authorities in the field from around the world, this comprehensive, updated release includes chapters on Metal-Catalyzed Direct Arylation of 1,2-Azoles, The Literature of Heterocyclic Chemistry, Part XVII, 2017, Pyrrolo-, Imidazoquinolines and Pyrroloquinazolines with a Bridgehead Nitrogen, Synthesis and Reactions of Arsole, Stibole, and Bismole, Advances in Synthesis and Chemistry of Aziridines, and more. Considered the definitive serial in the field of heterocyclic chemistry Serves as the go-to reference for organic chemists, polymer chemists and many biological scientists Provides the latest comprehensive reviews written by established authorities in the field Combines descriptive synthetic chemistry and mechanistic insight to enhance understanding of how chemistry drives the preparation and useful properties of heterocyclic compounds

Filling the gap in the market for comprehensive coverage of this hot topic, this timely book covers a wide range of organic transformations, e. g. reductions of unsaturated compounds, oxidation reactions, Friedel-Crafts reactions, hydroamination reactions, depolymerizations, transformations of carbon dioxide, oxidative coupling reactions, as well as C-C, C-N, and C-O bond formation reactions. A chapter on the application of zinc catalysts in total synthesis is also included. With its aim of stimulating further research and discussion in the field, this is a valuable reference for professionals in academia and industry wishing to learn about the latest developments.

Over the past decade, the field of photoredox catalysis has garnered increasing amounts of attention in the organic chemistry community due to its wide applicability in sustainable free radical-mediated processes. Several examples have demonstrated that under carefully optimized conditions, efficient and highly selective processes can be developed through excitation of a photosensitizer using inexpensive, readily available light sources. Furthermore, these reactions can generally be performed under milder conditions than thermal reactions, as all the energy required to overcome the reaction barrier is supplied by light. Despite all these recent advancements in the field, many of these discoveries often lack in depth investigations into the excited state kinetics and underlying mechanisms. Furthermore, the vast majority of these transformations are photocatalyzed by ruthenium and iridium polypyridyl complexes. Not only are these precious metal catalysts extremely costly, but these metals are also known to be toxic, limiting their potential use in the development of pharmaceutical protocols. Herein, we present our solutions to these shortcomings, which involve a three-prong approach in the development of novel protocols, understanding the underlying mechanisms through detailed kinetic analysis, and by the development of new tools to facilitate mechanistic investigation for practitioners who may not possess specialized photochemical equipment. In this work, we were the first to demonstrate that radicals derived from amines, commonly employed as "sacrificial" electron-donors, can also act as reducing agents in photoredox transformations. We also present examples in which Methylene Blue, an inexpensive, non-toxic organic dye, can be employed as a viable alternative to ruthenium complexes for photoredox transformations. By employing a photosensitizer with more favourable excited state kinetics for electron-transfer, we successfully demonstrated that Methylene Blue could be used to increase the efficiency of a previously developed photoredox transformation. While employing organic dyes is an excellent strategy to lowering the cost of photoredox transformations, another viable strategy is to employ heterogeneous semiconductors. Titanium dioxide is an example of a semiconductor which is often employed in photocatalytic applications due to its low cost, desirable redox properties, and high chemical stability which allows for continued use. However, titanium dioxide has seen limited use in organic synthesis due to the requirement of UV irradiation for excitation. Herein, we present a process which led to the discovery of visible light photochemistry with titanium dioxide, generated through the adsorption of indole substrates creating a new, visible light absorbing complex. Employing this strategy, we were able to promote the photocatalytic Diels-Alder reaction of indoles with electron-rich dienes, giving access to valuable tetrahydrocarbazole scaffolds. Finally, in order to facilitate the characterization of chain processes in photoredox catalysis, we have successfully developed a visible light actinometer based on the ubiquitous photocatalyst, Ru(bpy)3Cl2. This actinometer offers many advantages compared to other visible light actinometers, such as completely eliminating the need for spectral matching, as the actinometer is also the photocatalyst. This technique should provide researchers with a mechanistic tool to properly characterize chain propagation in the transformation of interest.

The presented dissertation focuses on the design, synthesis, and characterization of metal-organic frameworks (MOFs) composed of earth-abundant elements the exhibit photoredox activity and studied their application as heterogeneous photocatalysts in organic synthesis and in solar-to-chemical energy conversion. In particular, the structure-property relationships of titanium-based MOFs relating the structure of the organic building unit and the photophysical and photochemical activity of the solid material is studied. The first novel family of seven MOFs isoreticular to MIL-125-NH2, includes functionalized with N-alkyl groups with increasing chain length (methyl to heptyl) and with varying connectivity (primary or secondary). The functionalized materials displayed reduced optical bandgaps correlated with the increased inductive donor ability of the alkyl substituents, enhanced excited-state lifetimes, mechanistic information towards visible light CO2 reduction, and improved water stability. The second family of titanium MOFs was prepared with a new secondary building unit and organic links of varying lengths, for which Their crystal structure was solved utilizing powder X-ray diffraction crystallography. This work provides guidelines for the next generation of photocatalyst for the conversion of solar-to-chemical energy and other organic transformations.

Filling the need for a ready reference that reflects the vast developments in this field, this book presents everything from fundamentals, applications, various reaction types, and technical applications. Edited by rising stars in the scientific community, the text focuses solely on visible light photocatalysis in the context of organic chemistry. This primarily entails photo-induced electron transfer and energy transfer chemistry sensitized by polypyridyl complexes, yet also includes the use of organic dyes and heterogeneous catalysts. A valuable resource to the synthetic organic community, polymer and medicinal chemists, as well as industry professionals.

Providing a thorough overview of leading research from internationally-recognized contributing authors, this book describes methods for the preparation and application of redox systems for organic electronic materials like transistors, photovoltaics, and batteries. Covers bond formation and cleavage, supramolecular systems, molecular design, and synthesis and properties Addresses preparative methods, unique structural features, physical properties, and material applications of redox active p-conjugated systems Offers a useful guide for both academic and industrial chemists involved with organic electronic materials Focuses on the transition-metal-free redox systems composed of organic and organo main group compounds