LeadIn a binational Swiss-German cooperation this project addresses fundamental aspects of hydrogen chemistry and developments emphasizing the timely aspects of “metal-free” and “ionic hydrogenation” catalyses proceeding with heterolytic splitting of the H-H bond.Hydrogen chemistry has recently gained importance in conjunction with its potential role as a “clean” energy carrier and its connection to chemical hydrogen storage. A conceptually new, basic research approach to hydrogen chemistry was chosen to solve the remaining chemical enigma of hydrogen transformations. For decades hydrogen research focused mainly on developments of Wilkinson transition metal catalyses with the characteristics of a homolytic splitting of H2. Major drawbacks of this chemistry were the use of noble metal catalysts and the preference for reactions with unpolar unsaturated molecules. These drawbacks are thought to be overcome by utilization of recently emerged aspects of hydrogenations splitting H2 by heterolysis, which are cumulatively denoted as “ionic hydrogenations” and are transition metal or main group element “metal-free” catalyzed. Polar transfer hydrogenations, operating on the basis of a simultaneously occurring double H transfers, are also studied in this project.A comprehensive fundamental approach to hydrogen chemistry is sought consisting of developments for “ionic hydrogenations” and polar transfer hydrogenations, preferably in catalytic form with emphasis on “metal-free” catalysis or very efficient noble metal catalysis. A broad search for new hydrogen related catalyses builds the chemical platform for this Swiss-German cooperation.In conjunction with the vision of dihydrogen as a “clean” future energy carrier and the involvement of dihydrogen reactivity in chemical hydrogen storage materials, this bi-national collaborative project attains considerable socialrelevance. The project would like to contribute to an ultimate profound understanding of dihydrogen chemistry exploring the missing facets of polar and “metal-free” hydrogen and hydrogen related catalyses. Respective new insights are thought to lay the grounds for future chemical developments in hydrogen technology.