Merging Homogeneous and Heterogeneous Catalysis

For decades gold catalysis has been a dormant field of research due to the metals perceived inertness. However, recent advances in the 21st century have created a veritable gold rush in homogeneous catalysis. This burst of catalytic interest has been associated with an array of new reactivity being uncovered, further leading to the development of numerous novel transformation reactions. Nowadays gold catalysts find versatile applications in a broad spectrum of mild organic syntheses, representing expressive examples of environmental benign green chemistry. Among these reactions can be found simple transformations of fine chemicals as well as multistep total syntheses of natural products. For this reason there exists a continually growing demand for novel tailored gold catalysts. This project covers on the one hand the preparation of innovative electrochemical tunable homogeneous gold(III) catalysts, representing highly stable water soluble compounds for mild reaction conditions. This part will focus on reactions in solution, starting from basic proof of concept reactions and leading to sophisticated multi-component tandem reactions. On the other hand metal- organic frameworks (MOFs) will be investigated. These heterogeneous congeners are of paramount importance in many areas of the chemical and energy industry. In detail, the idea is to create a synergistical system by the heterogenization of well-defined homogeneous gold(III) catalysts, accompanied by beneficial properties such as enhanced stability, substrate size selectivity and catalyst recycling. Besides the synthesis of the mentioned novel catalysts, the scope of this project lies also on the in-depth spectroscopic and computational investigation of the catalytic cycle. This unique combination of preparative, analytical and computational chemistry will help to develop powerful catalytic tools for challenging reactions and further will foster the understanding of their mechanisms.

For decades gold catalysis has been a dormant field of research due to the metal's perceived inertness. However, recent advances have created a veritable "gold rush" in homogeneous catalysis. This burst of catalytic interest has been associated with an array of new reactivity being uncovered, further leading to the development of numerous novel transformation reactions. Today gold catalysts find versatile applications in a broad spectrum of mild organic syntheses, representing expressive examples of environmental benign "green chemistry". Among these reactions can be found simple transformations of fine chemicals as well as multistep total syntheses of natural products. For this reason there exists a continually growing demand for novel tailored gold catalysts. This project aimed at the preparation of innovative electrochemical tunable homogeneous gold(III) catalysts, representing highly stable water soluble compounds for mild reaction conditions. In the course of this endeavor, a convenient and straightforward procedure, utilizing aqua regia, could be established. Moreover, metal-organic frameworks (MOFs) have been investigated in order to heterogenize well-defined homogeneous gold(III) catalysts and thus synergistically combining the enhanced stability and recyclability of MOFs with highly active catalytic gold centers. For the reason that the latter proved to be a rather challenging topic, various side projects with collaboration partners from the University of Innsbruck, the Eberhard Karl University of Tübingen and the Freie Univerität Berlin were initiated and gratifyingly led to numerous joint publications. In conclusion, this project has already yielded in four publications in renowned journals and will further lead to two more papers within the next few months, a delay, linked to the currently prevailing COVID-19 pandemic.