The Art and Beauty of Inorganic Synthesis on the Path to Discovery: Transition Metal Coordination and Activation of Sulfur Dioxide and Dihydrogen

Abstract

Transition metal compounds often possess spectacular gem-like colors and crystallinity that have attracted quite a few individuals to careers in chemistry. This was especially true for myself when I carried out undergraduate research in John Fackler's laboratory and I began to appreciate the art and beauty of inorganic synthesis. These facets were invaluable later on in my discovery of both new types of sulfur dioxide complexes and especially dihydrogen complexes where keen observation of reaction colors was key to uncovering reversible binding of H₂ to Mo/W complexes. Synthesis can be as much art as science, and the factors leading to the discovery of dihydrogen complexes will be a major focus of this article. The key structure/bonding/reactivity features and importance of metal-H₂ binding in the development of hydrogen as a future fuel will also be discussed. Coordination of H₂ facilitates its heterolytic cleavage, a key process in metalloenzymes such as hydrogenases that provide valuable models for the microscopic reverse, biomimetic formation of H₂ from protons and electrons. Coupling this with photochemistry would be key to production of so-called solar fuels.

Keywords:

• activation of dihydrogen
• dihydrogen complexes
• heterolytic cleavage of dihydrogen
• hydrogenase
• sigma bond complex
• sulfur dioxide complexes

ACKNOWLEDGEMENT

This paper is dedicated to John Fackler, who inspired my early passion for inorganic synthesis and was instrumental in guiding my career during my undergraduate research with him.