(700a) Fundamental Concepts in Catalytic Oxidative-Coupling Reactions On Metallic Gold
Despite the chemical inertness of metallic gold under ambient conditions, once activated by atomic oxygen, gold surface is extremely active and selective towards many key oxidative chemical transformations. A molecular-level understanding of the mechanism is critical in the discovery and design of “green” catalytic processes mediated by gold-based materials. Our work establishes of the mechanistic framework for oxidative-coupling reactions on the gold surface through fundamental surface science studies on the model system, atomic oxygen activated Au(111). The self-coupling mechanism for alcohols is unequivocally established by accurately predicting the cross-coupling of alcohols and aldehydes, which also expands the scope of the mechanism to other oxidative-coupling reactions. The mechanistic framework further demonstrates its generality by predicting new oxidative-coupling reactions between amines and aldehydes, amines and alcohols, as well as carbonylations. Strong parallels between reactions taking place on the model surface at low pressure and reactions carried out on nanoporous gold or supported gold catalysts under working catalytic conditions demonstrates the practical relevance of the fundamental mechanistic studies.