Snapshots of Cooperative Trimetallic Alkene Hydrogenation

High Resolution Image Download MS PowerPoint Slide Bimetallic cooperativity and synergistic effects have emerged as powerful tools that can enhance the reactivity and selectivity of catalytic systems, offering a pathway toward the development of catalysts based on Earth-abundant elements. Although not uncommon in nature, discrete molecular systems featuring more than two cooperative metal sites are virtually unknown. Herein we report the design of a well-defined molecular heterotrimetallic [Ga 2 Ni] system, which is effective in alkene hydrogenation catalysis. Species representing ‘snapshots’ of the catalytic cycle are isolated through consecutive addition of ethylene and dihydrogen, allowing for in-depth experimental mechanistic elucidation of two sequential 2-electron oxidative processes. Alongside combined computational, kinetic, and isotopic labeling studies, these findings reveal a fully mapped hydrogenation mechanism in which all three metal sites partake in the alkene hydrogenation process. This system thus provides unique insights into cooperative molecular multimetallic catalysis and establishes a blueprint for rationally designed multicentered cooperativity beyond established diatomic concepts.