ja7b05112_si_001.pdf (3.25 MB)
Molecular Adsorbates Switch on Heterogeneous Catalysis: Induction of Reactivity by N‑Heterocyclic Carbenes
journal contribution
posted on 2017-06-21, 00:00 authored by Johannes
B. Ernst, Christian Schwermann, Gen-ichi Yokota, Mizuki Tada, Satoshi Muratsugu, Nikos L. Doltsinis, Frank GloriusWe report the N-heterocyclic
carbene (NHC)-induced activation of
an otherwise unreactive Pd/Al2O3 catalyst. Surface
analysis techniques demonstrate the NHC being coordinated to the palladium
particles and affecting their electronic properties. Ab initio calculations provide further insight into the electronic effect
of the coordination with the NHC injecting electron density into the
metal nanocluster thus lowering the barrier for bromobenzene activation.
By this NHC modification, the catalyst could be successfully applied
in the Buchwald–Hartwig amination of aryl chlorides, bromides,
and iodides. Various heterogeneity tests could additionally show that
the reaction proceeds via a heterogeneous active species.