Postsynthetic Metalation of a Robust Hydrogen-Bonded Organic Framework for Heterogeneous Catalysis

Hydrogen-bonded organic framework
(HOF)-based catalysts still remain
unreported thus far due to their relatively weak stability. In the
present work, a robust porous HOF (HOF-19) with a Brunauer–Emmett–Teller
surface area of 685 m2 g–1 was reticulated
from a cagelike building block, amino-substituted bis­(tetraoxacalix[2]­arene[2]­triazine),
depending on the hydrogen bonding with the help of π–π
interactions. The postsynthetic metalation of HOF-19 with palladium
acetate afforded a palladium­(II)-containing heterogeneous catalyst
with porous hydrogen-bonded structure retained, which exhibits excellent
catalytic performance for the Suzuki–Miyaura coupling reaction
with the high isolation yields (96–98%), prominent stability,
and good selectivity. More importantly, by simple recrystallization,
the catalytic activity of deactivated species can be recovered from
the isolation yield 46% to 92% for 4-bromobenzonitrile conversion
at the same conditions, revealing the great application potentials
of HOF-based catalysts.