# Regioselective Arene C–H Borylation with a MOF-Immobilized Iridium Bipyridine Catalyst

## TL;DR

A new iridium-based catalyst immobilized in a metal-organic framework efficiently performs selective borylation of aromatic compounds.

## Contribution

A MOF-immobilized iridium catalyst achieves high regioselectivity and turnover numbers for arene C–H borylation.

## Key findings

- 1-Ir-0.5 achieves up to 1560 turnover numbers per Ir for toluene substrate.
- The MOF-immobilized catalyst shows higher meta:para regioselectivity than a homogeneous catalyst for bulky arene substrates.
- DFT calculations show MOF pore confinement increases the energy barrier for para C–H activation.

## Abstract

Postsynthetic ligand exchange and metalation have been
used to
immobilize iridium bipyridine precatalysts in MFU-4l with controlled loadings. The resulting materials, 1-Ir-

x
(x = 0.1–0.5),
exhibit high activity for catalytic C–H borylation of arenes,
and 1-Ir-0.5 achieves up to 1560 turnover numbers per
Ir for toluene substrate. Remarkably, 1-Ir-0.5 exhibits
high meta:para product regioselectivity
compared to a homogeneous catalyst analogue for arene substrates bearing
bulky triisopropylsilyl groups. Density functional theory (DFT) calculations
reveal that steric constraints imposed by metal-organic framework
(MOF) pore confinement increase the free energy barrier for para C–H activation, biasing product formation toward
the meta isomer.