Incorporating Photochromic Triphenylamine into a Zirconium–Organic Framework for Highly Effective Photocatalytic Aerobic Oxidation of Sulfides

A zirconium-based
metal–organic framework (MOF) was successfully
constructed via solvothermal assembly of a triphenylamine-based
tricarboxylate ligand and Zr­(IV) salt, the structure simulation of
which revealed that it possesses a two-dimensional layered framework
with a relatively rare dodecnuclear Zr12 cluster as the
inorganic building unit. The inherent photo-responsive property derived
from the incorporated photochromic triphenylamine groups combined
with its high stability makes the constructed MOF an efficient heterogeneous
photocatalyst for the oxidation of sulfides, which is a fundamentally
important reaction type in both environmental and pharmaceutical industries.
The photocatalytic activity of the constructed MOF was first investigated
under various conditions with thioanisole as a representative sulfide
substrate. The MOF exhibited both high efficiency and selectivity
on aerobic oxidation of thioanisole in methanol utilizing molecular
oxygen in air as the oxidant under blue light irradiation for 10 h.
Its high photocatalytic performance was also observed when extending
the sulfide substrate to diverse thioanisole derivatives and even
a sulfur-containing nerve agent simulant (2-chloroethyl ethyl sulfide).
The high photocatalytic efficiency and selectivity to a broad set
of sulfide substrates make the triphenylamine-incorporating zirconium-based
MOF a highly promising heterogeneous photocatalyst.