Porous Metal–Organic Framework Catalyzing the Three-Component Coupling of Sulfonyl Azide, Alkyne, and Amine

The
robustly porous metal–organic framework MOF–Cu2I2(BTTP4) (BTTP4 = benzene-1,3,5-triyl triiso­nicotinate)
was shown to work as an efficiently heterogeneous catalyst for the
three-component coupling of sulfonyl azides, alkynes, and amines,
leading to the formation of N-sulfonyl amidines in
good yields. MOF–Cu2I2(BTTP4) can be
recycled by simple filtration and reused at least four times without
any loss in yield. Studies of the ligand effects on the three-component
coupling reactions showed that BTTP4 could enhance the rate, as well
as the chemoselectivity, when aromatic alkynes were employed. The
catalytic process has been thoroughly studied by means of single-crystal
and powder X-ray diffraction, gas and solvent adsorption, in situ 1H NMR and FT-IR spectroscopy, X-ray photoelectron spectra
(XPS), and ICP analysis of Cu leaching.