Tubular-Shape Evolution of Microporous Organic Networks

This work suggests a synthetic method for tubular-shape evolution of amorphous and microporous organic networks. The gradual addition of a dihalo building block to its mixture with tetrakis(4-ethynylphenyl)methane under conventional Sonogashira coupling conditions resulted in the formation of tubular materials. The resulting tubular materials were characterized by scanning and transmission (TEM) electron microscopies, Brunauer-Emmett-Teller and thermogravimetric analyses, and solid-phase C-13 NMR spectroscopy. In comparison, when the mixture of a dihalo building block and tetrakis(4-ethynylphenyl)methane was heated under conventional Sonogashira coupling conditions, granular materials were formed. We suggest that the tubular-shape evolution is attributed to the differences of steric situations in networking steps. In TEM, the oriented attachment of the tubular materials was observed.