An Emerging Opportunity for Aromatic Linker Nanoarchitectonics Around C_<i>n</i>TMA-Templated Mesopores

The molecularly ordered organization of accessible aromatic groups, for example, those around uniform mesopores, is fascinating for the versatile design of unique functions for electric and catalytic applications. However, this cutting-edge nanoarchitectonics design has been achieved so far through the synthesis of periodic mesoporous organosilica (PMO)-type materials only. This is possibly due to the difference in the formation of nanoscale inorganic units in inorganic–organic hybrid frameworks between silica and others. Herein, we demonstrated the well-balanced organization of phenylene (–Ph–) linkers with the retention of cylindrical, small-sized mesopores. By surveying a wide range of the synthetic conditions, mainly the amount of hexadecyltrimethylammonium chloride (C16TMACl), the formation of highly ordered (lamellar and 2-d hexagonal) and less ordered mesostructures was confirmed during the synthesis of –Ph– containing aluminum organophosphonate (AOP-Ph) using C16TMACl. In addition, a molecular-scale periodicity of the –Ph– linker was found in the AOP-Ph-type frameworks of 2-d hexagonal and less ordered mesostructured materials. Although the highly ordered 2-d hexagonal structure collapsed by calcination even at low temperature (e.g., 250 °C) with an enhancement of the molecular-scale periodicity, an exceptional AOP-Ph-type mesoporous and crystalline material can result during calcination of the disordered one at 350 °C. This is an emerging opportunity for –Ph– linker nanoarchitectonics around small-sized cylindrical mesopores.