Stereoselective gridization and polygridization with centrosymmetric molecular packing

Abstract The gridarenes, with well-defined edges and vertices, represent versatile nanoscale building blocks for the installation of frameworks and architectures but suffer from difficulty in stereoselective control during their synthesis. Here we report a diastereoselective gridization of superelectrophilic diazafluorene-containing substrates (A m B n ) with crescent shapes into Drawing Hands grids (DHGs). The meso -selectivity reaches 75.6% diastereomeric excess ( de ) during the gridization of A 1 B 1 -type substrates and maintains ~80% de during the polygridization of A 2 B 2 -type monomers. Such stereocontrol originates from the centrosymmetric molecular packing of two charge-delocalized superelectrophiles with synergistically π – π stacking attractions and coulombic repulsions. As meso -stereoregular structures show 20∼30 nm in length, the rigid ring/chain-alternating polygrids have a Mark–Houwink exponent of 1.651 and a molecular weight ( M ) dependence of the hydrodynamic radius R h ∼ M 1.13 . Via the simulation of chain collapse, meso -configured polygridarenes still adopt rod-like conformations that facilitate the high rigidity of organic nanopolymers, distinguished from toroid backbones of rac -type polygrids.