Fig. 2: Relative DFT energies for minimum-energy configurations for [x[2+3]+y]cages.
From: Computationally guided synthesis of a hierarchical [4[2+3]+6] porous organic ‘cage of cages’
x = number of Cage-3-Cl cages, y = number of TFHQ linkers. Atom colours: carbon, grey; nitrogen, blue; oxygen, red; fluorine, green. Hydrogen atoms are omitted for clarity. Note the break in the energy scale for the highly strained [2[2+3]+3]cage, which has by far the highest relative energy (660.8 kJ mol−1). The DFT energies indicate that the [4[2+3]+6] stoichiometry is predicted to form a stable, shape-persistent cage structure that has a lower relative energy (24.04 kJ mol−1) than the alternative [8[2+3]+12] topology.
