Shape-Asymmetry Supramolecular Isomerism in Asymmetrical Ligand PCPs and the Expression Method of Three-Level Isomerism

We
show here the supramolecular isomerism, with respect to shape-asymmetry
of ligand and the new hierarchical classification for supramolecular
isomerism, the three-level isomerism, which was advanced based on
a thorough investigation for the four new Ni/dpt24 polymorphs [Hdpt24
= 3-(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole)]. Compounds 1, 2, and 3 are three-dimensional twofold
interpenetrated porous coordination polymers with NbO topology, while 4 with two-dimensional grid structure is termed as the primary
isomer of 1/2/3 due to the
difference of dimensionality. Complex 3 possessing different
shape-asymmetry of single networks from 1 and 2, is called as the secondary isomer of 1 and 2. Complexes 1 and 2 possess the same topology,
single shape-asymmetry networks, but different interpenetration-orientation
and interpenetration-asymmetry, and are defined as the tertiary isomers.
Distinct differences in H2 and CO2 adsorption
capacity were observed among each level of isomers. In addition, the
hierarchical classification’s relationship with characteristic
classifications has been discussed.