Architectures and DFT calculations of polyrotaxane MOFs with nanoscale macrocycles

Abstract

Polyrotaxane metal–organic frameworks (PMOFs) have attracted considerable attention due to their aesthetic topologies and potential biological applications. In this paper, we synthesized two kinds of hcb networks with nanoscale macrocycles. The hcb networks interlocked with each other in inclined and parallel interlocking modes respectively, giving rise to two new PMOFs, {[Ni(DPDBT)(bdc)]·(H₂O)₂}_n (1) and {[Zn(DPDBT)(fuma)]}_n (2). DFT calculations are used to elucidate why the inclined interlocking mode is preferential for 1 while the parallel interlocking mode is preferential for 2. The networks of 1 with a parallel interlocking mode, as well as 2 with an inclined interlocking mode, were simulated. The total energies of the parallel and inclined structures proved that the as-synthesized interlocking modes of 1 and 2 are more stable. Moreover, photophysical properties and thermal analyses of related ligands and complexes are investigated and discussed in detail.