Size and Shape Selectivity of Host Networks Built Based on Tunable Secondary Building Units

By modulating the secondary building units derived from the primary building units, N-acylsalicylhydrazides (H3xshz), we have been able to construct isostructural but tunable host networks, [Mn6(xshz)6(dmf)2(bpea)2], with
different cavity sizes and shapes where the secondary building units, [Mn6(xshz)6], were linked through exo-bidentate
bridging ligand, 1,2-bis(pyridyl)ethane (bpea) to form 3-D networks. With a short length linear N-acyl side chain at
the primary building unit, the host networks have a 3-D network with three-dimensional cavities. With an appropriate
length linear N-acyl side chain at the primary building unit, the host network keeps the isostructural 3-D network
but with two types of one-dimensional channels of reduced cavity volume. The tuned host networks showed not
only size selectivity for the guest molecules but also shape selectivity. While the three-dimensional channeled host
showed selectivity depending on the length of the podal guests, the one-dimensional channeled host showed
selectivity depending on both the length and/or the podality of the guest molecules.