Research ArticleMATERIALS SCIENCE

Readily accessible shape-memory effect in a porous interpenetrated coordination network

See allHide authors and affiliations

Science Advances  27 Apr 2018:
Vol. 4, no. 4, eaaq1636
DOI: 10.1126/sciadv.aaq1636

You are currently viewing the abstract.

View Full Text

Abstract

Shape-memory effects are quite well-studied in general, but there is only one reported example in the context of porous materials. We report the second example of a porous coordination network that exhibits a sorbate-induced shape-memory effect and the first in which multiple sorbates, N2, CO2 and CO promote this effect. The material, a new threefold interpenetrated pcu network, [Zn2(4,4′-biphenyldicarboxylate)2(1,4-bis(4-pyridyl)benzene)]n (X-pcu-3-Zn-3i), exhibits three distinct phases: the as-synthesized α phase; a denser-activated β phase; and a shape-memory γ phase, which is intermediate in density between the α and β phases. The γ phase is kinetically stable over multiple adsorption/desorption cycles and only reverts to the β phase when heated at >400 K under vacuum. The α phase can be regenerated by soaking the γ phase in N,N′-dimethylformamide. Single-crystal x-ray crystallography studies of all three phases provide insight into the shape-memory phenomenon by revealing the nature of interactions between interpenetrated networks. The β and γ phases were further investigated by in situ coincidence powder x-ray diffraction, and their sorption isotherms were replicated by density functional theory calculations. Analysis of the structural information concerning the three phases of X-pcu-3-Zn-3i enabled us to understand structure-function relationships and propose crystal engineering principles for the design of more examples of shape-memory porous materials.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text