Hawes, CS, Knowles, GP, Chaffee, AL, White, KF, Abrahams, BF, Batten, SR and Turner, DR (2016) Porous Polyrotaxane Coordination Networks Containing Two Distinct Conformers of a Discontinuously Flexible Ligand. Inorganic Chemistry, 55 (20). 10467 -10474. ISSN 0020-1669

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Abstract

A new divergent homopiperazine-derived ligand N,N′-bis(4-carboxyphenyl)-1,4-diazacycloheptane H2L has been prepared, containing a semirigid saturated heterocyclic core which is capable of providing multiple distinct bridging geometries. Reaction of H2L with zinc acetate in DMSO gives a two-dimensional parallel interpenetrated polyrotaxane structure 1 in which the loops and rods are formed by the bent cis-(eq,ax) twist boat and trans-(ax,ax) twist chair conformers, respectively. By matching the distances between the solvated metal sites in the structure of 1, a related material 2 can be prepared incorporating the pillaring ligand trans-1,2-bis(4-pyridyl)ethylene bpe. Compound 2 displays a similar polyrotaxane interpenetration mode, permitted by the presence of both cis and trans ligand conformers, but displays a three-dimensional 2.69 topology related to the dia diamondoid network. The guest exchange and gas adsorption properties of both materials were investigated; while compound 1 displays poor stability to guest exchange and negligible gas uptake, the higher connectivity microporous compound 2 shows facile guest exchange and a surprisingly high CO2 capacity of 12 wt % at 1 bar and 273 K, and a zero-loading enthalpy of adsorption of −32 kJ mol−1 . High-pressure adsorption isotherms also show moderate physisorption of H2 and CH4 within the material.

Item Type: Article
Additional Information: This is the accepted author manuscript (AAM). The final published version (version of record) is available online via ACS at http://doi.org/10.1021/acs.inorgchem.6b01713 - please refer to any applicable terms of use of the publisher.
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 29 May 2018 14:59
Last Modified: 04 Jul 2018 13:37
URI: https://eprints.keele.ac.uk/id/eprint/4957

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