title: Mixed-linker solid solutions of functionalized pillared-layer MOFs - adjusting structural flexibility, gas sorption, and thermal responsiveness.
abstract: Flexible metal-organic frameworks (MOFs) can undergo fascinating structural transitions triggered by external stimuli, such as adsorption/desorption of specific guest molecules or temperature changes. In this detailed study we investigate the potentials and limitations of tuning framework flexibility systematically by exploiting the powerful concept of mixed-linker solid solutions. We chose the prototypical family of functionalized pillared-layer MOFs of the general type Zn2(fu(1)-bdc)2x(fu(2)-bdc)(2-2x)dabco (with x = 1.00, 0.75, 0.50, 0.25 and 0.00; fu-bdc = 2,5-dialkoxy-1,4-benzenedicarboxylate with varying alkoxy chain length, dabco = 1,4-diazabicyclo[2.2.2]octane) and examined their guest responsive, as well as intrinsic temperature dependent structural flexibility by X-ray diffraction, gas physisorption and calorimetric measurements. The ratio of the different fu-bdc linkers can be adjusted freely, offering opportunity for a targeted design of these functional materials by modulating their key features, such as magnitude of framework contraction upon guest removal, breathing behaviour upon CO2 adsorption/desorption, thermoresponsive phase behaviour, and their general thermal expansivity, by the careful choice of fu-bdc linkers and their combination.
authors.affiliation: Lehrstuhl für Anorganische Chemie II - Organometallics and Materials, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany. sebastian.henke-2@rub.de roland.fischer@rub.de and Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK. akc30@cam.ac.uk.
authors.forename: Inke
authors.initials: I
authors.lastname: Schwedler
authors.affiliation: Lehrstuhl für Anorganische Chemie II - Organometallics and Materials, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany. sebastian.henke-2@rub.de roland.fischer@rub.de and Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK. akc30@cam.ac.uk.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Henke
authors.affiliation: Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK. akc30@cam.ac.uk and Diamond Light Source Ltd. Diamond House, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Wharmby
authors.affiliation: Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK. akc30@cam.ac.uk.
authors.forename: Sneha R
authors.initials: SR
authors.lastname: Bajpe
authors.affiliation: Functional Inorganics and Hybrid Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK. akc30@cam.ac.uk.
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Cheetham
authors.affiliation: Lehrstuhl für Anorganische Chemie II - Organometallics and Materials, Ruhr-Universität Bochum, Universitätsstraße 150, D-44801 Bochum, Germany. sebastian.henke-2@rub.de roland.fischer@rub.de.
authors.forename: Roland A
authors.initials: RA
authors.lastname: Fischer