@article{aa8200a2942a47d18964042154b21c0f,
title = "Proton Conductivity via Trapped Water in Phosphonate-Based Metal-Organic Frameworks Synthesized in Aqueous Media",
abstract = "Metal-organic frameworks (MOFs) are promising candidates for proton-conducting applications. Herein, we report the aqueous synthesis of two new phosphonate-based MOFs comprising glyphosate linkers, [Mg(dpmp)]·2H2O (Mg-NU-225) and [Fe(dpmp)]·2H2O (Fe-NU-225), (dpmp = N,N′-diphosphonomethyl-2,5-piperazinedione), and explore their proton conductivities. Single crystal X-ray diffraction measurements revealed that both frameworks display a two-dimensional layered structure with a cyclic ring ligand which forms in situ from the condensation of two glyphosate molecules. Under humid conditions and over a wide temperature range, water molecules are trapped between adjacent layers and facilitate rapid proton conduction. Mg-NU-225 and Fe-NU-225 recorded proton conductivities of 1.5 × 10-5 and 1.7 × 10-5 S cm-1, respectively, along the plane direction and 1.6 × 10-3 and 9.1 × 10-5 S cm-1 perpendicular to the plane direction at 55 °C and 95% relative humidity, as confirmed by two-contact probe impedance methods. The mechanism of proton transport was found to be that of the Grotthuss model from the low activation energy for proton hopping. ",
author = "Unjila Afrin and Mian, {Mohammad Rasel} and Otake, {Ken Ichi} and Drout, {Riki J.} and Redfern, {Louis R.} and Satoshi Horike and Timur Islamoglu and Farha, {Omar K.}",
note = "Funding Information: O.K.F. is grateful for the financial support from the Army Research Office (Grant W911NF1910340). Use was made of the IMSERC X-ray facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN). This work made use of the EPIC facility of Northwestern University{\textquoteright}s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSFECCS-1542205), the MRSEC program (NSF DMR-1720139) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois through the IIN. Funding Information: O.K.F. is grateful for the financial support from the Army Research Office (Grant W911NF1910340). Use was made of the IMSERC X-ray facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN). This work made use of the EPIC facility of Northwestern University?s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSFECCS-1542205), the MRSEC program (NSF DMR-1720139) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois through the IIN. Publisher Copyright: {\textcopyright} ",
year = "2021",
month = jan,
day = "18",
doi = "10.1021/acs.inorgchem.0c03206",
language = "English (US)",
volume = "60",
pages = "1086--1091",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "2",
}