Robust pyridylbenzoate metal–organic frameworks as sorbents for volatile solvents and gases?

CrystEngComm Pub Date: 2021-09-21 DOI: 10.1039/D1CE01052B

Abstract

Two activated isostructural porous compounds, [Co(34pba)(44pba)]n (1d) and [Zn(34pba)(44pba)]n (2d) (where 34pba is 3-(pyridin-4-yl)benzoate, 44pba is 4-(pyridin-4-yl)benzoate, and d indicates the activated phase) were used for the adsorption of halogenated volatile organic compounds (VOCs), iodine, carbon dioxide (CO2), and hydrogen. Elucidation of single-crystal structures found that the desolvated phases 1d and 2d show rotational disorder of one ring on each linker. The crystal structure of {[Co(34pba)(44pba)]·1.6 I2}n (1dI2) was obtained by vapour sorption of iodine into 1d, and this could be desolvated to a phase isostructural with 1d. Thus the MOF is robust to cycling through sorption/desorption processes with an accompanying order/disorder phase transition. Activation energies for the desorption of dichloromethane, dibromomethane, and iodine were measured as 70, 60, and 77 kJ mol?1 respectively. Both activated compounds were tested as gas sorbents, with 1d showing higher adsorption capacity than 2d for both carbon dioxide and hydrogen.

Graphical abstract: Robust pyridylbenzoate metal–organic frameworks as sorbents for volatile solvents and gases
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