Highly Hydrophobic Isoreticular Porous Metal–Organic Frameworks for the Capture of Harmful Volatile Organic Compounds

Abstract

Tunable hydrophobicity: Efficient air filters for the protection against chemical warfare agents might be achieved by surface functionalization of the pores in robust metal–organic frameworks (MOFs) with fluoroalkyl residues and the precise control of their pore size (see picture). These MOFs capture harmful volatile organic compounds even under extremely moist conditions (80 % relative humidity).

Metal–Organic Frameworks Containing Missing‐Linker Defects Leading to High Hydroxide‐Ion Conductivity

“…[12,13] MOFs 10 + clusters with enhanced basicity (Figure 1), 2) the deprotonation of the hydroxo tags of the BDP_OH linker, 3) the generationo fm issing-linker defects, and 4) the introductiono fe xtra-framework potassium ions. [12] The resulting materials 1@KOH, 2@KOH,a nd 3@KOH,a re chemically stable to this treatment, since they maintain the originalt opology,a s corroborated by the maintenance of XRPD patterns( FigureS1 in the Supporting Information).…”

Design and Construction of Chemically Stable Metal-Organic Frameworks

“…36 introducing fluorinated methyl groups to the organic linkers. 29 Interestingly, the fluorinated methyl groups are able to increase the partial pressure at which water vapor begins to condense in the framework to a larger extent than nonfluorinated methyl groups (P/P 0 > 0.65 with nonfluorinated methyl group, P/P 0 > 0.8 with fluorinated methyl group), further corroborating the strong hydrophobicity of fluorinated groups and their ability to produce water stable MOFs.…”

“…34 Both MOFs demonstrate their stability in boiling water for 7 days, concentrated HCl for 24 h, and NaOH solution (pH = 10) for 24 h. It is purposed that the presence of methyl groups on the central phenyl ring of the organic linker increases the hydrophobic character of the frameworks and therefore raises their water stability. 29 By examining the contact angle of water with the material, the extent of hydrophobicity of the framework and thus water stability can be anticipated. A hydrophobic material exhibits a contact angle between 90° and 150° with water and a material displaying a contact angle over 150° is considered superhydro- phobic.…”

“…Besides modulating agents, the concentration of coordinative ligands can also be controlled by adding protecting groups in the ligands, such as tert-butoxycarbonyl (Boc) groups in the case of a Ni 8 -pyrzaolate framework. 29 In this way, organic linkers can be slowly released into the system to guarantee a moderate forward reaction rate and therefore the crystallinity of the generated MOF can be ensured. With the aid of modulating agents and ligand protecting groups, de novo synthesis becomes an efficient and universal method to prepare a wide variety of stable MOFs, making it the first attempt for preparation of most robust MOFs.…”

Perspective: Metal-organic frameworks—Opportunities and challenges

“…These properties can include classic porous materials functions such as gas storage, e.g., for fuel gases such as hydrogen 13 and methane. 14 However, the tailorable internal surface chemistry is now opening up applications in delivery of medical actives 15 (e.g., NO, 16 exploiting chemisorption to metal centres which can be combined with loading of other drugs) and in toxic gas sorption, 17 where highly stable MOF chemistries allow removal of agents that can be hard to treat with other porous materials. 18 MOFs are now among the leading candidate materials for key separations, where strong complementarity in performance can exist with classical systems.…”