Tuning the Moisture and Thermal Stability of Metal–Organic Frameworks through Incorporation of Pendant Hydrophobic Groups

Abstract

An isostructural series of NbO-type porous metal-organic frameworks (MOFs) with different dialkoxy-substituents of formula Cu 2 (TPTC-OR) (TPTC-OR = 2',5'-di{alkyl}oxy-[1,1':4',1''-terphenyl]-3,3'',5,5''-tetracarboxylate, R = Me, Et, n Pr, n Hex) has been synthesized and characterized. The moisture stability of the materials has been evaluated and a new superhydrophobic porous MOF has been identified. The relationship between pendant side chain length and thermal stability has been analyzed by in situ synchrotron powder X-ray diffraction, showing decreased thermal stability as the side chain length is increased, contradictory to thermogravimetric decomposition studies. Additionally, the four materials exhibit moderate Brunauer-Emmett-Teller (BET) and Langmuir surface areas (1127 -1396 m 2 g -1 and 1414 -1658 m 2 g -1 ), and H 2 capacity up to 1.9 wt% at 77 K and 1 bar.

Microporous metal-organic frameworks with suitable pore spaces for acetylene storage and purification

“…The BET surface areas are higher than previous reported 1855 m 2 g -1 [36] of Cu 2 TPTC-Me and 1127 m 2 g -1 [41] of Cu 2 TPTC-OMe, which could be attributed to the difference of activated processes and computational methods [22]. is comparable to those in other MOFs with the same copper paddlewheels [44].…”

“…Cu 2 TPTC-Me and Cu 2 TPTC-OMe were solvothermally synthesized similarly to the literatures [36,41]. Organic linkers H 4 TPTC-Me and H 4 TPTC-OMe were synthesized via Suzuki coupling reaction followed by hydrolysis and acidification (Scheme S1).…”

“…MOFs Cu 2 TPTC-Me and Cu 2 TPTC-OMe have been obtained according to the literature method except for the change of the solvents[36,41]. The single crystal X-ray diffraction measurements indicate that the structures of both Cu 2 TPTC-Me and Cu 2 TPTC-OMe are same with the MOF NOTT-106[36].…”

Enhanced Uptake and Selectivity of CO2 Adsorption in a Hydrostable Metal–Organic Frameworks via Incorporating Methylol and Methyl Groups

“…29−31 To date, some studies have reported the functionalization of the parent NOTT series materials, including tuning the moisture and thermal stability and introduction of mesopores. 32,33 However, it appears to be almost ignored that the MOFs exhibit excellent CO 2 adsorption properties, especially under ambient temperature and pressure. The incorporation of polar groups like amino or hydroxy into the organic linkers is more favorable for the enhancement of CO 2 uptake through increasing interactions of CO 2 molecules with the framework of MOFs, and a higher selectivity of CO 2 upon other permanent gases may be achieved thereupon.…”

Hydrophobic Metal–Organic Frameworks: Assessment, Construction, and Diverse Applications

“…MOFs synthesized from some tritopic, tetratopic, and octatopic carboxylic acid ligands have also shown characteristics of hydrophobicity . Cai et al reported two Cu 2 paddle‐wheel SBU based MOFs, [Cu 3 (mbtc) 2 ] (CuMBTC) and [Cu 3 (ebtc) 2 ] (CuEBTC), which were obtained from methyl‐ and ethyl‐ group‐functionalized H 3 btc ligands, H 3 mbtc and H 3 ebtc, respectively .…”