173267-23-7Relevant articles and documents
Little change but great effect: Varying supra-molecular interactions in 2,5-dimethoxyterephthalic acid and 2,5-diethoxyterephthalic acid
Boehle, Tony,Eissmann, Frank,Seichter, Wilhelm,Weber, Edwin,Mertens, Florian O.R.L.
, p. o350-o353 (2011)
The title terephthalic acid derivatives, namely 2,5-dimethoxyterephthalic acid, C10H10O6, (I), and 2,5- diethoxyterephthalic acid, C12H14O6, (II), exhibit nearly planar molecular structures, with maximum deviations from the leastsquares planes calculated for all non-H atoms of 0.0418 (6) and 0.0902 (10) A for (I) and (II), respectively. The molecules of both title compounds contain an inversion centre and thus the asymmetric unit of both crystal structures consists of only half a molecule. It is a remarkable fact that a comparatively small change in the substitution of the terephthalic acid [dimethoxy in (I) versus diethoxy in (II)] causes major differences in the dominating supramolecular interactions. While in (II) the packing structure is stabilized by typical intermolecular hydrogenbonded carboxylic acid dimer interactions, the carboxyl group in (I) forms an unusual intramolecular hydrogen bond with the O atom of the neighbouring methoxy group.
Experimental, Structural, and Computational Investigation of Mixed Metal-Organic Frameworks from Regioisomeric Ligands for Porosity Control
Choi, Jiyoon,Ha, Hyeonbin,Kim, Dongwook,Kim, Dopil,Kim, Hyungjun,Kim, Min,Kim, Youngik,Kim, Youngjo,Park, Myung Hwan,Son, Younghu,Yoon, Minyoung
, p. 5338 - 5345 (2020)
Porosity control and structural analysis of metal-organic frameworks (MOFs) can be achieved using regioisomeric ligand mixtures. While ortho-dimethoxy-functionalized MOFs yielded highly porous structures and para-dimethoxy-functionalized MOFs displayed almost nonporous properties in their N2 isotherms after evacuation, regioisomeric ligand-mixed MOFs showed variable N2 uptake amount and surface area depending on the ligand-mixing ratio. The quantity of N2 absorbed was tuned between 20 and 300 cm3/g by adjusting the ligand-mixing ratio. Both experimental analysis and computational modeling were performed to understand the porosity differences between ortho- A nd para-dimethoxy-functionalized MOFs. Detailed structural analysis using X-ray crystallographic data revealed significant differences in the coordination environments of DMOF-[2,3-(OMe)2] and DMOF-[2,5-(OMe)2] (DMOF = dabco MOF, dabco = 1,4-diazabicyclo[2.2.0]octane). The coordination bond between Zn2+ and carboxylate in the ortho-functionalized DMOF-[2,3-(OMe)2] was more rigid than that in the para-functionalized DMOF-[2,5-(OMe)2]. Quantum-chemical simulation also showed differences in the coordination environments of Zn secondary building unit surrounded by methoxy-functionalized ligands and pillar ligands. In addition, the binding energy differences between Zn2+ and regioisomeric ligands (ortho- A nd para-dimethoxy-functionalized benzene-1,4-dicarboxylates) explained the rigidity and porosity changes of the mixed MOFs upon evacuation and perfectly matched with experimental N2 adsorption and X-ray crystallography data.
Defect Engineering into Metal-Organic Frameworks for the Rapid and Sequential Installation of Functionalities
Park, Hyojin,Kim, Seongwoo,Jung, Byunghyuck,Park, Myung Hwan,Kim, Youngjo,Kim, Min
supporting information, p. 1040 - 1047 (2018/02/14)
Postsynthetic treatments are well-known and important functionalization tools of metal-organic frameworks (MOFs). Herein, we have developed a practical and rapid postsynthetic ligand exchange (PSE) strategy using a defect-controlled MOF. An increase in the number of defects amounts to MOFs with enhanced rates of ligand exchange in a shorter time frame. An almost quantitative exchange was achieved by using the most defective MOFs. This PSE strategy is a straightforward method to introduce a functionality into MOFs including bulky or catalytically relevant moieties. Furthermore, some mechanistic insights into PSE were revealed, allowing for a sequential ligand exchange and the development of multifunctional MOFs with controlled ligand ratios.
Flexibility in metal-organic frameworks derived from positional and electronic effects of functional groups
Ha, Hyeonbin,Hahm, Hyungwoo,Jwa, Dong Gyun,Yoo, Kwangho,Park, Myung Hwan,Yoon, Minyoung,Kim, Youngjo,Kim, Min
, p. 5361 - 5368 (2017/09/26)
The position of identical functional groups and the subsequent electron density of structural benzene rings in a zinc-based metal-organic framework (MOF) have been controlled to reveal flexibility (or breathing behavior) differences. Both ortho- and para-positioned bi-functional benzene-1,4-dicarboxylic acid (BDC) ligands were synthesized with amino-, chloro-, methoxy-, and nitro groups. Additionally, two tri-functionalized, dimethoxy-amino and dimethoxy-nitro BDCs were prepared. All bi- and tri-functionalized BDCs were successfully incorporated into DABCO MOFs (DMOFs), except two diamino BDCs which were insoluble and thermally unstable. Among the eight bi-/tri-functionalized DMOFs, only para-dimethoxy exhibited flexibility in its framework after evacuation in preparation for N2 isotherm measurement. Since the dimethoxy combination has the most electron-rich environment in the benzene ring of the BDC in this series, this indicates that electron density plays a role in the flexibility changes of identically bi-functionalized DMOFs. However, the electron density alone could not fully explain the flexibility changes suggesting that the position of the functional groups is also important. These findings have been corroborated through the synthesis of two tri-functionalized DMOFs with identical functional group locations but opposite electronic environments.
