Sulfonyl-bridged oligo(benzoic acid)s: synthesis, X-ray structures, and properties as metal extractants

Morohashi, Naoya; Nagata, Kazutoshi; Hayashi, Tomoko; Hattori, Tetsutaro

doi:10.1007/s10847-012-0283-9

Cited by 2 publications

(1 citation statement)

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“…We previously studied on the chemical modification of a sulfur-bridged phenol tetramer that has a structure formally derived from p - tert -butylthiacalix[4]arene by removing a sulfur atom from the macrocycle and capping the termini of the resulting open chain with hydrogen atoms . Dicarboxylic acid 3 derived from the phenol tetramer formed a macrocyclic dimer through a couple of intermolecular hydrogen bonds between the carboxy groups .…”

Section: Results and Discussionmentioning

confidence: 99%

Design and Synthesis of Open-Chain Hosts Having a Partial Structure of p-tert-Butylthiacalixarene

et al. 2018

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The development of separation materials for hard-to-separate molecular mixtures is highly desired from environmental and economic perspectives. Although the crystal of p-tert-butylthiacalix[4]arene exhibits high guest selectivity in inclusion from a mixture of molecules with similar sizes and shapes, it cannot include molecules larger than its calix cavity. To extend its guest inclusivity, we designed and synthesized an open-chain host, [3,3'-thiobis(5-tert-butyl-2-hydroxybenzene)-1,1'-diyl]diacetic acid (4). The competitive inclusion among toluidine isomers using compound 4 gave inclusion crystals containing the p-isomer in 1:1 (host/guest) ratio, with lesser amounts of other isomers and/or solvent molecules. The isomer selectivity varied between 66% and 97% depending on the solvent employed. X-ray analysis of inclusion crystals 4·p-toluidine·MeCN and 4·p-toluidine·(o-toluidine) revealed that compound 4 includes p-toluidine by forming macrocyclic 2:2 inclusion complex(es) and that its higher-order structure has vacant spaces, in which molecules other than p-toluidine are included. Compound 4 was then transformed into monopropyl ester 5 to fill the vacant spaces with propyl moieties. Compound 5 included p-toluidine with high selectivity (∼96%) without the coinclusion of other molecules, regardless of the solvent employed.

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Section: Results and Discussionmentioning

confidence: 99%