p-tert-Butylcalix[4]arenes containing azacrown ether substituents at the lower rim as potential polytopic receptors was written by Alekseeva, E. A.;Basok, S. S.;Mazepa, A. V.;Luk’yanenko, A. P.;Snurnikova, O. V.;Gren, A. I.. And the article was included in Russian Journal of General Chemistry in 2013.COA of Formula: C10H21NO4 This article mentions the following:
A series of disubstituted p-tert-butylcalix[4]arenes with N-methoxycarbonylmonoazacrown ether and N-ethoxymonoazacrown ether residues at the lower rim has been prepared via the reaction of di(carboxymethoxy)-p-tert-butylcalix[4]arene with azacrown ethers and subsequent reduction of the resulting amide derivatives Using UV titration and 1H NMR spectroscopy we have demonstrated the ability of the calixarene with two N-carbonylmonoaza-18-crown-6-ether substituents to form the 1:3 complexes with K+ and Na+ and the 1:2 complexes with Cs+, Sr2+, Cu2+, and Zn2+. The calixarene with two fragments of N-ethoxymonoaza-18-crown ether has formed binuclear complexes with alkali metals cations and mononuclear complexes with transition metals cations. In the experiment, the researchers used many compounds, for example, 1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3COA of Formula: C10H21NO4).
1,4,7,10-Tetraoxa-13-azacyclopentadecane (cas: 66943-05-3) belongs to ethers. Ether is less polar than esters, alcohols or amines because of the oxygen atom that is unable to participate in hydrogen bonding due to the presence of bulky alkyl groups on both sides of the oxygen atom. Ethers feature bent C閳ユ彊閳ユ弲 linkages. In dimethyl ether, the bond angle is 111鎺?and C閳ユ彊 distances are 141 pm. The barrier to rotation about the C閳ユ彊 bonds is low. The bonding of oxygen in ethers, alcohols, and water is similar. In the language of valence bond theory, the hybridization at oxygen is sp3.COA of Formula: C10H21NO4
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem