Encapsulation of alkyl and aryl derivatives of quaternary ammonium cations within cucurbit[n]uril (n = 6,7) and their inverted diastereomers: density functional investigations

Computational study on the interactions of mustard gas with cucurbituril macrocycles

“…To confirm the proper converges to minima and to evaluate the zero point vibrational energy, vibrational frequencies were computed at the same level of theory and were confirmed to have no negative frequencies. The reported frequencies were calculated at B3LYP‐D3/ 6–311G level and are scaled down using single scaling factor of 0.976 to discard the anharmonicity present in real systems . The calculated vibrational frequencies for the CB[7] macromolecule are in good agreement with the observed frequencies …”

Coordination of Alkaline‐Earth Metal Ions in Inverted Cucurbit[6]uril Supramolecular Assemblies Formed in the Presence of Tetrachloride Zincates

“…cently, the same research group further compared through density functional calculations the electronic structure, vibrational frequencies, and 1 H chemical shifts of inclusion complexes between cucurbit[n]urils (Q[n]s) (n = 6, 7), their iQ[n] diastereomer hosts, and quaternary diammonium guests, namely, 1,6-hexyldiammonium or p-xylyldiammonium. [4] Recently, we found that iQ [6] can be easily isolated from Q[6] by column chromatography on Dowex resin, and the facile isolation demonstrated the significance of iQ [6] chemistry. [5] In the present work, iQ [6] was used as a ligand (Figure 1 2--HCl interaction system immediately produced precipitates, preventing isolation of any crystal under similar synthetic conditions.…”

Coordination of lanthanides in the inverted cucurbituril supramolecular assemblies formed in the presence of tetrachloride zincate anion: Potential applications for isolation of lighter lanthanides

“…Given the structure-directing function of the [ZnCl 4 ] 2À anions and poor water solubility iQ [6], we investigated the coordination of iQ[6]-Ln(NO 3 ) 3 in the presence of [ZnCl 4 ] 2À anions in aqueous HCl solutions, and obtained 10 iQ[6]-Ln 3+ complex crystals in four isomorphous groups with increasing atomic number of the lanthanide.…”

“…A similar process was used to prepare crystals of related compounds: Ln(NO 3 In order to show a whole system of lanthanides, the number of compounds increased with an increase of atomic number of the lanthanide series. Moreover, we did not obtain single crystals for compounds 1, 2, 6, and 7, which corresponded to La 3+ , Ce 3+ , Sm 3+ and Eu 3+ respectively, but precipitations immediately resulted for La 3+ -and Ce 3+ -systems, and Sm 3+ -and Eu 3+ -containing systems stayed in solution; crystals of compounds 3 and 11 were very unstable, and the quality of the collected was unsatisfactory.…”

“…1) was first reported by Isaacs and Kim in 2005 [1], no additional studies have been reported on this compound, with the exception of a couple of papers on density functional investigations based on the B3LYP hybrid functional to predict the properties of the iQ[n]s [2], and mechanism of the conversion of iQ [6] to Q [6] [3]. The low yield of inverted cucurbit[n]uril compounds (iQ[n]s) in the synthesis process and the difficult separation process for these compounds could hinder the investigation of iQ[n] chemistry [4][5][6][7][8][9].…”