title: Hemispherand-Strapped Calix[4]pyrrole: An Ion-pair Receptor for the Recognition and Extraction of Lithium Nitrite.
abstract: The hemispherand-strapped calix[4]pyrrole (1) acts as an ion pair receptor that exhibits selectivity for lithium salts. In organic media (CD2Cl2 and CD3OD, v/v, 9:1), receptor 1 binds LiCl with high preference relative to NaCl, KCl, and RbCl. DFT calculations provided support for the observed selectivity. Single crystal structures of five different lithium ion-pair complexes of 1 were obtained. In the case of LiCl, a single bridging water molecule between the lithium cation and chloride anion was observed, while tight contact ion pairs were observed in the case of the LiBr, LiI, LiNO3, and LiNO2 salts. Receptor 1 proved effective as an extractant for LiNO2 under both model solid-liquid and liquid-liquid extraction conditions.
authors.affiliation: Department of Chemistry, The University of Texas at Austin , 105 East 24th, Street-Stop A5300, Austin, Texas 78712-1224, United States.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Institute for Supramolecular and Catalytic Chemistry, Shanghai University , 99 Shangda Road, Shanghai 200444, China.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, The University of Texas at Austin , 105 East 24th, Street-Stop A5300, Austin, Texas 78712-1224, United States.
authors.forename: James T
authors.initials: JT
authors.lastname: Brewster
authors.affiliation: Department of Chemistry, The University of Texas at Austin , 105 East 24th, Street-Stop A5300, Austin, Texas 78712-1224, United States.
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Lynch
authors.affiliation: Department of Chemistry and Research Institute of National Science, Gyeongsang National University , Jinju 660-701, Korea.
authors.forename: Sung Kuk
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Department of Chemistry, The University of Texas at Austin , 105 East 24th, Street-Stop A5300, Austin, Texas 78712-1224, United States.
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Sessler