Double loading of ZnCl2 by polytopic ligands which co-extract Zn2+ and tetrachloridozincate

Abstract

Combining cation- and anion-binding functionalities in a salen-type extractant leads to multiple loading of ZnCl(2). Zn(ii) cations are bound by the salen N(2)O(2)(2-) donor set, and chlorozincate anions are associated with protonated pendant amine groups.

Applications of Supramolecular Anion Recognition

“…Early work by the same group had shown that salen -type receptors such as 241 (Figure ) can bind and extract metal­(II)­sulfates, where the metal is bound by the N 2 O 2 salen moiety and the sulfate anion is bound by the protonated tertiary ammonium groups . In a recent communication, it was shown that 241 can also extract zinc into chloroform from an aqueous 1 M ZnCl 2 solution . It was observed that the zinc loading of the chloroform solution of 241 was >100%, suggesting that 241 functions as a ditopic receptor.…”

“…368 In a recent communication, it was shown that 241 can also extract zinc into chloroform from an aqueous 1 M ZnCl 2 solution. 369 It was observed that the zinc loading of the chloroform solution of 241 was >100%, suggesting that 241 functions as a ditopic receptor. Presumably, zinc(II) is bound by the deprotonated salen moiety to form an overall neutral complex, whereas the positively charged tertiary ammonium groups coordinate a zinc(II) metalate such as [ZnCl 4 ] 2− to provide an overall charge-neutral complex with two zinc atoms per receptor.…”

ZnII and PbII coordination chemistry of 2,6-bis(1,2,3-triazol-4-yl)pyridine (clickate) and the metal ion-dependent emission of ‘clickate’–appended anthracene

“…Interestingly, instead of a 1:1 (ligand/Zn II ) complex as we anticipated based on the known structures of tpy/ZnCl 2 complex (38, 39) and a recently reported clickate/ZnBr 2 complex (20), the solved structure consists of a 2:1 complex (ligand/Zn II ) and a tetrachlorozincate anion for an overall 1:1 stoichiometry (40)(41)(42). In the clickate/ZnBr 2 complex reported by Hecht et al, the 1:1 stoichiometry was postulated to be enforced via the p -p stacking between N1-aryltriazolyl groups in the solid state.…”