Ditopic receptors containing urea groups for solvent extraction of Cu(ii) salts. Issue 10 (21st February 2017)

• Record Type: Journal Article
• Authors: Carreira-Barral, Israel; Mato-Iglesias, Marta; de Blas, Andrés; Platas-Iglesias, Carlos; Tasker, Peter A.; Esteban-Gómez, David
• Is Part Of: Dalton transactions. Volume 46:Issue 10(2017)
• Page Start: 3192
• Page End: 3206
• Publication Date: 2017-02-21
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt00093f
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Ditopic receptors containing a macrocyclic cyclen unit and a urea moiety provide selective recognition of first-row divalent metal salts. Abstract : The ditopic receptorL 3 [1-(2-((7-(4-( tert -butyl)benzyl)-1, 4, 7, 10-tetraazacyclododecan-1-yl)methyl)phenyl)-3-(3-nitrophenyl)urea] containing a macrocyclic cyclen unit for Cu(ii )-coordination and a urea moiety for anion binding was designed for recognition of metal salts. The X-ray structure of [CuL 3 (SO4 )] shows that the sulfate anion is involved in cooperative binding via coordination to the metal ion and hydrogen-bonding to the urea unit. This behaviour is similar to that observed for the related receptorL 1 [1-(2-((bis(pyridin-2-ylmethyl)amino)methyl)phenyl)-3-(3-nitrophenyl)urea], which forms a dimeric [CuL 1 (μ-SO4 )]2 structure in the solid state. In contrast, the single crystal X-ray structure of [ZnL 3 (NO3 )2 ] contains a 1 : 2 complex (metal : anion) where one anion coordinates to the metal and the other is hydrogen-bonded to the urea group. Spectrophotometric titrations performed for the [CuL 3 (OSMe2 )] 2+ complex indicate that this system is able to bind a wide range of anions with an affinity sequence: MeCO2 − > Cl − > H2 PO4 − > Br − > NO2 − > HSO4 − > NO3 − . Lipophilic analogues ofL 1 andL 3 extract CuSO4 and CuCl2 from water into chloroform with high selectivity over the corresponding Co(ii ), Ni(ii ) and Zn(ii ) salts.