Adhikari, Birendra Babu published the artcileCation complexation with p-tert-butylcalix[5]arene pentacarboxylic acid derivative: An allosteric regulation of the first metal ion for stepwise extraction of the second ion, Safety of 2-(4-(tert-Butyl)phenoxy)acetic acid, the publication is Analyst (Cambridge, United Kingdom) (2011), 136(18), 3758-3769, database is CAplus and MEDLINE.
A calix[5]arene based solvent extraction reagent 3, appending carboxylic acid groups at the lower rim, has been developed and its complexation behavior towards some transition metal ions has been studied. The host 3 can selectively and quant. extract Pb(2+) ions above pH 1.8 while other divalent ions such as Cu(2+), Zn(2+), Co(2+), Ni(2+) are extracted quant. only above pH 3.0. The outstanding Pb(2+) selectivity of 3 comes from the size fit complementarity effect of the Pb(2+) ion in the calix[5]arene cavity. One mol. of 3 extracts two Pb(2+) ions in a stepwise manner. The first Pb(2+) ion is extracted into the deep cavity of the calix[5]arene defined by phenoxy oxygen atoms. The first complexed Pb(2+) ion acts as a template to bring the host into a cone conformation and induces a pos. allosteric effect for the extraction of the second Pb(2+) ion at an oxygen rich coordinating site composed of carboxyl groups. Both the Pb(2+) ions are extracted through an ion exchange mechanism and the electroneutral complex in the organic phase is formed by the release of an equivalent number of hydrogen ions into aqueous solution The loaded Pb(2+) is easily back-extracted from Pb(2+)-complexed 3 using dilute acid solution
Analyst (Cambridge, United Kingdom) published new progress about 1798-04-5. 1798-04-5 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ether, name is 2-(4-(tert-Butyl)phenoxy)acetic acid, and the molecular formula is C12H16O3, Safety of 2-(4-(tert-Butyl)phenoxy)acetic acid.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia