title: Calix[4]quinones derived from double calix[4]arenes: synthesis, complexation, and electrochemical properties toward alkali metal ions.
abstract: Bis(calix[4]diquinones) 1 and 2 and double calix[4]diquinone 3 have been synthesized from their corresponding double calix[4]arenes 4, 5, and 6, respectively. Compounds 4-6 have been prepared from one-pot and stepwise syntheses under high pressure. Complexation studies of ligands 1-3 with alkali metal ions such as Li+, Na+, K+, and Cs+ were carried out by 1H NMR titrations. Receptors 1 can selectively form 1:1 complexes with Na+. Ligand 2 prefers to form 1:1 complexes with K+ and Cs+. Receptor 3 retained the cone conformation of the calix[4]arene unit upon binding K+ but changed the conformation when complexing Li+ and Na+. Electrochemical studies using cyclic voltammetry and square wave voltammetry showed significant changing of voltammograms of 2 and 3 in the presence of alkali metal ions. Receptor 3 showed the electrochemically switched binding property toward Na+ and K+.
authors.affiliation: Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Nuttavut
authors.initials: N
authors.lastname: Kerdpaiboon
authors.forename: Boosayarat
authors.initials: B
authors.lastname: Tomapatanaget
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
authors.forename: Thawatchai
authors.initials: T
authors.lastname: Tuntulani