Optical control of divalent metal ion binding to a photochromic catechol: Photoreversal of tightly bound Zn2+

Citation
Mt. Stauffer et Sg. Weber, Optical control of divalent metal ion binding to a photochromic catechol: Photoreversal of tightly bound Zn2+, ANALYT CHEM, 71(6), 1999, pp. 1146-1151
Citations number
56
Categorie Soggetti
Chemistry & Analysis","Spectroscopy /Instrumentation/Analytical Sciences
Journal title
ANALYTICAL CHEMISTRY
ISSN journal
00032700 → ACNP
Volume
71
Issue
6
Year of publication
1999
Pages
1146 - 1151
Database
ISI
SICI code
0003-2700(19990315)71:6<1146:OCODMI>2.0.ZU;2-P
Abstract
Photochromic molecules with functional groups that bind metal ions strongly make possible the development of photoreversible sensors and preconcentrat ors for detection of metal ions at trace concentrations. While several phot ochromic metal chelators have been reported, none have been shown to bind s trongly to divalent metal ions. A novel photochromic benzopyran 2, which is a photochromic catechol, binds Zn2+ strongly and reversibly. The thermal e quilibrium between open and closed 2 is slow. Thus, binding of Zn2+ to 2 is slow in the dark. Under illumination with 306-416-nm light, Zn2+ binds rap idly to open 2. The stable complex dissociates upon illumination with visib le light, showing that both formation and dissociation of the complex are c ontrollable with light. A binding constant of 1.1 x 10(9) is estimated from a Job plot, which also indicates formation of a 1:1 Zn2+/open 2 complex.