A new class of azobenzene chelators for Mg2+ and Ca2+ in buffer at physiological pH

✍ Scribed by Atsuya Momotake; Tatsuo Arai

• Publisher: Elsevier Science
• Year: 2003
• Tongue: French
• Weight: 131 KB
• Volume: 44
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(03)01863-x

✦ Synopsis

A new class of azobenzene-based chelators, trans-3a and trans-3b (3a and 3b), were designed and synthesized in two steps. Both 3a and 3b were readily dissolved in a buffer solution at physiological pH. The values of the dissociation constant of 3a and 3b for Mg 2+ and Ca 2+ were determined by the Hills plot; K d Mg =1.12 mM and K d Ca =660 mM for 3a and K d Mg =158 mM and K d Ca =200 mM for 3b, respectively. On irradiation at 489 nm light, 3a isomerized to give cis-form, which underwent cis-to-trans thermal isomerization in darkness at room temperature. The change in the absorption spectrum of the irradiated solution of 3a in the presence of Mg 2+ , showing the cis-to-trans thermal isomerization, indicates that the affinity of cis-3a for Mg 2+ is lower than that of 3a.