<p>Two calixarene derivatives with modified bipyridine as binding sites have been designed and synthesized. Compounds 1 and 2 are the first 2,2′-bipyridine-modified calixarene-based sensors that can detect Zn2+ selectively with respect to ratiometric fluorescent changes and red shift. A binuclear complex structure has been demonstrated in the binding modes of 1-Zn2+ and 2-Zn2+ complexes.</p>
J. Feng Zhang, Bhuniya, S., Lee, Y. Hoon, Bae, C., Lee, J. Hae, and Kim, J. Seung, “Novel 2,2′-bipyridine-modified calixarenes: ratiometric fluorescent chemosensors for Zn2+ ion”, Tetrahedron Letters, vol. 51, pp. 3719 - 3723, 2010.