Synfacts 2006(8): 0785-0785  
DOI: 10.1055/s-2006-941957
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart · New York

Hexaphyrin-Based Mercuric Ion Sensors

Contributor(s): Timothy Swager, Scott Meek
X.-J. Zhu, S.-T. Fu, W.-K. Wong*, J.-P. Guo, W.-Y. Wong
Hong Kong Baptist University, Wuhan University and Shanxi University, P. R. of China
Further Information

Publication History

Publication Date:
21 July 2006 (online)

Significance

The synthesis and ion sensing properties of a new expanded porphyrin are reported. A condensation of pyrrole and pentafluorobenzaldehyde under acidic conditions followed by dehydration with DDQ afforded macrocycle 1 in poor yields (8-12%). X-ray crystallography revealed the non-planar structure of 1. Additionally, this compound was found to have absorption bands at 543, 704, and 768 nm and exhibit NIR emission at 959 and 1085 nm with photoexcitation at 514 nm. Complexation studies with various metal ions (Mn2+, Co2+, Cd2+, Zn2+, Fe3+, Ag+, Hg2+, Li+, K+, Ca2+, and Ba2+) in methanol indicated a high affinity of 1 for Hg2+ to the virtual exclusion of all the others. A complexation ratio of 2:1 of Hg2+ to macrocycle was determined via titration experiments. The interaction with Hg2+ ions had pronounced effects on the absorption spectrum, with a large bathochromic shift, and on the emission spectrum in the form of marked fluorescence quenching. Spectroscopic detection of Hg2+ was possible in the ppb range.