A novel luminescent pH sensor based on a tricarbonylpolypyridylrhenium(I) complex with three protonation sites

M. CATTANEO; F. FAGALDE; N. E. KATZ; C. D. BORSARELLI

Jerusalén, Israel

Conferencia; 38th INTERNACIONAL CONFERENCE ON COORDINATION CHEMISTRY; 2008

ICCC

Following a previous report on proton-induced luminescence changes of tricarbonylpolypyridylrhenium(I) complexes,[1] we address in this work the possibility of increasing the dynamic range of pH-sensing by using a complex with three protonation sites: the ion [Re(4,4’-(CO2H)2-bpy)(CO)3(4,4’-bpy)]+, (bpy = 2,2’-bipyridine, 4,4’-bpy = 4,4’-bipyridine), synthesized as a CF3SO3- salt, and characterized by spectroscopic, electrochemical and photophysical techniques. By studying the pH dependence in aqueous solution of its luminescence decay, three values of pKa* could be determined, as shown in the Figure. The amplification factor is near 13, making it a promising luminescent pH sensor of the on-off-on type over a pH range of 0-8.