Rhenium bipyridine complexes for the recognition of glucose.
Bipyridine ligands containing pendant methyl, amino, and amino-boronic acid groups were synthesized. Coordination complexes of these ligands with rhenium were prepared straightforwardly and in good yield. The fluorescence behavior of the Re complexes was studied as a function of pH and exposure to various concentrations of glucose. The methyl bipyridine complex showed no change in fluorescence with pH, the amino derivative showed a rapid decrease from low pH to neutral, and the amino-boronate derivative showed little change from pH 4 to 10. Fluorescence quenching was observed at high pH as expected on the basis of a photoinduced electron transfer (PET) signaling mechanism. This behavior can be explained on the basis of the first oxidation and reduction potentials of these complexes. Glucose testing showed a significant dependence on the solvent system used. In pure methanol, the rhenium boronate complex exhibited a 55% fluorescence intensity increase upon increasing glucose concentration from 0 to 400 mg/dL. However, in 50 vol % methanol/phosphate buffered saline, none of the complexes showed significant response in the glucose range of physiological interest.
Cary
Douglas R
DR
University of California, Lawrence Livermore National Laboratory, P.O. Box 808, L-092, Livermore, California 94551, USA. dcary@pcpy.com
Zaitseva
Natasha P
NP
Gray
Kelsey
K
O'Day
Kira E
KE
Darrow
Christopher B
CB
Lane
Stephen M
SM
Peyser
Thomas A
TA
Satcher
Joe H
JH
Van Antwerp
William P
WP
Nelson
A J
AJ
Reynolds
John G
JG
D002384:Catalysis; D004563:Electrochemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D005947:Glucose / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*
D005456:Fluorescent Dyes; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D012211:Rhenium; D005947:Glucose