Organometallic Rhenium Dyes for Nitric Oxide Detection and Imaging

Authors

Lissette I. Lozano-Lewis, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Chemistry

First Advisor's Name

Konstantinos Kavallieratos

First Advisor's Committee Title

Committee Chair - Advisor

Second Advisor's Name

Jaroslava Miksovska

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Nikolaos M Tsoukias

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Yong Cai

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Martin Quirke

Fifth Advisor's Committee Title

Committee member

Keywords

Nitric Oxide, Ratiometric Fluorescent Dye, Rhenium, diazodiene, sensor

Date of Defense

11-10-2015

Abstract

The importance of sensing Nitric Oxide (NO) in physiology and medicine has led us to explore the reactivity of NO with organometallic Re dyes. Rhenium complexes were synthesized with the ability to react with NO and sense it under physiological conditions. Fluorescent 1,10-phenantroline complexes (phen)Re(PPh₃)(CO)₂OSO₂CF₃ (1) and (phen)Re(CH₃CN)(CO)₂OSO₂CF₃ (3) can sense NO in the range of 10 - 150 mM showing a decrease in fluorescence response at 514 nm and 532 nm respectively, upon NO-donor addition (l_exc = 360 nm). (phen)Re(THF)(CO)₂OSO₂CF₃ (2) showed a ratiometric response with a decrease in fluorescence intensity at 585 nm and an increase at 445 nm. These complexes were characterized by FT-IR, ¹H-NMR, ¹³C-NMR, and ¹⁹F‑NMR. The quantum yields (F) and lifetimes (t) were also determined. On the basis of ¹⁹F‑NMR and ¹H-NMR spectroscopic evidence, the proposed mechanism of action involves dissociation of CF₃SO₃^- (abbreviated as OTf^-) together with PPh₃, (for 1), THF (for 2), or CH₃CN (for 3). Fluorescence microscopy showed that 1 permeates through the cell membrane of rat aortic endothelial cells (RAOEC) and 2 gives increase in cell fluorescence response at 450 nm when exogenous NO is added to RAOEC. The Re complexes of dppz (dppz = 2,2’-dipyrido[3,2-a:2,3’-c]phenazine) (dppz)Re(THF)(CO)₂OSO₂CF₃ (A2) and (dppz)Re(CH₃CN)(CO)₂OSO₂CF₃) (A3) were synthesized using the same methods as for complexes 1 and 3. Even though the dppz complexes exhibited similar behavior than the phenanthroline analogs, the signal changes were small and the results were inconclusive. The a-Diimine Re complexes of Xy-DAD (XyDAD = 1,4-bis-[2,6-dimethylphenyl]-1,4-diazo-1,3-butadiene) (Xy-DAD)Re(THF)(CO)₂OSO₂CF₃ (8) and (Xy-DAD)Re(CH₃CN)(CO)₂OSO₂CF₃ (9) showed reactivity with NO and CN^- with a response in the visible range of the absorption spectrum. These diazadiene (DAD) complexes showed decreased reactivity with NO and CN^- in the presence of oxidants. The i-PrDAD complexes (i-PrDAD = 1,4‑bis-[2,6-diisopropylphenyl]-1,4-diazo-1,3-butadiene) (i‑Pr‑DAD)Re(THF)(CO)₂OTf (10) and (i‑Pr‑DAD)Re(CH₃CN)(CO)₂OTf (11) exhibited similar behavior with the Xy-DAD analogs, but the spectral changes were much smaller and the results were inconclusive. The ESI-MS Mass Spectrometry studies of the phenanthroline complexes 1, and 2, after reaction with NO-donor showed that 1 and 2 react with NO to give [Re(CO)₂(NO)₂S₂]⁺ species, while (phen)Re(CO)₃Cl and (phen)Re(CO)₃OSO₂CF₃ do not show any metal-NO containing products, which is consistent with the fluorescence studies.

Identifier

FIDC000203

Recommended Citation

Lozano-Lewis, Lissette I., "Organometallic Rhenium Dyes for Nitric Oxide Detection and Imaging" (2015). FIU Electronic Theses and Dissertations. 2306.
https://digitalcommons.fiu.edu/etd/2306