Walters, Robert W
(2009)
Repeat Sequence Fluorene-co-Methylene Polymers and Phosphorescent Mercury Sensors.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The synthesis of liquid crystalline alternating copolymers containing exact segment lengths of fluorene and methylene units is described. The copolymers were made by first assembling the 9,9-bis-(2-ethylhexyl)-flourene oligomers with repeat units of 3-8 followed by attachment of alkyl groups with terminal olefins capable of undergoing acyclic diene metathesis (ADMET) polymerization. The photophysical and thermal properties of these polymers were studied and are described. The absorption and emission maximums as well as the liquid crystalline transition temperatures are directly related to the number of repeat fluorene and methylene units contained in each segment.Two different mercury sensors that use long lived luminescence as the detecting signal are described. The long lived emission allows for time resolved emission spectroscopy that can eliminate background noise that is problematic in detecting very low levels of mercury in samples. Both sensors use mercury coordinating species based upon thymine groups that are capable on binding mercury ions selectively over other metal ions that may be present in mercury containing samples. The two sensors differ greatly in the mechanism for the generation of long lived luminescence. One is based on phosphorescent 2-phenylpyridine iridium complexes and the other is based upon fluorene sensitized europium complexes. The two sensors both show the ability to detect mercury ions at 10-6 molar levels and it is believed that the detection level should be even lower when time resolved emission spectroscopy is used. The iridium sensor shows a quenching of phosphorescence in the presence of mercury and the europium sensor shows an increase in the long lived luminescence but a decrease in fluorescence in the presence of mercury ions.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Walters, Robert W | rww4@pitt.edu | RWW4 | |
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| ETD Committee: |
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| Date: |
1 October 2009 |
| Date Type: |
Completion |
| Defense Date: |
30 July 2009 |
| Approval Date: |
1 October 2009 |
| Submission Date: |
3 August 2009 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
copolymers; Fluorene; iridium; lanthanide; mercury; Methylene; phosphorescent; repeat; sensor; sequence |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-08032009-181117/, etd-08032009-181117 |
| Date Deposited: |
10 Nov 2011 19:56 |
| Last Modified: |
15 Nov 2016 13:48 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8867 |
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