Fluorescent carbazole dendrimers for the detection of nitroaliphatic taggants and accelerants

Clulow, Andrew J., Burn, Paul L., Meredith, Paul and Shaw, Paul E. (2012) Fluorescent carbazole dendrimers for the detection of nitroaliphatic taggants and accelerants. Journal of Materials Chemistry, 22 25: 12507-12516. doi:10.1039/c2jm32072j


Author Clulow, Andrew J.
Burn, Paul L.
Meredith, Paul
Shaw, Paul E.
Title Fluorescent carbazole dendrimers for the detection of nitroaliphatic taggants and accelerants
Journal name Journal of Materials Chemistry   Check publisher's open access policy
ISSN 0959-9428
1364-5501
Publication date 2012-07-07
Year available 2012
Sub-type Article (original research)
DOI 10.1039/c2jm32072j
Open Access Status Not Open Access
Volume 22
Issue 25
Start page 12507
End page 12516
Total pages 10
Place of publication Cambridge, United Kingdom
Publisher Royal Society of Chemistry
Language eng
Formatted abstract
The detection of explosive taggant 2,3-dimethyl-2,3-dinitrobutane (DMNB) and accelerant nitromethane (NM) by oxidative quenching of dendrimer fluorescence is examined. Two fluorescent dendrimers incorporating a 3,6-disubstituted-9-n-hexylcarbazole-based core and first-generation biphenyl-based dendrons linked directly or with acetylene bridges are reported. The dendrimers display good photoluminescence (PL) quantum yields in both solution and thin films and appropriate excited state energies for oxidation by the nitroaliphatic analytes. The dendrimer natural excited state lifetimes in solution of 6.8 and 7.4 ns were found to be significantly longer than previously reported fluorescent conjugated polymers and dendrimers for sensing applications. Steady-state PL quenching measurements in solution revealed the highest quenching efficiencies for the detection of nitroaliphatics reported to date of 59 ± 1 M-1 for DMNB and 78 ± 1 M-1 for NM. Furthermore, PL lifetime quenching measurements confirmed that the dendrimers were quenched by a predominantly collisional quenching mechanism. As such, the unprecedented quenching efficiencies with nitroaliphatics in solution are due to the combination of the long excited state lifetimes of the dendrimers and efficient collisional quenching. The fluorescence of dendrimer thin films was also reversibly quenched by exposure to pulses of sub-saturation concentrations of analyte vapours. However, in the thin film case the sensitivity towards DMNB was found to be greater than NM, highlighting the disparity between solution and thin film fluorescence quenching measurements.
Keyword Conjugated polymers
Explosives
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
Official 2013 Collection
School of Chemistry and Molecular Biosciences
 
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