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A carbazole-fluorene molecular hybrid for quantitative detection of TNT with combined fluorescence and quartz crystal microbalance methods

Authors:
Krishnan Kartha Kalathil at Mahatma Gandhi University
Krishnan Kartha Kalathil
Sandeep Anjamkudy
Sandeep Anjamkudy
Sandeep Anjamkudy
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Vijayakumar Chakkooth at CSIR - National Institute for Interdisciplinary Science and Technology (CSIR-NIIST)
Vijayakumar Chakkooth
  • CSIR - National Institute for Interdisciplinary Science and Technology (CSIR-NIIST)
Masayuki Takeuchi at National Institute for Materials Science
Masayuki Takeuchi
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Abstract and Figures

A combined fluorescence and quartz-crystal microbalance approach for the quantitative sensing of nitroaromatics, particularly TNT, using morphologically different self-assemblies of a carbazole bridged fluorene (CBF) derivative is described. Picomolar level detection of TNT was possible in water by the CBF nanoparticles and nanogram level TNT sensing in vapour phase could be achieved with the CBF supramolecular rods.
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Supporting Information for Fluorescent nanostructures for sensing nitroaromatics
Supporting Information for
A carbazole-fluorene molecular hybrid for quantitative detection of
TNT with combined fluorescence and quartz crystal microbalance
methods
Kalathil K. Kartha,a Anjamkudy Sandeep,a Vijayakumar C. Nair,a Masayuki Takeuchi
*b and Ayyappanpillai Ajayaghosh*a
aPhotosciences and Photonics Group, Chemical Sciences and Technology Division, National
Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum 695 019,
India
E-mail: ajayaghosh@niist.res.in
bOrganic Materials Group, Polymer Materials Unit, National Institute for Materials Science
(NIMS), 1-2-1 Sengen, Tsukuba, 305-0047, Japan
E-mail: TAKEUCHI.Masayuki@nims.go.jp
Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics.
This journal is © the Owner Societies 2014
Supporting Information for fluorescent nanostructures for sensing nitroaromatics
S2
Supporting Information figures
Fig. S1 (a) Absorption and (b) emission spectra of CBF in THF (—), water (—) and
methylcyclohexane (—) with a conc. of 5 × 10-5 M (l = 1 cm,
ex = 350 nm).
Supporting Information for fluorescent nanostructures for sensing nitroaromatics
S3
Fig. S2 Normalized emission spectra of CBF in (a) solution, (b) corresponding normalised
spectra, (c) film state and (d) corresponding normalised spectra, from THF (—), water (—) and
MCH (—) with a conc. of 5 × 10-5 M (l = 1 cm,
ex = 350 nm). Film prepared from 10 µL of
each solution drop casted on a glass plate and dried under vacuum for 12 h.
Supporting Information for fluorescent nanostructures for sensing nitroaromatics
S4
Fig. S3 AFM images of (a) CBF nanorods from MCH solution (5 × 10-5 M) and (b) CBF
nanoparticles from water (1 × 10-5 M), respectively.
Fig. S4 Fluorescence changes of CBF nanoparticles upon addition of (a) DNT solution in water
and (b) CBF (1 × 10-6 M) upon addition 10 equiv. DNT solution in THF (l = 1 cm,
ex = 370
nm).
Supporting Information for fluorescent nanostructures for sensing nitroaromatics
S5
Fig. S5 Fluorescence quenching studies of CBF film prepared from (a) water, (b) MCH, and (c)
THF upon exposure to TNT vapors (
ex = 370 nm).
Fig. S6 (a) Fluorescence quenching studies of CBF film prepared from solution of MCH
exposed to DNT vapors (b) A plot of quenching % vs time (
ex = 370 nm).
Supporting Information for fluorescent nanostructures for sensing nitroaromatics
S6
Table S1. A comparison of adsorption and fluorescence quenching by different CBF
architectures with time.
% Quenching efficiency (QCM freq. shift Hz), approximate weight of adsorbed TNT
(ng)
Time (s)
Nanoparticles from water
Ill-defined structure from
THF
100
34.75 (-2.23), 2.12
6.6 (-1.65), 1.57
200
40.99 (-3.57), 3.39
12.11 (-2.51), 2.39
300
46.20 (-4.55), 4.33
14.10 (-3.01), 2.86
500
63.87 (-6.16), 5.85
23.6 (-3.06), 2.91
... Well-defined 1D structures having long exciton migration lengths exhibit better fluorescence quenching when exposed to explosives than illdefined aggregates. [69] In this work, authors reported distinct self-assembly formation upon tactful alteration of the end alkyl chain lengths. Interestingly, Probe 8 and 10 went through a morphological transition from kinetically stable wide nano-ribbons to thermodynamically stable nanoribbons, which was in contrast to other oligomers that either form only stable nanoribbons (Probe 7 and 9) or nanoparticle-nanoribbon mixed structures (Probe 11) (Figure 11b). ...
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... Carbazole-based molecules have been proven to be highly fluorescent and sensitive to a variety of explosives. [9,12,13,[20][21][22] However, these molecules suffer from excited-state mediated aerobic photooxidation, thereby exhibiting distinct fluorescence decay behaviors and causing photostability issues in sensing under ambient conditions. [13,23] Recently, we reported that the introduction of only a small number of photostable energy acceptors into a nonphotostable fluorene oligomer host can afford photostable coassemblies that preserve the electron donation of fluorene oligomers. ...
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