The use of
CTC in the
Design of
Molecular
Sensors
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To discuss
 Introduction to CTC
 Formation of CTC
 Role of CTC in MS
 What are Molecular sensors
 Key Components of MS
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Background
 Chemical weapons in wars
serious health issues—including cancer, birth defects,
rashes and severe psychological and neurological
problems
 Toxic Pollutants
From mining, agriculture
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According to Shakya & Khan, a CTC is any
complexation that occurs because of an
excitation of an e- from a donating molecule
to the accepting molecule new molecule
distinct properties.
Charge Transfer
Complexes
(CTC)
Charge transfer transition, HOMO & LUMO of
donor and acceptor moieties
Bands occur in UV-vis region of EM
Spectrum
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Role in Molecular Sensing Design
 Enable the detection of specific analytes through unique e- properties and
sensitivity to environmental changes
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CTC Formation
 E-transfer leads to formation of stable complexes with altered e- properties
 Stability influenced by molecular structure, solvent polarity, temperature
  impacts the longevity and responsiveness in sensing applications.
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Molecules that interact with an analyte to
produce a detectable signal
Combine molecular recognition with a signaling
mechanism for the detection of an analyte
Molecular
Sensors
Recognized as intelligent devices since 1867
Capable of addressing important issues
Environmental Monitoring
Detection of Toxic pollutants and Chemical
Explosives
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Key Components of MS
Recognition moiety +
Signaling moiety
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Signaling based on
changes in optical
properties like
absorption or emission
in the UV-vis range.
The recognition moiety
binds to the analyte
selectively and
reversibly.
Factors like the
receptor design and
the sensing
environment affect the
host-guest recognition
communication route
between the
recognition and
signaling parts for the
sensor to function.
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Schematic Representation
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E-transfer properties
Selectivity
Features of CTC
useful in MS
Sensitivity
Changes in Conductivity
Real-time detection
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Types of MS with CTC
 Fluorescent PET cation sensors
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Forster
Resonance
Energy
Transfer
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Conclusions
 The use of CTC promises real-time calorimetric sensing ability towards
different hazardous material including chemical explosives like
Nitroaromatic compounds
 Toxic Metal ions like Fe2+, Fe3+, Cr2+, Ni2+, Mn2+, Pb2+, Hg2+, Ag2+,
Co2+, Ni2+, Mg2+, Cu2+, Ca2+, Zn2+, Ba2+, K+, Na+, and Li+
 and anions like CN-, Cl , I , F-, Br , ClO4, HCO3, CO3 2 , PO4 3 , HSO4,
H2PO4, HPO4 2 , SO4 2 , SO3 2 , S2O3 2 , NO2 and NO3 ions
 CT complexes are spectrophotometric, and fluorescence based
colorimetric sensors as they display a rapid change in color on adding
analyte to it.
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…
 CT complexes designed as chemosensors promise results with low
detection limits, high selectivity, high sensitivity and discriminating sensing
ability.
 The ability of CT complex to dissolve in water and detecting analytes in
aqueous medium makes it preferable.
 Easy preparation and require slight chemical modification- adding suitable
functional groups improves sensitivity
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