SILVA OSCAR FERNANDO
Congresos y reuniones científicas
Título:
Nitroanilines as Quencher of Pyrene and 1-Methyl Pyrene Fluorescence
Autor/es:
OSCAR FERNANDO SILVA; CARLOS AGUDELO-MORALES; RAQUEL E. GALIAN; JULIA PÉREZ-PRIETO
Lugar:
cordoba
Reunión:
Congreso; XI ELAFOT 2012; 2012
Resumen:
Nitroanilines are intermediates in the synthesis of dyes, drugs, pesticides, and
herbicides. They have been used as fluorescence quenchers of organic chromophores,
biomacromolecules, as well as nanomaterials.[1] In fact, some of these fluorescent systems
have been used as isomeric aromatic amine probes.[2] In addition, the capacity of
nitroanilines as quenchers has been used to study materials, such as fluorescent surfactant
aggregates.
It has been suggested that, depending on the nature of the fluorophore, its emission
quenching by nitroanilines is static or dynamic, can occur via electron or energy transfer, or
can involve formation of transitory charge-transfer complexes or exciplexes (which decay by
electron transfer, intersystem crossing, or internal conversion). Therefore, a systematic study
on the interaction between a well-known and extensively used fluorophore, such as pyrene,
and NAs appeared of interest to gain insight into their role as quenchers. Pyrene has been
widely used as a probe due to i) its absorption (strength) features, ii) its long singlet lifetime (>
100 ns), and the information that can be obtained from its fluorescence emission (I3/I1 ratio)
and iii) its long-lived triplet excited state (microsecond scale). This chromophore has being
used in fluorescent chemosensors that can recognize selectively chemical species in potential
analytical applications [3]. In fact, nitrated explosives have been detected by fluorescence
quenching of pyrene and related compounds.[4]
We report here on the quenching of pyrene and 1-methylpyrene fluorescence by
unsubstituted NAs, methylnitroanilines, and a dinitroaniline in toluene and 1,4-dioxane.
Steady-state and time-resolved absorption and fluorescence studies were used to gain insight
into the quenching mechanism and the species involved in this process. These studies show
the tendency of NAs to establish specific interactions with the pyrene singlet excited state and,
depending on their structure, to be adjacent to the fluorophore at the ground state, some
forming a ground state complex.
herbicides. They have been used as fluorescence quenchers of organic chromophores,
biomacromolecules, as well as nanomaterials.[1] In fact, some of these fluorescent systems
have been used as isomeric aromatic amine probes.[2] In addition, the capacity of
nitroanilines as quenchers has been used to study materials, such as fluorescent surfactant
aggregates.
It has been suggested that, depending on the nature of the fluorophore, its emission
quenching by nitroanilines is static or dynamic, can occur via electron or energy transfer, or
can involve formation of transitory charge-transfer complexes or exciplexes (which decay by
electron transfer, intersystem crossing, or internal conversion). Therefore, a systematic study
on the interaction between a well-known and extensively used fluorophore, such as pyrene,
and NAs appeared of interest to gain insight into their role as quenchers. Pyrene has been
widely used as a probe due to i) its absorption (strength) features, ii) its long singlet lifetime (>
100 ns), and the information that can be obtained from its fluorescence emission (I3/I1 ratio)
and iii) its long-lived triplet excited state (microsecond scale). This chromophore has being
used in fluorescent chemosensors that can recognize selectively chemical species in potential
analytical applications [3]. In fact, nitrated explosives have been detected by fluorescence
quenching of pyrene and related compounds.[4]
We report here on the quenching of pyrene and 1-methylpyrene fluorescence by
unsubstituted NAs, methylnitroanilines, and a dinitroaniline in toluene and 1,4-dioxane.
Steady-state and time-resolved absorption and fluorescence studies were used to gain insight
into the quenching mechanism and the species involved in this process. These studies show
the tendency of NAs to establish specific interactions with the pyrene singlet excited state and,
depending on their structure, to be adjacent to the fluorophore at the ground state, some
forming a ground state complex.
