trapping is injection of electronic excitation energy. This was performed on the
B493/503-{Ox
+
-ZL} shown on the left side of Fig. 30, lower. Again, we first
characterized the Ox
+ -ZL and the nanocrystals modified with B493/503 separately,
as seen in Fig. 30c. The spectral overlap integral between the emission spectrum of
B493/503 and the excitation spectrum of Ox
+ is favorable for FRET. The B493/503{Ox
+
-ZL} composite was investigated by selectively exciting the B493/503 stopcocks at 21,740 cm
À1 . The resulting emission spectrum seen in Fig. 30d shows that
impressive energy transfer takes place from the B493/503 stopcocks to the Ox
+
located inside of the channels and emitting strongly at 16,000 cm
À1 . This marked the
beginning of many successful experiments with luminescent stopcocks. Luminescent metal complexes as stopcock objects such Ru-ph4-TMS [216] and ZnPc
[217, 218] were used as donor and acceptor chromophores, respectively, while Ir
3+
complexes were investigated for the creation of photo- and electro-responsive
properties [219]. Also quantum dots were tested as chromophores at the channel
entrances for FRET properties [220]. Communication between a dye located inside
of the channels and a stopcock-acceptor dye was explored by attaching biotin to a
DMPOPOP-ZL by using sequential functionalization similar as seen in Fig. 30.
Addition of a weak-binding antigen modified with ATTO-488 leads to important
FRET features, thus proving that bio-labels based on dye-ZL composites have
interesting properties as phototherapeutic agents [46, 181]. Luisa De Cola extended
this by showing that bio-conjugate dye-ZL composites can be used as labels in
protein microarrays [221]. Embedding stopcock-{dye-ZL} composites into polymers by applying electrospinning resulted in highly interesting nanofiber-FRET
communication systems using Cy02702 as a stopcock [222] and in a sophisticated
combination to white light-emitting fibers [215].
The preparation of robust ZL monolayers of ZL crystals on a glass substrate with
open channels on the free ends, we have discussed in Sect. 5.1, allows creating
mono-directional antenna properties [111]. The consecutive insertion of two different dyes which cannot glide past each other as a result of spatial restrictions is the
basis for the preparation of an antenna system capable of efficiently transporting
electronic excitation energy. The consecutive insertion also allows to insert a dye
and in a next step to plug the channel ends on the free part of the crystals standing on
the substrate with a desired stopcock, acting either as an acceptor in FRET experiments or as a donor. The Py
+ /Ox
+ pair has been used for testing this in the
experiments reported in Fig. 31. To an oriented ZL monolayer, seen in the upper
part of this figure, Py
+ was inserted by cation exchange followed by insertion of Ox
+
,
resulting in the pattern seen in Scheme (a). The spectra illustrate that considerable
energy transfer from the electronically excited Py
+ to the Ox
+ occurs after selective
excitation of the Py
+
. We have discussed that extension beyond the interior of the ZL
is achieved by selectively positioning molecules at the entrances. Here we show that
this can be realized in a completely anisotropic way. Two different stopcock dyes
have been used. ATTO-520, after selective excitation of at 460 nm, acts as injector to
the acceptors Ox
+ located inside of the ZL nanochannels, as seen in Fig. 30b. The
reverse is the case for the Cy02702 stopcock, which captures the electronic excitation energy of the selectively excited Py
+ located inside of the ZL channels, Fig. 30c.
58
G. Calzaferri
B493/503-{Ox
+
-ZL} shown on the left side of Fig. 30, lower. Again, we first
characterized the Ox
+ -ZL and the nanocrystals modified with B493/503 separately,
as seen in Fig. 30c. The spectral overlap integral between the emission spectrum of
B493/503 and the excitation spectrum of Ox
+ is favorable for FRET. The B493/503{Ox
+
-ZL} composite was investigated by selectively exciting the B493/503 stopcocks at 21,740 cm
À1 . The resulting emission spectrum seen in Fig. 30d shows that
impressive energy transfer takes place from the B493/503 stopcocks to the Ox
+
located inside of the channels and emitting strongly at 16,000 cm
À1 . This marked the
beginning of many successful experiments with luminescent stopcocks. Luminescent metal complexes as stopcock objects such Ru-ph4-TMS [216] and ZnPc
[217, 218] were used as donor and acceptor chromophores, respectively, while Ir
3+
complexes were investigated for the creation of photo- and electro-responsive
properties [219]. Also quantum dots were tested as chromophores at the channel
entrances for FRET properties [220]. Communication between a dye located inside
of the channels and a stopcock-acceptor dye was explored by attaching biotin to a
DMPOPOP-ZL by using sequential functionalization similar as seen in Fig. 30.
Addition of a weak-binding antigen modified with ATTO-488 leads to important
FRET features, thus proving that bio-labels based on dye-ZL composites have
interesting properties as phototherapeutic agents [46, 181]. Luisa De Cola extended
this by showing that bio-conjugate dye-ZL composites can be used as labels in
protein microarrays [221]. Embedding stopcock-{dye-ZL} composites into polymers by applying electrospinning resulted in highly interesting nanofiber-FRET
communication systems using Cy02702 as a stopcock [222] and in a sophisticated
combination to white light-emitting fibers [215].
The preparation of robust ZL monolayers of ZL crystals on a glass substrate with
open channels on the free ends, we have discussed in Sect. 5.1, allows creating
mono-directional antenna properties [111]. The consecutive insertion of two different dyes which cannot glide past each other as a result of spatial restrictions is the
basis for the preparation of an antenna system capable of efficiently transporting
electronic excitation energy. The consecutive insertion also allows to insert a dye
and in a next step to plug the channel ends on the free part of the crystals standing on
the substrate with a desired stopcock, acting either as an acceptor in FRET experiments or as a donor. The Py
+ /Ox
+ pair has been used for testing this in the
experiments reported in Fig. 31. To an oriented ZL monolayer, seen in the upper
part of this figure, Py
+ was inserted by cation exchange followed by insertion of Ox
+
,
resulting in the pattern seen in Scheme (a). The spectra illustrate that considerable
energy transfer from the electronically excited Py
+ to the Ox
+ occurs after selective
excitation of the Py
+
. We have discussed that extension beyond the interior of the ZL
is achieved by selectively positioning molecules at the entrances. Here we show that
this can be realized in a completely anisotropic way. Two different stopcock dyes
have been used. ATTO-520, after selective excitation of at 460 nm, acts as injector to
the acceptors Ox
+ located inside of the ZL nanochannels, as seen in Fig. 30b. The
reverse is the case for the Cy02702 stopcock, which captures the electronic excitation energy of the selectively excited Py
+ located inside of the ZL channels, Fig. 30c.
58
G. Calzaferri