Chemistry Reference
In-Depth Information
2PA antenna
dyes
Phosphorescence
2PA antenna
Protecting
dendrons
O
2
a
S
2P
a
S
1
Core
800 nm
c
S
1
ic
c
T
1
E
T
Oxygen
Triplet
core
2PA
ET
1
g
O
2
Phos
Quenching
3
g
O
2
a
S
0
c
S
0
c
T
1
-
c
S
0
Antenna
emission
400
800
λ
Antenna
2PA
Core
absorption
Core
phosph.
800-
FIGURE 14.15
Scheme of a two-photon-enhanced phosphorescent oxygen sensor, its
Jablonski diagram and related wavelength scale. (See the color version of this figure in Color
Plates section.)
example of coumarin-343 (C343), is compatible with Q-band absorption of Pt
porphyrins (
25,800M
1
cm
1
), suggesting high efficiency FRET.
C343 fluoresces with quantum yield
l
max
¼
510 nm,
e¼
s
2
value is about
25 GM. Four C343 moieties can be attached to PtTCPP via ethylenediamine linkers
using standard peptide chemistry, giving a simple FRET-enhanced two-photon-
absorbing phosphorescent probe (Figure 14.16).
f
fl
¼
0.75 in DMF and its
7.6
1
25
50
75
Excitation power (MW)
600
650
700
nm
FIGURE 14.16
Pt porphyrin (PtP)-coumarin-343 (C343) adduct and its 2PA-induced
phosphorescence spectra. The action cross-section spectrum for the phosphorescence of the
adduct is increased 7.6 times compared to the parent Pt porphyrin. The inset shows quadratic
power dependence of the phosphorescence upon excitation by 100 fs pulses from a regenerative
amplifier (780 nm, 1 kHz, unfocused beam).
