1.1 Porphyrins - Friedrich-Alexander-Universität Erlangen-Nürnberg

fluorescence (normalized and adapted)
1.0
0.8
0.6
0.4
0.2
707 698
0
650 700 750 λ [nm] 850
fluorescence (normalized and adapted)
1.0
λexc = 540 nm λexc = 588 nm
0.8
0.6
0.4
0.2
744 729
760
0
650 700 750 λ [nm] 850
Discussion and Results 3
Table 23. UV/Vis data for 91 and 92 in comparison to those for 53 obtained from
measurements in CH2Cl2. Given values are absorption maxima λmax in nm and corresponding
extinction coefficients ε in M -1 ·cm -1 in parenthesis.
Compound SORET (B)
53 96
91
92
442
(223000)
442
(219000)
445
(183000)
QI
543
(11300)
545
(10600)
546
(11300)
QII
587
(9000)
588
(9700)
592
(9900)
QIII
689
(9000)
688
(8600)
692
(9100)
3.2.8.2.5 Photophysical Parameters for Free Base Cycloketo-Porphyrins 91 and 92
Both 91 and 92, were investigated in cooperation with the group of Prof. Dr. B. RÖDER at
Berlin in terms of fluorescence spectroscopy and time-resolved measurements on 1 O2
luminescence to determine quantum yields for fluorescence Φfl and the PDT related values
for singlet oxygen generation ΦΔ. All measurements were performed in DMF solution.
For both systems, a general dependency of the fluorescence spectra on the excitation
wavelength is found analog to 53. Thus, these compounds do not follow KASHA’s rule. 105
While furthermore the data obtained for nitro derivative 91 are in great accordance to those
of non-functionalized 53, amino derivative 92 behaves quite different as the value for Φfl is
determined one order of magnitude lower (0.003 for 92 versus 0.03 for 91 and also 53).
Figure 47. Fluorescence spectra of 91 and 92 in DMF at given excitation wavelengths.
Intensities are given in arbitrary units whereat adaptions concerning those were done to
achieve a correlation to measured quantum yields.
91
92
119