Chemistry Letters Vol.33, No.4 (2004)
471
2
3
4
5
6
W. Denk, J. H. Strickler, and W. W. Webb, Science, 248, 73
(1990).
D. A. Parthenopoulos and P. M. Rentzepis, Science, 245, 843
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´
M. Albota, D. Beljonne, J. L. Bredas, J. E. Ehrlich, J. Y. Fu,
A. A. Heikal, S. E. Hess, T. Kogej, M. D. Levin, S. R. Marder,
phores exist. Compounds T01, T02, and T03 emit strong fluores-
cence under the irradiation of light at the maximum absorption
wavelengths. The fluorescence quantum yield was determined
to be about 0.47 using fluorescein in 0.1 N NaOH as the standard.
Although the absorption spectra are of great difference, these
compounds show similar fluorescence spectra with the peaks lo-
cated at about 554 nm. The Stokes’ shifts for T01, T02, and T03
are 134, 129 and 125 nm, respectively.
TPA cross sections of these compounds were determined by
femtosecond open aperture Z-scan technique according to previ-
ously described method.21 As shown in Table 1, the TPA cross
sections for T01, T02, and T03 are 0:31 ꢁ 10ꢂ20 cm4/GW,
0:365 ꢁ 10ꢂ20 cm4/GW and 1:64 ꢁ 10ꢂ20 cm4/GW, respective-
ly. These values are comparable to those of the most representa-
tive materials reported in the literatures measured with similar
molecular weight.9,11,13 The TPA cross section of T02 is only
slightly higher than that of T01 although its chromophore densi-
ty is much larger. But, the TPA cross section of T03 is nearly 5
times higher than those of T01 and T02. In compound T03,
1,3,5-triazine is connected with three styryl units and forms
tri-branched octupolar structure. The increased chromophore
density, delocalization interaction and the octupolar structure
are responsible for its much larger TPA cross sections than the
other two molecules.
D. McCord-Moughon, J. W. Perry, H. Rockel, M. Rumi, G.
¨
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7
8
9
O.-K. Kim, K.-S. Lee, H. Young Woo, K.-S. Kim, G. S. He, J.
Swiatkiewicz, and P. N. Prasad, Chem. Mater., 12, 284 (2000).
10 Z. Q. Liu, Q. Fang, D. Wang, D. X. Cao, G. Xue, W. T. Yu, and H.
Lei, Chem.—Eur. J., 9, 5074 (2003).
11 A. Abbotto, L. Beverina, R. Bozio, A. Facchetti, C. Ferrante, G. A.
Pagani, D. Pedron, and R. Signorini, Org. Lett., 4, 1495 (2002).
12 B. R. Cho, M. J. Piao, K. H. Son, S. H. Lee, S. J. Yoon, S. J. Jeon,
and M. Cho, Chem.—Eur. J., 8, 3907 (2002).
13 S. J. Chung, K. S. Kim, T. C. Lin, G. S. He, J. Swiatkiewicz, and
P. N. Prasad, J. Phys. Chem. B, 103, 10741 (1999).
14 J. Yoo, S. K. Yang, M.-Y. Jeong, H. C. Ahn, S.-J. Jeon, and B. R.
Cho, Org. Lett., 5, 645 (2003).
Under the excitation of 800 nm laser pulse (140 fs), com-
pounds T01, T02, and T03 emit strong frequency upconverted
fluorescence with the peaks located at 578, 577, and 576 nm, re-
spectively. The maximum wavelengths of two-photon fluores-
cence are red-shifted about 21 to 26 nm compared with those
of linear fluorescence emission. Since there is no absorption at
wavelength longer than 550 nm, the upconverted fluorescence
comes from two-photon process. As an example, the two-photon
fluorescence spectra of T03 under different laser intensity are
shown in Figure 3. The linear dependence of fluorescence inten-
sity on the square of the excitation intensity as shown in the inset
confirms that TPA is the main excitation mechanism of two-pho-
ton fluorescence.
`
15 O. Mongin, L. Porres, C. Katan, T. Pons, J. Mertz, and M.
Blanchard-Desce, Tetrahedron Lett., 44, 8121 (2003).
16 A. Abbotto, L. Beverina, R. Bozio, A. Facchetti, C. Ferrante, G. A.
Pagani, D. Pedron, and R. Signorini, Chem. Commun., 2003, 2124.
´
17 A. Adronov, J. M. J. Frechet, G. S. He, K. S. Kim, S. J. Chung, J.
Swiatkiewicz, and P. N. Prasad, Chem. Mater., 12, 2838 (2000).
`
18 O. Mongin, J. Brunel, L. Porres, and M. Blanchard-Desce, Tetrahe-
dron Lett., 44, 2813 (2003).
19 M. Drobizhev, A. Karotki, Y. Dzenis, A. Rebane, Z. Suo, and
C. W. Spangler, J. Phys. Chem. B, 107, 7540 (2003).
20 T01: mp 174–176 ꢃC. 1H NMR (CDCl3, 500 MHz): ꢃ 2.48 (s, 6H),
3.82 (s, 3H), 6.87 (d, 2H, J ¼ 8:72 Hz), 7.02 (m, 3H), 7.10 (m, 4H),
7.26 (m, 4H), 7.37 (d, 4H, J ¼ 7:90 Hz), 7.41 (d, 2H, J ¼ 8:36 Hz),
7.66 (d, 2H, J ¼ 8:07 Hz), 8.66 (d, 4H, J ¼ 7:87 Hz), 8.73 (d, 2H,
J ¼ 8:02 Hz). 13C NMR (CDCl3, 100 MHz): ꢃ 22.39, 56.14,
115.51, 122.63, 123.21, 124.31, 126.53, 126.97, 128.19, 128.26,
129.59, 129.87, 129.95, 129.99, 130.80, 130.85, 134.41, 135.68,
140.98, 142.37, 143.52, 148.33, 148.79, 157.11, 171.66, 172.02.
TOF–MS (ESþ): 636.3 (M, 8%), 637.4 (M + 1, 100%), 638.3
3500
3000
576nm 1.66GW/cm2
2500
3000
2000
1500
2500
1000
500
(M
+
2, 30%). T02: mp 106–108 ꢃC. 1H NMR (CDCl3,
1.33GW/cm2
2000
1500
1000
500
0
0
500 MHz): ꢃ 2.48 (s, 3H), 3.82 (s, 6H), 6.87 (m, 4H), 7.02 (m,
7H), 7.10 (m, 9H), 7.25 (m, 6H), 7.37 (d, 2H, J ¼ 8:10 Hz), 7.41
(d, 4H, J ¼ 8:64 Hz), 7.66 (d, 4H, J ¼ 8:41 Hz), 8.66 (d, 2H,
J ¼ 7:15 Hz), 8.73 (d, 4H, J ¼ 8:33 Hz). 13C NMR (CDCl3,
100 MHz): ꢃ 21.745, 55.45, 114.79, 121.90, 122.50, 123.60,
125.80, 126.26, 127.50, 127.57, 128.89, 129.18, 129.25, 129.30,
130.06, 130.11, 133.64, 134.90, 140.25, 141.64, 142.84, 147.60,
148.05, 156.38, 170.87, 171.23. TOF–MS (ESþ): 921.5 (M,
37%), 922.5 (M + 1, 100%), 923.5 (M + 2, 30%). T03: mp
256–258 ꢃC. 1H NMR (CDCl3, 500 MHz): ꢃ 3.81 (s, 9H), 6.87
(d, 6H, J ¼ 8:81 Hz), 7.02 (m, 12H), 7.09 (m, 12H), 7.18 (d, 3H,
J ¼ 16:23 Hz), 7.24 (t, 6H), 7.39 (d, 6H, J ¼ 8:55 Hz), 7.62 (d,
6H, J ¼ 8:30 Hz), 8.68 (d, 6H, J ¼ 8:32 Hz). 13C NMR (CDCl3,
100 MHz): ꢃ 56.16, 115.49, 122.60, 123.20, 124.31, 126.51,
126.98, 128.21, 128.28, 129.88, 129.96, 130.80, 135.58, 140.95,
142.37, 148.29, 148.75, 157.06, 171.57. TOF–MS (ESþ): 1206.6
(M, 43%), 1207.6 (M + 1, 100%), 1208.7 (M + 2, 60%), 1209.7
(M + 3, 20%).
0.0 0.5 1.0 1.5 2.0 2.5 3.0
I2pump (GW2/cm4)
0.83GW/cm2
0.33GW/cm2
500
550
600
650
700
750
800
Wavelength /nm
Figure 3. The two-photon excited fluorescence spectra of T03
in chloroform.
We thank the National Science Foundation of China and
Shanghai Education Committee for the financial support.
References and Notes
1
A. Abbotto, L. Beverina, R. Bozio, S. Bradamante, C. Ferrante,
G. A. Pagani, and R. Signorini, Adv. Mater., 12, 1963 (2000).
21 F. S. Meng, J. Mi, S. X. Qian, K. C. Chen, and H. Tian, Polymer,
44, 6851 (2003).
Published on the web (Advance View) March 23, 2004; DOI 10.1246/cl.2004.470