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One-pot synthesis of meso–meso directly linked diheteroporphyrin dimers
Tetrahedron Letters 53 (2012) 6376–6379
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Tetrahedron Letters journal homepage: www.elsevier.com/locate/tetlet
One-pot synthesis of meso–meso directly linked diheteroporphyrin dimers Yi-Zhou Zhu, Yan Zhu, Shao-Chun Zhang, Hai-Bin Song, Jian-Yu Zheng ⇑ State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
a r t i c l e
i n f o
Article history: Received 6 July 2012 Revised 3 September 2012 Accepted 7 September 2012 Available online 19 September 2012
a b s t r a c t A one-pot synthesis strategy to synthesize the novel meso–meso directly linked dithiaporphyrin dimer (DDSP) was achieved for the first time. And the described methodology also can work smoothly to prepare the oxathiaporphyrin dimers DOSP and DSOP. This work offers a facile and convenient way to get the meso–meso directly linked diheteroporphyrin dimer from simple non-porphyrin precursors. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Meso–meso directly linked diheteroporphyrin dimer One-pot synthesis Heteroporphyrin Core-modified porphyrin
In recent years, covalently linked multiporphyrin arrays have attracted much attention because of their potential applications in molecular devices and functional materials.1 Among the reported structures, meso–meso directly linked porphyrin arrays possess a unique position because they are favorable for achieving rapid energy- and electron-transfer owing to the direct linking and a short center-to-center distance between porphyrin subunits.2 The strong excitonic interaction between two porphyrin rings imparted predominant spectroscopic properties, nonlinear optical properties, and photovoltaic properties to the molecules.3 Over the past two decades, great efforts have been devoted to synthesizing such interesting compounds. Meso–meso directly linked porphyrin arrays now can be obtained through oxidative coupling reaction from metalloporphyrin monomer bearing meso-H by Ag+,2b DDQ,2g PIFA,2i,j alkyl or aryl lithium/DDQ,2f and electrochemical oxidation.2d,e Other synthesis strategies are also explored.2a,c,h Heteroporphyrins (also named core-modified porphyrins),4 in which one or more internal nitrogen atoms are replaced with other heteroatoms or carbon, have showed some novel properties such as stabilizing metals in unusual oxidation states, photodynamic therapy (PDT), and nonlinear optical properties.5 Compared to outer rim modification of porphyrin, core modification results in more direct and remarkable change of the electronic structures of porphyrin ring. So, multiporphyrin arrays which contain heteroporphyrin subunits are reasonably expected to be distinctive and useful.6 A series of unsymmetrical covalently linked multiporphyrin arrays with heteroporphyrin in chain have been synthesized.7 ⇑ Corresponding author. Tel./fax: +86 022 2350 5572. E-mail address: [email protected] (J.-Y. Zheng). 0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tetlet.2012.09.048
Only one case about the synthesis of meso–meso directly linked unsymmetrical porphyrin dyad containing ZnN4 and N3S porphyrin subunits via Suzuki–Miyura cross-coupling methodology was reported by Ravikanth and co-workers.7g A meso–meso directly linked core-modified smaragdyrins which was found to have negligible excitonic coupling was also achieved by Chandrashekar.8 But up to now, meso–meso directly linked diheteroporphyrin dimer has not been reported. Herein, we report a one-pot synthesis strategy for accessing the first meso–meso linked dithiaporphyrin dimer, and its application in the synthesis of other meso–meso directly linked diheteroporphyrin dimers. Initial attempts were carried out by oxidative coupling of dithiaporphyrin monomer (DSP) bearing one meso-H which had been synthesized by Ravikanth et al. from 16-thiatripyrrin 1 and unsymmetrical thiophene diol 2 in refluxed propionic acid9 (Scheme 1). Unfortunately, we failed to obtain the meso–meso directly linked dithiaporphyrin dimer with DDQ, AgPF6, and PIFA according to the reported method for regular porphyrin. However, an interesting phenomenon was observed when 16-thiatripyrrin 3 and symmetrical thiophene diol 4 were selected to improve the yield of DSP by Lindsey protocol.10 Not only DSP, but also another thiaporphyrin with smaller polarity was obtained when TFA was used as catalyst (Scheme 1). The identification result (1H NMR, 13C NMR, HR-MS, and 1H/1H COSY, see Supplementary data) consists of the novel meso–meso directly linked dithiaporphyrin dimer (DDSP). A [M+H]+ peak at m/z = 1143.2681 (calculated for [M+H]+: m/z = 1143.2678) was found with the MALDI HR-MS and the evidence of the meso–meso coupling came from the 1H NMR characterization with the disappearance of meso-H signal of DSP at 10.8 ppm (Fig. 1). At the same time, an obvious upfield shift of b-protons near
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Figure 2. Absorption and fluorescence (inset, kex = 430 nm) spectra of DSP and DDSP in chloroform (5 10 6 mol/l).
Scheme 1. Synthesis of DSP and meso–meso directly linked DDSP.
the coupling site compared to that of DSP is observed due to the shielding effect of the adjacent porphyrin ring. The molecular structure of DDSP was further confirmed by X-ray crystallography and showed that two dithiaporphyrin monomers were directly linked at meso positions (see Supplementary data). The distance between two coupling meso carbons was 1.495 Å and the dihedral angel of two dithiaporphyrin planes was about 78o. The absorption spectra of DDSP and DSP are showed in Figure 2. In contrast to absorption spectrum of DSP with a sharp Soret band at 428 nm, DDSP exhibits typically broadened and split Soret band (434 and 458 nm) due to excitonic coupling.11 Meanwhile the Q bands exhibit a bathochromic shift about 15 nm and the intensity increases. The emission spectra of DDSP have similar shape as DSP with 18 nm bathochromic shift (Fig. 2, inset). The fluorescence quantum yields of DSP and DDSP, relative to tetraphenylporphyrin, are determined to be 0.007 and 0.014, respectively. The fluorescence lifetime of DDSP is 1.05 ns, shorter than DSP (1.16 ns) because of the excitation-energy migration (see Supplementary data).12 Encouraged by the above results, the screening of reaction conditions for improving the yield of DDSP was further investigated. Several acid catalysts were chosen and reactions were performed with 10 mM of reactants 3 and 4 in CH2Cl2 at room temperature followed by oxidation with DDQ. Brønsted acid was found to be more efficient to produce DDSP and DSP than Lewis acid in this
Table 1 The effects of feeding method and solventa,b
a b c
Entry
Method13
Solvent
Timec, min
Yield (DDSP,%)
Yield (DSP,%)
1 2 3 4 5 6 7
A B C B B B B
CH2Cl2 CH2Cl2 CH2Cl2 CH2Cl2 CHCl3 CH3CN Toluene
60 60 60 60 20 60 15
2.3 8.4 1.1 8.4 1.1 0.5 0.4
18.2 22.0 3.4 22.0 31.0 5.4 27.3
Reactions were performed with 10 mM reactants and 20 mM TFA. Isolated yield. The oxidation time was not included.
reaction. TFA was selected to continue the further exploring for its better performance than methanesulfonic acid and p-toluenesulfonic acid. During the course of the catalyst examining, an interesting result was observed when compound 3 was treated with TFA (20 mM) for 10 min prior to feeding thiophene diol 4. Reaction carried out in this way showed a significant yield increase of DDSP (up to 8.4%, Table 1 entry 2), and the yield of DSP was also enhanced to 22.0%. On the contrary, when thiophene diol 4 was treated with TFA prior to compound 3 feeding, yields of both DSP (3.4%) and DDSP (1.1%) decreased obviously. Dichloromethane was found to be more efficient to yield DDSP (Table 1). Therefore, all other attempts to improve the yield of DDSP were carried out in CH2Cl2 by treating 3 with TFA for 10 min prior to 4 feeding.
Figure 1. 1H NMR spectrum of DSP (bottom) and DDSP (top) in CDCl3.
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Table 2 The concentration effects of TFA and reactantsa,b
a b c
Entry
[TFA], mM
[Reactant], mM
Timec, min
Yield (DDSP,%)
Yield (DSP,%)
1 2 3 4 5 6 7 8 9 10 11 12
5 10 20 40 40 10 10 10 10 2.5 5 20
10 10 10 10 10 2.5 2.5 5 20 2.5 5 20
60 60 60 10 60 10 60 60 60 60 60 60
4.3 8.7 8.4 2.9 2.0 2.4 1.8 6.8 3.1 6.6 8.0 4.1
25.3 23.2 22.0 24.5 19.4 34.2 23.6 22.6 15.3 28.5 24.1 18.4
Scheme 4. One-pot synthesis of meso–meso linked oxathiaporphyrin with 16oxatripyrrin 8.
Reactions were performed in CH2Cl2 with TFA as catalyst. Isolated yield. The oxidation time was not included.
Scheme 2. The structures of porphyrinogen 5 (H6DSP) and 6 (H12DDSP).
Scheme 3. One-pot synthesis of meso–meso linked oxathiaporphyrin.
The concentration effects of acid catalyst and reactant are found to be obvious (Table 2). When reaction was carried out with 10 mM reactant, the optimal TFA concentration was determined to be 10 mM (Table 2, entry 2). The same result was found when reaction was carried out with 10 mM TFA and varied reactant concentration. It seems to be more efficient to yield DDSP with the same catalyst concentration relative to reactants. The maximum yield (8.7%) of DDSP was obtained when 10 mM concentration was used. The yields of DDSP from a reaction of 10 mM reactants and TFA were also followed as a function of time (see Supplementary data). The maximum yield of DDSP was gotten by DDQ oxidation of the reaction mixture after feeding thiophenediol 4 and stirring for 60 min, and it was also the time that reactants disappeared. Along with time extending, yields of DDSP and DSP were slowly decreased together.
Efforts on understanding the mechanism were further done. We obtained two porphyrinogens (Scheme 2) after the first acid catalyzed process, and analyzed it by HR-MS. One has m/z = 579.1925 corresponding to [H6DSP+H]+ (5), the other has only peaks of [H10DDSP+H]+ and other dehydrogenizated compound of H12DDSP (6) for its poor stability. Moreover, results of the oxidation experiments of the independent porphyrinogen indicated that the yield of DDSP only lies on the presence of porphyrinogen 6. That means if there was only porphyrinogen 5 being generated at the first acid catalyzed step, there would be no DDSP after subsequent oxidation. The coupling site came from the methylene in 16-thiatripyrrin 3, this was further confirmed by the application experiments (Schemes 3 and 4). The substrate tolerance of this one-pot reaction was subsequently explored. When funan diol 7 was used instead of thiophene diol 4, bis(21-thia-23-oxaporphyrin) (DOSP)14 and 21-thia-23-oxaporphyrin (OSP) were obtained simultaneously with yields of 4.7% and 15.7%, respectively (Scheme 3). A typical split Soret band (430 and 451 nm) was also observed. Compared to DDSP, there is an obvious blue shift due to the strong electron-withdrawing ability of oxygen atom. The reaction shown in Scheme 4 confirms that this one-pot reaction strategy is a general approach to synthesize meso–meso directly linked diheteroporphyrin dimer. When 16-oxatripyrrin 815 was selected to replace the feedstock 3 in Scheme 1, the coupling reaction can also occur at the nonsubstituted methylene of 8, and results in another novel meso–meso directly linked diheteroporphyrin dimer (DSOP)16 with yield of 3.6%, accompanied by 9.0% yield of OSP. In conclusion, a one-pot synthesis strategy to synthesize the meso–meso directly linked dithiaporphyrin dimer was achieved for the first time, and the yield of DDSP can be improved to 8.7% under the optimum reaction conditions. It is noteworthy that the described methodology also can work smoothly to prepare the oxathiaporphyrin dimer DOSP, and can be extended to obtain DSOP by using tripyrrin 8 containing funan group. A preliminary investigation into the reaction mechanism showed that the meso–meso linked dithiaporphyrinogen dimer is formed at the first acid-catalyzed step and subsequently oxidized to DDSP. This work offers a facile and convenient way to get the meso–meso directly linked diheteroporphyrin dimer from simple non-porphyrin precursors. Acknowledgments We thank the 973 Program (2011CB932902) and NSFC (Nos. 21172126 and 20802038) for their generous financial support.
Y.-Z. Zhu et al. / Tetrahedron Letters 53 (2012) 6376–6379
Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.tetlet.2012.09. 048. These data include MOL files and InChiKeys of the most important compounds described in this article. References and notes 1. (a) Schwab, P. F. H.; Levin, M. D.; Michl, J. Chem. Rev. 1999, 99, 1863–1933; (b) Chou, J.-H.; Kosal, M. E.; Nalwa, H. S.; Rakow, N. A.; Suslick, K. S. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, 2000; Vol. 6, pp 43–129. 2. (a) Susumu, K.; Shimidzu, T.; Tanaka, K.; Segawa, H. Tetrahedron Lett. 1996, 37, 8399–8402; (b) Osuka, A.; Shimidzu, H. Angew. Chem., Int. Ed. 1997, 36, 135– 137; (c) Khoury, R. G.; Jaquinod, L.; Smith, K. M. Chem. Commun. 1997, 1057– 1058; (d) Ogawa, T.; Nishimoto, Y.; Yoshida, N.; Ono, N.; Osuku, A. Chem. Commun. 1998, 337–338; (e) Ogawa, T.; Nishimoto, Y.; Yoshida, N.; Ono, N.; Osuka, A. Angew. Chem., Int. Ed. 1999, 38, 176–179; (f) Senge, M. O.; Feng, X. Tetrahedron Lett. 1999, 40, 4165–4168; (g) Shi, X.; Liebeskind, L. S. J. Org. Chem. 2000, 65, 1665–1671; (h) Aratani, N.; Osuka, A. Org. Lett. 2001, 3, 4213–4216; (i) Jin, L.-M.; Chen, L.; Yin, J.-J.; Guo, C.-C.; Chen, Q.-Y. Eur. J. Org. Chem. 2005, 3994–4001; (j) Ouyang, Q.; Zhu, Y.-Z.; Li, Y.-C.; Wei, H.-B.; Zheng, J.-Y. J. Org. Chem. 2009, 74, 3164–3167; (k) Yang, J.; Yoo, H.; Aratani, N.; Osuka, A.; Kim, D. Angew. Chem., Int. Ed. 2009, 48, 4323–4327; (l) Song, J.; Aratani, N.; Kim, P.; Kim, D.; Shinokubo, H.; Osuka, A. Angew. Chem., Int. Ed. 2010, 49, 3617–3620. 3. (a) Tsuda, A.; Osuka, A. Science 2001, 293, 79–82; (b) Aratani, N.; Osuka, A. Chem. Rec. 2003, 3, 225–234; (c) Kim, D.; Osuka, A. Acc. Chem. Res. 2004, 37, 735–745; (d) Ahn, T. K.; Kim, K. S.; Kim, D. Y.; Noh, S. B.; Aratani, N.; Ikeda, C.; Osuka, A.; Kim, D. J. Am. Chem. Soc. 2006, 128, 1700–1704; (e) Cho, S.; Yoon, M.C.; Lim, J. M.; Kim, P.; Aratani, N.; Nakamura, Y.; Ikeda, T.; Osuka, A.; Kim, D. J. Phys.Chem. B 2009, 113, 10619–10627; (f) Park, J. K.; Chen, J.; Lee, H. R.; Park, W. S.; Shinokubo, H.; Osuka, A.; Kim, D. J. Phys. Chem. C 2009, 113, 21956–21963. 4. (a) Ulman, A.; Manassen, J. J. Am. Chem. Soc. 1975, 97, 6540–6544; (b) Sridevi, B.; Narayanan, S. J.; Srinivasan, A.; Reddy, M. V.; Chandrashekar, T. K. J. Porphyr. Phthalocya. 1998, 2, 69–78; (c) Gupta, I.; Ravikanth, M. Coord. Chem. Rev. 2006, 250, 468–518. _ ´ ski, L.; Lisowski, J.; Olmstead, M. M.; Balch, A. L. Inorg. Chem. 5. (a) Latos-Grazyn 1989, 28, 1183–1188; (b) Pandian, R. P.; Chandrashekar, T. K. Inorg. Chem. 1994, 33, 3317–3324; (c) Gopinath, C. S.; Pandian, R. P.; Manoharan, P. T. J. Chem. Soc., Dalton Trans. 1996, 1255–1259; (d) You, Y.; Gibson, S. L.; Detty, M. R. Bioorg. Med. Chem. 2005, 13, 5968–5980; (e) Ngen, E. J.; Daniels, T. S.; Murthy, R. S.; Detty, M. R.; You, Y. Bioorg. Med. Chem. 2008, 16, 3171–3183; (f) Zhu, Y.; Zhu, Y.-Z.; Song, H.-B.; Zheng, J.-Y.; Liu, Z.-B.; Tian, J.-G. Tetrahedron Lett. 2007, 48, 5687–5691. 6. Van Patten, P. G.; Shreve, A. P.; Lindsey, J. S.; Donohoe, R. J. J. Phys.Chem. B 1998, 102, 4209–4216. 7. (a) Ravikanth, M. Tetrahedron Lett. 2000, 41, 3709–3712; (b) Kumaresan, D.; Agarwal, N.; Ravikanth, M. J. Chem. Soc., Perkin Trans. 1 2001, 1644–1648; (c) Gupta, I.; Agarwal, N.; Ravikanth, M. Eur. J. Org. Chem. 2004, 1693–1697; (d) Gupta, I.; Ravikanth, M. J. Org. Chem. 2004, 69, 6796–6811; (e) Punidha, S.; Agarwal, N.; Ravikanth, M. Eur. J. Org. Chem. 2005, 2500–2517; (f) Gupta, I.; Fröhlich, R.; Ravikanth, M. Chem. Commun. 2006, 3726–3728; (g) Punidha, S.; Agarwal, N.; Gupta, I.; Ravikanth, M. Eur. J. Org. Chem. 2007, 1168–1175; (h) Shetti, V. S.; Ravikanth, M. Eur. J. Org. Chem. 2010, 494–508; (i) Yedukondalu, M.; Maity, D. K.; Ravikanth, M. Eur. J. Org. Chem. 2010, 1544–1561; (j) Khan, T. K.; Ravikanth, M. Eur. J. Org. Chem. 2011, 7011–7022. 8. Misra, R.; Kumar, R.; Chandrashekar, T. K.; Suresh, C. H. Chem. Commun. 2006, 4584–4586. 9. Punidha, S.; Agarwal, N.; Burai, R.; Ravikanth, M. Eur. J. Org. Chem. 2004, 2223– 2230. 10. (a) Lindsey, J. S.; Hsu, H. C.; Schreiman, I. C. Tetrahedron Lett. 1986, 27, 4969– 4970; (b) Lindsey, J. S.; Schreiman, I. C.; Hsu, H. C.; Kearney, P. C.; Marguerettaz, A. M. J. Org. Chem. 1987, 52, 827–836. 11. (a) Cho, H. S.; Song, J. K.; Ha, J.-H.; Cho, S.; Kim, D.; Yoshida, N.; Osuka, A. J. Phys.Chem. A 2003, 107, 1897–1903; (b) Cho, S.; Yoon, M.-C.; Lim, J. M.; Kim, P.; Aratani, N.; Nakamura, Y.; Ikeda, T.; Osuka, A.; Kim, D. J. Phys. Chem. B 2009, 113, 10619–10627. 12. Aratani, N.; Takagi, A.; Yanagawa, Y.; Matsumoto, T.; Kawai, T.; Yoon, Z. S.; Kim, D.; Osuka, A. Chem. Eur. J. 2005, 11, 3389–3404. 13. General information: Typical reactions were carried out on a 0.5 mmol scale. Method A: Compounds 3 and 4 were dissolved in dry dichloromethane and
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stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 60 min. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Method B: Compound 3 was dissolved in dry solvent and stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 10 min, then thiophene diol 4 was added. The mixture was stirred for the indicated time. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Method C: Compound 4 was dissolved in dry solvent and stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 10 min, then 16-thiatripyrrin 3 was added. The mixture was stirred for the indicated time. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Data for DDSP: 1H NMR (400 MHz, CDCl3): d = 7.70–7.77 (m, 12H, phenyl), 7.84–7.88 (m, 6H, phenyl), 7.993 (d, J = 4.4, 2H, pyrrole), 8.19–8.23 (m, 4H, phenyl), 8.27–8.32 (m, 6H, phenyl), 8.49 (d, J = 4.4 Hz, 2H, pyrrole), 8.74 (dd, J = 4.4 and 17.6 Hz, 4H, pyrrole), 9.07 (d, J = 5.2 Hz, 2H, thiophene), 9.45 (d, J = 5.2 Hz, 2H, thiophene), 9.78 (s, 4H, thiophene) ppm. 13C NMR (400 MHz, CDCl3): d = 126.3, 126.4, 126.7, 127.4, 127.4, 127.5, 128.0, 128.1, 128.2, 131.0, 134.0, 134.2, 134.2, 134.4, 134.9, 135.0, 135.6, 135.8, 136.0, 137.0, 141.0, 141.0, 141.2, 147.2, 147.9, 148.5, 151.4, 156.2, 156.5, 157.1, 160.2 ppm. ESI-MS: m/z calculated for C76H47N4S4 [M+H]+: 1143.27; found: 1143.61. MALDI-HRMS: m/ z calculated for C76H47N4S4 [M+H]+: 1143.2678; found: 1143.2681. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 434 (153206), 458 (146109), 522 (56336), 636 (3664), 700 (6870). Fluorescence (in CH2Cl2, kex = 434 nm): 715 nm (U = 0.014). Data for DSP: 1H NMR (400 MHz, CDCl3): d = 7.80–7.87 (m, 9H, phenyl), 8.23– 8.28 (m, 6H, phenyl), 8.70–8.73 (m, 2H, pyrrole), 8.81 (d, J = 4.4 Hz, 1H, pyrrole), 9.10 (d, J = 4.4 Hz, 1H, pyrrole), 9.73 (dd, J = 4.8 and 12.4 Hz, 2H, thiophene), 9.83 (d, J = 4.8 Hz, 1H, thiophene), 10.04 (d, J = 4.8 Hz, 1H, thiophene), 10.79 (s, 1H, meso-H) ppm. 13C NMR (400 MHz, CDCl3): d = 119.1, 127.6, 127.7, 128.3, 133.9, 134.0, 134.4, 134.5, 134.5, 134.6, 134.8, 134.9, 135.0, 135.1, 135.6, 135.8, 136.1, 141.3, 141.4, 141.6, 147.5, 147.9, 148.3, 149.0, 155.2, 156.3, 156.8 ppm. ESI-MS: m/z calculated for C45H27N3S2 [M+H]+: 573.15; found: 573.42. ESI-HR-MS: m/z calculated for C38H24N2S2 [M+H]+: 573.1454; found: 573.1451. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 428 (275146), 507 (29707), 538 (4244), 624 (2593), 687 (4480). Fluorescence (in CH2Cl2, kex = 428 nm): 697 nm (U = 0.007). 14. Data for DOSP: 1H NMR (600 MHz, CDCl3): d = 7.72–7.91 (m, 18H, phenyl), 8.00 (d, J = 4.8 Hz, 2H, pyrrole), 8.26–8.33 (m, 14H, phenyl and pyrrole), 8.55 (d, J = 4.8 Hz, 2H, pyrrole), 8.67 (d, J = 4.8 Hz, 2H, pyrrole), 9.18 (d, J = 4.8 Hz, 2H, thiophene), 9.32 (dd, J = 4.8 and 8.4 Hz, 4H, furan), 9.59 (d, J = 4.8 Hz, 2H, thiophene) ppm. 13C NMR (100 MHz, CDCl3): d = 122.0, 126.5, 126.6, 126.8, 127.3, 127.7, 128.0, 128.2, 128.3, 128.7, 129.0, 129.3, 129.8, 130.1, 130.3, 130.6, 130.7, 133.7, 133.9, 134.3, 134.8, 135.1, 136.1, 136.2, 136.6, 136.7, 137.0, 137.2, 137.3, 140.7, 142.5, 142.8, 150.5, 154.9, 155.2, 155.9, 156.7, 157.2, 159.9, 163.0 ppm. ESI-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.31; found: 1111.18. MALDI-HR-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.3135; found: 1111.3133. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 430 (82287), 451 (80074), 520 (32995), 645 (2817), 713 (6036). Fluorescence (in CH2Cl2, kex = 430 nm): 726 nm (U = 0.009). 15. Chmielewski, P. J.; Latos-Grazynski, L.; Olmstead, M. M.; Balch, A. L. Chem. Eur. J. 1997, 3, 268–278. 16. Data for DSOP: 1H NMR (600 MHz, CDCl3): d = 7.62–7.72 (m, 12H, phenyl), 7.75 (d, J = 4.2 Hz, 2H, pyrrole), 7.79–7.84 (m, 6H, phenyl), 8.13–8.15 (t, J = 6.0 Hz, 4H, phenyl), 8.20 (d, J = 7.8 Hz, 4H, phenyl), 8.26–8.28 (m, 6H, phenyl and pyrrole), 8.43 (d, J = 4.2 Hz, 2H, pyrrole), 8.56 (d, J = 5.4 Hz, 2H, furan), 8.62 (d, J = 4.2 Hz, 2H, pyrrole), 8.90 (d, J = 4.8 Hz, 2H, furan), 9.74–9.76 (dd, J = 4.8 and 9.0 Hz, 4H, thiophene) ppm. 13C NMR (75 MHz, CDCl3): d = 118.3, 121.3, 126.9, 127.5, 127.6, 128.0, 128.1, 128.3, 130.3, 132.0, 134.0, 134.1, 134.2, 134.3, 135.2, 135.4, 135.7, 135.1, 137.7, 140.5, 140.7, 142.2, 151.1, 151.3, 155.8, 156.1, 158.9, 159.0, 159.2, 160.0 ppm. ESI-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.31; found: 1111.23. MALDI-HR-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.314; found: 1111.314. UV/Vis (in CH2Cl2, kmax/nm, e/ mol 1dm3cm 1): 430 (73034), 462 (84270), 525 (33924), 644 (1513), 712 (4322). Fluorescence (in CH2Cl2, kex = 430 nm): 720 nm (U = 0.014).
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Tetrahedron Letters journal homepage: www.elsevier.com/locate/tetlet
One-pot synthesis of meso–meso directly linked diheteroporphyrin dimers Yi-Zhou Zhu, Yan Zhu, Shao-Chun Zhang, Hai-Bin Song, Jian-Yu Zheng ⇑ State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
a r t i c l e
i n f o
Article history: Received 6 July 2012 Revised 3 September 2012 Accepted 7 September 2012 Available online 19 September 2012
a b s t r a c t A one-pot synthesis strategy to synthesize the novel meso–meso directly linked dithiaporphyrin dimer (DDSP) was achieved for the first time. And the described methodology also can work smoothly to prepare the oxathiaporphyrin dimers DOSP and DSOP. This work offers a facile and convenient way to get the meso–meso directly linked diheteroporphyrin dimer from simple non-porphyrin precursors. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Meso–meso directly linked diheteroporphyrin dimer One-pot synthesis Heteroporphyrin Core-modified porphyrin
In recent years, covalently linked multiporphyrin arrays have attracted much attention because of their potential applications in molecular devices and functional materials.1 Among the reported structures, meso–meso directly linked porphyrin arrays possess a unique position because they are favorable for achieving rapid energy- and electron-transfer owing to the direct linking and a short center-to-center distance between porphyrin subunits.2 The strong excitonic interaction between two porphyrin rings imparted predominant spectroscopic properties, nonlinear optical properties, and photovoltaic properties to the molecules.3 Over the past two decades, great efforts have been devoted to synthesizing such interesting compounds. Meso–meso directly linked porphyrin arrays now can be obtained through oxidative coupling reaction from metalloporphyrin monomer bearing meso-H by Ag+,2b DDQ,2g PIFA,2i,j alkyl or aryl lithium/DDQ,2f and electrochemical oxidation.2d,e Other synthesis strategies are also explored.2a,c,h Heteroporphyrins (also named core-modified porphyrins),4 in which one or more internal nitrogen atoms are replaced with other heteroatoms or carbon, have showed some novel properties such as stabilizing metals in unusual oxidation states, photodynamic therapy (PDT), and nonlinear optical properties.5 Compared to outer rim modification of porphyrin, core modification results in more direct and remarkable change of the electronic structures of porphyrin ring. So, multiporphyrin arrays which contain heteroporphyrin subunits are reasonably expected to be distinctive and useful.6 A series of unsymmetrical covalently linked multiporphyrin arrays with heteroporphyrin in chain have been synthesized.7 ⇑ Corresponding author. Tel./fax: +86 022 2350 5572. E-mail address: [email protected] (J.-Y. Zheng). 0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tetlet.2012.09.048
Only one case about the synthesis of meso–meso directly linked unsymmetrical porphyrin dyad containing ZnN4 and N3S porphyrin subunits via Suzuki–Miyura cross-coupling methodology was reported by Ravikanth and co-workers.7g A meso–meso directly linked core-modified smaragdyrins which was found to have negligible excitonic coupling was also achieved by Chandrashekar.8 But up to now, meso–meso directly linked diheteroporphyrin dimer has not been reported. Herein, we report a one-pot synthesis strategy for accessing the first meso–meso linked dithiaporphyrin dimer, and its application in the synthesis of other meso–meso directly linked diheteroporphyrin dimers. Initial attempts were carried out by oxidative coupling of dithiaporphyrin monomer (DSP) bearing one meso-H which had been synthesized by Ravikanth et al. from 16-thiatripyrrin 1 and unsymmetrical thiophene diol 2 in refluxed propionic acid9 (Scheme 1). Unfortunately, we failed to obtain the meso–meso directly linked dithiaporphyrin dimer with DDQ, AgPF6, and PIFA according to the reported method for regular porphyrin. However, an interesting phenomenon was observed when 16-thiatripyrrin 3 and symmetrical thiophene diol 4 were selected to improve the yield of DSP by Lindsey protocol.10 Not only DSP, but also another thiaporphyrin with smaller polarity was obtained when TFA was used as catalyst (Scheme 1). The identification result (1H NMR, 13C NMR, HR-MS, and 1H/1H COSY, see Supplementary data) consists of the novel meso–meso directly linked dithiaporphyrin dimer (DDSP). A [M+H]+ peak at m/z = 1143.2681 (calculated for [M+H]+: m/z = 1143.2678) was found with the MALDI HR-MS and the evidence of the meso–meso coupling came from the 1H NMR characterization with the disappearance of meso-H signal of DSP at 10.8 ppm (Fig. 1). At the same time, an obvious upfield shift of b-protons near
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Figure 2. Absorption and fluorescence (inset, kex = 430 nm) spectra of DSP and DDSP in chloroform (5 10 6 mol/l).
Scheme 1. Synthesis of DSP and meso–meso directly linked DDSP.
the coupling site compared to that of DSP is observed due to the shielding effect of the adjacent porphyrin ring. The molecular structure of DDSP was further confirmed by X-ray crystallography and showed that two dithiaporphyrin monomers were directly linked at meso positions (see Supplementary data). The distance between two coupling meso carbons was 1.495 Å and the dihedral angel of two dithiaporphyrin planes was about 78o. The absorption spectra of DDSP and DSP are showed in Figure 2. In contrast to absorption spectrum of DSP with a sharp Soret band at 428 nm, DDSP exhibits typically broadened and split Soret band (434 and 458 nm) due to excitonic coupling.11 Meanwhile the Q bands exhibit a bathochromic shift about 15 nm and the intensity increases. The emission spectra of DDSP have similar shape as DSP with 18 nm bathochromic shift (Fig. 2, inset). The fluorescence quantum yields of DSP and DDSP, relative to tetraphenylporphyrin, are determined to be 0.007 and 0.014, respectively. The fluorescence lifetime of DDSP is 1.05 ns, shorter than DSP (1.16 ns) because of the excitation-energy migration (see Supplementary data).12 Encouraged by the above results, the screening of reaction conditions for improving the yield of DDSP was further investigated. Several acid catalysts were chosen and reactions were performed with 10 mM of reactants 3 and 4 in CH2Cl2 at room temperature followed by oxidation with DDQ. Brønsted acid was found to be more efficient to produce DDSP and DSP than Lewis acid in this
Table 1 The effects of feeding method and solventa,b
a b c
Entry
Method13
Solvent
Timec, min
Yield (DDSP,%)
Yield (DSP,%)
1 2 3 4 5 6 7
A B C B B B B
CH2Cl2 CH2Cl2 CH2Cl2 CH2Cl2 CHCl3 CH3CN Toluene
60 60 60 60 20 60 15
2.3 8.4 1.1 8.4 1.1 0.5 0.4
18.2 22.0 3.4 22.0 31.0 5.4 27.3
Reactions were performed with 10 mM reactants and 20 mM TFA. Isolated yield. The oxidation time was not included.
reaction. TFA was selected to continue the further exploring for its better performance than methanesulfonic acid and p-toluenesulfonic acid. During the course of the catalyst examining, an interesting result was observed when compound 3 was treated with TFA (20 mM) for 10 min prior to feeding thiophene diol 4. Reaction carried out in this way showed a significant yield increase of DDSP (up to 8.4%, Table 1 entry 2), and the yield of DSP was also enhanced to 22.0%. On the contrary, when thiophene diol 4 was treated with TFA prior to compound 3 feeding, yields of both DSP (3.4%) and DDSP (1.1%) decreased obviously. Dichloromethane was found to be more efficient to yield DDSP (Table 1). Therefore, all other attempts to improve the yield of DDSP were carried out in CH2Cl2 by treating 3 with TFA for 10 min prior to 4 feeding.
Figure 1. 1H NMR spectrum of DSP (bottom) and DDSP (top) in CDCl3.
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Table 2 The concentration effects of TFA and reactantsa,b
a b c
Entry
[TFA], mM
[Reactant], mM
Timec, min
Yield (DDSP,%)
Yield (DSP,%)
1 2 3 4 5 6 7 8 9 10 11 12
5 10 20 40 40 10 10 10 10 2.5 5 20
10 10 10 10 10 2.5 2.5 5 20 2.5 5 20
60 60 60 10 60 10 60 60 60 60 60 60
4.3 8.7 8.4 2.9 2.0 2.4 1.8 6.8 3.1 6.6 8.0 4.1
25.3 23.2 22.0 24.5 19.4 34.2 23.6 22.6 15.3 28.5 24.1 18.4
Scheme 4. One-pot synthesis of meso–meso linked oxathiaporphyrin with 16oxatripyrrin 8.
Reactions were performed in CH2Cl2 with TFA as catalyst. Isolated yield. The oxidation time was not included.
Scheme 2. The structures of porphyrinogen 5 (H6DSP) and 6 (H12DDSP).
Scheme 3. One-pot synthesis of meso–meso linked oxathiaporphyrin.
The concentration effects of acid catalyst and reactant are found to be obvious (Table 2). When reaction was carried out with 10 mM reactant, the optimal TFA concentration was determined to be 10 mM (Table 2, entry 2). The same result was found when reaction was carried out with 10 mM TFA and varied reactant concentration. It seems to be more efficient to yield DDSP with the same catalyst concentration relative to reactants. The maximum yield (8.7%) of DDSP was obtained when 10 mM concentration was used. The yields of DDSP from a reaction of 10 mM reactants and TFA were also followed as a function of time (see Supplementary data). The maximum yield of DDSP was gotten by DDQ oxidation of the reaction mixture after feeding thiophenediol 4 and stirring for 60 min, and it was also the time that reactants disappeared. Along with time extending, yields of DDSP and DSP were slowly decreased together.
Efforts on understanding the mechanism were further done. We obtained two porphyrinogens (Scheme 2) after the first acid catalyzed process, and analyzed it by HR-MS. One has m/z = 579.1925 corresponding to [H6DSP+H]+ (5), the other has only peaks of [H10DDSP+H]+ and other dehydrogenizated compound of H12DDSP (6) for its poor stability. Moreover, results of the oxidation experiments of the independent porphyrinogen indicated that the yield of DDSP only lies on the presence of porphyrinogen 6. That means if there was only porphyrinogen 5 being generated at the first acid catalyzed step, there would be no DDSP after subsequent oxidation. The coupling site came from the methylene in 16-thiatripyrrin 3, this was further confirmed by the application experiments (Schemes 3 and 4). The substrate tolerance of this one-pot reaction was subsequently explored. When funan diol 7 was used instead of thiophene diol 4, bis(21-thia-23-oxaporphyrin) (DOSP)14 and 21-thia-23-oxaporphyrin (OSP) were obtained simultaneously with yields of 4.7% and 15.7%, respectively (Scheme 3). A typical split Soret band (430 and 451 nm) was also observed. Compared to DDSP, there is an obvious blue shift due to the strong electron-withdrawing ability of oxygen atom. The reaction shown in Scheme 4 confirms that this one-pot reaction strategy is a general approach to synthesize meso–meso directly linked diheteroporphyrin dimer. When 16-oxatripyrrin 815 was selected to replace the feedstock 3 in Scheme 1, the coupling reaction can also occur at the nonsubstituted methylene of 8, and results in another novel meso–meso directly linked diheteroporphyrin dimer (DSOP)16 with yield of 3.6%, accompanied by 9.0% yield of OSP. In conclusion, a one-pot synthesis strategy to synthesize the meso–meso directly linked dithiaporphyrin dimer was achieved for the first time, and the yield of DDSP can be improved to 8.7% under the optimum reaction conditions. It is noteworthy that the described methodology also can work smoothly to prepare the oxathiaporphyrin dimer DOSP, and can be extended to obtain DSOP by using tripyrrin 8 containing funan group. A preliminary investigation into the reaction mechanism showed that the meso–meso linked dithiaporphyrinogen dimer is formed at the first acid-catalyzed step and subsequently oxidized to DDSP. This work offers a facile and convenient way to get the meso–meso directly linked diheteroporphyrin dimer from simple non-porphyrin precursors. Acknowledgments We thank the 973 Program (2011CB932902) and NSFC (Nos. 21172126 and 20802038) for their generous financial support.
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Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.tetlet.2012.09. 048. These data include MOL files and InChiKeys of the most important compounds described in this article. References and notes 1. (a) Schwab, P. F. H.; Levin, M. D.; Michl, J. Chem. Rev. 1999, 99, 1863–1933; (b) Chou, J.-H.; Kosal, M. E.; Nalwa, H. S.; Rakow, N. A.; Suslick, K. S. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, 2000; Vol. 6, pp 43–129. 2. (a) Susumu, K.; Shimidzu, T.; Tanaka, K.; Segawa, H. Tetrahedron Lett. 1996, 37, 8399–8402; (b) Osuka, A.; Shimidzu, H. Angew. Chem., Int. Ed. 1997, 36, 135– 137; (c) Khoury, R. G.; Jaquinod, L.; Smith, K. M. Chem. Commun. 1997, 1057– 1058; (d) Ogawa, T.; Nishimoto, Y.; Yoshida, N.; Ono, N.; Osuku, A. Chem. Commun. 1998, 337–338; (e) Ogawa, T.; Nishimoto, Y.; Yoshida, N.; Ono, N.; Osuka, A. Angew. Chem., Int. Ed. 1999, 38, 176–179; (f) Senge, M. O.; Feng, X. Tetrahedron Lett. 1999, 40, 4165–4168; (g) Shi, X.; Liebeskind, L. S. J. Org. Chem. 2000, 65, 1665–1671; (h) Aratani, N.; Osuka, A. Org. Lett. 2001, 3, 4213–4216; (i) Jin, L.-M.; Chen, L.; Yin, J.-J.; Guo, C.-C.; Chen, Q.-Y. Eur. J. Org. Chem. 2005, 3994–4001; (j) Ouyang, Q.; Zhu, Y.-Z.; Li, Y.-C.; Wei, H.-B.; Zheng, J.-Y. J. Org. Chem. 2009, 74, 3164–3167; (k) Yang, J.; Yoo, H.; Aratani, N.; Osuka, A.; Kim, D. Angew. Chem., Int. Ed. 2009, 48, 4323–4327; (l) Song, J.; Aratani, N.; Kim, P.; Kim, D.; Shinokubo, H.; Osuka, A. Angew. Chem., Int. Ed. 2010, 49, 3617–3620. 3. (a) Tsuda, A.; Osuka, A. Science 2001, 293, 79–82; (b) Aratani, N.; Osuka, A. Chem. Rec. 2003, 3, 225–234; (c) Kim, D.; Osuka, A. Acc. Chem. Res. 2004, 37, 735–745; (d) Ahn, T. K.; Kim, K. S.; Kim, D. Y.; Noh, S. B.; Aratani, N.; Ikeda, C.; Osuka, A.; Kim, D. J. Am. Chem. Soc. 2006, 128, 1700–1704; (e) Cho, S.; Yoon, M.C.; Lim, J. M.; Kim, P.; Aratani, N.; Nakamura, Y.; Ikeda, T.; Osuka, A.; Kim, D. J. Phys.Chem. B 2009, 113, 10619–10627; (f) Park, J. K.; Chen, J.; Lee, H. R.; Park, W. S.; Shinokubo, H.; Osuka, A.; Kim, D. J. Phys. Chem. C 2009, 113, 21956–21963. 4. (a) Ulman, A.; Manassen, J. J. Am. Chem. Soc. 1975, 97, 6540–6544; (b) Sridevi, B.; Narayanan, S. J.; Srinivasan, A.; Reddy, M. V.; Chandrashekar, T. K. J. Porphyr. Phthalocya. 1998, 2, 69–78; (c) Gupta, I.; Ravikanth, M. Coord. Chem. Rev. 2006, 250, 468–518. _ ´ ski, L.; Lisowski, J.; Olmstead, M. M.; Balch, A. L. Inorg. Chem. 5. (a) Latos-Grazyn 1989, 28, 1183–1188; (b) Pandian, R. P.; Chandrashekar, T. K. Inorg. Chem. 1994, 33, 3317–3324; (c) Gopinath, C. S.; Pandian, R. P.; Manoharan, P. T. J. Chem. Soc., Dalton Trans. 1996, 1255–1259; (d) You, Y.; Gibson, S. L.; Detty, M. R. Bioorg. Med. Chem. 2005, 13, 5968–5980; (e) Ngen, E. J.; Daniels, T. S.; Murthy, R. S.; Detty, M. R.; You, Y. Bioorg. Med. Chem. 2008, 16, 3171–3183; (f) Zhu, Y.; Zhu, Y.-Z.; Song, H.-B.; Zheng, J.-Y.; Liu, Z.-B.; Tian, J.-G. Tetrahedron Lett. 2007, 48, 5687–5691. 6. Van Patten, P. G.; Shreve, A. P.; Lindsey, J. S.; Donohoe, R. J. J. Phys.Chem. B 1998, 102, 4209–4216. 7. (a) Ravikanth, M. Tetrahedron Lett. 2000, 41, 3709–3712; (b) Kumaresan, D.; Agarwal, N.; Ravikanth, M. J. Chem. Soc., Perkin Trans. 1 2001, 1644–1648; (c) Gupta, I.; Agarwal, N.; Ravikanth, M. Eur. J. Org. Chem. 2004, 1693–1697; (d) Gupta, I.; Ravikanth, M. J. Org. Chem. 2004, 69, 6796–6811; (e) Punidha, S.; Agarwal, N.; Ravikanth, M. Eur. J. Org. Chem. 2005, 2500–2517; (f) Gupta, I.; Fröhlich, R.; Ravikanth, M. Chem. Commun. 2006, 3726–3728; (g) Punidha, S.; Agarwal, N.; Gupta, I.; Ravikanth, M. Eur. J. Org. Chem. 2007, 1168–1175; (h) Shetti, V. S.; Ravikanth, M. Eur. J. Org. Chem. 2010, 494–508; (i) Yedukondalu, M.; Maity, D. K.; Ravikanth, M. Eur. J. Org. Chem. 2010, 1544–1561; (j) Khan, T. K.; Ravikanth, M. Eur. J. Org. Chem. 2011, 7011–7022. 8. Misra, R.; Kumar, R.; Chandrashekar, T. K.; Suresh, C. H. Chem. Commun. 2006, 4584–4586. 9. Punidha, S.; Agarwal, N.; Burai, R.; Ravikanth, M. Eur. J. Org. Chem. 2004, 2223– 2230. 10. (a) Lindsey, J. S.; Hsu, H. C.; Schreiman, I. C. Tetrahedron Lett. 1986, 27, 4969– 4970; (b) Lindsey, J. S.; Schreiman, I. C.; Hsu, H. C.; Kearney, P. C.; Marguerettaz, A. M. J. Org. Chem. 1987, 52, 827–836. 11. (a) Cho, H. S.; Song, J. K.; Ha, J.-H.; Cho, S.; Kim, D.; Yoshida, N.; Osuka, A. J. Phys.Chem. A 2003, 107, 1897–1903; (b) Cho, S.; Yoon, M.-C.; Lim, J. M.; Kim, P.; Aratani, N.; Nakamura, Y.; Ikeda, T.; Osuka, A.; Kim, D. J. Phys. Chem. B 2009, 113, 10619–10627. 12. Aratani, N.; Takagi, A.; Yanagawa, Y.; Matsumoto, T.; Kawai, T.; Yoon, Z. S.; Kim, D.; Osuka, A. Chem. Eur. J. 2005, 11, 3389–3404. 13. General information: Typical reactions were carried out on a 0.5 mmol scale. Method A: Compounds 3 and 4 were dissolved in dry dichloromethane and
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stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 60 min. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Method B: Compound 3 was dissolved in dry solvent and stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 10 min, then thiophene diol 4 was added. The mixture was stirred for the indicated time. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Method C: Compound 4 was dissolved in dry solvent and stirred for 20 min with nitrogen bubbling. Acid was added and the mixture was stirred for 10 min, then 16-thiatripyrrin 3 was added. The mixture was stirred for the indicated time. DDQ (2 equiv) was added and stirring was continued for 1.5 h. The solvent was evaporated in vacuum, and the residue was purified by silica gel column (400–500 mesh) chromatography with chloroform to afford DDSP and DSP as a purple solid. Data for DDSP: 1H NMR (400 MHz, CDCl3): d = 7.70–7.77 (m, 12H, phenyl), 7.84–7.88 (m, 6H, phenyl), 7.993 (d, J = 4.4, 2H, pyrrole), 8.19–8.23 (m, 4H, phenyl), 8.27–8.32 (m, 6H, phenyl), 8.49 (d, J = 4.4 Hz, 2H, pyrrole), 8.74 (dd, J = 4.4 and 17.6 Hz, 4H, pyrrole), 9.07 (d, J = 5.2 Hz, 2H, thiophene), 9.45 (d, J = 5.2 Hz, 2H, thiophene), 9.78 (s, 4H, thiophene) ppm. 13C NMR (400 MHz, CDCl3): d = 126.3, 126.4, 126.7, 127.4, 127.4, 127.5, 128.0, 128.1, 128.2, 131.0, 134.0, 134.2, 134.2, 134.4, 134.9, 135.0, 135.6, 135.8, 136.0, 137.0, 141.0, 141.0, 141.2, 147.2, 147.9, 148.5, 151.4, 156.2, 156.5, 157.1, 160.2 ppm. ESI-MS: m/z calculated for C76H47N4S4 [M+H]+: 1143.27; found: 1143.61. MALDI-HRMS: m/ z calculated for C76H47N4S4 [M+H]+: 1143.2678; found: 1143.2681. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 434 (153206), 458 (146109), 522 (56336), 636 (3664), 700 (6870). Fluorescence (in CH2Cl2, kex = 434 nm): 715 nm (U = 0.014). Data for DSP: 1H NMR (400 MHz, CDCl3): d = 7.80–7.87 (m, 9H, phenyl), 8.23– 8.28 (m, 6H, phenyl), 8.70–8.73 (m, 2H, pyrrole), 8.81 (d, J = 4.4 Hz, 1H, pyrrole), 9.10 (d, J = 4.4 Hz, 1H, pyrrole), 9.73 (dd, J = 4.8 and 12.4 Hz, 2H, thiophene), 9.83 (d, J = 4.8 Hz, 1H, thiophene), 10.04 (d, J = 4.8 Hz, 1H, thiophene), 10.79 (s, 1H, meso-H) ppm. 13C NMR (400 MHz, CDCl3): d = 119.1, 127.6, 127.7, 128.3, 133.9, 134.0, 134.4, 134.5, 134.5, 134.6, 134.8, 134.9, 135.0, 135.1, 135.6, 135.8, 136.1, 141.3, 141.4, 141.6, 147.5, 147.9, 148.3, 149.0, 155.2, 156.3, 156.8 ppm. ESI-MS: m/z calculated for C45H27N3S2 [M+H]+: 573.15; found: 573.42. ESI-HR-MS: m/z calculated for C38H24N2S2 [M+H]+: 573.1454; found: 573.1451. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 428 (275146), 507 (29707), 538 (4244), 624 (2593), 687 (4480). Fluorescence (in CH2Cl2, kex = 428 nm): 697 nm (U = 0.007). 14. Data for DOSP: 1H NMR (600 MHz, CDCl3): d = 7.72–7.91 (m, 18H, phenyl), 8.00 (d, J = 4.8 Hz, 2H, pyrrole), 8.26–8.33 (m, 14H, phenyl and pyrrole), 8.55 (d, J = 4.8 Hz, 2H, pyrrole), 8.67 (d, J = 4.8 Hz, 2H, pyrrole), 9.18 (d, J = 4.8 Hz, 2H, thiophene), 9.32 (dd, J = 4.8 and 8.4 Hz, 4H, furan), 9.59 (d, J = 4.8 Hz, 2H, thiophene) ppm. 13C NMR (100 MHz, CDCl3): d = 122.0, 126.5, 126.6, 126.8, 127.3, 127.7, 128.0, 128.2, 128.3, 128.7, 129.0, 129.3, 129.8, 130.1, 130.3, 130.6, 130.7, 133.7, 133.9, 134.3, 134.8, 135.1, 136.1, 136.2, 136.6, 136.7, 137.0, 137.2, 137.3, 140.7, 142.5, 142.8, 150.5, 154.9, 155.2, 155.9, 156.7, 157.2, 159.9, 163.0 ppm. ESI-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.31; found: 1111.18. MALDI-HR-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.3135; found: 1111.3133. UV/Vis (in CH2Cl2, kmax/nm, e/mol 1dm3cm 1): 430 (82287), 451 (80074), 520 (32995), 645 (2817), 713 (6036). Fluorescence (in CH2Cl2, kex = 430 nm): 726 nm (U = 0.009). 15. Chmielewski, P. J.; Latos-Grazynski, L.; Olmstead, M. M.; Balch, A. L. Chem. Eur. J. 1997, 3, 268–278. 16. Data for DSOP: 1H NMR (600 MHz, CDCl3): d = 7.62–7.72 (m, 12H, phenyl), 7.75 (d, J = 4.2 Hz, 2H, pyrrole), 7.79–7.84 (m, 6H, phenyl), 8.13–8.15 (t, J = 6.0 Hz, 4H, phenyl), 8.20 (d, J = 7.8 Hz, 4H, phenyl), 8.26–8.28 (m, 6H, phenyl and pyrrole), 8.43 (d, J = 4.2 Hz, 2H, pyrrole), 8.56 (d, J = 5.4 Hz, 2H, furan), 8.62 (d, J = 4.2 Hz, 2H, pyrrole), 8.90 (d, J = 4.8 Hz, 2H, furan), 9.74–9.76 (dd, J = 4.8 and 9.0 Hz, 4H, thiophene) ppm. 13C NMR (75 MHz, CDCl3): d = 118.3, 121.3, 126.9, 127.5, 127.6, 128.0, 128.1, 128.3, 130.3, 132.0, 134.0, 134.1, 134.2, 134.3, 135.2, 135.4, 135.7, 135.1, 137.7, 140.5, 140.7, 142.2, 151.1, 151.3, 155.8, 156.1, 158.9, 159.0, 159.2, 160.0 ppm. ESI-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.31; found: 1111.23. MALDI-HR-MS: m/z calculated for C76H46N4O2S2 [M+H]+: 1111.314; found: 1111.314. UV/Vis (in CH2Cl2, kmax/nm, e/ mol 1dm3cm 1): 430 (73034), 462 (84270), 525 (33924), 644 (1513), 712 (4322). Fluorescence (in CH2Cl2, kex = 430 nm): 720 nm (U = 0.014).