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Structural concept for fluorinated Y-enynes with solvatochromic properties

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Abstract

An approach to the development of fluorescent probes to follow polymerizations in situ using fluorinated cross-conjugated enediynes (Y-enynes) is reported. Different substitution patterns in the Y-enynes result in distinct solvatochromic behavior. β,β-Bis(phenylethynyl)pentafluorostyrene 7, which bears no donor substituents and only fluorine at the styrene moiety, shows no solvatochromism. Donor substituted β,β-bis(3,4,5-trimethoxyphenylethynyl)pentafluorostyrene 8 and β,β-bis(4-butyl-2,3,5,6-tetrafluorophenylethynyl)-3,4,5-trimethoxystyrene 9 exhibit solvatochromism upon change of solvent polarity. Y-enyne 8 showed the largest solvatochromic shift (94 nm bathochromic shift) upon changing solvent from cyclohexane to acetonitrile. A smaller solvatochromic response (44 nm bathochromic shift) was observed for 9. Lippert-Mataga treatment of 8 and 9 yields slopes of −10,800 and −6,400 cm−1, respectively. This corresponds to a change in dipole moment of 9.6 and 6.9 D, respectively. The solvatochromic behavior in 8 and 9 supports the formation of an intramolecular charge transfer (ICT) state. The low fluorescence quantum yields are caused by competitive double bond rotation. The fluorescence decay time of 9 decreases in methyltetrahydrofuran from 2.1 ns at 77 K to 0.11 ns at 200 K. Efficient single bond rotation in 9 was frozen at −50 °C in a configuration in which the trimethoxyphenyl ring is perpendicular to the fluorinated rings. 7–9 are photostable compounds. The X-ray structure of 7 shows it is not planar and that its conjugation is distorted. Y-enyne 7 stacks in the solid state showing coulombic, actetylene—arene, and fluorine—π interactions.

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References

  1. Contribution # 470 from the Center for Photochemical Sciences.

  2. For reviews, see: (a) P. Suppan, Invited review. Solvatochromic shifts. The influence of the medium on the energy of electronic states, J. Photochem. Photobiol., A, 1990, 50, 293–330.

    Article  CAS  Google Scholar 

  3. C. Reichardt, Solvatochromic Dyes as Solvent Polarity Indicators, Chem. Rev., 1994, 94, 2319–2358.

    Article  CAS  Google Scholar 

  4. W. F. Jager, A. A. Volkers, D. C. Neckers, Solvatochromic Fluorescent Probes for Monitoring the Photopolymerization of Dimethacrylates, Macromolecules, 1995, 28, 8153–8158.

    Article  CAS  Google Scholar 

  5. B. Strehmel, J. H. Malpert, A. M. Sarker, D. C. Neckers, New Intramolecular Fluorescence Probes That Monitor Photoinduced Radical and Cationic Cross-Linking, Macromolecules, 1999, 32, 7476–7482.

    Article  CAS  Google Scholar 

  6. Z. J. Wang, J. C. Song, R. Bao, D. C. Neckers, Fluorescence probes for monitoring polymerization processes, J. Polym. Sci. Part B: Polym. Phys., 1996, 334, 325–333.

    Article  Google Scholar 

  7. J. C. Song, D. C. Neckers, Characterization of photocurable coatings using fluorescence probes, Polym. Eng. Sci., 1996, 36, 394–402.

    Article  CAS  Google Scholar 

  8. S. Hu, R. Popielarz, D. C. Neckers, Fluorescence Probe Techniques (FPT) for Measuring the Relative Efficiencies of Free-Radical Photoinitiators, Macromolecules, 1998, 31, 4107–4113.

    Article  CAS  Google Scholar 

  9. J.-P. Fouassier, in Photoinitiation, Photopolymerization, and Photocuring: Fundamentals and Applications, Hanser Publications, Cincinnati, OH, 1995.

    Google Scholar 

  10. Y. Zhao, R. McDonald, R. R. Tykwinski, Study of cross-conjugated iso-polytriacetylenes and related oligoenynes, J. Org. Chem., 2002, 67, 2805–2812 and references therein.

    Article  CAS  Google Scholar 

  11. G. T. Hwang, H. S. Son, J. K. Ku, B. H. Kim, Novel fluorophores: efficient synthesis and photophysical study, Org. Lett., 2001, 3, 2469–2471.

    Article  CAS  Google Scholar 

  12. L. Fomina, R. Salcedo, Synthesis and polymerization of β,β-dibromo-4-ethynylstyrene; preparation of a new polyconjugated, hyperbranched polymer, Polymer, 1996, 37, 1723–1728.

    Article  CAS  Google Scholar 

  13. L. Fomina, P. Guadarrama, S. Fomine, R. Salcedo, T. Ogawa, Synthesis and characterization of well-defined fully conjugated hyperbranched oligomers of β,β-dibromo-4-ethynylstyrene, Polymer, 1998, 39, 2629–2635.

    Article  CAS  Google Scholar 

  14. L. Fomina, H. Allier, S. Fomine, R. Salcedo, T. Ogawa, Synthesis and molten-state polymerization of some novel conjugated diacetylenes, Polym. J. (Tokyo), 1995, 27, 591–600.

    Article  CAS  Google Scholar 

  15. S. Fomine, L. Fomina, H. Q. Florentino, J. M. Mendez, T. Ogawa, Novel polymers containing discrete conjugated units, produced by the Heck reaction, Polym. J. (Tokyo), 1995, 27, 1085–1093.

    Article  CAS  Google Scholar 

  16. L. Eshdat, H. Berger, H. Hopf, M. Rabinovitz, Anionic Cyclization of a Cross-Conjugated Enediyne, J. Am. Chem. Soc., 2002, 124, 3822–3823.

    Article  CAS  Google Scholar 

  17. B. R. Kaafarani, A. A. Pinkerton, D. C. Neckers, High order stacking of a perfluoro ‘Y-enyne’, Tetrahedron Lett., 2001, 42, 8137–8139.

    Article  CAS  Google Scholar 

  18. B. R. Kaafarani, D. C. Neckers, Photocyclization of a conjugated triaryl ‘Y-enyne’, Tetrahedron Lett., 2001, 42, 4099–4102.

    Article  CAS  Google Scholar 

  19. B. R. Kaafarani, B. Wex, J. A. K. Bauer, D. C. Neckers, Photocyclization of a naphthyl substituted Y-enyne, Tetrahedron Lett., 2002, 8227–8230.

    Google Scholar 

  20. B. Strehmel, A. M. Sarker, J. H. Malpert, V. Strehmel, H. Seifert, D. C. Neckers, Effect of aromatic ring substitution on the optical properties, emission dynamics, and solid state behaviour of fluorinated oligophenylenevinylenes, J. Am. Chem. Soc., 1999, 121, 1226–1236.

    Article  CAS  Google Scholar 

  21. B. Strehmel, K. B. Henbest, A. M. Sarker, J. H. Malpert, D. Y. Chen, M. A. J. Rodgers, D. C. Neckers, Ion-induced manipulation of photochemical pathways in crown ether compounds based on fluorinated oligophenylenevinylenes: the border between ultrafast photoswitches and photoproduced nanomaterials, J. Nanosci. Nanotechnol., 2001, 1, 107–124.

    Article  CAS  Google Scholar 

  22. B. Strehmel, Fluorescence Probes for Material Science, in Advanced Functional Molecules and Polymers, ed. H. S. Nalwa, Gordon and Breach Publishing Group, Amsterdam, 2001, Vol. 3, pp. 299–384.

  23. L. Gobbi, N. Elmaci, H. P. Lüthi, F. Diederich, N,N-Dialkylaniline-substituted tetraethynyl-ethenes: a new class of chromophores possessing an emitting charge-transfer state. Experimental and computational studies, ChemPhysChem, 2001, 2, 423–433 and references therein.

    Article  CAS  Google Scholar 

  24. W. R. Dawson, M. W. Windsor, Fluorescence yields of aromatic compounds, J. Phys. Chem., 1968, 72, 3251–3260.

    Article  CAS  Google Scholar 

  25. H. Sanyo, F. J. Hirayama, Actinometric determination of absolute fluorescence quantum yields, Phys. Chem., 1983, 87, 83–89.

    Article  Google Scholar 

  26. D. Venkatesan, M. Yoneda, M. Ueda, Conjugated polymers for nonlinear optics. 1. Synthesis and properties of poly(aryleneethynylenevinylene)s, React. Funct. Polym., 1996, 30, 341–352.

    Article  CAS  Google Scholar 

  27. N. J. Lawrence, A. F. Ghani, L. A. Hepworth, J. A. Hadfield, A. T. McGown, R. G. Pritchard, The synthesis of (E)- and (Z)-combretastatins A-4 and a phenanthrene from Combretum caffrum, Synthesis, 1999, 1656–1660.

    Google Scholar 

  28. S. Huang, J. M. Tour, Rapid bi-directional synthesis of oligo(1,4-phenylene ethynylene)s, Tetrahedron Lett., 1999, 40, 3347–3350.

    Article  CAS  Google Scholar 

  29. Bruker (1999). SMART (Ver. 5.05) and SAINT-Plus (Ver. 7.08). Bruker AXS Inc, Madison, Wisconsin, USA.

  30. G. M. Sheldrick, 1996. SADABS. Program for the empirical Absorption correction of Area detector data, University of Göttingen, Germany.

    Google Scholar 

  31. G. M. Sheldrick, 1996. SADABS. Program for the empirical Absorption correction of Area detector data, University of Göttingen, Germany.

    Google Scholar 

  32. E. J. Corey, P. L. Fuchs, Synthetic method for conversion of formyl groups into ethynyl groups (RCHO.far. RC.idn. CH or RC.idn. CR1), Tetrahedron Lett., 1972, 3769–3772.

    Google Scholar 

  33. K. Sonogashira, Y. Tohda, N. Hagihara, Convenient synthesis of acetylenes. Catalytic substitutions of acetylenic hydrogen with bromo alkenes, iodo arenes, and bromopyridines, Tetrahedron Lett., 1975, 4467–4470.

    Google Scholar 

  34. The crystallographic data is deposited at the Cambridge Crystallographic Data Center (CCDC # 174497).

  35. G. W. Coates, A. R. Dunn, L. M. Henling, J. W. Ziller, E. B. Lobkovsky, R. H. Grubbs, Phenyl-perfluorophenyl stacking interactions: topochemical [2+2] photodimerization and photopolymerization of olefinic compounds, J. Am. Chem. Soc., 1998, 120, 3641–3649.

    Article  CAS  Google Scholar 

  36. G. W. Coates, A. R. Dunn, L. M. Henling, D. A. Dougherty, R. H. Grubbs, Phenyl-perfluorophenyl stacking interactions: a new strategy for supermolecule construction, Angew. Chem., Int. Ed., 1997, 36, 248–251.

    Article  CAS  Google Scholar 

  37. A. S. Shetty, J. Zhang, J. S. Moore, Aromatic π-Stacking in Solution as Revealed through the Aggregation of Phenylacetylene Macrocycles, J. Am. Chem. Soc., 1996, 118, 1019–1027.

    Article  CAS  Google Scholar 

  38. The distance between the aromatic centroid of the pentafluorophenyl ring in molecule A and the center of the carbon-carbon triple bond in molecule B is 4.097Å.

  39. X-ray structure analysis of 8 and 9 is in progress.

  40. E. Lippert, W. Z. Lüder, Spectroscopic investigations and dipole measurements on the electron structure of cis- and trans-p-dimethylamino cinnamic acid nitrile and related nitriles, Z. Physik. Chem. (Frankfurt), 1962, 33, 60–81.

    Article  CAS  Google Scholar 

  41. E. Lippert, Spectroscopic determination of the dipole moment of aromatic compounds in the first excited singlet state, Z. Elektrochem., 1957, 61, 962–975.

    CAS  Google Scholar 

  42. N. Mataga, Y. Kaifu, M. Koizumi, The solvent effect on fluorescence spectrum. Change of solute-solvent interaction during the lifetime of excited solute molecule, Bull. Chem. Soc. Jpn., 1955, 28, 690–691.

    Article  CAS  Google Scholar 

  43. N. Mataga, Y. Kaifu, M. Koizumi, Solvent effects upon fluorescence spectra and the developments of excited molecules, Bull. Chem. Soc. Jpn., 1956, 29, 465–470.

    Article  CAS  Google Scholar 

  44. L. Onsager, Electric moments of molecules in liquids, J. Am. Chem. Soc., 1936, 58, 1486–1493.

    Article  CAS  Google Scholar 

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Authors and Affiliations

  1. Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA

    Bilal R. Kaafarani, Brigitte Wex & Douglas C. Neckers

  2. Institute of Chemistry, Physical Chemistry, University of Potsdam, Karl-Liebknecht Str. 24/25, D-14476, Golm, Germany

    Bernd Strehmel

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  1. Bilal R. Kaafarani
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  2. Brigitte Wex
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  3. Bernd Strehmel
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  4. Douglas C. Neckers
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Correspondence to Douglas C. Neckers.

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This paper is dedicated to Professor Dr J. W. Neckers on the occasion of his 100th birthday.

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Kaafarani, B.R., Wex, B., Strehmel, B. et al. Structural concept for fluorinated Y-enynes with solvatochromic properties. Photochem Photobiol Sci 1, 942–950 (2002). https://doi.org/10.1039/b208326d

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