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陳順基 明志科技大學化工系

4- 苯基二苯甲酮與三乙胺電荷 - 轉移誘導激態複合體的形成及其光化學的應用. 陳順基 明志科技大學化工系. The Exciplex Formation of Charge-Transfer Induced 4- Phenylbenzophenone with Triethylamine and the Application in Photochemistry. 中華民國一百年十二月二十四日. Jablonski Diagram. Photophysics. Photochemistry. 2.

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陳順基 明志科技大學化工系

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  1. 4-苯基二苯甲酮與三乙胺電荷-轉移誘導激態複合體的形成及其光化學的應用4-苯基二苯甲酮與三乙胺電荷-轉移誘導激態複合體的形成及其光化學的應用 陳順基 明志科技大學化工系 The Exciplex Formation ofCharge-Transfer Induced 4- Phenylbenzophenone withTriethylamine and the Application in Photochemistry 中華民國一百年十二月二十四日

  2. Jablonski Diagram Photophysics Photochemistry 2

  3. Identification of (n, *) & (,*) 單態的（n , *）及（, *）性質： 參態的（n , *）及（, *）性質： 3

  4. Molecular Complex E A I D + - S D + A 1 D H E 1 S D + A 0 D E CT D H 0 間 距 離 D A Electron donor-acceptor complex (EDA complex) Mulliken CT吸收理論 Ψ(S0) = aΨ(DA) + bΨ(D+A-) Ψ(S1) = aΨ (D+A-)bΨ (DA) ECT = ID  EA  (H1 H0) 4

  5. 激態雙體(Excimer, Excited dimer) (Forster et alZ. Phys. Chem. 1954) 5

  6. 激態複合體(exciplex, excited complex) (Leonhardt et alBer. Bunsenges. Phys. Chem. 1963) 6

  7. Photophysics of BP & PBP BP及PBP吸收及溶劑效應 7

  8. Vibrational structure Vibrational structure provides clues as to which transitions are most possible Emission of biphenyl 8

  9. Lifetimes & Quantum yields BP及PBP在EPA中的低溫磷光生命期 BP及PBP螢、磷光相對量子產率 9

  10. State energy diagram Phenyl-substitutent can stabilize the (, *) energy levels. 10

  11. Phosphorescence Quenching of BP a. Monitored at 450nm 11

  12. Stern-VolmerAnalysis a：steady-state b：transient lifetime c：Fouassier J. Chim Phys. 1983 12

  13. Phosphorescence Quenching of PBP Excitation spectra 13

  14. Solvent Effect of PBP-TEA Exciplex 14

  15. Stern-VolmerPlot kq = 4.52 107 M-1s-1 a. Monitored at 480nm 15

  16. Thermodynamics of Exciplex E‡a=1.8 kcal/mol Arrhenius plot kq = Aexp(-E‡a/RT) 16

  17. Thermodynamics of Exciplex Stevens-Ban plot ln[(CT)/(LE)] = A H/RT 17

  18. Potential Energy Curve Erep(LE) = E LE hvLE Erep(CT) = E LE hvCT H 18

  19. 各種胺類在室溫的Stern-Volmer plot 19

  20. 不同胺類的淬熄效應 20

  21. Temperature-dependent quenching 不同溫度各種胺類的淬熄速率常數kq×10–7(M-1s-1) 21

  22. Temperature-dependent quenching 各種胺類淬熄參態PBP的活化能與前指數因子 各種胺類的Arrhenius plot 22

  23. PBP-TiPA系統在不同溫度的磷光光譜 PBP-TiPA系統的Stevens-Ban圖 23

  24. Photoreduction of BP 24

  25. Photoreduction of PBP 25

  26. Photoreduction of PBP PBP-TEA隨照光時間產物消長的HPLC圖 （tR = 7為PBP， tR =11.5為4-phenylbenzopinacol） 26

  27. Photoreduction of PBP 電荷-轉移誘導的光還原反應機構 27

  28. BP-系列光引發聚合反應 TMPTA-PBP-TEA硬化後之FTIR圖 TMPTA硬化前之FTIR圖 28

  29. Conclusion • The photophysical analysis confirmed that the low-lying excited singlet and triplet states of PBP is 1(n, *), 3( , *) respectively. Thus, an intramolecular energy transfer has occurred from the n * of carbonyl to the *  of biphenyl. • Direct evidence for triplet exciplex formation of excited PBP triplet with amines was provided by the observation of emission at longer wavelengths than that of the phosphorescence of PBP. • The quenching rate constants were dependent on the ionization potentials of amines. The trend reflects on the calculated activation energies (Ea) for exciplex formation of 3PBP and amines. 29

  30. Conclusion • The stabilization enthalpy (H) of exciplex increases with increasing steric effect of amines from TEA to TiPA, " Entropy Control" is expected to widely contribute to the exciplex formation for PBP-TiPA system under high-temperature limit region. • The bimolecular reactivity of photoreduction is very fast for lowest 3(n, *), but (, *) triplet is almost unreactive without amine electron donor. A new mechanism of hydrogen atom abstraction has been proposed by rapid charge-transfer to form an exciplex with TEA following proton transfer. • The PBP-TEA is an efficient photoinitiator and shows the same charge-transfer induced radical’s formations that are able to initiate the polymerization of acrylic type monomers. 30

  31. Thank you for your attention! 31

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