Construction Of Near Infrared Chiroptical Switches Based On Electrochromic Viologens

1. Construction of Near-Infrared Chiroptical Polymers Based on Electrochromic viologens Peking University Deng Jian 2007.07.18

6. Chirality Molecular Chirality Chirality in Nature Supramolecular Chirality

7. Symmetry Chirality of a molecule is a symmetry properties Asymmetric :no any symmetry element (C 1 ) Dissymmetric: only axes of rotation (C n and D n )

8. Light and Chiroptical Properties Electromagnetic waves Optical rotation Circular Dichroism

9. α ， θ (degree) d=cell length (cm) d’=cell length (dm) c=concentration (M) c’=concentration (g/cm 3 ) n=refractive index ε=absorption coefficient (M -1 cm -1 ) λ=wavelength of incident light (nm) Polarimeter and Circular dichroism Spectrometer

14. Structural Design II and Contents of Researches

15. (R)-BEBPP (R)-BEBPB (R)-CBEBPB Axially Dissymmetric Compounds:

16. Synthetic Approach:

17. 4 mg / 1 mL 0.1 M Bu 4 NClO 4 DMF - 0.7 V

18. 4 mg / 1 mL 0.1 M Bu 4 NClO 4 DMF - 0.7 V

19. Demonstration of electrochemical Switching of CD signals of ( R )-CBEBPB in 0.1 M Bu4NClO4/DMF. (a) first reduction at -0.5 V for 5 s; (b) recovered tetracation by bubbling slowly nitrogen into the solution; (c) second reduction at -0.7 V for 1 min. Demonstration of electrochemical Switching of CD signals of ( R )-CBEBPB by tin. (a) first reduction by tin bubling nitrogen; (b) recovered tetracation by bubbling slowly air into the solution; Repeat (a) and (b) five times.

20. Near-infrared chiroptical properties ORD caculated from experimental data (a) (b) J.Phys.Chem. A, 2003, 107 , 2524 J.Am.Chem.Soc., 2004, 126 , 7514

21. R-BEBPB Rotational strength calculated from this diagram.via formula (a). ORD calculated via formula (b).

22. R-CBEBPB

23. R-CBEBPB Reduced

24. 1. [ α ] D 23.9 = -224.5 o (4.0 mg/10 mL DMF), Mn:5295 2. [α] D 23.7 = -399 o (4.0 mg/10 mL DMF), Mn:15477, PD:1.42 Polymer Based on Model Compounds

26. 1. [ α ] D 23.9 = -100.0 o (4.0 mg/10 mL DMF), M n :6695 Grafting: 50% 2. [ α ] D 23.9 = -?, Mn:? Grafting: 50%

29. DJ-E-55

30. Helical polymers:

31. Alkynyl Monomer

32. Synthesis of achiral monomers

33. Synthesis of chiral monomers based on L-lactic acid

34. 含羧基的分子溴化后，不好分离。 溴化时，炔基会被加成。 应该先溴化，再引入手性单元和炔键。

35. Synthesis of chiral monomers based on L-alanine

36. 对甲苯甲酰氯的活性比溴乙酰溴的活性低，可以在水中进行反应。 此反应尽管产率低但是可以发生，产率低的原因可能是苄溴和氨基 发生了反应，自然就想到把氨基保护起来，所以就选择了 BOC-L-alanine 。

37. Synthesis of chiral monomers based on BOC-L-alanine

39. Rh + (BDN)[B(C 6 H 5 ) 4 ] - Synthesis of Catalysts

40. Rh(COD)(tos)(H 2 O)

41. Polymerization of monomers

43. DT1 Samples [M 0 ] [M 0 ]/[Cat] T/ 0 C Time/h Solvent Yield/% M n PD [a] D DJ-C-85 0.08 100 50 12 THF 84 5896 1.25 DJ-C-79 0.08 100 r.t. 12 THF 68 6478 1.61 -86 THF 6338 1.51 -123 DJ-C-95 0.16 100 r.t 24 THF 85 9115 1.56 -182.5 DJ-D-7-2 0.1 100 r.t 20 THF 85 7792 1.69 -217.5 DJ-D-7-3 0.16 200 r.t. 20 THF 77 7882 1.9 -341.5 DJ-D-7-4 0.1 100 0 20 THF 83 7344 2.46 -479

44. poor resolution of polymer small optical rotation small molecular weight

45. Samples [M 0 ] [M 0 ]/[Cat] T/0C Time/h Solvent Yield/% M n PD [a] D / 0 C DJ-D-13-A 0.1 50 30 1 64 10683 -571 DJ-D-13-B 0.2 200 50 1 84 40522 -1616.5

46. ? A yellow solid product. [α] D 20.7 = -755.5 0 (4 mg/10 mL MeCN) [α] D 20.7 = +743.0 0 (4 mg/10 mL DMF) poor resolution of polymer small optical rotation small molecular weight