Designing a helical polymer that reverses its handedness at a selected, continuously variable, temperature

Angewandte Chemie - International Edition

Volumn 39, Issue 8, 2000, Pages 1482-1485

  Cheon, Kap Soo ^a   Selinger, Jonathan V ^b   Green, Mark M ^a  

^a POLYTECHNIC UNIVERSITY   (United States)

^b NAVAL RESEARCH LABORATORY   (United States)

Author keywords

Chirality; Cooperative effects; Helical structures; Polymers; Thermodynamics

Indexed keywords

POLYMER;

ARTICLE; CHIRALITY; POLYMERIZATION; STEREOCHEMISTRY; TEMPERATURE;

EID: 0001021879     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1521-3773(20000417)39:8<1482::AID-ANIE1482>3.0.CO;2-7     Document Type: Article

References (43)

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7. For recent examples and leading references, see: a) E. Yashima, T. Matsushima, Y. Okamoto, J. Am. Chem. Soc. 1997, 119, 6345; b) A. R. A. Palmans, J. A. J. M. Vekemans, E. E. Havinga, E. W. Meijer, Angew. Chem. 1997, 109, 2753; Angew. Chem. Int. Ed. 1997, 36, 2648; c) D. R. Link, G. Natale, R. Shao, J. E. Maclennan, N. A. Clark, E., Korblova, D. M. Walba, Science 1997, 278, 1924; d) J. J. L. M. Cornelissen, M. Fischer, N. A. J. M. Sommerdijk, R. J. M. Nolte, Science 1998, 280, 1427; e) D. S. Schlitzer, B. M. Novak, J. Am. Chem. Soc. 1998, 120, 2196.
8. For recent examples and leading references, see: a) E. Yashima, T. Matsushima, Y. Okamoto, J. Am. Chem. Soc. 1997, 119, 6345; b) A. R. A. Palmans, J. A. J. M. Vekemans, E. E. Havinga, E. W. Meijer, Angew. Chem. 1997, 109, 2753; Angew. Chem. Int. Ed. 1997, 36, 2648; c) D. R. Link, G. Natale, R. Shao, J. E. Maclennan, N. A. Clark, E., Korblova, D. M. Walba, Science 1997, 278, 1924; d) J. J. L. M. Cornelissen, M. Fischer, N. A. J. M. Sommerdijk, R. J. M. Nolte, Science 1998, 280, 1427; e) D. S. Schlitzer, B. M. Novak, J. Am. Chem. Soc. 1998, 120, 2196.
9. For recent examples and leading references, see: a) E. Yashima, T. Matsushima, Y. Okamoto, J. Am. Chem. Soc. 1997, 119, 6345; b) A. R. A. Palmans, J. A. J. M. Vekemans, E. E. Havinga, E. W. Meijer, Angew. Chem. 1997, 109, 2753; Angew. Chem. Int. Ed. 1997, 36, 2648; c) D. R. Link, G. Natale, R. Shao, J. E. Maclennan, N. A. Clark, E., Korblova, D. M. Walba, Science 1997, 278, 1924; d) J. J. L. M. Cornelissen, M. Fischer, N. A. J. M. Sommerdijk, R. J. M. Nolte, Science 1998, 280, 1427; e) D. S. Schlitzer, B. M. Novak, J. Am. Chem. Soc. 1998, 120, 2196.
10. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
11. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
12. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
13. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
14. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
15. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
16. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
17. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
18. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
19. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
20. For leading references see refs. [1], [2], and: a) Y.-D. Wu, D.-P. Wang, J. Am. Chem Soc. 1999, 121, 9352; b) D. H. Appella, L. A. Christianson, I. L. Karle, D. R. Powell, S. H. Gellman, J. Am. Chem. Soc. 1999, 121, 6206; c) R. B. Prince, T. Okada, J. S. Moore, Angew. Chem. 1999, 111, 245; Angew. Chem. Int. Ed. 1999, 38, 233; d) M. Fujiki, J. Am. Chem. Soc. 1996, 118, 7424; e) K. Yashima, K. Maeda, Y. Okamoto, Nature 1999, 399, 449; f) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 1046; g) K. Maeda, Y. Okamoto, Macromolecules 1998, 31, 5164; h) K. Maeda, N. Yamamoto, Y. Okamoto, Macromolecules 1998, 31, 5924; i) S. Mayer, G. Maxein, R. Zentel, Macromolecules 1998, 31, 8522; j) G. Maxein, H. Keller, B. M. Novak, R. Zenlel, Adv. Mater. 1998, 3, 341.
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22. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
23. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
24. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
25. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
26. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
27. [5d t] a) A. Fredga, Ark. Kemi 1954, 7, 241; b) K. Pettersson, Ark. Kemi 1956, 10, 283; c) A.-M. Weidler, G. Bergson, Acta Chem. Scand. 1963, 17, 2724; d) J. Weinstock, J. Org. Chem. 1961, 26, 3511; e) C. Kaiser, J. Weinstock, Org. Synth. 1971, 51, 48; f) J. Hooz, S. S. H. Gilani, Can. J. Chem. 1968, 46, 86. The circular dichroism spectra of (R)-1 and (R)-2 are found in ref. [1] and in the doctoral thesis of B. Muñoz (B. Muñoz, Polytechnic University, New York (USA), 1993, respectively. The circular dichroism spectrum of (R)-3 will he published later in a full paper.
28. For an assignment of the relationship of helical sense to optical rotation, see: S. Lifson, C. E. Felder, M. M. Green, Macromolecules 1992, 25, 4142.
29. 589 versus T slopes.
30. J. V. Selinger, R. L. B. Selinger, Macromolecules 1998, 31, 2488.
31. S. K. Jha, K. S. Cheon, M. M. Green, J. V. Selinger, J. Am. Chem. Soc. 1999, 121, 1665.
32. In unpublished work consistent with this interpretation, steeper slopes for p*(T) versus T are seen also for insertion of a methylene group between the backbone and the stereocenter in 3 and by terpolymerization of the compelling enantiomers with n-hexyl isocyanate.
33. [Q]
34. Random copolymerization of isocyanates has, so far, been the rule. See: a) M. M. Green, M. P. Reidy, R. D. Johnson, G. Darling, D. J. O'Leary, G. Willson, J. Am. Chem. Soc. 1989, 111, 6452; b) S. H. Hoke, R. G. Cooks, B. Muñoz, H. Chang, M. M. Green, Macromolecules 1995, 28, 2955.
35. Random copolymerization of isocyanates has, so far, been the rule. See: a) M. M. Green, M. P. Reidy, R. D. Johnson, G. Darling, D. J. O'Leary, G. Willson, J. Am. Chem. Soc. 1989, 111, 6452; b) S. H. Hoke, R. G. Cooks, B. Muñoz, H. Chang, M. M. Green, Macromolecules 1995, 28, 2955.
36. Both the 75:25 ratio of copoly((R)-2/(S)-1) and the 55:45 ratio of copoly((R)-1/(S)-3) were decomposed to trimers and studied by NMR following ref. [12a]. Work is in progress, to be reported in a full paper to follow, in explore other sources of the discrepancy including the effects of polydispersity.
37. Various polymers, although with mechanisms unrelated to the work here, can show a large chiral optical sensitivity to temperature. See: a) M. M. Boumann, E. W. Meijer, Adv. Mater. 1995, 7, 385; b) S. Yue, G.C. Berry, M. M. Green, Macromolecues 1996, 29, 6175; c) J. M. Guenet, H. S. J. Jeon, C. Khatri, S. K. Jha, N. P. Balsara, M. M. Green, A. Brulet, A. Thierry, Macromolecules 1997, 30, 4590; d) ref. [2e] above; e) J. R. Koe, M, Fujiki, M. Motonaga, H. Nakashima, Chem. Commun. 2000, in press.
38. Various polymers, although with mechanisms unrelated to the work here, can show a large chiral optical sensitivity to temperature. See: a) M. M. Boumann, E. W. Meijer, Adv. Mater. 1995, 7, 385; b) S. Yue, G.C. Berry, M. M. Green, Macromolecues 1996, 29, 6175; c) J. M. Guenet, H. S. J. Jeon, C. Khatri, S. K. Jha, N. P. Balsara, M. M. Green, A. Brulet, A. Thierry, Macromolecules 1997, 30, 4590; d) ref. [2e] above; e) J. R. Koe, M, Fujiki, M. Motonaga, H. Nakashima, Chem. Commun. 2000, in press.
39. Various polymers, although with mechanisms unrelated to the work here, can show a large chiral optical sensitivity to temperature. See: a) M. M. Boumann, E. W. Meijer, Adv. Mater. 1995, 7, 385; b) S. Yue, G.C. Berry, M. M. Green, Macromolecues 1996, 29, 6175; c) J. M. Guenet, H. S. J. Jeon, C. Khatri, S. K. Jha, N. P. Balsara, M. M. Green, A. Brulet, A. Thierry, Macromolecules 1997, 30, 4590; d) ref. [2e] above; e) J. R. Koe, M, Fujiki, M. Motonaga, H. Nakashima, Chem. Commun. 2000, in press.
40. Various polymers, although with mechanisms unrelated to the work here, can show a large chiral optical sensitivity to temperature. See: a) M. M. Boumann, E. W. Meijer, Adv. Mater. 1995, 7, 385; b) S. Yue, G.C. Berry, M. M. Green, Macromolecues 1996, 29, 6175; c) J. M. Guenet, H. S. J. Jeon, C. Khatri, S. K. Jha, N. P. Balsara, M. M. Green, A. Brulet, A. Thierry, Macromolecules 1997, 30, 4590; d) ref. [2e] above; e) J. R. Koe, M, Fujiki, M. Motonaga, H. Nakashima, Chem. Commun. 2000, in press.
41. Various polymers, although with mechanisms unrelated to the work here, can show a large chiral optical sensitivity to temperature. See: a) M. M. Boumann, E. W. Meijer, Adv. Mater. 1995, 7, 385; b) S. Yue, G.C. Berry, M. M. Green, Macromolecues 1996, 29, 6175; c) J. M. Guenet, H. S. J. Jeon, C. Khatri, S. K. Jha, N. P. Balsara, M. M. Green, A. Brulet, A. Thierry, Macromolecules 1997, 30, 4590; d) ref. [2e] above; e) J. R. Koe, M, Fujiki, M. Motonaga, H. Nakashima, Chem. Commun. 2000, in press.
42. In the absence of speed considerations, the temperature independence of the phase boundary in lyotropic liquid crystals holds an advantage over thermotropic liquid crystals. See: M. M. Green, S. Zanella, H. Gu, T. Sato, G. Gottarelli, S. K. Jha, G. P. Spada, A. M. Schoevaars, B. Feringa, A. Teramoto, J. Am. Chem. Soc. 1998, 120, 9810. There are opportunities in thermotropic liquid crystals following on the solubility of polymers in such mesogenic states, see: Y.-C. Chiang, A. M. Jamieson, M. Kawasumi, V. Percec. Macromolecules 1997, 30, 1992.
43. In the absence of speed considerations, the temperature independence of the phase boundary in lyotropic liquid crystals holds an advantage over thermotropic liquid crystals. See: M. M. Green, S. Zanella, H. Gu, T. Sato, G. Gottarelli, S. K. Jha, G. P. Spada, A. M. Schoevaars, B. Feringa, A. Teramoto, J. Am. Chem. Soc. 1998, 120, 9810. There are opportunities in thermotropic liquid crystals following on the solubility of polymers in such mesogenic states, see: Y.-C. Chiang, A. M. Jamieson, M. Kawasumi, V. Percec. Macromolecules 1997, 30, 1992.