Studies of the formation of poly(ester rotaxane)s from diacid chlorides, diols, and crown ethers and their properties

Macromolecules

Volumn 30, Issue 13, 1997, Pages

  Gibson, Harry W ^a   Liu, Shu ^a   Gong, Caiguo ^a   Ji, Qing ^a   Joseph, Eugene ^b  

^a VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY   (United States)

^b 3M COMPANY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 3943073863     PISSN: 00249297     EISSN: None     Source Type: Journal    
DOI: None     Document Type: Article

References (80)

1. (a) Harrison, I. T. J. Chem. Soc., Chem. Commun. 1972, 231.
2. (b) Harrison, I. T. J. Chem. Soc., Perkin Trans. 1 1974, 301.
3. (c) Harrison, I. T. J. Chem. Soc., Chem. Common. 1977, 384.
4. (a) Schill, G. Catenanes, Rotaxanes and Knots; Academic Press: New York, 1971.
5. (b) Schill, G.; Logemann, E.; Littke, W. Chem. Uns. Z. 1984, 18, 129.
6. (c) Schill, G.; Beckmann, W.; Schweikert, N.; Fritz, H. Chem. Ber. 1988, 119, 2647.
7. (a) Gibson, H. W.; Bheda, M. C.; Engen, P. T. Prog. Polym. Sci. 1994, 19, 843
8. (b) Gibson, H. W. In Large Ring Molecules; Semlyen, J. A., Ed.; John Wiley & Sons: New York, 1996; Chapter 6, pp. 191-262.
9. (a) Ashton, P. R.; Huff, J.; Menzer, S.; Parsons, I. W.; Preece, J. A.; Stoddan, J. F.; Tolley, M. S.; White, A. J. P.; Williams, D. J. Chem. Eur. J. 1996, 2, 31.
10. (b) Ambalino, D. B.; Stoddart, J. F. Chem. Revs. 1995, 95, 2725.
11. Maciejewski, M. J. Macromol. Sci., Chem. 1979, A13, 77 (1979) Maciejewski, M.; Gwizdowski, A.; Peczak, P.; Pietrzak, A. J. Macromol. Sci., Chem. 1979, A13, 87.
12. Maciejewski, M. J. Macromol. Sci., Chem. 1979, A13, 77 (1979) Maciejewski, M.; Gwizdowski, A.; Peczak, P.; Pietrzak, A. J. Macromol. Sci., Chem. 1979, A13, 87.
13. Lipatova, T. E.; Kosyanchuk, L. F.; Gomza, T. P.; Shilov, V. V.; Lipator, Y. S. Dokl. Akad. Nauk SSSR (Engl. Transl.), 1982, 263, 140. Lipatova, T. E.; Kosyanchuk, L. F.; Gomza, Yu. P. Polym. Sci., U.S.S.R. (Engl. Transl.), 1985, 27, 622.
14. Lipatova, T. E.; Kosyanchuk, L. F.; Gomza, T. P.; Shilov, V. V.; Lipator, Y. S. Dokl. Akad. Nauk SSSR (Engl. Transl.), 1982, 263, 140. Lipatova, T. E.; Kosyanchuk, L. F.; Gomza, Yu. P. Polym. Sci., U.S.S.R. (Engl. Transl.), 1985, 27, 622.
15. Agam, G.; Graiver, D.; Zilkha, A. J. Am. Chem. Soc. 1976, 98, 5206.
16. Weickenmeier, M.; Wenz, G. Macromol. Rapid Commun. 1996, 17, 731. Steinbrunn, M. B.; Wenz, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 2139. Wenz, G.; Keller, B. Macromol. Symp. 1994, 87, 11.
17. Weickenmeier, M.; Wenz, G. Macromol. Rapid Commun. 1996, 17, 731. Steinbrunn, M. B.; Wenz, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 2139. Wenz, G.; Keller, B. Macromol. Symp. 1994, 87, 11.
18. Weickenmeier, M.; Wenz, G. Macromol. Rapid Commun. 1996, 17, 731. Steinbrunn, M. B.; Wenz, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 2139. Wenz, G.; Keller, B. Macromol. Symp. 1994, 87, 11.
19. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
20. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
21. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
22. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
23. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
24. Born, M.; Ritter, H. Macromol. Rapid Commun. 1996, 17, 197. Born, M.; Ritter, H. Adv. Mater. 1996, 8, 149. Born, M.; Koch, T.; Ritter, H. Macromol. Chem. Phys. 1995, 196, 1761. Born, M.; Ritter, H. Angew. Chem. Int. Ed. Engl. 1996, 34, 309. Born, M.; Koch, T.; Ritter, H. Acta Polym. 1994, 45, 68. Ritter, H. Macromol. Symp. 1994, 77, 73.
25. Harada, A.; Okada, M.; Li, J.; Kamachi, M. Macromolecules 1995, 28, 8406. Harada, A.; Li, J.; Kamachi M. Nature 1994, 370, 126. Harada, A.; Li, J.; Kamachi, M. Macromolecules 1994, 27, 4538. Li, J.; Harada, A.; Kamachi, M. Bull. Chem. Soc. Jpn. 1994, 67, 2808. Li, J.; Harada, A.; M. Kamachi Polym. J. 1994, 26, 1019.
26. Harada, A.; Okada, M.; Li, J.; Kamachi, M. Macromolecules 1995, 28, 8406. Harada, A.; Li, J.; Kamachi M. Nature 1994, 370, 126. Harada, A.; Li, J.; Kamachi, M. Macromolecules 1994, 27, 4538. Li, J.; Harada, A.; Kamachi, M. Bull. Chem. Soc. Jpn. 1994, 67, 2808. Li, J.; Harada, A.; M. Kamachi Polym. J. 1994, 26, 1019.
27. Harada, A.; Okada, M.; Li, J.; Kamachi, M. Macromolecules 1995, 28, 8406. Harada, A.; Li, J.; Kamachi M. Nature 1994, 370, 126. Harada, A.; Li, J.; Kamachi, M. Macromolecules 1994, 27, 4538. Li, J.; Harada, A.; Kamachi, M. Bull. Chem. Soc. Jpn. 1994, 67, 2808. Li, J.; Harada, A.; M. Kamachi Polym. J. 1994, 26, 1019.
28. Harada, A.; Okada, M.; Li, J.; Kamachi, M. Macromolecules 1995, 28, 8406. Harada, A.; Li, J.; Kamachi M. Nature 1994, 370, 126. Harada, A.; Li, J.; Kamachi, M. Macromolecules 1994, 27, 4538. Li, J.; Harada, A.; Kamachi, M. Bull. Chem. Soc. Jpn. 1994, 67, 2808. Li, J.; Harada, A.; M. Kamachi Polym. J. 1994, 26, 1019.
29. Harada, A.; Okada, M.; Li, J.; Kamachi, M. Macromolecules 1995, 28, 8406. Harada, A.; Li, J.; Kamachi M. Nature 1994, 370, 126. Harada, A.; Li, J.; Kamachi, M. Macromolecules 1994, 27, 4538. Li, J.; Harada, A.; Kamachi, M. Bull. Chem. Soc. Jpn. 1994, 67, 2808. Li, J.; Harada, A.; M. Kamachi Polym. J. 1994, 26, 1019.
30. Ooya, T.; Mori, H.; Terano, M.; Yui, N. Makromol. Rapid Commun. 1995, 16, 259.
31. Zhu, S. S.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1996, 118, 8713. Marsella, M. J.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 9832. Zhou, Q.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 7017. Marsella, M. J.; Fu, D.-K.; Swager, T. M. Adv. Mater. 1995, 7, 145.
32. Zhu, S. S.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1996, 118, 8713. Marsella, M. J.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 9832. Zhou, Q.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 7017. Marsella, M. J.; Fu, D.-K.; Swager, T. M. Adv. Mater. 1995, 7, 145.
33. Zhu, S. S.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1996, 118, 8713. Marsella, M. J.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 9832. Zhou, Q.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 7017. Marsella, M. J.; Fu, D.-K.; Swager, T. M. Adv. Mater. 1995, 7, 145.
34. Zhu, S. S.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1996, 118, 8713. Marsella, M. J.; Carroll, P. J.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 9832. Zhou, Q.; Swager, T. M. J. Am. Chem. Soc. 1995, 117, 7017. Marsella, M. J.; Fu, D.-K.; Swager, T. M. Adv. Mater. 1995, 7, 145.
35. (a) Gong, C.; Gibson, H. W. Macromol. Chem. Phys., in press.
36. (b) Gong, C.; Gibson, H. W. Macromolecules 1996, 29, 7029.
37. (c) Gibson, H. W.; Liu, S.; Lecavalier, P.; Wu, C.; Shen, Y. X. J. Am. Chem. Soc. 1995, 117, 852.
38. (d) Delaviz, Y.; Gibson, H. W. Macromolecules, 1992, 25, 18.
39. (e) Wu, C.; Bheda, M. C.; Lim, C.; Shen, Y. X.; Sze, J.; Gibson, H. W. Polym. Commun. 1991, 32, 204.
40. (f) Gibson, H. W.; Liu, S. Makromol. Chem., Macromol. Symp. 1996, 102, 55.
41. (g) Gong, C.; Gibson, H. W. J. Am. Chem. Soc., in press.
42. (h) Gong, C.; Ji, Q.; Glass, T. E.; Gibson, H. W. Macromolecules, submitted for publication.
43. (i) Gibson, H. W.; Nagvekar, D.; Powell, J.; Bryant, W. Tetrahedron, submitted for publication.
44. (j) Gong, C.; Gibson, H. W. Unpublished results.
45. Delaviz, Y.; Gibson, H. W. Macromolecules, 1992, 25, 4859. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Sze, J.; Engen, P.; Prasad, A.; Marand, H.; Loveday, D.; Wilkes, G. Polym. Prepr. 1991, 32 (3), 593. Delaviz, Y.; Gibson, H. W. Polym. Mater. Sci. Eng. 1992, 66, 301. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Prasad, A.; Marand, H.; Marand, E.; Keith, D. Polym. Prepr. 1992, 33 (1), 235.
46. Delaviz, Y.; Gibson, H. W. Macromolecules, 1992, 25, 4859. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Sze, J.; Engen, P.; Prasad, A.; Marand, H.; Loveday, D.; Wilkes, G. Polym. Prepr. 1991, 32 (3), 593. Delaviz, Y.; Gibson, H. W. Polym. Mater. Sci. Eng. 1992, 66, 301. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Prasad, A.; Marand, H.; Marand, E.; Keith, D. Polym. Prepr. 1992, 33 (1), 235.
47. Delaviz, Y.; Gibson, H. W. Macromolecules, 1992, 25, 4859. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Sze, J.; Engen, P.; Prasad, A.; Marand, H.; Loveday, D.; Wilkes, G. Polym. Prepr. 1991, 32 (3), 593. Delaviz, Y.; Gibson, H. W. Polym. Mater. Sci. Eng. 1992, 66, 301. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Prasad, A.; Marand, H.; Marand, E.; Keith, D. Polym. Prepr. 1992, 33 (1), 235.
48. Delaviz, Y.; Gibson, H. W. Macromolecules, 1992, 25, 4859. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Sze, J.; Engen, P.; Prasad, A.; Marand, H.; Loveday, D.; Wilkes, G. Polym. Prepr. 1991, 32 (3), 593. Delaviz, Y.; Gibson, H. W. Polym. Mater. Sci. Eng. 1992, 66, 301. Gibson, H. W.; Wu, C.; Shen, Y. X.; Bheda, M.; Prasad, A.; Marand, H.; Marand, E.; Keith, D. Polym. Prepr. 1992, 33 (1), 235.
49. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
50. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
51. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
52. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
53. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
54. Marand, E.; Hu, Q.; Gibson, H. W.; Veytsman, B. Macromolecules 1996, 29, 2555. Loveday, D.; Wilkes, G. L.; Bheda, M. C.; Shen, Y. X.; Gibson, H. W. J. Macromol. Sci., Chem. 1995, A32, 1. Shen, Y. X.; Xie, D.; Gibson, H. W. J. Am. Chem. Soc. 1994, 116, 537. Shen, Y. X.; Gibson, H. W. Macromolecules 1992, 25, 2058. Gong, C.; Gibson, H. W. J. Am. Chem. Soc., submitted for publication. Gong, C.; Gibson, H. W. Angew. Chem., submitted for publication.
55. Lee, S.-H.; Engen, P. T.; Gibson, H. W. Macromolecules 1996, submitted. Gibson, H. W.; Bheda, M. C. Polymer 1995, 36, 2615. Gibson, H. W.; Engen, P. T.; Lee, S.-H.; Liu, S.; Marand, H.; Bheda, M. C. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 1993, 34 (1), 64.
56. Lee, S.-H.; Engen, P. T.; Gibson, H. W. Macromolecules 1996, submitted. Gibson, H. W.; Bheda, M. C. Polymer 1995, 36, 2615. Gibson, H. W.; Engen, P. T.; Lee, S.-H.; Liu, S.; Marand, H.; Bheda, M. C. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 1993, 34 (1), 64.
57. Lee, S.-H.; Engen, P. T.; Gibson, H. W. Macromolecules 1996, submitted. Gibson, H. W.; Bheda, M. C. Polymer 1995, 36, 2615. Gibson, H. W.; Engen, P. T.; Lee, S.-H.; Liu, S.; Marand, H.; Bheda, M. C. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 1993, 34 (1), 64.
58. 3,4 as a macrocycle threaded by a linear molecule without bulky end blocking groups. Thus, technically, all of the polyrotaxanes described here with the exception of 19 are polypseudorotaxanes.
59. Odian, G. Principles of Polymerization, 2nd ed.; John Wiley & Sons: New York, 1970; pp 423-445.
60. Since the completion of this work we, in collaboration with Prof. Colin Booth and his colleagues at the University of Manchester, U.K., have discovered by GPC, HPLC, and mass spectroscopy that the crown ethers with target ring sizes of 36, 42, 48, and 60 atoms are not pure, single-sized macrocycles. Rather, they are mixtures of cyclics and perhaps catenanes. By NMR spectroscopy there are no detectable amounts of the linear tosylate or glycol starting materials, nor vinyl ether moieties in the samples; this was confirmed by elemental analyses. In a separate publication we will describe the results of these studies. The 30-crown-10 is a pure compound, however. In the paper we will use quotation marks around the name to designate the size of the crown ether that was the target of the synthesis, but generally speaking, the average size of the macrocycle is larger.
61. Clarson, S. J.; Mark, J. E.; Semlyen, J. A. Polym. Commun. 1987, 27, 244.
62. Atkins, P. W. Physical Chemistry, 3rd Ed., W. H. Freeman and Co.: New York, 1986, p. 587.
63. Joyce, S. J.; Hubbard, R. E.; Semlyen, J. A. Eur. Polym. J. 1993, 29, 305.
64. (a) Franke, J.; Vögtle, F. Top. Curr. Chem. 1986, 132, 135.
65. (b) Diederich, F. Angew. Chem., Int. Ed. Engl. 1988, 27, 363.
66. (c) Inoue, Y.; Gokel, G. W. Cation Binding by Macrocycles, Complexation of Cationic Species by Crown Ethers; Marcel Dekker: New York, 1990.
67. (d) Izatt, R. M.; Pawlak, K.; Bradahaw, J. S. Chem. Rev. 1991, 91, 1721.
68. (e) Izatt, R. M.; Bradshaw, J. S.; Pawlak, K.; Bruening, R. L.; Tarbet, B. J. Chem. Rev. 1992, 92, 1261.
69. Korshak, V. V.; Vingradova, S. V.; Vlasova, E. S. Dokl. Akad. Nauk S.S.S.R. 1964, 94, 61.
70. Howard, G. J.; Knutton, S. Polymer 1968, 9, 527.
71. Woo, E. M.; Barlow, J. W.; Paul, D. R. Polymer 1985, 26 , 763.
72. Fernandes, A. C.; Barlow, J. W.; Paul, D. R. Polymer 1986, 27, 1799.
73. Keith, H. D.; Padden, F. J., Jr.; Russell, Macromolecules 1989, 22, 666. Elias, H.-G. Macromolecules, Structure and Properties; Plenum Press: New York, 1984, pp 397-400.
74. Keith, H. D.; Padden, F. J., Jr.; Russell, Macromolecules 1989, 22, 666. Elias, H.-G. Macromolecules, Structure and Properties; Plenum Press: New York, 1984, pp 397-400.
75. Marvel, C. S.; Johnson, J. H. J. Am. Chem. Soc. 1950, 72, 1674.
76. Liu, S.; Lee, S.-H.; Gibson, H. W. J. Org. Chem. 1995, 60, 3155.
77. The internal diameter of a fully opened 30-crown-10 was calculated by the equation D = (10/x)[(1.52) sin(108.95/2) + (2)(1.42) sin(107.00/2)] - 4.5, where 1.52 Å is the length of the carbon-carbon bond, 1.42 Å the length of the carbon-oxgen bond, 108.95° is the C-C-C bond angle, and 107.00° is the C-O-C bond angle. 4.5 Å is the cross sectional diameter of a poly(ethylene oxide) chain.
78. Douglas, B.; McDaniel, D.; Alexander, J. J. Concepts and Models of Inorganic Chemistry; John Wiley & Sons: New York, 1983; p 219.
79. Bheda, M.; Merola, J.; Woodward, W.; Vasudevan, V.; Gibson, H. W. J. Org. Chem. 1994, 59, 1694.
80. Gibson, H. W.; Bheda, M. C.; Engen, P.; Shen, Y. X.; Sze, J.; Zhang, H.; Gibson, M. D.; Delaviz, Y.; Lee, S.-H.; Liu, S.; Wang, L.; Rancourt, J.; Taylor, L. T. J. Org. Chem. 1994, 59, 2186.