Novel dimers of 2,2′-(m-phenylene)bis(4,5-diphenyl-1-imidazolyl) diradical

Chemistry Letters

Volumn , Issue 9, 1998, Pages 891-892

  Okada, Keiji ^a   Imamura, Kunihiko ^b   Oda, Masaji ^b   Kozaki, Masatoshi ^a   Morimoto, Yoshiki ^a   Ishino, Kiyotaka ^b   Tashiro, Kohji ^b  

^a Osaka Prefecture University   (Japan)

^b OSAKA UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0032333889     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.1998.891     Document Type: Article

References (14)

1. B. Radziszewski, Ber., 10, 70 (1877); M. Trautz, Z. Physik. Chem., 53, 86 (1905); T. Hayashi and K. Maeda, Bull. Chem. Soc. Jpn., 35, 2057 (1962); K Maeda, H. Ojima, and T. Hayashi, Bull Chem. Soc. Jpn., 38, 76 (1965).
2. B. Radziszewski, Ber., 10, 70 (1877); M. Trautz, Z. Physik. Chem., 53, 86 (1905); T. Hayashi and K. Maeda, Bull. Chem. Soc. Jpn., 35, 2057 (1962); K Maeda, H. Ojima, and T. Hayashi, Bull Chem. Soc. Jpn., 38, 76 (1965).
3. B. Radziszewski, Ber., 10, 70 (1877); M. Trautz, Z. Physik. Chem., 53, 86 (1905); T. Hayashi and K. Maeda, Bull. Chem. Soc. Jpn., 35, 2057 (1962); K Maeda, H. Ojima, and T. Hayashi, Bull Chem. Soc. Jpn., 38, 76 (1965).
4. B. Radziszewski, Ber., 10, 70 (1877); M. Trautz, Z. Physik. Chem., 53, 86 (1905); T. Hayashi and K. Maeda, Bull. Chem. Soc. Jpn., 35, 2057 (1962); K Maeda, H. Ojima, and T. Hayashi, Bull Chem. Soc. Jpn., 38, 76 (1965).
5. K. Maeda and T. Hayashi, Bull. Chem. Soc. Jpn., 43, 429 (1962).
6. a) D. M. White and J. Sonnenberg, J. Am. Chem. Soc., 88, 3825 (1966).
7. b) H. Tanino, T Kondo, K. Okada, and T. Goto, Bull. Chem. Soc. Jpn., 45, 1474 (1972).
8. c) T. Goto, H. Tanino, and T. Kondo, Chem. Lett., 1980, 431.
9. B. Krieg and G. Maecke, Macromol. Chem., 108, 210 (1967).
10. 3) δ 112.7, 126.2, 127.1, 127.5, 127.7, 127.8, 128.0, 128.3, 128.6(8), 128.7(4), 129.3, 129.8, 130.6, 130.7, 130.8, 131.0, 131.2, 131.3, 131.5, 131.7, 132.0, 132.5, 133.3, 134.3, 134.5, 135.7, 138.0, 147.9, 164.7, 169.2
11. 3 carbon. (formula presented) Ar: 3,5-dimethylphenyl Tol: Tolyl
12. 2); R = 0.098, Rw = 0.175. Because of rather poor refinement factors, the argument on the bond distance and bond angles was avoided.
13. The piezochromic dimer 2 which is metastable amorphous solid would have a weak C-N bond that is cleaved by external mechanical force such as grinding. The development of blue color when grinded would be due to the generation of the imidazolyl radical in a solid state. For this reason, it is not clear whether the isomerization of 2 to 3 in solution proceeds via simple bond rotation without bond cleavage or via C-N bond cleavage mechanism, although the solution isomerization proceeds without color change at room temperature.
14. 2-proton in the anti isomer generally appears in higher field than that of the syn isomer as exemplified in the following compounds; see D. Krois and H. Lehner, Tetrahedron Lett., 38, 3319 (1982), and references cited therein.