Tetraphenylthieno thiophene, structures

Mass spectrometry was also used to analyze mixtures of deuterated and nondeuterated thiophenes and thienothiophenes 1 and 2, as well as to confirm the structure of l,3,5,6-tetraphenylthieno[3,4-c]thiophene (149) (see also Bugge ). 

Cava and Pollack s elegant synthesis of benzo[c]thiophene52 has been extended to the synthesis of, for example, naphtho[l,2-c]thio-phene (47),52 methyl benzo[c]thiophene-5-carboxylate,54 and 1,3-dimethyl- (48)55 and l,3,4,6-tetraphenylthieno[3,4-c]thiophene (49).56 The last compound is of particular interest because it is a remarkably stable (cf. compound 48 which only exists transiently) nonclassical thiophene containing ten n electrons for which the only uncharged resonance structure (49) contains a tetravalent sulfur atom. When the sulfoxide (50) is pyrolyzed over aluminum oxide, it gives the parent cyclic sulfide and 51 by disproportionation.57 However, when 50 is heated in acetic anhydride in the presence of iV-phenylmaleimide,... 

The crystal structure of tetraphenylthieno[3,4-c]thiophene (26) has been determined (see Chapter 3.18). 

The structures of l,3,4,6-tetraphenylthieno[3,4-Z)]thiophene (272) (83JA1705), 1,4-bis(rerr-butylthio)-3,6-diphenylthieno[3,4-c]thiophene, 4-(terr-butylthio)-3,6-diphe-nylthieno[3,4-c]thiophene-l(3//)-thione, 4-( rerr-butylthio)-3,6-diphenylthieno[3,4-... 

R. Gleiter, R. Bartetzko, G. Brahler and H. Bock, Electronic-structure of sulfur-compounds. 28. Electronic-structure of tetraphenylthieno[3,4-c]thiophene - photoelectron, electron-spin resonance and electronic absorption-spectra, J. Org. Chem., 43, 3893-3897 (1978). 

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