2-Phenylthiophene, theoretical calculations

The results of theoretical calculations on 2-phenylthiophene fit the experimental results (Fig. 8) [99H(50) 1115]. In fact, in this case, the formation of the triplet state of 2-phenylthiophene cannot allow the formation of the biradical intermediate allowing the formation of the Dewar thiophene. 

Substituted Thiophens. Aryl-substituted thiophens cannot be planar, and several theoretical studies have been made to predict preferred conformations. EHT computations for 2- and 3-phenylthiophen (40) predict an angle of distortion of 37° between the two planes of the cyclic ir-systems the electron distribution in these conformations was calculated by the CNDO/2-approach and comparison was made between the theoretical and experimental dipole moments. The calculations were later extended to (41) and its hetero-analogues. Bond-length calculations predict a very long bond between the heterocycles, which largely preserves the geometries of individual furan and thiophen ring systems. 

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See also in sourсe #XX -- [ , ]

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