Benzene Heterobenzenes Substituted benzenes

The Jen-values have been measured for all the heterobenzenes. All values are extremely close to that of benzene. Indeed, the larger variation for the 4-substituted stiba- and bismabenzenes may be a substituent effect. Jq, values are a sensitive function of hybridization 59). Thus, the near identity of all the 1JCH values indicates a hybridization identical to that of benzene. 

Silabenzene 24 reveals a characteristic Si—H stretching vibration at 2217 cm as expected for hydrogen attached to a sp -hybridized silicon atom. Compound 24 shows a typical benzene-type UV spectrum with absorptions at X = 217, 272 and 320 nm, which fit into the series of the already known donor-substituted heterobenzenes . An additional structural proof was the partially reversible photochemical conversion of 24 into Dewar... 

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