Phenyl 0 carbon central, chemical shift

In contrast to these experimental and computational results, lithiated 1-silafluorenide 50, which was prepared by the reductive cleavage of the central Si—Si bond of disilane 49 with lithium under ultrasonic activation, provides some evidence for the existence of localized metalated siloles (equation 55)111. Thus, upon metalation of 49 to form 50, a highfield shift of the 29Si nucleus (AS = —47.9 ppm) is observed. In addition, the chemical shifts of the phenyl carbons indicate that there is no accumulation of tt electron density, which would be expected for a delocalized lithium silafluorenide111. 

Figure 9. Chemical shift of the central phenyl C(l) carbon of the pentamer.

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