Dichlorocarbene, electronic structure

The addition of dichlorocarbenes also allows for further conversions as the existing substituents can be replaced. Normally, PhHgCCbBr is used as carbene source in this reaction, but it succeeds with other carbenes or carbene sources as well. The addition of dichlorocarbene markedly changes the electronic structure of the functionahzed nanotube. Metallic SWNT, for instance, turn into semiconductors, which is due to altered electronic transitions close to the Fermi level. What is more, the intensity of interband transitions decreases for both the original metalHc and the semiconducting species because the extended n-network is severely disturbed by the functionalization and the concomitant introduction of sp -carbon atoms. However, a completely different picture of the carbene or nitrene addition is... 

Figure 7.6 The structure of dichlorocarbene. Electrostatic potential maps show how the positive region (blue) coincides with the empty p orbital in both dichlorocarbene and a carbocation (CH3+). The negative region (red) in the dichlorocarbene map coincides with the lone-pair electrons.

Triethylamine, (C2H6)3N, like aU amines, has a nitrogen atom with an unshared pair of electrons. Dichlorocarbene also has an unshared pair of electrons. Both can be represented as shown below. Draw the structures of compounds D, E, and F. 

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