Molecular spiro linkage

A completely different access to molecules with a scissor-like shape is opened up via spiro-linkage. Typical examples following this building principle are the spiro-bifluorenes 22 3) and 23 43 which differ also in the functional groups. In case of the spirocompounds, the flexible hinge is not applicable-and the edges of the molecular scissors are fixed at an angle of 90°. 

Figure 3.13. Molecular glasses based on a spiro linkage.

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