Reaction location, topochemical

The topochemical aspect of the reaction varies depending on the type of mesomorphic state. Topochemical polymerization can be expected in smectic mesophases (l2) where the functional groups of the layer formed by the parallel chains are located in one plane (1 4- 1 ) Homogeneous topochemical Reactions may proceed in a layer with either uni- or bimolecular structure. 

The second structure type is constructed from cwoid dienes related by a two-fold screw axis parallel to the long molecular axis, and again with the adjacent double bonds suitably located for topochemical reaction (Scheme 7). 

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