Rigid moiety

The impact of the choice of the substrate to be either gold or silver upon a different molecular orientation of rigid moieties within a SAM was recently demonstrated by Somashekarappa and Sampath [107]. They studied the impact of the different orientation of 2,9,6,23-tetraamino cobalt phtalocyanine bound as a SAM onto silver or gold upon their behavior in electrocatalysis. It was found that the different tilt of the phtalocyanine macrocyles and the consequently different accessibility of the metal surfaces and catalytic center results in a different reaction pathway and oxidation products. 

V C chains with rigid moieties and virtual bonds copolymers e. g. polyesters, polyamides, and polybutadienes... 

The enamine group should be planar when the surrounding of the enamine fragment allows a relatively free conformational change and it cannot be planar when the N atom and/or the C=C group are part of a rigid moiety. 

Figure 5.39 Spacer concept for a more efficient grafting of functional moieties onto the surface of a diamond particle. Higher surface coatings can be achieved when using a space (b) than without this rigid moiety (a).

The incorporation of rigid moieties into the main chain increases the melting temperature. However, a melting temperature causes a poor melt processability. The melting temperature can he reduced by structural modification, such as the introduction of ... 

The polysiloxanes are not noted for high grass transition temperatures. Actually it is the opposite, and many have very low Tg-s. If rigid moieties are... 

As mentioned above, the formation and stabilization of 2D-columnar structures by the macromolecules of POCS including PMCS-4 are caused by the tendency to nanoscale phase separation on inter- and intramolecular levels. The presence of the two rigid moieties in their macromolecules ensures a stability of the intra-molecular correlations of the cyclic fragments creating the molecular conformational state where the siloxane chain are enveloped by the organic side groups (Figure 4). 

Many of the polymers reported in this section are formed from reaction with rigid and semirigid Lewis acids. Thus the resulting polymers can be rigid to semirigid because the metallocene moiety acts as a rigid moiety within polymer chains. Thus these polymers can be liquid crystals and should behave as such. 

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