Rigid fragments

The incorporation of rigid fragments of low-molecular compounds within a macromolecule may thus lead to manifestation of LC properties by polymers even if the respective low-molecular compounds do not form a LC phase by themselves. The possibility to induce mesomorphism in organic compounds is of significant interest as extending the line of LC compounds and exploiting non-mesogenic low-molecular compounds as a raw material to make polymeric LC compounds. 

Further structural dissection has shown that the essential requirement for an apomorpine-1ike action in the periphery is a relatively rigid fragment where the amino group is tertiary and is held approximately in the plane of the aromatic ring. Within the 2-amino-l,2,3,4-tetrahydronaphthalenes, it is the 5-hydroxy which is essential for emetic and DA2 activity. When the reduced ring is contracted to yield a 2-aminoindan such as 111, substantial activity is still observed (5 ). Thus, the view of... 

Figure 17.1 Schematic picture of the pipeline for automatic docking developed by our group. The automatic decomposition of the molecules into rigid fragments is carried out by the program DAIM [71],...

A method which allows testing NMR data such as dipolar couplings, anisotropic chemical shieldings and quadrupolar interactions has been proposed by Zidek et aV The authors have used the fact that only a limited number of frequencies corresponding to these parameters can be measured indepedently in a rigid fragment of the macromolecule. Additional values can be predicted as linear combinations of a set of independent frequencies. Comparison of the experimental data with the predicted values of the parameters studied provides a test of the reliability of the former. 

Figure 16.4 Energy decomposition analysis (EDA) at TPSS-D3/def2-TZVP level for donor-acceptor bond formation in MejN-BMej (rigid fragment approximation). For a definition and explanation of the energy terms, see text.

In the SVRT model for a polyatom-polyatom reaction, the target molecule T is composed of two rigid fragments B and C while the reactant molecule R is treated as a rigid rotor as depicted in Figure 14.1. The reactive collision between molecules T and R can be expressed as ... 

Fig. 1.14. Possible types of nematic phases for comb-shaped copolymers [cf. Fig. 1.12b) [81] a) only rigid fragments are ordered b) ordering of rigid fragments results in significant anisotropy of the main chain and spacers c) ordering of rigid fragments results in the fact that the main chain is primarily located in a plane perpendicular to the axis of ordering d) the rigid main chain is ordered.

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