Polysilanes helix amplification

On the other hand, noticeable helix amplification— sergeants and soldiers—was reported in rod-like polysilane copolymers bearing (S)-2-methyl-butyl and 2-methylpropyl groups (10) and (,R)-2-methylbutyl and 2-methyl-propyl groups (11) in isooctane (Scheme 3). Since the UV-CD spectral features of the polysilane copolymers are almost identical with those of 4-6 and the kmax varies sensitively with changes in the molar fraction of chiral substituents and temperature [45,46], the copolymer systems are suitable for testing the sergeants and soldiers phenomenon by their CD-UV... 

This chapter focused on several types of chiroptical amplification in optically active chromophoric polysilane helix systems, which exist in isotropic... 

Keywords Amplification Helix Optically active Polymer Polysilane... 

This section will demonstrate the first sergeants and soldiers-type helix command surface experiment, in which thermo-driven chiroptical transfer and amplification in optically inactive polysilane film from grafted (or spin-coated) optically active helical polysilane onto quartz substrate [92]. Although helix and optical activity amplification phenomena based on the sergeants and soldiers principle was mainly investigated in polymer stereochemistry, the orientation and physical properties of a thick layer deposited onto a solid surface and controlled by a monolayer command film based on command surface principles was established in photochemical material and surface science [93,94]. Both sergeants and soldiers and command surface experiments appear to have been developed independently. 

A noncovalent chiral amplification based on the sergeants and soldiers effect between chiral and achiral polymers in the film state has been developed by Fujiki et al., which results in the formation of helix bundles (Fig. 35) [ 159]. An optically active, helical polysilane 84 with an almost single-handed screw-sense was chemically bonded or spin-coated on the surface of a quartz plate, followed by further spin-coating of an optically inactive polysilane 85 to give... 

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