Polysilanes water-soluble

UV data for the non-ionic water-soluble polysilane 41 (see Section 3.11.4.2.1.(0) were recorded in 20 different solvents.149 Selected spectra are shown in Figure 17. 

FIGURE 25. Molecular structure of synthesized water-soluble polysilane (a) HSC, (b) PSC, and (c) HTSC. (Reprinted from Ref. 106.)... 

With the success of CgK in the syntheses of 41 and related co-polymers, the same methodology was applied to the synthesis of polysilanes bearing pendant crown ether substituents, viz. 42-44,150,151 which were synthesized in yields from 6% to 28%, with molecular weights of the order of 104. The polymers were found to be water soluble and thermochromic in accordance with the Schweizer thermochromism theory (see Section 3.11.5.2.4).152... 

Polysilanes with several oxygen atoms in the side chains have been studied by Cleij and coworkers.83 84 These polysilanes may become water soluble, as is the case for [MeSi(CH2)3(OCH2CH2)3OCFl3] . In THF solution at 20 °C this polymer absorbs at 305 nm, but in water the UV band is shifted to 281 nm. The water may cause tighter coiling of the polymer chains, perhaps due to micelle formation. Between 46 and 70 °C, the water solution undergoes phase separation. The UV band shifts to 320 nm, consistent with partial straightening of the polymer chain after phase transition. These polymers also display ionochromism. 

In addition to the polymers described above, the polysilanes having aromatic side groups222 225 and the copolymers of a chiral monomer and an achiral monomer224-228 have been shown to adopt a helical conformation. A water-soluble, helical polysilane having an ammonium moiety has also been prepared.229... 

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