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Volumn 2, Issue 6, 2007, Pages 755-763

Unexpected thermally stable, cholesteric liquid-crystalline helical polyisocyanides with memory of macromolecular helicity

Author keywords

Chirality; Helical structures; Helicity memory; Liquid crystals; Polyisocyanides

Indexed keywords

AMIDE; AMINE; CYANIDE; POLYMER;

EID: 34250670272     PISSN: 18614728     EISSN: 1861471X     Source Type: Journal    
DOI: 10.1002/asia.200700051     Document Type: Review
Times cited : (40)

References (81)
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    • We also measured time-dependent CD spectral changes of some helical polyisocyanides in water and DMF at different temperatures and confirmed that the intensities of the Cotton effect at the polymer backbones (the first Cotton effect at 280-450 nm) as well as at the pendant aromatic regions (200-280 nm) decreased linearly with time at high temperatures. Therefore, the changes in the first Cotton effect that correspond to the main-chain (C=N) chromophore region, which reflects the helical-sense excess of the polyisocyanides, were followed Figure 3
    • We also measured time-dependent CD spectral changes of some helical polyisocyanides in water and DMF at different temperatures and confirmed that the intensities of the Cotton effect at the polymer backbones (the first Cotton effect at 280-450 nm) as well as at the pendant aromatic regions (200-280 nm) decreased linearly with time at high temperatures. Therefore, the changes in the first Cotton effect that correspond to the main-chain (C=N) chromophore region, which reflects the helical-sense excess of the polyisocyanides, were followed (Figure 3).
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    • The difference in the thermal stability of A-poly-1 polymers in DMF and water (e.g., Table 1, runs 3 and 4) may not only be due to the difference in hydrogen bonding in these solvents, but also to the synergic effect (hydrogen bonding and hydrophobic effects, including steric effect) of the pendant aromatic amide residues as described in the text. Furthermore, solvent effects involved in solvation of the amide residues should be taken into consideration on the basis of the difference in thermal stability in DMF and water.
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* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.