74754-58-8Relevant academic research and scientific papers
Helical Disubstituted Polyacetylenes: Synthesis and Chiroptical Properties of Poly(phenylpropiolate)s
Lam, Jacky W.Y.,Dong, Yuping,Cheuk, Kevin K.L.,Tang, Ben Zhong
, p. 7927 - 7938 (2007/10/03)
Disubstituted polyacetylenes with helical chirality have been rarely prepared due to the involved synthetic difficulty, and we here report a facile polymerization system for the synthesis of such polymers. Two groups of chiral acetylenes, i.e., C6H5C≡CCO2R* {R* = [(1S)-endo]-(-)-borneyl (1), (1R,2S,5R)-(-)-menthyl (5), cholesteryl (6)} and C6H5C≡CCO2C 6H4CO2R* [R* = borneyl (2), menthyl (3), cholesteryl (4)], are prepared by esterifications of phenylpropiolic acids with borneol, menthol, and cholesterol. Polymerizations of 1-4 are effected by WCl6-Ph4Sn, giving poly(phenylpropiolate)s P1-P4 with high molecular weights in moderate yields. The structures and properties of the polymers are characterized and evaluated by IR, UV, NMR, CD, TGA, and SEM analyses. All the polymers are stable: neither decreases in their molecular weights nor changes in their spectra are detected after the polymers have been stored on shelf for ～3 years, and no weight losses are recorded when the polymers are heated to ～300 °C. Although the polymers do not possess regioregular Z or conformations, the polyacetylene backbones are induced to helically rotate by the chiral pendants, as verified by the strong Cotton effects in the backbone absorption region of the polymers (molar ellipticity up to 102 300 deg cm2 dmol-1). The polymers exhibit helical thermochromism, with their chain helicity being continuously and reversibly tunable by temperature change. The helical polymers are capable of self-assembling, as demonstrated by the formation of twisted ribbons upon diffusing a THF solution of P3 into hexane.
Thermal Properties of Pentaerythritol Derivatives with Chiral Moiety
Uedaira, Takahiro,Koide, Naoyuki
, p. 23 - 32 (2007/10/03)
Pentaerythritol derivatives containing four mesogenic groups with chiral moieties were synthesized. Cholesterol and 2-methyl-1-butanol were used as a chiral moiety. All compounds which derivative from pentaerythritol and mesogenic group showed a glass transition temperature above room temperature. Crystallization from melt of these compounds was strongly suppressed. The compound that the mesogenic group has one benzene ring linked by ester bonding between mesogenic and cholesteryl group exhibited the smectic A1 phase. While the compounds that the mesogenic group has two benzene rins linked by ester bonding with cholesteryl group exhibited the cholesteric phase. The compounds that the mesogenic group has three benzene rings linked by one ester bonding with 2-methylbutyl group also exhibited the smectic A2 phase and the cholesteric phase.
An Amphiphilic Trinuclear Cobalt Cluster-containing Molecular Unit: Synthesis, Characterization and Langmuir-Blodgett Films
Deschenaux, Robert,Masoni, Claudio,Stoeckli-Evans, Helen,Vaucher, Sebastien,Ketterer, Juergen,et al.
, p. 1051 - 1060 (2007/10/02)
An amphiphilic polynuclear transition-metal cluster has been prepared and its capability for forming layers at the air-water interface and Langmuir-Blodgett films on different substrates investigated.The compound was obtained by linking a Co3(CO)9 cluster
