周边含己氧基的三代光致变色液晶树枝状大分子的光化学

报道了新化合物含108个己氧基端基的三代(G3)碳硅烷光致变色液晶树状大分子在溶液中的反-顺光异构化反应速率常数k_p, 光回复异构化正/逆反应速率常数k_t和k_c, 热回复异构化反应速率常数k_H, 光回复异构化反应平衡常数k_t/k_c, 活化能E, 异构转化率A/A₀及组分比A'/A₀. G3的光致变色反应速率常数的数量级为10^－1 s^－1, 而侧链含偶氮基元的光致变色聚硅氧烷的光致变色反应速率常数的数量级为10^－8 s^－1, 因此G3的光响应速率比后者快10⁷倍.

Photochemistry of Photochromic Liquid Crystalline Dendrimer of the Third Generation Containing Hexyloxy Groups on Its Periphery

The activation energy E, trans/cis isomer absorbance ratio A/A0, trans/cis photo isomerization reaction rate constant kp, photo back-isomerization positive/counter reaction rate constant kt and kc, thermal back-isomerization rate constant kH at different temperatures, photo back-isomerization reaction equilibrium value kt/kc and trans/cis isomer absorbance ratio at thermal back-isomerization reaction A'/A0 of a new car- bosilane photochromic liquid crystalline (LC) dendrimer of the third generation (G3) containing 108 4-hexyloxyazobenzene moieties on its periphery in solvent were described. The photochromic rate constants of G3 is 10-1 s-1, but that of photochromic polysiloxane containing the azobenzene moieties in side-chain is 10-8 s-1, thus the photoresponsive rate of G3 is 107 times larger than that of the latter.