一代树状碳硅烷液晶的光化学研究－－端基含12个4－丁氧基氮苯介晶基元

研究了新的含12个丁氧基偶氮苯介晶基元的五代树状碳硅烷液晶D1及偶氮苯介 晶基元化合物M5在氯仿、四氢呋喃、N，N－二甲基甲酰胺、乙醇和苯等溶剂中的量 子产率、反－顺光异构化、光回复异构、反／顺异构组分比、热回复异构及活化能 。D1和M5的光致变色速率常数为10~(-1)s~(-1)，而含同一偶氮基元的光致变色液 晶聚硅氧烷的光致变色速率常数为10~(-8)s~(-1)，因此，液晶树状物D1的光响应 速度比后者快10~7倍。

Study on Photochemistry of Carbosilane Liquid Crystalline Dendrimer of the First Generation -Containing Twelve 4-Butoxyazobenzene Mesogenic Groups in Its Periphery

The quantum yield, trans/cis photoisomerization, photo back-isomerization, trans/cis isomer ratio, thermal back-isomerization, activation energy of a new carbosilane liquid crystalline (LC) dendrimer of the first generation (D1) containing twelve 4-butoxyazobenzene mesogen in its periphery and azobenzene unit compound M5 in CHCl3, THF, DMF, EtOH and C6H6 are described. Photochromic rate constant of D1 and M5 are 10-1 s-1, but that of photochromic LC polysiloxanes containing the same azobenzene moieties is 10-8 s-1, thus the photoresponsive rate of LC dendrimer Dl is 107 times larger than that of the latter.