我們合成以香豆素與??為主體在乙醇與正己烷溶劑下，總共進行三個反應步驟，形成能量予體(donor)與能量受體(acceptor)的1,2-雙芳乙烯非共平面之光致變色物，總產率36-39%，並且也從X-ray晶體確認結構的正確性。這些化合物以碳碳雙鍵為架橋，隨著紫外光(306 nm)照射皆會造成順反式雙鍵異構化(trans-cis isomerzation)，這個特殊的設計，使得雙芳乙烯兩邊的取代基接近，進而產生高效率的分子內能量轉移(intramolecular energy transfer)，造成大幅度的紅位移，化合物從黃色變為紅色，並可藉由避光或加熱再度回到原本的顏色。 Several non-coplanar quinoline-based donor-acceptor 1,2-disubstituted ethenes were chemically synthesized in three steps with an overall yield of 36-39% to investigate their photochromic properties. The key step involves the condensation of 4-chloro-7-dimethylamino-2-oxo-2H-chromene-3-carbaldehyde and 4-methyl-1-(trimethylsilyl)quinolinium chloride in the presence of triethylamine in ethanol and hexane. The molecular structures of the prepared compounds were unambiguously characterized by the X-ray crystallography. The yellow coumarin-containing compounds turned red (red shift) upon UV irradiation (306 nm) and underwent reverse reaction while being heated. The photochromism presumably involved a light-induced trans-cis isomerization of the central double bond, which brought the two substituents in close proximity for the donor acceptor electron transfer. In this particular design, an efficient energy transfer occurred for the cis isomer. Here we report on a system exhibiting a large change in the energy transfer associated with a geometric change of the photochromic unit incorporated in the bridge in a Donor-bridge-Acceptor structure.
