立體組態鎖定具有非線性光學活性的發色團

Abstract

我們發展出一種合成方法來製備帶有極性用具有二次非線性光學活性的發色團，這種發色團有四個π-共軛雙鍵，其中的二個π-共軛雙鍵被置於一雙環中，相對於沒有取代基直鏈式的四個共軛雙鍵的類似化合物，此種立體組態鎖定的方法可增強發色團的熱穩定性，我們比較這些化合物的紫外線及可見光光譜得知剛性的環形結構並沒有降低π-共軛雙鍵的平面性與其π電子的非軌域效能。 除此之外，我們也利用合成的方法將有四個π-共軛雙鍵的發色團其所有的π-共軛雙鍵置於三個剛性環狀中使其立體組態完全被鎖定，這種發色團具有更高的熱穩定性。

We have developed a synthetic strategy for prepareation dipolar NLO chromophores with an interposed conjugated tetraene segment which contains all but four of the methine groups iscorporated into a double annulated ring. The configuration-locking approch furnishes NLO chromophores possessing enhanced thermal stability compared with their simple tetraaene analogues. The data from UV-vis spectroscopy reveal that the rigidity of the annulated rings do not diminish the planarity and the electron delocaliation efficiency of the polenic chain. In addition, we have synthesized a NLO chromophone with all the methine groups in the tetraene segment incorporated into a rigidified triple annulated ring. This kind of approch yields the NLO chromophore with even better thermal stability.