本篇為系統性的設計與合成數個系列含?并?喔?基團(indenoquinoxaline)模型分子，藉由延伸模型分子之π-電子共軛長度以增進其π-電子非定域化範圍，並改變模型分子連接之推/拉電子官能基集團、π- bridge結構及其分岐數以探討模型分子結構對雙光子吸收性質及其他光學性質之影響。透過線性光學的量測結果得知模型分子的最大吸收波長、最大發射波長及螢光量子產率 其非線性光學量測，透過飛秒時域雷射量測雙光子激發螢光與激發光源強度之關係證實此螢光經由雙光子吸收機制所產生、利用雙光子誘導螢光法計算得到雙光子吸收截面值。分析各模型分子之光學性質與分子結構間的關聯性，可歸納出以下結果： [1] 分子結構中導入indenoquinoxaline 拉電子性官能基結構，具有明顯的溶劑效應。 [2] 以氮原子作為分子核心直接與外圍取代基相連，形成多重推拉電子基交錯的情形，增加π-電子非定域化的範圍，可具有較佳的雙光子激發截面。其中compound 8 在量子產率(80.1%)與雙光子吸收截面(13200 GM)都具有很好的性質，未來在生物雙光子螢光顯微技術中值得探討。compound 9 擁有高雙光子吸收截面高達31700 GM，且具有優越的光學限幅現象。 [3] 引入兩層indenoquinoxaline單元，能有效的使最佳雙光子激發截面波長往短波長位移。 This research focues on the design, synthesis and characterization of several series of molecules containing indenoquinoxaline group. Their linear optical properties were studied by one-photon absorption, one-photon fluorescence, fluorescence quantum yield and life time. The experimental results from one-photon fluorescence has shown that model molecules with indenoquinoxaline units incorporated possess large Stokes shifts on their ?uorescence emission which is mainly due to intramolecular charge-transfer (ICT). The two-photon absorption (2PA) properties were measured by two-photon induced fluorescence techniques with a mode-locked Ti: sapphire pulsed laser in the range of 680 nm-1000 nm. The compound 9 exhibits 31700 GM on 730 nm. This result indicates that increasing the branch number and inserting indenoquinoxaline units into a D-π-A structure framework could be an effective approach to achieve a strong molecular 2PA and also, such structural motif could be a useful approach for the molecular design for quick-responsive optical-suppressing-related applications.
