以車輪烷為基礎的分子開關之合成與研究

Abstract

我們成功地開發出一種可受pH值控制的分子開關(molecular switch)系統－[2]車輪烷與具TTF側臂分子夾錯合體。在不同pH值的條件下，藉由TTF與[2]車輪烷之間電荷轉移吸收改變所造成的顏色變化，使一般人可憑肉眼觀察顏色來判別其操作狀態。此分子開關系統在溶液中呈現深綠色，加入鹼(三乙基胺)後顏色迅速轉為黃色，稍後加入酸(三氟醋酸)又會再變回深綠色。

Herein, we used a complex made up of a pH-controllable molecular switch and a molecular clip with TTF side walls. The molecular switch consisted of a [2]rotaxane with a dumbbell component that had dibenzylammonium and 4,4'-bipyridinium 'stations' that were able to 'lock up' the ring-shaped component known as a macrocycle. Under basic conditions the macrocyle moved to the bipyridinium station, displacing the molecular clip and dissociating the switch/clip complex. The sequential addition of a base and an acid induces migration of the macrocyclic unit of this [2]rotaxane from the NH2+ station to the bipyridinium unit and back again. In turn this controls the availability of the bipyridinium station for complexation with the molecular clip and results in significant colour changes that are clearly visible to the naked eye.