氫鍵是一個非常重要的非共價鍵之作用力，因為其具有方向性和適當的強度，所以在自然界、超分子化學、自我組裝、主客分子和分子辨識中被廣泛的使用。如果我們可以控制多重氫鍵的鍵結能力，就可以間接改變超分子的型態。 我們設計一個三元件系統—包含一反應中心、共軛架橋和可以形成多重氫鍵的鍵結中心，藉由在反應中心進行質子化反應之方式，將訊號經由共軛架橋傳到鍵結中心（主分子），間接改變與客分子間的氫鍵鍵結能力。我們成功地藉由質子化方式控制多重氫鍵的鍵結強度、鍵結方式和鍵結選擇性。在複合物為AAA･･･DDD（A表氫鍵之質子受基，D表質子供給基；AAA表示分子內有三個質子受基、DDD表示分子內有三個質子供給基，餘類推）之系統中，我們藉由質子化方式使氫鍵鍵結強度強烈減少；在複合物為AAA･･･DDD和ADA･･･DAD之系統中，我們藉由質子化方式使鍵結方式改變；在複合物為ADAD･･･DADA之系統中，我們藉由質子化方式讓複合物有專一的選擇性。透過以上系統之研究，我們也歸納出一些分子設計之原則，以利多重氫鍵系統之控制。 Hydrogen bonding is one of the most important non-covalent interactions found in nature, supramolecular chemistry, self-assembly, host-guest complexes and molecular recognition, and is widely used in molecular design because hydrogen bonds are directional and moderately strong. If we can control the binding affinity in multiply hydrogen-bonded complexes, we can change the morphology of supramolecules. We have studied a three-component system consisting of a reaction center, a conjugated bridge and a binding center with multiple hydrogen-bonding sites. Protonation of the reaction center induces intramolecular charge transfer to the binding center via the conjugated bridge, altering the ability of the three-component system to bind with a partner. We have succeeded in controlling the binding strength, orientation and selectivity in various systems by protonation. The binding energy decreases when the AAA system is protonated (A stands for a proton acceptor in a hydrogen-bonded pair and D stands for a proton donor. An AAA system means the binding center has three acceptor sites). The binding orientation changes when the ADA･･･DAD and AAA･･･DDD systems are protonated. The binding selectivity can be optimized by protonation in the DADA system. We also provides some ideas for chemists to design molecules whose hydrogen-bonding sites can be controlled.
