以聯三吡啶雜配錯合反應理性建構超分子組裝結構

Abstract

多年來科學家致力於挑戰、模仿和自然界類似的精確分子自我辨識能力，已有許多成功的例子以及諾貝爾獎的肯定；但在使用有機金屬錯合物的自辨識系統也蓬勃發展的同時，以純粹聯三吡啶金屬錯合物為基底之分子自辨識系統仍未被挑戰成功。 本篇的研究主軸即以尋找聯三吡啶金屬錯合物自辨識組合為出發，我們設計並合成了許多飾以各種官能基團的聯三吡啶，在這些特化的配位基中找出一個可以完美地消除自配錯合物，僅產生雜配錯合物的配對組合。此配對組合使用了帶有2,6-雙甲氧基苯基取代在聯三吡啶6,6"-位置的化合物來誘導雜配錯合物的生成，而從此配對組合來延伸接下來的研究。 我們將有此取代基的聯三吡啶修飾在180o、120o與60o的角度上，合成三種雙聯三吡啶的配位基，並用它們進行超分子錯合物的組裝。我們成功的組裝出三角形、環中環、平行四邊形、六邊形、謝爾賓斯基三角形與其他多種立體籠狀超分子結構，並且這些超分子組裝體可以表現出結構轉換、自分類、金屬交換等性質，並且具有相對高的螢光量子產率。 在實驗的過程中，我們也發現有該取代基的聯三吡啶可以形成自配錯合物，並且此自配錯合物能夠在鈴木偶聯反應條件下依舊存在。因此，我們設計了經由錯合和兩次偶聯反應得到的有機金屬配位基，成功得到有機金屬單環與有機金屬聯烷化合物。而所有的配位基、有機金屬超分子配位基所組裝的超分子結構通過一維氫核磁共振光譜、二維相關氫譜（DOSY、COSY、ROESY）、電噴灑游離質譜、行波離子遷移二維質譜、基質輔助雷射脫附電離飛行時間質譜、原子力顯微鏡與穿透式電子顯微鏡等方式鑑定。

To achieve self-selective coordination and self-sorting behavior, we successfully installed 2,6-dimethoxyphenyl groups at 6,6′′-positions of 2,2′:6′,2′′-terpyridine and brought this building block to supramolecular structural design. The functionalized terpyridine could easily generate a heteroleptic complex with a non-functionalized terpyridine in the presence of CdII ions. The substituted ligand moiety was introduced to the bisterpyridine ligands with a 180°, 120° or 60° bend angle, and further used in constructing supramolecular structures. The functionalized linear bisterpyridine ligand could form edge-elongated triangle and the ditrigonal ring-in-ring structure which showed the selective elongation process. The 120°-bent bisterpyridine ligand could construct rhombus and rhomboid when mixing with 60o-bent non-functionalized bisterpyridines with identical or different lateral lengths, respectively. Interestingly, mixing 120°-bent bisterpyridine and both two kinds of 60o-bent non-functionalized ligands in 2:1:1 molar ratio in the presence of CdII ions would be able to observe the self-sorting phenomenon. The functionalized bisterpyridine ligand in 60o-bent could form a Sierpiński triangle and the transmetallation behavior was observed when treated the complex with ZnII ions. The complicated 3D cages and tetrapod structure were successfully constructed using flexable non-functionalized tristerpyridine ligand with the bent functionalized ligands and the planar functionalized tristerpyridine ligand. These supramolecular structures were found to have relatively high quantum yields. The structures were fully characterized by 1H NMR, DOSY, COSY, ROESY, ESI-MS, TWIM-MS, AFM, and TEM experiments. The kinetically inert homoleptic complex was synthesized, and it was stable enough for post-coordination reactions. The matallo-ligand with two free terpyridine moieties and three CdII homoleptic complex centers was successfully synthesized using Suzuki-Miyaura coupling reaction. Metallomacrocycle and metallo-[2]catenane could be constructed by the metallo-ligand, suggested the application of heteroleptic and homoleptic complexation we have developed in this work.