新穎雙鋁金屬錯合物之合成及應用於分子辨識與矽氫加成催化反應之研究

Synthesis of Novel Dinuclear Aluminum Complexes and Their Applications on Molecular Recognition of Neutral N-Donor Ligands and Catalytic Hydrosilation Reactions.

崔子慶(Tz-Ching Tsui)

指導教授 ： 劉學儒

國立交通大學/理學院/應用化學系所/碩士(2019年)

摘要

在我們的研究中使用大立障的配位基pPhN2與pPhCp2並以正丁基鋰去質子化後，分別與三氯化鋁反應得到雙鋁路易士酸1-(Et2O)2及2-(Et2O)2。在第一部分的研究中，1-(Et2O)2及2-(Et2O)2皆能藉由調整自身結構的方式來鉗合雙牙路易士鹼如吡嗪(Pyrazine)，得到以κ2形式存在的超分子1-κ2-pyz與2-κ2-pyz；為了瞭解兩路易士酸的鉗合能力，我們參考Gutmann-Beckett method對路易士酸性程度的測定並搭配2-κ2-pyz與1-(Et2O)2競爭反應的設計，歸納出1-(Et2O)2擁有更好的鉗合能力；根據1-κ2-pyz與2-κ2-pyz的單晶結構，我們推測較強的π-π stacking作用力增強了1-(Et2O)2對於吡嗪分子的鉗合能力。
1-(Et2O)2也能與喹喔啉(quinoxaline)反應得到超分子1-κ2-qul，而對於較短N…N距離的路易士鹼如酞嗪(Phthalazine)，或是立障較大的結構如吩嗪(Phenazine)，1-(Et2O)2則沒有辦法形成分子內超分子結構；對於其他路易士鹼如4-二甲氨基吡啶(4-dimethylaminopyridine)或是三亞乙基二胺(1,4-Diazabicyclo[2.2.2]octane)，只能形成兩當量的加成物1-(DMAP)2與1-(DABCO)2。此外，1-(Et2O)2也能以雙分子的形式，共同鉗合較長N…N距離的路易士鹼如4,4′-聯吡啶(4,4′-bipyridine)，得到分子間超分子[1-κ2-(4,4′-bipy)]2。
在第二部分的研究中，我們以催化量的雙鋁路易士酸1-(Et2O)2催化苯甲醛衍生物進行矽氫加成反應，其中拉電子基的修飾如對硝基苯甲醛(4-Nitrobenzaldehyde)擁有較高的轉換頻率(Turnover frequency, TOF)與產率。而1-(Et2O)2與二苯基甲酮(benzophenone)的加成物1-(Ph2CO)2也說明了羰基的活化可能是催化反應進行的重要關鍵。

關鍵字

雙鋁路易士酸 ； 超分子 ； 吡嗪 ； 路易士鹼 ； 平衡常數 ； 矽氫加成反應

並列摘要

In this study, we designed two novel bidentate Lewis acids(BLA) 1-(Et2O)2 and 2-(Et2O)2 which can be obtained by reactions of deprotonated ligands pPhN′2Li2 and pPhCp′2Li2 with AlCl3. In the first parts of our research, 1-(Et2O)2 and 2-(Et2O)2 possess the ability to bind with bidentate neutral N-donors such as pyrazine and form 1-κ2-pyz and 2-κ2-pyz supermolecules. From Lewis acidity of 1-(Et2O)2 and 2-(Et2O)2 probed by Gutmann-Beckett method, together with results from the competitive reaction of 2-κ2-pyz and 1-(Et2O)2, we concluded that 1-(Et2O)2 is a better BLA to capture pyrazine, and intramolecular π-π stacking might be an important factor leading to the stronger coordination of pyrazine to 1-(Et2O)2.
Similarly, 1-(Et2O)2 was found to bind quinoxaline to form 1-κ2-qul. Besides, the reaction of 1-(Et2O)2 with N-donor ligands with the longer N…N distance such as 4,4′-bipyridine resulted in a intermolecular, dimeric supermolecule [1-κ2-(4,4′-bipy)]2.
1-(Et2O)2 can not form any κ2 type supermolecules with bulkier or shorter N-donor ligands such as phenazine and phthalazine, respectively. On the other hand, we obtained 1:2 adducts 1-(DMAP)2 and 1-(DABCO)2 from the reactions of 1-(Et2O)2 with excess of 4-dimethylaminopyridine (DMAP) and 1,4-diazabicyclo[2.2.2]octane (DABCO).
In the second parts of our research, we utilized 1-(Et2O)2 as catalyst for hydrosilation of benzaldehyde derivatives. Presence of electron withdrawing groups such as nitro group at the para - position was found to increase the yield and turnover frequency. We also demonstrated that the activation of carbonyl group is a key point to push the reaction.

並列關鍵字

bidentate Lewis acids ； supermolecule ； pyrazine ； Lewis bases ； equilibrium constant ； hydrosilation

參考文獻

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