非鍵結作用力的理論研究： (1)質子化與氧化三元件系統遠端調控氫鍵的比較 (2)π- π與CH- π作用力的取代基效應;Theoretical Study on Non-bonded Interactions : (1)Differences between Protonated & Oxidized Systems (2)Substituent Effect in π- π & CH- π Interactions

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/6419

Title:	非鍵結作用力的理論研究： (1)質子化與氧化三元件系統遠端調控氫鍵的比較 (2)π- π與CH- π作用力的取代基效應;Theoretical Study on Non-bonded Interactions : (1)Differences between Protonated & Oxidized Systems (2)Substituent Effect in π- π & CH- π Interactions
Authors:	黃君豪;Chun-Hao Huang
Contributors:	化學研究所
Keywords:	遠端調控;取代基效應;氫鍵;remote control;hydrogen bond;substituent effect
Date:	2009-07-07
Issue Date:	2009-09-22 10:19:13 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本實驗室設計了一個由鍵結中心、π-共軛架橋與反應中心組成的三元件系統，藉由反應中心發生質子化或氧化過程，遠端調控鍵結中心的氫鍵鍵結能力。反應前後氫鍵強度的差異我們稱為敏感度，而敏感度受到架橋長度的影響則稱為訊號維持能力。我們嘗試在共軛架橋上加入CN取代基，探討取代基在不同位置對於三元件系統遠端調控氫鍵能力與訊號維持能力的影響。我們發現CN取代基接在靠近反應中心位置的架橋形式(RRCN)可以使得質子化三元件系統具有最好的敏感度與訊號維持能力，然而在氧化三元件系統中，含CN取代基架橋的敏感度卻比不含取代基的架橋更差，不過訊號維持能力仍然是RRCN最優秀。在以thiophene為構築單元的架橋部分，我們發現不論是質子化或是氧化三元件系統，將所有thiophene(Th)分子氧化成thiophene S,S-dioxide (ThD)都可以提高敏感度，假使我們只希望氧化某一個thiophene，則應該選擇較靠近反應中心的thiophene分子進行氧化，可以得到較高的敏感度。但在訊號維持能力上，(ThDTh)n形式的架橋比(ThDTh)n更優秀。在本論文的第二部分中，我們以M05-2X與M06-2X計算方法研究π-π與CH-π作用力的取代基效應。結果發現這兩種計算方法雖然在預估π-π與CH-π作用力強度上並不如CCSD(T)方法，但是對於預估不同取代基之間的相對作用力差異卻能夠近似於CCSD(T)方法。在取代基的加成效應上，M05-2X與M06-2X的預測結果與MP2類似，也就是取代基個數對於sandwich形式的作用力強度的影響具有良好的線性關係，但是對於T-shaped形式作用力強度的影響則有例外，這是因為當取代基接在不同位置時，取代基本身與另一個benzene之間的作用力有相當程度的差異所致。 Three-component systems constructed with a hydrogen-bond binding center, a π-conjugated bridge and a reaction center is used to modulate the strengths of hydrogen bonding. Remote control of hydrogen bond strengths can be achieved by protonation or oxidation of the reaction center. We explore how position/pattern of CN substitution on the bridge affects the remote control ability. Meanwhile, the bridge length effect on remote control ability is also examined. We find that for the protonated three-component systems, some cyanated bridges outperform the non-substituted bridge. However in the oxidized systems, non-substituted bridge is better than all the CN-substituted bridges. For thiophene-based bridges, remote control ability can be enhanced by changing all thiophene units into thiophene S,S-dioxide units, no matter in protonated or oxidized three-component systems. In the second part of the thesis, we apply M05-2X and M06-2X methods to study the substitution effect on π-π and CH-π interactions in benzene dimers. These two methods do not predict absolute interaction energies well, but they can predict relative interaction energies almost the same as CCSD(T) method. We find that parallel to MP2 results, there is a good linear relation between the number of substituents and the sandwich-form π-π interaction energies. However, this relation does not always hold in T-shaped CH-π interaction energies.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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