開發與合成新型多苯環材料分子

Synthesis and Characterization of New Polyaromatic Hydrocarbons (PAHs)

陳則安(Tse-An Chen)

指導教授 ： 劉瑞雄

國立清華大學/理學院/化學系/博士(2012年)

https://doi.org/10.6843/NTHU.2012.00238

摘要

第一章節：
線型多苯環分子因其於有機薄膜電晶體中具有良好的效率，一直都受到科學家的重視。因此我們利用鉑以及釕金屬催化合成三個不同系列的的線型多苯環分子，並量測以及探討其光學以及電化學性質，研究發現其分子隨著共軛苯環數的增加其 Band gap 也跟著下降。並利用變溫 NMR 觀察其苯環間扭曲的現象。

第二章節：
第一部份：結合實驗室所建立DBC分子以及線形多芳香環碳氫化合物的合成策略，我們合成了三個不同系列以 Dibenzo[g,p]chrysenes (DBC)分子為核心架構，並於不同的位置延長其共軛的苯環單元的Cata-condensed polyaromatic hydrocarbons， 並探討其光化學以及電化學性質與分子的扭曲度以及芳香度的關係。
第二部份：以相同合成策略，我們也嘗試了使用鉑以及釕金屬錯合物催化環化反應，合成以 Triphenylene 為核心的 Cata-condensed PAHs，但其反應選擇性不如預期，伴隨著副產物的生成。

第三章節：
第一部份：我們利用DDQ促進Scholl反應，可將第二章所建立一系列 Cata-ondensed PAHs上的 Fjord region 進行環化反應，合成具有低Clar sextet 的盤狀多芳香環碳氫化合物，也研究了 Clar sextet 所在的位置與電化學以及光化學性質上的關係。
第二部份：我們沿用第二章節所使用的合成策略，使用 PtCl2 催化Bis(biaryl)diynes 進行兩次成環反應，接著同樣以DDQ來促進 Scholl 反應合成一系列大型的盤狀PAHs化合物且同樣具有較少的 Clar sextets，使分子上的 π 電子共軛效率更加，可有效率的降低此類化合物的Energy gap。

第四章節：
最後一章節我們嘗試於平面多芳香環碳氫化合物 Dibenzo[de, op]bisanthracene (DBBA)上的 Interior 碳原子進行化學反應，但測試了許多不同的條件皆無法證明反應可發生於中心的 sp2 碳原子上，實驗中我們也發現了許多特別的反應，於 DBBA 分子上具有不錯的位向選擇性，例如 Friedal-craft 反應、Nucleophilic addition、Epoxidation以及分子間的 Scholl 反應。

關鍵字

多苯環芳香化合物

並列摘要

Chapter I：
We reported regiocontrolled syntheses of ethene-bridged para-phenylene oligomers in three distinct classes using Pt(II)- and Ru(II)-catalyzed aromatization. This synthetic approach is developed based on two-fold aromatization of 1-aryl-2-alkynylbenzene functionality, which proceeds via distinct regioselectivity for platinum and ruthenium catalysts. Variable-temperature NMR spectra provide evidence that large arrays of these oligomers are prone to twist from planarity. The ultra violet (UV), photoluminescence (PL) and band gaps of these regularly growing arrays show a pattern of extensive π-conjugation with increasing array sizes except for one instance.

Chapter II：
Part 1：A facile synthesis of three series cata-condensed polyaromatic hydrocarbons, initial ICl-promoted cyclization of bis(biaryl)acetylenes, followed by the Mizoroki-Heck coupling reaction has been reported. This approach works well for various bis(biaryl)acetylenes to afford dibenzo[g,p]chrysenes as core structure and extended the conjugated benzene ring from different direction. The photophysical and electronic properties of these highly twist cata-ondensed polyaromatic hydrocarbons has affected by aromaticity and the position of new extended conjugated benzene ring.
Part 2：We also demonstrated Pt(II)- and Ru(II)-catalyzed cyclization of 1,3,5-(tri-4-tert-butylbenzene)-2,4,6-triethynylbenzene to synthesis new cata-ondensed polyaromatic hydrocarbons.

Chapter III：
Part 1：A new synthesis of large PAHs with low Clar sextets was developed. Dibenzochrysene derivatives can be transformed into planar polyaromatic hydrocarbons by using DDQ-oxidation reaction. The photophysical and electronic properties of these compound including UV/Vis, photoluminscence and cyclic voltammetry indicate that these properties are greatly affected by the increasing array size.
Part 2：We have developed a new synthesis of large-sized PAHs with low Clar sextets. This two-step synthesis involves starting bis(biaryl)diynes, which undergo initial PtCl2-catalyzed aromatizations, and subsequent DDQ-oxidation. The resulting PAH products have aromatic characters on the outer benzenes and polyene properties on indicates an efficient electron-delocalization within the frameworks of these PAHs. This convenient approach is applicable to a large PAH that has small energy gap (2.07 eV).

Chapter IV：
The last chapter study for interior aromatic addition chemistry on planar dibenzo[de, op]bisanthracene (DBBA), unfortunately we didn’t find any evidence for addition chemistry on interior carbon, but still find some interesting reaction bear high regioselectivity on DBBA compound, such as Friedal-craft reaction, nucleophilic addition, epoxidation and new type intermolecular Scholl reaction.

並列關鍵字

PAHs

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