16,453 research outputs found
Ignat Solzhenitsyn, Piano, and Hsin-Yun Huang, Viola
No full textApril 3rd, 2015
Ignat Solzhenitsyn, piano; Hsin-Yun Huang, viola, performed Sonatas from the Soviet Era — Prokofiev: Piano Sonata No. 8 in B-flat Major, Op. 84; Shostakovich: Sonata for Viola and Piano, Op. 147
Photo courtesy of Hsin-Yun Huanghttps://digitalcommons.rockefeller.edu/tri-institutional-noon-recitals/1178/thumbnail.jp
Electronic Properties of Star-Shaped Oligofluorenes Containing an Isotruxene Core: Interplay of Para and Ortho Conjugation Effects in Phenylene-Based π Systems
No full textHuman and proud of it! A structural treatment of headhunting rites and the social definition of enemies
No full textThis article is a reprint of McKinley, Robert. 1976. “Human and proud of it! A structural treatment of headhunting rites and the social definition of enemies.” In Studies in Borneo societies: Social process and anthropological explanation , edited by G. N. Appell, 92–126. DeKalb, IL: The Center for Southeast Asian Studies at Northern Illinois University. The appendix, containing reflections on a debate between J. van Baal and the author, was written for publication in HAU
Studies on the Synthesis and Electrochemiluminecent Properties of Donor-Acceptor Substituted Arylethynyl Coumarins and Benzothiazoles
No full text本篇論文主要是討論D-π-A(Donor-π-Acceptor)系統的電致化學發光性質(ECL)，其中D為-H(H)、-Me (M)、-OMe (OM)、-OiPr (OP)或-NMe2 (DMA)，π為苯乙炔或二苯乙炔，A為香豆素(coumarin)或苯并噻唑(benzathiazole)。我們希望探討位置異構物對D-π-A系統ECL性質的影響。
以香豆素為電子受體的化合物為5-香豆素(5Cs)及7-香豆素(7Cs)
系列。除了5C-DMA和7C-DMA之外，其餘化合物隨著推電子基增強
(H<M<OM~OP<DMA)，螢光光譜有紅位移的趨勢，螢光量子產率也增高。雖然DMA取代基的推電子能力是五個取代基中最強的，但5C-DMA的螢光最大放射波長(450 nm)位於5C-H(430 nm)和5C-OM(473 nm)之間；7C-DMA的螢光光譜有447 nm及560 nm兩個放射峰，其中447 nm介於7C-H(406 nm)和7C-OM(458 nm)的放射峰之間。5C-DMA及7C-DMA的螢光量子產率較其他化合物低且均小於0.01。在氮氣除氧的乙腈溶液中，5Cs和7Cs沒有任何ECL的行為。但在通氧氣的條件下且當還原電壓大於氧氣的還原電位時，我們便可測得ECL的訊號(λmax = 460- 500 nm)。
以苯并噻唑作為電子受體的化合物為2-苯并噻唑(BTs)、m-PhBTs
及p-PhBTs系列化合物。除了m-PhBT-DMA有425 nm及556 nm兩個放射峰，其餘化合物只有一放射峰。隨著推電子基增強，此系列化合物的螢光光譜有紅位移的趨勢。如同5C-DMA和7C-DMA，BT-DMA、m-PhBT-DMA及p-PhBT-DMA的螢光量子產率均小於0.01，其餘化合XIII物隨則著推電子基增強，螢光量子產率也增高。與5Cs、7Cs不同的是m-PhBTs及p-PhBTs在氮氣除氧的乙腈溶液環境下，可觀察到與螢光光譜相似的ECL訊號。此外，在通氧氣的條件下，施加化合物氧化電位及大於氧氣還原電位的電壓時，所有BTs、m-PhBTs及p-PhBT化合物所表現的ECL光譜均極為相似(λmax = 460- 500 nm)，且與相對應的螢光
光譜無特定關係。In this dissertation, we report the photophysical, electrochemical, and electrogenerated chemiluminescent properties of a series of donor-p-acceptor (D-p-A) systems, where D is H(H), Me(M), OMe(OM), OiPr(OP) or NMe2(DMA),p is phenylacetylene or diphenylacetylene, and A is coumarin or benzathiazole. The position-dependent substituent effects on the ECL behavior of these D-p-A systems are also reported.
The investigated coumarin systems are 5- and 7-substitued coumarins, which are referred to as 5Cs and 7Cs, respectively. The fluorescence of 5Cs and 7Cs are at longer wavelengths for those with stronger donors(i.e., H < M < OM < OP < DMA). Except for 5C- DMA and 7C-DMA that possess low fluorescene quantum yields (<0.01), 5Cs and 7Cs display stronger fluorescence for those with stronger donors. ECL signals (λmax = 460- 500 nm) can be observed for 5Cs and 7Cs under aerated conditions but not under outgassed solutions.
Three benzathiazole systems (BTs, m-BTPhs and p-BTPhs) were inwestigated herein.The dependence of fluorescence position and fluorescence quantum yield on the donor group for these benzathiazole systems resembles that for 5Cs and 7Cs. However, unlike the cases of 5Cs and 7Cs, BT-DMA, m-BTPhs and p-BTPhs display ECL signals in outgassed acetonitrile solution, and the ECL spectra can be correlated to the corresponding fluorescence spectra. Under aerated conditions, all these benzathiazole systems show ECL signals and maxima are all within the range of 460-500 nm, independent of the nature of substrates. The ECL mechanisms for both the coumarin and benzathiazole systems are also elucidated and discussed.目錄……………………………………………………………………..Ⅰ
圖表目錄……………………………………………….………………Ⅲ
附圖目錄………………………………………………………………Ⅵ
中文摘要………………….…………………..…………………...…......ⅩⅢ
英文摘要……………………..………………………………..………... ⅩⅤ
第一章 緒論 …………………………………………………...…………1
一、 電致化學放光簡介……………………..………………………1
二、 電致化學放光機制……………………………………………2
三、 電致化學放光的應用………………………………………11
四、 分子內電子轉移……………………………………………12
五、 超氧陰離子(O2•-; superoxide)…………….…………………14
第二章 結果與討論 ………………………………...…………………23
一、 化合物的合成與設計…………………….……………………23
二、 光物理和電化學性質………………………………….………28
(1) 5Cs和7Cs系列……………………………………………..28
(2) BTs、m-BTPhs 和 p-BTPhs 系列………………...………41
三、 結論…………………………………………………………….56
第三章 實驗部份 ………...……………………………………………58
一、 儀器部分…………..…………………………………………58
二、 實驗步驟……………..………………………………………59
三、 合成步驟………………..……………………………………67
(1) 合成末端炔基化合物………………………………….….68
(2) 7Cs系列化合物的合成………………………………..…69
(3) 5Cs系列化合物的合成……………………….…..………73
(4) BTs系列化合物的合成 ………………..………………. 79
(5) m-BTPhs系列化合物的合成………………….…………83
(6) p-BTPhs系列化合物的合成…………….………..…..88
參考資料……………………………………………………………..…93
附錄…………………………………………….………………………9
Synthesis and Properties of Isotruxene and Its Derivatives
No full text異參茚并苯為不對稱二維平面分子，具有鄰位及對位共軛效應。本論文的目的為探討異參茚并苯的共軛結構。在本研究中，我們開發了三種可大量合成異參茚并苯的方法，並進一步合成異參茚并苯茀衍生物ITF1-ITF4及異參茚并苯星狀梯型衍生物Sn。藉由探討其衍生物的光物理及電化學行為進一步了解寡聚苯類分子系統的鄰、對共軛效應。
在異參茚并苯合成方面，首先利用[2 + 2 + 2]三聚反應或是狄耳士-阿德爾反應建立起不對稱的鄰-對位共軛骨架，再經由氧化、合環、還原等步驟獲得異參茚并苯及異參茚并苯酮。相較於之前的合成方法，本論文所發表的方法有較高的產率(27-36%:18%)及較易純化(不須經過管柱層析)且能大量反應等優點。
星狀化合物ITFn和Sn顯示有趣的光電性質。化合物ITF1-ITF4的光物理及電化學性質均顯示三個茀支鏈間有很強的電子偶合，主要由於異參茚并苯的鄰、對共軛效應所造成的。ITF1-ITF4的吸收光譜顯示，隨著共軛的增長鄰位共軛效應的影響會減弱，而以對位共軛效應為主。由於較剛硬及較平面的結構，化合物Sn的系統相較於ITF1及ITF2有更強的鄰位共軛效應。而研究中也發現Sn系統相較於線型的一維共軛系統有較長的有效共軛長度。對此現象，我們提出了二維共軛系統的概念Isotruxene is a planar unsymmetrical star-shaped molecule, which have ortho- and para-conjugation interaction. This thesis is oriented to explore isotruxene-derivatives structured π-conjugation. In this context, three new synthetic methods for isotruxene have been developed. Further, a series of isotruxene-oligofluorenes ITF1-ITF4 and a series of isotruxene-based star-shaped ladder-type oligophenylenes Sn (n = 4, 7, 10, 13, 16) have been prepared in order to understand the ortho- and para-conjugation effect in oligophenylene systems.
Regarding the synthesis of isotruxene building blocks, the backbone was constructed by either Co-catalyzed [2 + 2 + 2] cyclotrimerization or the [4 + 2] Diels-Alder reactions. The subsequebt oxidation, Friedel-Crafts acylation, and reduction reactions lead to isotruxene and isotruxone. Compared to the previous method, the current approaches are more efficient in terms of product yield (27-36% vs 4-18%) and purification (i.e., no column chromatography required).
We observed strong electronic couplings among the three oligofluorene arms in star-shaped compound ITFn and Sn as a result of the para-ortho interactions. According to the absorption spectra of ITF1-ITF4, the ortho-conjugation effect becomes weaker as the oligofluorene arms are longer. Compounds Sn have stronger ortho-conjugation effect than ITF1, ITF2, and ITF3 due to the more planar and rigid structures. The effective conjugation length in Sn systems is larger than that in rod-shaped ladder-type polyphenylene systems. We thus proposed the concept of two-dimensional conjugation interactions
Edmund Terence Gomez et Michael Hsiao Hsin-Huang éds., Chinese Business in South-East Asia. Contesting Cultural Explanations, Researching Entrepreneurship
No full textGuiheux Gilles. Edmund Terence Gomez et Michael Hsiao Hsin-Huang éds., Chinese Business in South-East Asia. Contesting Cultural Explanations, Researching Entrepreneurship. In: Perspectives chinoises, n°70, 2002. pp. 70-71
Synthesis and Electronic Properties of Isotruxene-Derived Star-Shaped Ladder-Type Oligophenylenes: Bandgap Tuning with Two-Dimensional Conjugation
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