Part Ⅰ. Poly(1,6-heptadiyne) Derivatives for Photonic Application.
A new class of multifunctional polymers based on poly(1,6-heptadiyne) derivatives have been synthesized by metathesis cyclopolymerization. Firstly, new photorefractive polymers based on the work for the photoconductivity and electro-optic activity of poly(1,6-heptadiyne) derivatives containing a carbazole moiety or NLO chromophores. Herein, all functional groups are covalently linked to the polymer backbone to overcome some problems such as phase separation and instability of electro-optic activities, etc.. The resulting polymers were obtained from the copolymerization of 1,6-heptadiyne derivatives containing several chromophores in various monomer feed ratio. The molecular weights of the resulting polymers were estimated by gel-permeation chromatography (GPC) to be in the range $Mn=2.3×10^4$ to $4.5×10^4$ and the polydispersities were in the range of 2.1-3.1. The mole ratios of the resulting copolymers were determined by $^1H$-NMR analysis. All the copolymers were polymerized nearly quantitatively as a monomer feed. And all copolymers of various mole ratios was relatively well soluble in common organic solvents and were easily cast on ITO glass plate or quartz plate to give violet, shiny thin films. Furthermore, all polymers were amorphous. Secondly, we have described new conjugated poly(1,6-heptadiyne) derivatives with various substituents such as fluorinated alkyl, carbazole, and silicon-containing pendant groups for the third-order optical nonlinearity of these polymers via metathesis cyclopolymerization. The third-order optical nonlinearity of these polymers for photonic applications were investigated by degenerate four-wave mixing method. These polymers were of quite high molecular weight ($~10^5$) and were highly soluble in common organic solvents. The third-order nonlinear optical coefficient, $X^{(3)}$, of the resulting polymers were found to be 0.44 to $4.1× 10^{-11}$ esu. Esepecially, in the case of the polymer containing fluorinated alkyl group, both two fast electronic grating component and slow thermal grating were observed interestingly at several nano scale time duration. And, the resulting polymers were of quite high hyperpolarizabilites ($~10^{32}$ esu).
Part Ⅱ. Charge-Transfer Complexing Polymers.
A new class fo charge-transfer complexing polymers including electron accepting polymers were synthesized from 1,6-heptadiyne derivatives by metathesis polymerization and palladium-catalyzed coupling reaction. Firstly, a new electron-acceptor polymer, poly {2-[(3,5-dinitrobenzoyl)-oxy]ethyl dipropargyl acetate} poly(DNBEDPA), was synthesized for the first time by metathesis polymerization with various transition metal catalyst systems such as $MoCl_5$, $WCl_6-$ and $PdCl_2$-based catalysts. The $MoCl_5$-based catalysts all showed effective catalytic activity. However, the $WCl_6$-based catalysts showed no catalytic activity. The polymers obtained by most catalysts were partially soluble in organic solvents and the soluble portion of the polymer was less than 43% of the polymer yield. The weight-average molecular weight ($\overline{Mw}$) values of the polymers were in the range of $3.1-2.1×10^4$, relative to polystyrene standards in gel-permeation chromatography (GPC). The resulting polymer is an example of a homopolymer system with an intramolecular charge transfer complex between the electron-acceptor (3,5-dinitrobenzoyl groups) in the side chain and the conjugated double bonds in the main chain. Secondly, The present dissertation deals with the development of a new synthetic route to novel charge-transfer complexing polymers using a palladium-catalyzed carbon-carbon coupling reaction. The polycondensations of DPAEC (3-dipropargylamino-9-ethylcarbazole) as electron donor monomer with various diiodoaryl compounds were carried out in palladium catalytic system. All the polymers were obtained quantitatively. The weight-average molecular weight ($\bar{M}w$) values of the polymers were in the range of $(7.1 - 14.1)×10^3$. The chemical structures of the polymers obtained were confirmed by $^1H$-, $^{13}C$-NMR, and IR spectroscopy and their electrochemical properties were also characterized by using cyclic voltammetry. From the DSC curve of polymer, it was found that a broad exothermic peak was observed at around 196℃ in the first heating, whereas there was no exothermic peak in the second heating. The broad exothermic peak is deduced to be due to the thermal cross-linking of the internal acethylene groups in the polymer main chain. On the other hand, We have synthesized the new electron accepting polymer and intramolecular charge-transfer complexing polymer having both carbazole group as a donor and 2,4-dinitrobenzoate group as an acceptor. These polymeric systems are believed to be the first polycondensation type electron-accepting polymer or intramolecular charge-transfer complexing polymer prepared by palladium-catalyzed coupling reaction. The resulting polymers were easily soluble in common organic solvents such as chloroform, DMSO, THF, etc.. The polymerization of DNBEDPA as a electron accepting monomer with p- diiodobenzene (DIB) was carried out in various solvent systems such as piperidine, morpholine, and pyridine. The weight-average molecular weight ($\bar{M}w$) values of the polymers were in the range of $(4.3-11.2)×10^3$. In the case of intramolecular charge-transfer complexing polymer having both carbazole group as a donor and 2,4-dinitrobenzoate group as an acceptor, the polymer yield and the weight-average molecular weight ($\bar{M}w$) values were 59% and $12,1×10^3$, respectively. It was found that, in the case poly(DNBEDPA-DIB-DPAEC), the absorbance was considerably increased and the tailing absorption in the visible range was increased due to an intramolecular charge-transfer complexes between donor and acceptor groups.
Part Ⅰ. 광통신 시대에 있어 중요한 새로운 종류의 다기능성(광굴절성, 이차/삼차 비선형 광학 특성 등)고분자들이 1,6-heptadiyne 유도체로부터 메타세시스 중합을 통해 합성되었다. 먼저 모든 기능성 관능기들이 고분자 사슬에 공유결합되어 있어 기존의 복합체의 단점 예를 들면 상분리현상, 또는 그로인한 전기광학성질의 불안전성등을 극복하리라 생각되는 새로운 광굴절성 고분자를 합성하였다. 이는 전자 주게로서 카바졸을 측쇄에 가지고 있는 모노머와 또한 전기광학특성을 가지기 위해 NLO chromophore들을 측쇄에 가진 모노머들의 공중합에 의해 합성되어졌다. 얻어진 고분자들은 일반적인 유기 용매에 잘 녹으며 ITO가 코팅된 유리위에도 잘 코팅되어진다. 그 수 평균 분자량은 23,000-45,000 사이였고 polydispersity는 2.1 -3.1 사이였다. 얻어진 고분자의 조성은 NMR등에 의해 확인되었으며 모든 조성에서 거의 정량적으로 합성되어졌다. 얻어진 고분자는 모든 조성에서 비정질 상태로 존재함을 x-ray diffractogram을 통해 알 수 있었다. 둘째로 삼차 비선형 특성을 조사 하기위해 여러 치환체 fluorinate alkyl, carbazole, silicon 등을 가지고 있는 Poly(1,6-heptadiyne) 유도체들을 합성하여 그들의 광학 특성을 관찰한 결과 비교적 높은 값의 삼차 비선형 계수를 얻었다.($4.1×10^{-11}$ esu) 특히 fluorinated alkyl이 치환되어 있는 고분자의 경우 nano scale의 time duration에서 electronic grating에 의한 signal이 분리되는 특이한 성질을 보였다. 대개의 nano scale에서의 DFWM signal은 thermal grating에 의한 것이라고 알려져 있는 것을 생각해보면 이러한 현상은 특이하다. 그러한 성질에 대한 정확한 이해는 아직 밝혀지지 않았다.
Part Ⅱ. 여러가지 관능기 (예를 들면, 전자 주게, 전자 받게 등)를 가지고 있는 1,6,-heptadiyne 유도체들을 메타세시스와 Pd를 이용한 커플링 반응을 이용해 지금까지 합성하기 어려웠던 electron a accepting polymers 또는 Intramolecular charge-transfer complexing polymers을 비교적 좋은 수율로 얻었다. 먼저 메타세시스 중합을 통해 3,5-dinitrobenzoate group이 치환되어 있는 electron accepting polymer를 합성하였다. 몰리브덴계 촉매를 사용하였을 때가 가장 좋은 촉매활성을 보였지만 얻어진 고분자는 부분적으로 일반 유기 용매에 녹지 않았다. 용해성 고분자는 최고 43%까지 얻을 수 있었다. soluble한 고분자의 무게 평균 분자량은 31,000 -21,000 사이였다. 얻어진 고분자는 conjugated main chain과 측쇄에 있는 electron acceptor groups사이의 상호작용으로 인해 분자내 전하 착체를 형성함이 UV-Vis spectrum을 통해 알 수 있었다. 한편 고분자 주쇄에 electron donor(carbazole group)와 electron acceptor(3,5-dinitrobenzoate group)를 동시에 가지는 intramolecular charge-transfer complexing 고분자를 각각의 모노머들로부터 공중합을 이용해 합성하였다. 얻어진 고분자의 무게 평균 분자량은 약 12,000 정도였으며, 중합수율은 약 60% 정도였다. 얻어진 고분자의 UV-Vis absorption은 small electron acceptor or electon donor등이 도핑되어진 고분자 blend의 경우 보다 훨씬 크게 나타났는데 이는 chromophore들이 고분자 주쇄에 연결되어 있는 경우 전하착체를 형성하기에 훨씬 용이하기 때문인 것으로 이해된다.
