Part Ⅰ. Cyclopolymerization of 1,6-Heptadiyne Derivatives by Metathesis Catalysts : This thesis deals with the effects of the size and the type of substituents on the fine and conformational structure, environmental stability and optical properties for the poly(1,6-heptadiynes) with substituents. A variety of 1,6-heptadiyne monomers were polymerized to give organo-soluble polymers in high yield with $MoCl_5$-based catalysts. From a series of $\lambda_\max$ values of the resulting polymers, it was found that the incorporation of the bulkier substituent into the 4-position of 1,6-heptadiyne enforces the conjugated polyene into more planar structure as indicated by the bathochromic shift of maximum absorption bands resulting from the $\pi$-$\pi^*$ transition of the conjugated polymer backbone. It appears that the chain twisting of the substituted poly(1,6-heptadiynes) is primarily determined by the steric bulk of the substituent group at 4-position rather than by that at the point of attatchment to the polymer chain which usually decreases the effective conjugation length-coplanarity- of the polymer $\pi$-system. When an extremely bulky substituent was introduced at 4 position, the resulting polymer tends to have mostly one size ring, five- membered ring. The poly 5c ($\lambda_\max$ = 606 nm) with an extremely bulky substituent such as tert - butyldiphenylsiloxymethyl group is environmentally very stable. This stability, reluctance to the backbone toward air oxidation, is thought to be due to the effective shielding of highly conjugated backbone by the bulky substituents. The nonlinear optical properties of the resulting polymers were evaluated by degenerate four wave mixing experiment. The $\chi^{(3)}$ values were increased with increasing the steric bulk of the substituents at 4-position. These unusual optical behavior could be explained by the trans-cis structure (in case of all five-membered ring structure) or transoid-cisoidal conformation (in case of all six-membered ring structure) firstly proposed by us.
Part Ⅱ : New Sythetic Route to a New Crosslinkable Polymer for Second-order Nonlinear Optics : The present thesis deals with the development of a new synthetic route to a novel crosslinkable polymer for second-order nonlinear optics using a palladium-catalyzed carbon-carbon coupling reaction. Bis(triphenylphosphine)palladium(II) chloride $(PdCl_2(PPh_3)_2$ was used as a catalyst in this work. Diethynylbenzene unit, which is readily formed from the coupling reaction of p-diiodobenzene(DIB) and nonconjugated terminal diacetylenes, was used as a crosslinkable moiety in the polymer backbone. Polycondensation between DIB and diacetylenes containing the NLO-chromophores(DASS-6, MONS-8, DANS-6 and DPANAB) catalyzed by the palladium complex catalyst in piperidine gave quantitative yields of polymers soluble in common organic solvents. When diethyldipropargyl malonate(DEDPM) was used as a comonomer with chromophore-containing monomers, the reaction required the shorter reaction time to reach a moderate molecular weight of polymer highly soluble in organic solvents. When the present polymers were annealed at 160℃ for some time, the absorption due to the ethynylbenzene moiety in the polymer main chain was considerably decreased and a tailing absorption in the visible range appeared. X-ray diffractograms of all polymers showed typical broad amorphous patterns. The poly(DASS-6) bearing the sulfone group as an electron withdrawing group was thermally more stable than the polymers with nitro group. The electro-optic coefficients of the poled polymers were measured using the simple reflection method reported by Teng and Man. The electro-optic coefficients of the polymer films measured at 1.3 μm were in the range 7 - 15 pm/V.
Part Ⅰ. 전이 금속 촉매를 이용한 1,6-Heptadiyne 유도체들의 고리 화 중합
1,6-heptadiyne의 4 위치에 위치한 치환기가 고분자의 구조와 안정도, 광학적 성질에 미치는 영향에 관하여 연구 하였다. 새롭게 합성된 1,6-heptadiyne 유도체 단량체들은 $MoCl_5$ 계 촉매를 사용 하였을 때 높은 분자량을 가진 고분자를 높은 수율로 얻을 수 있었다. 얻어진 일련 의 고분자의 $\lambda_\max$로부터 1,6-heptadiyne 4-위치에 보다 부피가 큰 치환기를 도입 할수록 공액화 된 주사슬의 평면성을 증가 시켜 보다 장파장에서 흡수띠를 가졌다. 이로부터 4 위치에 치환기를 갖는 고분자는 주사슬에 인접한 부분의 입체적 장해 보다는 4 위치 치환기들의 입체적 작용으로 인해 그 평면성이 결정 됨을 알았다. 아주 부피가 큰 치환기가 도입된 고분자들은 대부분 6 각 고리의 반복 단위가 아닌 5 각 고리의 반복 단위를 가졌고 큰 치환기들이 주사슬을 효과적으로 에워싸 산소에 의한 산화가 단기간 내에는 일어나지 않았다. 합성된 중합체의 전기 전도도는 도핑하지 않았을 때 $10^{-10}S/cm$ 이하의 값을 나타 내었지만 전자 수용체인 $I_2$ 로 도핑 하였을 때 $10^{-2}-10^{-3}S/cm$ 사이의 값을 보였다. 1.3 μm laser 를 이용한 degenerate four wave mixing(DFWM) 실험에의해 측정된 $\chi^{(3)}$값은 $10^{-10}-10^{-11}esu$ 사이의 값을 나타내었고 더 큰 치환기를 갖는 고분자가 더 높은 값을 보였다. 이러한 비이상적인 광학적 거동은 본 연구에서 최초로 제안된 고분자 구조 -trans -cis structure (모두 5각 고리의 반복 단위인 경우), transoid-cisoidal conformation (모두 6각 고리의 반복 단위인 경우)- 에의해 설명 가능하다.
Part Ⅱ. 이차 비선형 광학을 위한 새로운 가교성 고분자의 신 합성방법의 개발.
Palladium 촉매에의한 탄소-탄소간 결합 반응을 이용하여 2 차 비선형광학에 응용 가능한 새로운 가교성 고분자의 신 합성법의 개발에대해 연구하였다. Bis(triphenylphosphine)palladium(II) chloride $[PdCl_2(PPh_3)_2]$를 촉매로 사용하여 p-diiodobenzene과 nonconjugated terminal diacetylene을 반응 시켜 고분자 주사슬에 열과 빛에의해 가교 가능한 diethynylbenzene unit를 갖게 하였다. Piperidine을 중합 용매로 사용 하였을 때 높은 수율로 NLO-chromophore를 갖는 고분자를 얻었고 chromophore containing monomer들과 diethyldipropargyl malonate(DEDPM)을 공중합시켜 용해도와 분자량을 증가 시킬 수 있었다. 합성 된 고분자를 고온에서 annealing시켰을 때 가교가 일어남을 용해도 변화와 UV-vis. spectra, DSC, TGA 분석을 통해 확인 하였다. X-ray diffraction pattern으로 부터 모든 고분자는 amorphous 함을 알았다. Teng과 Man에의해 보고된 simple reflection method를 이용하여 측정한 poling된 고분자의 electro-optic coefficient는 7 - 15 pm/V사이의 값을 가졌다.