以紫質為懸掛或聯結基團之單股與雙股降冰片烯高分子

Abstract

利用Grubbs-I催化的開環歧化反應，將藉由不同長度烷鏈連接降冰片烯與鋅-紫質的單體化合物，合成了一系列的單股高分子，利用核磁共振氫譜、紫外/可見吸收及螢光放射光譜之測量，得知不同長短的連接基團影響了高分子鏈中紫質之間的相互作用，隨著長度增長，相互作用力越小。我們也合成雙降冰片烯取代的鋅-紫質衍生物，利用Grubbs-I催化進行開環歧化聚合的相對應雙股高分子，高分子中鋅-紫質以共價鍵方式形成緊密規則性的排列，我們將此雙股結構稱之為¬¬¬高分子環芃。 另一方面，我們以含有二個配位基的1,4-diazabicyclo[2.2.2]octane (DABCO)分子分別與單體、二聚體、單股高分子及雙股高分子滴定混合。利用1H NMR、紫外/可見吸收及螢光放射光譜技術討論鋅-紫質衍生物與配位基進行軸配位所形成的錯合物的形式及其穩定性。結果顯示DABCO分子在低濃度下可以與二聚體、單股高分子及雙股高分子中的鋅-紫質形成三明治錯合物，而與單體只能形成T字型錯合物。由紫外/可見吸收結果與曲線回歸所得到之結合常數顯示，雙股高分子中鋅-紫質與DABCO所形成三明治錯合物的穩定度大於單股高分子又大於二聚體。 我們也合成了懸掛鋅-紫質與無金屬紫質組成比例為1比1的單股嵌段及無規共聚高分子，比較其螢光放射及時間解析螢光光譜，由於無規共聚高分子中鋅-紫質 (能量給體) 與無金屬紫質 (能量受體) 相鄰的機會較高，因此可以避免鋅-紫質之間的自身淬熄的競爭途逕發生，結果顯示無規共聚高分子中能量轉移的效率較高。 另外，我們合成了懸掛鎂-紫質之降冰片烯單體衍生物及外向懸掛鋅-紫質的7-氧雜雙環[2.2.1]庚烯衍生物單體及其相對應之開環聚合高分子。由1H NMR、紅外及紫外/可見吸收實驗，我們發現單體單體分子自組裝行為，藉由異原子與紫質中金屬離子互補鍵結形成穩定的二聚物結構。

Coherently aligned porphyrin-appended polynorbornenes derived from 5,6-endo-fused N-arylpyrrolidenonorbornenes are synthesized by Grubbs-I catalyst-promoted ring opening metathesis polymerization (ROMP). Splitting of the Soret band of the porphyrin pending groups suggests strong exciton coupling between chromophores on the polymer backbone. A polymer, which have double stranded polybisnorbornene skeleton with multilayer planar porphyrin linkers, defined as polymeric ladderphanes, is synthesized. The structures of the ladderphane is determined by spectroscopic means. Photophysical studies and time-resolved fluorescence spectroscopic investigations reveal that there is strong interaction between the chromophore linkers. The porphyrin-appended monomer, dimer, single stranded polymer and double stranded polymer were treated with DABCO of different molar ratios. The 1H NMR, UV/vis absorption and flourescence spectra of the titration indicate that interaction of bidentate ligand DABCO to dimer, single stranded and double stranded polymer leads to a 2 to 1 porphyrin-DABCO sandwich structure at both high and low concentration condition. The monomer can form 2 to 1 porphyrin-DABCO sandwich structure at high concentration condition, but only form 1 to 1 porphyrin-DABCO complex at low concentration condition. The stability of the porphyrin-DABCO sandwich complex form from double stranded polymer with DABCO is higher than that from single stranded polymer or dimer. We synthesis the single stranded random and block copolymers from the Zn-porphyrin and free base prophyrin-appended norbornene monomer. Time-resolved fluorescence spectra of the two kind copolymers indicate that the efficiency of the fluorescence resonance energy transfer (FRET) between Zn-porphyrin (donor) and free base porphyrin (acceptor) dyads of random copolymers is higher than another. Mg-porphyrin-appended norbornene derivatives and the Zn-porphyrin-appended exo furan adduct can form a stable dimer by complementary coordination. The strutures and stabilities of the supramolecular dimer were determined by using the 1H NMR, FT-IR and UV/vis absorption technique.