| 摘要: | 實驗室過去多年之主要研究領域為設計、製備、與探討含過渡金屬錯合物之中間相液晶材料，過渡元素主耍為銅(Cu)，鎳(Ni)，鋅(Zn)、鈀(Pd)等金屬。近一年來部份研究領域轉移至主族(Group 13, IIIB)，其中探討元素為硼(B)及鋁(Al)，計畫中於分子結構設計上有含單硼(BF2)及双硼化合物(BF2)2，分子形狀上有桿狀分子及盤狀分子，與具有之間形狀(catenar)之分子。硼為非金屬元素；缺電子、且較酸性等化性；其配位數多為三及四(CN=3, 4)，氧化數為OS=2, 3，配位幾何結構為平面三角形或四面體。另一探討Group 13元素為鋁；鋁為金屬；亦較缺電子、且較酸性，配位數多為四或六，配位幾何結構多為八面體。這二類化合物為本實驗室近期藉以發展之新穎液晶材料。硼(B)及鋁(Al)，含單硼或双硼化合物不僅展示新穎液晶行為，硼(B)更發現其爲發蓝及紅光材料。單晶結構分析証實單硼及双硼中心均為四面體，而双鋁中心則爲八面體結構。在配位基結構設計上主要為含；(a)具五圓及六圓環結構或其衍生物，例如1,3,4-oxadiazole,pyrozales, isoxazoles。雜環結構配位基具有一些特性；例如：(1) 其化學性質或結構穩定性及易製備；(2) 中心結構較不具共平面性，分子對稱性較低，產生液晶相之澄清點可較低，易於後續應用性之探考；(3) 多數具光學性質，可開發成發光材料；(4) 配位方式多樣性，可得單、或雙金屬結構化合物。本計畫中之設計分子結構多以探考具[O,O]及N,O]的配位方式為主。 ;Metallomesogens, i.e. metal-containing liquid crystals have been our research forcus during the past years. Recently, our research target has been partially shifted to liquic crystals containing Main group 13 (or IIIB) elements. Complexes or adducts containing boron difluoride (BF2) have received much attention during the past years. Many known boron difluoride complexes, widely investigated as fluorescent materials have shown the potential for application in many areas such as biological imaging, molecular probes, electroluminescent devices, photosensitizers and others. These complexes were often generated by reactions of boron trifluoride and pi-conjugated chelating ligands in non-oxygen containing solvents. Boron, a nonmetal element of Group 13 (IIIA), is considered as an electron deficient atom. It has an oxidation state of three or four (OS = 3, 4) and the resulting complexes all form a triangular or tetrahedral geometry. Many unique boron complexes have been reported and their optical properties were extensively investigated.Three common types of coordination modes, i.e. [O,O], [N,O] and [N,N0], have long been known for boron difluoride. Among the known complexes, the majority of boron complexes were coordinated with O,O-chelating ligands, such as diketonates and triketonates. Recently, much attention has been paid to such BF2-[O,O] complexes, when studied in applications of two-photo absorbing molecules, luminescent materials, sensors and near-IR probes. In contrast, rarer complexes coordinated to N,Nchelating ligands were known, such as diketiminates and formazanates. Only a few complexes were known to complex with N,O-chelating ligands, such as quinolone-ketones. These BF2-[N,O] complexes often showed interesting photophysical and photochemical properties, which might have applications in OLED, OFET, LCs and others. The diketiminate and formazanate moieties were often considered as redox-active and near-infrared dyes that showed larger Stokes shifts upon complexation to boron difluoride. In this proposal, a few series of borondifluoride complexes derived from heterocyclic compounds will be prepared, characterized and their potential mesomorphic properties are also investigated. Boron complexes containing mono-borondifluoride and bis-boron difluoride moieties will be studied. Columnar and smectic phases are expected to exhibit by these boron complexes depending the shape of the molecules. In addition, their optical properties will be also explored in detail. |
