手性聚合物基化学传感器的设计、合成及对映选择性识别性能

Investigations on both chiral recognition of organic molecules and enantioselective chemosensors have received intensive attention due to its importance in many disciplines such as chemistry, biology, and pharmacy. This project is proposed for designing and development of a new kind of chiral polymer-based sensors with FL-CD double detection channel for the discrimination of enantiomers. We will design two types of chiral monomers, i.e., reactive and coordinate, on the basis of the chiroptical switch mechanism and "stereodynamic probe" concept, and then synthesize the corresponding chiral polymers with linear, block or comb architectures via living/controlled radical polymerization techniques. The studies on the host-guest interaction will be conducted by quantum chemistry calculation for model compounds for exploring the chiral recognition mechanism. The effect of various factors including configuration center, lateral group, and solvent nature on the secondary structure of the polymers will be examined in detail. We will evaluate the sensing performance of the polymers towards chiral compounds such as alpha-amino acid, alpha-hydroxyl acid, and amino alcohol for selecting desired enantioselective chemosensors. Another task in the project is exploring the polymeric films as a chiral probe for enantioselective discrimination of the above-mentioned organic molecules. The polymer films are formed on the piezoid by using spin coating, layer-by-layer or covlent grafting method. In addition, we are to examine the relationship between the surface property of polymeric films and its chiral selectivity for gaining some additional insight into the molecular interaction on the solid-liquid surface. It is anticipated that this research would provide not only a suitable platform for understanding of the chiral molecular recognition but also a new avenue in the developing of chiral chemosensors with high enantioselectivity.

用于对映异构体识别的化学传感器因其在生物、化学、制药等诸多学科研究中占有重要地位而受到广泛关注。本项目借鉴"立体动态探针"概念，根据手光分子开关原理探索新型的荧光-圆二色双检测通道聚合物基手性传感器。为此，设计"反应型"和"配位型"两类手性功能单体，通过活性/可控自由基聚合方法合成结构明确的线形、嵌段及梳状结构聚合物。利用模型化合物结合量子化学计算探讨主-客体分子手性识别机理，研究立构中心位置、侧基类型、溶剂性质等因素对聚合物主链高层次结构的影响规律，系统考察聚合物溶液对手性a-氨基酸、a-羟基酸和氨基醇的对映选择性光学响应行为。采用旋涂、层层自组装和共价键合等方法制备以石英片为基材的手性聚合物薄膜，研究薄膜传感器的手性识别性能与聚合物结构、成膜方式以及表面聚集形态的内在联系，阐释固-液界面上的分子相互作用。本项研究有助于深入了解手性识别机理，将为设计、开发高选择性手性传感器提供新的途径。

分子识别，尤其是手性分子识别在复杂的生命过程中扮演了重要角色。从仿生角度出发，设计、合成具有手性结构的功能分子和纳米结构，探索不同于非手性结构的特殊物理和化学性能一直是备受关注的热点研究领域。. 本项目利用可控聚合反应技术和后修饰策略发展了新型的“反应型”和“配位型”两类化学传感器，已成功用于在水性介质中对半胱氨酸和组氨酸的高选择性检测，揭示了聚合物骨架在主客体分子识别中的协同作用及纳米组装体的传感放大效应。半胱氨酸荧光传感器可特异性识别底物，检测下限达到1 μM，实现了对半胱氨酸的裸眼直接识别。由两亲共聚物自组装得到的手性光学纳米探针，可高选择性区分组氨酸，且具有良好的对映体选择性。两种化学传感器有望在生物医学检测方面得到应用。.基于2-噁唑啉衍生物分子设计灵活、聚合反应可控的特点，设计、合成了新颖的拟肽手性选择剂及相应的硅基固定相用于高效液相色谱的对映体分离。侧链含有二聚脯氨酸残基的拟肽手性固定相对1,1’-联萘酚和偶姻类化合物表现出良好的拆分效果；由主链手性聚合物衍生的手性固定相具有更好的对映体识别能力，成功拆分了α-甲基苄胺、安息香、1-萘基乙胺等分析物。除了氢键、位阻和ππ相互作用外，聚合物主链的构象变化也是影响对映体选择性的一个重要因素。本项研究不仅开拓了聚(2-噁唑啉)新的应用领域，而且为手性分离材料的设计提供了新的思路。. 受聚肽分子链beta-折叠结构的启发，设计、合成了一种结构明确的2-噁唑啉齐聚物，并首次获得了一种新颖的超分子有机纳米晶体。该齐聚物的侧链同时含有氢键给体、受体位点，这种结构基元与蛋白质中导致β-折叠构象的聚甘氨酸十分类似。在2-噁唑啉功能单体的聚合过程中，齐聚物受分子间互补氢键驱动自组装(self-assembly)成超分子链，并进一步发生三维有序堆积直至晶体从反应介质中析出。该纳米晶表现出异乎寻常的耐溶剂性和溶致液晶现象。由于分子结构的可裁制性，此类超分子有机纳米晶可望成为功能纳米材料新的设计平台。

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