单向压缩调控下卟啉、酞菁等共轭pi体系分子的可控Langmuir-Blodgett组装

Molecular assmebly is currently considered to be an efficient strategy for organized molecular associations. From the viewpoint of the involved molecules, pi-conjugated species, such as porphyrins, phthalocyanines, etc., have received much attention as distinguished units for the formulation of supramolecular assemblies with motives for potential applications in various frontier fields. This is owing to their distinct chemical versatility, their fully understood planar and rigid molecular geometry, and their tunable spectroscopic features, which endow them with tunable spectroscopic, photophysical, photochemical, and assembly properties. On the other hand, from the viewpoint of assembly protocols, a variety of approaches, including Langmuir-Blodgett technique (LB), layer-by-layer assembly, organogelation, etc., have been developed. Among these, interfacial organization based on LB technique has been recognized to be an attractive way. This is owing to its nice reproducibility, low-cost, general applicability, etc. So far, numerous assemblies have been fabricated by conventional LB technique of bilateral compression. However, the precise structure of the assemblies, including staggering angle and direction, overlapping extent between the units, which could affect the functions of the assemblies, could not be controlled. It is still a great challenge to establish a general yet efficient LB based strategy to achieve such controllable assembly. In this application, we propose that such controllable assembly could be realized via a new-type LB technique. Instead of the bilateral compression that employed in the conventional LB technique, interfacial assemblies of pi-conjugated molecules, such as porphyrins and phthalocyanines etc. with precisely tunable structures (staggering angle and direction, overlapping extent between the units) will be accomplished by applying an unilateral compression geometry on our LB trough. Based on such controllable assembly, tunable functionality of the assemblies, including supramolecular chirality, photoelectronic devices, photocatalysts, etc., will be realized. The proposal will not only promote the innovative development of LB technique, but also paves new and varied avenues for the controllable assembly and tunable functionality of organic based supramolecular materials, which are of paramount importance for disclosing the intimate correlation between the internal molecular arrangement and external functions, and are projects of broad interest and general concern. Based on the possible achievements of the proposed investigations, the cooperative stacking principle of the involved building blocks, and the electron/energy transfer principle within the assemblies, which are the basic scientific issues of scientific community, will be disclosed from the viewpoint of interfacial molecular assembly. Our proposal is an important subject of sufficient novelty and creativity worth of investigation and support.

本申请拟以Langmuir-Blodgett（LB）界面组装技术为手段, 以卟啉、酞菁等功能pi体系有机分子为组装基元，以在LB组装体系上施加单向压缩模式并调控压缩方向为创新思想，来实现这些分子的导向性可控组装（pi体系基元的协同错位方向和角度、堆叠程度等结构特征）及组装体在超分子手性、光电器件、光催化等方面的性能调控。该研究将揭示压缩方向这一新型宏观参数对基元分子间微观协同性的影响和调控作用，重点关注压缩方向--基元分子的结构特征--组装体结构--组装体性能等的内在关联，为基元间各种非共价键相互作用的协同性规律、组装体中电子/能量的传输规律等核心科学问题提供信息，具有重要的科学意义。同时，该研究将发展具有一定普适性的新型可控组装方法，为构筑结构与性能可导向性调控的有机功能超分子体系提供新型科学平台，亦将有助于实现经典LB界面组装技术的可持续创新发展，是一个颇具特色和创新性的构思。

根据项目计划书所拟定研究内容与目标，本课题旨在以卟啉、酞菁等功能pi体系分子为基元，以Langmuir-Blodgett(LB)组装技术等为主要手段,通过在组装过程中施加物理矢量并调控其方向，来实现可控组装及组装体在超分子手性、分子电子器件等方面的性能调控。4年来，我们以卟啉、酞菁、吖啶、氧化石墨烯、石墨炔等pi体系分子为对象，通过在LB组装过程中引入单向压缩模、定向摩擦处理载片、二元分子体系的组装等思路展开了研究。同时，针对LB组装体须依附于固体载片/稳定性欠佳所导致的难以功能化等问题，将思路进一步拓展到了体相中手性分子调控的卟啉分子的组装、表面活性剂调控下油/水界面上pi体系分子的组装、基于pi体系共价键交联剂的固/液界面组装等方面，构筑了分子电子器件、传感、催化等功能体系。.. 主要进展如下：(1)利用单向压缩建立了具有一定普适性的由非手性卟啉所构筑LB界面组装体超分子手性的控制；(2)通过定向摩擦载片建立了具有一定普适性的构筑卟啉、酞菁等pi分子规则纳米阵列的方法；(3)通过二元体系的组装实现了LB界面组装体超分子手性的控制及放大；(4)在手性分子诱导下实现了非手性卟啉组装体超分子手性及螺旋方向的控制；(5)通过表面活性剂调控的油/水介质中的组装实现了卟啉分子纳米结构的调控，构筑了基于单根卟啉纳米线的传感器、超分子光催化等功能体系；(6)在surfactant-free介质中实现了非金属卟啉纳米结构的调控，研究了其形貌依赖的光催化性能；(7)以pi体系分子为共价键交联剂在大面积范围实现了具有高度稳定性的氧化石墨烯薄膜的组装及性能调控；(8)利用氧化石墨烯、含氟石墨烯、石墨炔、石墨等pi体系各自的结构特征，实现了其可控组装及在催化方面的性能调控。.. 上述研究诠释了物理矢量对基元分子协同性的影响和调控，为非共价键作用的协同性规律、组装体中电子/能量的传输规律等问题提供了科学信息。同时，该研究发展的具有一定普适性的组装方法，为构筑基于pi体系分子的功能材料提供了新契机。