Ultrafast monitoring and synthetic control of electronic properties of a self-assembled coordination system as a multi-site luminescent probe for sensoric and imaging applications

本方法旨在开发一种新的策略，以开发具有多个分子或离子识别位点的分子荧光探针。我们提出了一种新的多位点荧光探针的设计概念，它能够实现多路或逻辑系统响应或传感器功能的控制和切换，远远超出了传统分子探针中观察到的功能，需要在超快光谱和理论指导下进行先进的合成。目标化合物通过金属模板席夫碱反应以模块化方法构建，包含两个选择性结合位点，这两个结合位点构成了中心水杨醛亚胺生色团单元的组成部分。A位的过渡金属结合(锌、铜)增强了荧光，而B位的占据(Li、Na、K)调节了荧光性质。利用液-固界面的光电子发射光谱、连续探针的瞬时吸收和荧光寿命成像对体系的响应进行了监测，并用密度泛函理论对数据进行了解释，为选择性的合成改进提供了指导。

The present approach aims at a novel strategy to develop molecular fluorescent probes with more than one site for molecular or ion recognition. We propose a novel design concept for a multi-site fluorescence probe that enables a multiplex or logic system response or the control and switching of sensor features, much beyond those observed in conventional molecular probes, requiring advanced synthesis guided by ultrafast spectroscopy and theory. The target compounds, constructed in a modular approach by metal-templated Schiff-base reactions, contain two selective binding sites, which constitute an integral part of a central salicyclidene-aldimine chromophore unit. Transition metal binding (Zn2+, Cu+) at site A enhances the fluorescence, while occupation of site B (Li+, Na+, K+) modulates the fluorescence properties. The system responses are monitored with photoelectron emission spectroscopy from liquid and solid interfaces, continuum probe transient absorption and fluorescence lifetime imaging and the data are interpreted employing density functional theory providing the guidelines for selective synthetic improvements.