Phosphorus-based 3D functional materials

• Applicant: Privatdozent Dr. Carlos Romero Nieto
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation ; Synthesis and Properties of Functional Materials
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 381857201

This project is focused on implementing pi-extended systems containing phosphorus heterocycles into three-dimensional (3D) assemblies to investigate the luminescence mechanism of 3D frameworks.Building up 3D frameworks from highly luminescent molecules is a promising strategy to prevent intermolecular interactions that quench the luminescence processes and improve the performances of the materials for photonic applications. Despite the enormous potential of 3D architectures for light-based applications, photophysical studies that unambiguously shed light into the luminescent mechanism of 3D photonic architectures are only at a very early stage. In that context, phosphorus-based heterocycles possess a unique variety of reversible post-functionalization reactions that can be utilized to modulate the optoelectronic properties of phosphorus-based materials. This enables to generate isostructural materials with different photophysical properties through post-functionalization and to achieve accurate systematic investigations.Thus, we plan to synthesize new fluorescent phosphorus-based building blocks to construct well-defined 3D functional architectures and modulate their luminescence properties to achieve systematic photophysical investigations. Through an arsenal of avant-garde spectroscopic techniques, we will establish unambiguous photoluminescence mechanisms (origin, photo-induced excited states and their dynamics) and reveal the key parameters that lead to the best performances for photonic applications. We will also investigate the capacity of the 3D architectures to respond to different chemical media. We plan to achieve the following: 1) Synthesis of new luminescent phosphorus-based building blocks: We will synthesize highly fluorescent building blocks containing two fused phosphorus heterocycles. These building blocks will possess the suitable ligands to build up 3D structures by metal coordination. We plan to systematically extend the rigid scaffold of the molecules to obtain a library of 3D materials with both different optoelectronic properties and pore sizes.2) Construction of 3D architectures from phosphorus-based derivatives: Based on the phosphorus-based building blocks, we will employ established protocols that led to highly stable frameworks and construct well-defined 3D architectures by coordination to metal ions. We will subsequently achieve the systematic post-functionalization of the materials. 3) Investigation of the macromolecular properties of the extended building blocks and the 3D assemblies: we will meticulously investigate the photophysical properties of the building blocks and the 3D assemblies via electrochemical, steady-state and ultrafast spectroscopic techniques to establish robust luminescence mechanisms. We will evaluate the capabilities of the materials to respond to different chemical species (transition metals, oxidizing agents and Lewis acids).

• DFG Programme: Research Grants