Tetraphenylethene-Based Emissive Pt(II) Coordination Polymer toward Artificial Light-Harvesting Systems with Sequential Energy Transfer

Abstract

Supramolecular systems with sequential energy transfer have prospects in designing artificial light-harvesting systems (LHSs), which can mimic natural photosynthesis process. Here, we report a facile synthesis of a supramolecular coordination polymer (SCP) P as an emissive material through two-component coordination-driven self-assembly of a tetra-imidazole donor (L) containing tetraphenylethene backbone with a 180° trans-[Pt(PEt3)2(OTf)2] acceptor. P shows considerable enhancement in its emission in 90% water–DMSO mixture as it further self-assembles into spherical nanoaggregates. In addition, because of the framework structure of P with hydrophobic cavities and the interspaces present in the nanoaggregates of P, it can act as a suitable host to adsorb organic dyes. Therefore, polymeric material P in the nanoaggregate form in aqueous–DMSO medium was used as an efficient platform to fabricate two highly efficient light-harvesting materials with rare two-step cascade energy-transfer process. For the first-step energy-transfer process, P acts as an efficient energy donor by the Förster resonance energy-transfer (FRET) process to Eosin Y (EY) and Fluorescein (Fl) with high energy-transfer efficiency (58.8% for P-EY and 67.9% for P-Fl), good antenna effect (7.2 for P-EY, 5.2 for P-Fl), and increased quantum yield. Moreover, NiR (Nile Red) was used as a second acceptor to construct efficient two-step artificial light-harvesting materials (P-EY-NiR and P-Fl-NiR), which exhibit high FRET efficiencies of 68.5 and 76.2% as well as good antenna effect of 10.9 and 17.7, respectively. These light-harvesting materials represent the new examples of artificial LHSs based on nanoaggregates of an SCP with sequential two-step energy transfer in aqueous medium. Notably, emission/visual color changes from blue to yellow to pink for P-EY-NiR and blue to green to pink for P-Fl-NiR and cover the entire visible range spectrum.

Reversible and Turn-On Fluorescence Detection of Phosphate in Aqueous Solution and Living Cell Imaging by Supramolecular Metallacycles with AIE-Active Ligands

“…These materials exhibit intriguing photophysical characteristics that are not discernible in TPE cores alone, both in a dilute solution and in an aggregated state. − Aromatic heterocyclic compounds, specifically pyrazole and imidazole ligands, are of significant importance due to their attractive structural characteristics and extensive utilization in synthetic chemistry, coordination chemistry, and medicinal chemistry. − The combination of these two moieties into a single system has the potential to produce novel functional ligand materials that incorporate the benefits of both components. This would result in a system that exhibits a diverse coordination behavior, leading to the formation of various metal–organic supramolecules with unique topologies, while also demonstrating promising photoelectric properties. − …”

Cucurbit[8]uril Confinement-Based Secondary Coassembly for High-Efficiency Phosphorescence Energy Transfer Behavior

“…Supramolecular near-infrared (NIR) emissive materials have aroused significant research interest owing to their outstanding features such as good spatial resolution, deep tissue penetration, and low background noise, which possess promising application values in the fields of biological imaging, − disease theranostics, − organic light-emitting devices, , and biomedical sensors. − Particularly, macrocycle-involved host–guest complexation have been turned out to be a valid strategy to construct NIR luminescent materials especially in aqueous environment. − The guest chromophores are tightly encapsulated into the cavity of well-crafted artificial macrocyclic hosts like cyclodextrins, , cucurbiturils, − and pillararenes , enabled by noncovalent interactions, which can alter molecular conformation and packing modes, thereby ultimately restricting molecular rotation or forming J-aggregates with enhanced red-shifted emissions. Alternatively, Föster resonance energy transfer (FRET)-based supramolecular artificial light-harvesting system is recognized as another feasible protocol to realize long-range NIR luminescence with large Stokes shift at a relatively high donor/acceptor ratio, − which concurrently avoids burdensome covalent chemical synthesis or modification of fluorophores and endows the system with precise controllability. However, the nanosecond-level lifetimes arising from the inherent properties of most existing luminogens have severely obstructed their further practical applications.…”

A benzothiadiazole-based Pt(ii) coordination polymer as an efficient heterogeneous photocatalyst for visible-light-driven aerobic oxidative coupling of amines

“…Supramolecular coordination polymers (SCPs) are ordered arrangements of the repeating monomeric units into polymeric arrays by the metal-ligand coordination bonds with high directionality. [15][16][17][18] SCPs with well-defined ordered porosity and periodicity can be used to stabilize intermediates, adsorb organic substrates, and for diverse applications such as the adsorption of dyes, separation of gases, artificial lightharvesting, etc. [19][20][21][22][23][24] Multiple functionalities can be easily incorporated into the backbone of these SCPs.…”