Self-Assembled Fluorescent Pt(II) Metallacycles as Artificial Light-Harvesting Systems

Abstract

Light-harvesting is one of the key steps in photosynthesis, but developing artificial light-harvesting systems (LHSs) with high energy transfer efficiencies has been a challenging task. Here we report fluorescent hexagonal Pt­(II) metalla­cycles as a new platform to fabricate artificial LHSs. The metalla­cycles (4 and 5) are easily accessible by coordination-driven self-assembly of a triphenyl­amine-based ditopic ligand 1 with di-platinum acceptors 2 and 3, respectively. They possess good fluorescence properties both in solution and in the solid state. Notably, the metalla­cycles show aggregation-induced emission enhancement (AIEE) characteristics in a DMSO–H2O solvent system. In the presence of the fluorescent dye Eosin Y (ESY), the emission intensities of the metalla­cycles decrease but the emission intensity of ESY increases. The absorption spectrum of ESY and the emission spectra of the metalla­cycles show a considerable overlap, suggesting the possibility of energy transfer from the metalla­cycles to ESY, with an energy transfer efficiency as high as 65% in the 4 a +ESY system.

An Efficient Near‐Infrared Emissive Artificial Supramolecular Light‐Harvesting System for Imaging in the Golgi Apparatus

“…Owing to the nature of the non‐covalent interactions of supramolecular assemblies, supramolecular light‐harvesting systems can be more conveniently formed, by mixing the corresponding building blocks, than covalent light‐harvesting systems. To achieve an efficient supramolecular light‐harvesting system, there are two key considerations . One is that the donors should be capable of induced emission enhancement in the assemblies instead of fluorescence quenching.…”

“…To achieve an efficient supramolecular light-harvesting system, there are two key considerations. [4] One is that the donors should be capable of induced emission enhancement in the assemblies instead of fluorescence quenching. The other is donor/acceptor ratio should be high so that multiple donors can transfer energy to one acceptor.…”

“…A naphthyl-1,8-diphenyl pyridinium derivative (NPS) has been designed as a fluorescent donor in aqueous solution. NPS shows a weak fluorescence emission at 593 nm, while it undergoes a sharp aggregation induced emission enhancement (AIEE) and blue shift to 550 nm after co-assembling with lower-rim dodecylmodified sulfonato-calix [4]arene (SC4AD) [12] to form nanoparticles (Scheme 1). Then, Nile blue (NiB) is loaded as an acceptor into NPS-SC4AD supramolecular nanoparticles to develop the NIR emissive light-harvesting system due to sufficient overlap between the emission band of NPS-SC4AD nanoparticles and the absorption band of NiB.…”

Organic supramolecular aggregates based on water‐soluble cyclodextrins and calixarenes

“…Supramolecular artificial light‐harvesting systems (ALHSs) have found widespread applications in various fields, including biological imaging and optoelectronics. [ 84 ] Many types of materials have been employed to fabricate ALHSs, including organic nanocrystals, [ 85 ] metal complexes, [ 86 ] metallacycles, [ 87 ] surface‐cross‐linked micelles, [ 88 ] peptide‐modulated chromophores, [ 89 ] DNA oligonucleotides, [ 90 ] organic–inorganic hybrids, [ 91 ] and polymers. [ 92 ] In addition, a number of ALHSs based on macrocycles such as cyclodextrins, [ 28,93 ] pillar[ n ]arenes, [ 94 ] calix[ n ]arenes, [ 95 ] and cucurbiturils [ 96 ] were recently reported.…”

Site‐Selective, Multistep Functionalizations of CO2‐Based Hyperbranched Poly(alkynoate)s toward Functional Polymetric Materials

“…The high efficiency of our one-pot tandem polymerization, the triphenylamine (TPA) moieties in the hb-PAs, as well as natural photosynthesis and artificial light-harvesting systems (LHSs) [38][39][40][41][42][43][44][45][46][47][48][49][50] inspired investigations into further applications of these polymerizations. Therefore, we applied our strategy to constructing highly efficient, artificial LHSs by introducing lightharvesting groups onto the peripheries of the polymers (Figure 6 and Scheme S5, Supporting Information).…”