The construction of efficient artificial light-harvesting systems (ALHSs) is of vital importance in utilizing solar energy. Herein, we report the non-covalent syntheses of double helicatesPCP-TPy1/2andRp,Rp-PCP-TPy1/2by metal-coordination interaction and their applications in ALHSs and white light-emitting diode (LED) device. All double helicates exhibit significant aggregation-induced emission in tetrahydrofuran/water (1:9, v/v) solvent. The aggregated double helicates can be used to construct one-step or sequential ALHSs with fluorescent dyes Eosin Y (EsY) and Nile red (NiR) with the energy transfer efficiency up to 89.3%. Impressively, the PMMA film ofPCP-TPy1shows white-light emission when doped 0.075% NiR, the solid of double helicates (Rp,Rp-)PCP-TPy2can be used as the additive of a blue LED bulb to achieve white-light emission. In this work, we provided a general method for the preparation of novel double helicates and explored their applications in ALHSs and fluorescent materials, which will promote future construction and application of helicates as emissive devices.
We report herein the regioselective synthesis of all-carbon lemniscular nanohoops bis-po-CC and bis-pm-TC by the rational control of ring closures at the different positions of planar chiral tetrasubstituted [2.2]paracyclophane. Topological analyses reveal that bis-pm-TC is topologically chiral while bis-po-CC is topologically achiral. X-ray crystal analysis demonstrates that bis-pm-TC adopts a lemniscular conformation with a contiguous conjugation. CD and CPL measurements further reveal that the chiroptical properties of bis-pm-TC are obviously different from those of bis-po-CC due to their different topological chiralities.
Structural designs combining cycloparaphenylenes (CPPs) backbone with planar chiral [2.2]paracyclophane ([2.2]PCP) lead to optical‐active chiral macrocycles with intriguing properties. X‐ray crystal analysis revealed aesthetic necklace‐shaped structures and size‐dependent packages with long‐range channels. The macrocycles exhibit unique photophysical properties with high fluorescence quantum yield of up to 82 %, and the fluorescent color varies with ring size. In addition, size‐dependent chiroptical properties with moderately large CPL dissymmetry factor of 10−3 and CPL brightness in the range of 30–40 M−1 cm−1 were observed.
In this study, we synthesized and reported the heterotopic bisnanohoops P5-[8,10]CPPs containing cycloparaphenylenes (CPPs) and a pillar[5]arene unit, which act not only as energy donors but also as a host for binding energy acceptors. We demonstrated that a series of elegant FRET systems could be constructed successfully through self-assembly between donors P5-[8,10]CPPs and acceptors with different emissions via host–guest interaction. These FRET systems further allow us to finely adjust the donors P5-[8,10]CPPs and acceptors (BODIPY-Br and Rh-Br) for achieving multiple color-tunable emissions, particularly white-light emission. More importantly, these host–guest complexes were successfully utilized in the fabrication of white-light fluorescent films and further integrated with a 365 nm LED lamp to create white LED devices. The findings highlight a new application of carbon nanorings in white-light emission materials, beyond the common recognition of π-conjugated molecules.