Achieving multicolor photoluminescence especially white-light emission under mild conditions based on a single fluorescent compound is a great challenge. Herein, we report a novel colorful-emission host-guest complex BPCY, which is composed of a two-arm fluorescent guest molecule (BPC) and γ-cyclodextrin (γ-CD) as the host molecule. BPC bears a unique asymmetrical donor-acceptor-donor (D1-A +~D 2) type structure, where D1, A + , D2 stand for the binaphthol electron donor, pyridinium electron acceptor, and coumarin electron donor, respectively. The luminescence property of BPC shows dual-sensitivity, i.e. toward the excitation wavelength and the cyclodextrin host molecule. Under certain conditions the complex shows three different emission wavelengths allowing the realization of multicolor photoluminescence, including red (R), green (G), blue (B) and the various intermediate colors by orthogonally modulating these two stimuli. In this way, nearly pure white-light emission with CIE coordinates (0.33, 0.34) could be generated. A combination of structural, spectroscopic, and computational simulation studies revealed the occurrence of synergetic mechanistic processes for the stimuli-responsive multicolor luminescence of the BPCY complex, namely host-enhanced intramolecular charge-transfer (ICT) and host-induced restriction of intramolecular rotation (RIR). This new supramolecular complex with superior multicolor emission abilities may find wide applications in the fields of information processing and display media. Furthermore the molecular design rationale presented here may provide a new design strategy for the development of high performance optical materials using a single supramolecular platform.
Recent studies have implicated the lipid mediator platelet-activating factor (PAF) in UVB-mediated systemic immunosuppression known to be a major cause for skin cancers. Previously, our group has demonstrated that UVB irradiation triggers the production of PAF and oxidized glycerophosphocholines that act as PAF-receptor (PAF-R) agonists. The present studies explored the mechanisms by which UVB generates PAF-R agonists. UVB irradiation of human epidermal KB cells resulted in both increased levels of reactive oxygen species (ROS) and PAF-R agonistic activity. Pretreatment of KB cells with antioxidants vitamin C and N-acetylcysteine or the pharmacological inhibitor PD168393 specific for the epidermal growth factor receptor all inhibited UVB-induced ROS as well as PAF-R agonists, yet had no effect on fMLP-mediated PAF-R agonist production. In addition, in vivo production of PAF-R agonists from UVB-irradiated mouse skin was blocked by both systemic vitamin C administration and topical PD168393 application. Moreover, both vitamin C and PD168393 abolished UVB-mediated but not the PAF-R agonist 1-hexadecyl-2-Nmethylcarbamoyl glycerophosphocholine-mediated immunosuppression as measured by the inhibition of delayed type contact hypersensitivity to the chemical dinitrofluorobenzene. These studies suggest that UVB-induced systemic immunosuppression is due to epidermal growth factor receptor-mediated ROS which results in PAF-R agonist formation.Ultraviolet B (290-320 nm) radiation found in sunlight has a spectrum of profound effects on human skin ranging from vitamin D metabolism to skin aging and carcinogenesis (1,2). UVB exposure is believed to be the major cause for nonmelanoma skin cancer, the most common NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript type of human cancer (3,4). In addition to its ability to damage DNA, UVB is well known to exert an immunosuppressive effect via inhibiting cell-mediated immune responses that are indispensable for antitumor immunity (5,6). As such, effort has been put forth to study the mechanisms underlying UVB-induced immunosuppression, and contact allergy to chemical haptens such as dinitrofluorobenzene (DNFB) 3 has been widely used as a model (7).Platelet-activating factor (1-alkyl-2-acetyl glycerophosphocholine, PAF) is a potent inflammatory lipid mediator, exerting its effects through a single specific G-protein-coupled receptor, the PAF receptor (8). PAF is synthesized enzymatically in response to diverse stimuli including cytokines, endotoxin, Ca 2+ ionophores, and PAF itself (8-10). In addition, PAF and sn-2 short-chained acyl glycerophosphocholines (GPCs) with PAF-receptor (PAF-R) agonistic activity can also be produced through free radical-mediated damage (11). In contrast, PAFacetylhydrolase (PAF-AH) inactivates PAF and oxidized GPCs by hydrolyzing the acetyl oxidatively modified sn-2 group of the glycerol backbone (12). Previous studies by our group (13-17) and others (18)(19)(20) have indicated that PAF plays pivotal roles in mediating not ...
White-light emission from a single molecule was realized and tuned via multistimuli including excitation, solvent polarity, temperature and host–guest interactions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.