title: A mechanically interlocked [3]rotaxane as a light-harvesting antenna: synthesis, characterization, and intramolecular energy transfer.
abstract: A mechanically interlocked light-harvesting system [3]rotaxane A has been synthesized in high yield through Cu(I)-catalyzed azide-alkyne cycloaddition; the hexyl-substituted truxene units are introduced into the wheels as donors and an oligo(para-phenylenevinylene) (OPV) unit into the axis as the acceptor. The structure and the purity of [3]rotaxane A were confirmed by (1)H and (13)C NMR spectroscopy and ESI HRMS. The azide-alkyne cycloaddition is demonstrated to be an efficient stoppering method in the synthesis of the rotaxane containing dibenzo[24]crown-8 and dibenzyl ammonium units. Detailed steady-state UV/Vis absorption, photoluminescent, and time-resolved fluorescence spectroscopy were performed to investigate the photophysical properties of [3]rotaxane A and its reference compounds in solution and as thin films. Even in dilute solution, efficient energy transfer from the truxene-functionalized wheels to the OPV-based axis, through the dibenzo[24]crown-8 and dibenzyl ammonium interaction, is observed in [3]rotaxane A. The unique topology of [3]rotaxane A not only efficiently promotes the intramolecular energy-transfer process, but also prevents intermolecular aggregation in the solid state. The new antenna system opens up the possibility of controllable light-harvesting molecular machines or other optoelectronic devices on the nanometer scale.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, The Key Laboratories of Bioorganic Chemistry and Molecular Engineering, and Polymer Chemistry and Physics of Ministry of Education, College of Chemistry, Peking University, Beijing, China.
authors.forename: Jie-Yu
authors.initials: JY
authors.lastname: Wang
authors.forename: Ji-Min
authors.initials: JM
authors.lastname: Han
authors.forename: Jing
authors.initials: J
authors.lastname: Yan
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Ma
authors.forename: Jian
authors.initials: J
authors.lastname: Pei
mesh_terms: D000480:Alkynes / Q000138:chemical synthesis / Q000737:chemistry; D001386:Azides / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D003500:Cyclization; D004735:Energy Transfer; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D008027:Light; D010777:Photochemistry; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000480:Alkynes; D001386:Azides; D005456:Fluorescent Dyes; D043862:Rotaxanes; D003300:Copper