Synthesis and Photophysics of Coaxial Threaded Molecular Wires: Polyrotaxanes with Triarylamine Jackets
Journal article, 2014
Conjugated polyrotaxanes jacketed with hole-transport groups have been synthesized from water-soluble polyrotaxanes consisting of a polyfluorene-alt-biphenylene (PFBP) conjugated polymer threaded through beta-cyclodextrin macrocycles. The hydroxyl groups of the oligosaccharides were efficiently functionalized with triphenylamine (TPA) so that every polyrotaxane molecule carries a coat of about 200 TPA units, forming a supramolecular coaxial structure. This architecture was characterized using a range of techniques, including small-angle X-ray scattering. Absorption of light by the TPA units results in excitation energy transfer (EET) and photoinduced electron transfer (ET) to the inner conjugated polymer core. These energy- and charge-transfer processes were explored by steady-state and time-resolved fluorescence spectroscopy, femtosecond transient absorption spectroscopy, and molecular modeling. The time-resolved measurements yielded insights into the heterogeneity of the TPA coat: those TPA units which are close to the central polymer core tend to undergo ET, whereas those on the outer surface of the polyrotaxane, far from the core, undergo EET. Sections of the backbone that are excited indirectly via EET tend to be more remote from the TPA units and thus are less susceptible to electron-transfer quenching. The rate of EET from the TPA units to the PFBP core was effectively modeled by taking account of the heterogeneity in the TPA-PFBP distance, using a distributed monopole approach. This work represents a new strategy for building and studying well-defined arrays of >100 covalently linked chromophores.
ANNALEN DER PHYSIK
BINARY BLENDS
P269
ELECTRON-TRANSFER
V2
P517
NATURE
1995
ATOM FORCE-FIELD
V374
CYCLODEXTRIN
ENERGY-TRANSFER
DERMOTT G
PHOTOSYNTHETIC BACTERIA
CONJUGATED POLYROTAXANES
RSTER T
CHARGE-TRANSPORT
1978
WHITE
ARCHIVES OF MICROBIOLOGY
1948
ELECTROLUMINESCENCE
V119
SUPRAMOLECULAR CONTROL
AEHELIN LA
P55
Author
G. Sforazzini
University of Oxford
Axel Kahnt
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Michael Wykes
Université de Mons
Johannes K. Sprafke
University of Oxford
S. Brovelli
UCL
Universita degli Studi di Milano - Bicocca
D. Montarnal
University of California, Santa Barbara
F. Meinardi
Universita degli Studi di Milano - Bicocca
F. Cacialli
UCL
David Beljonne
Université de Mons
Bo Albinsson
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Harry L. Anderson
University of Oxford
Journal of Physical Chemistry C
1932-7447 (ISSN) 1932-7455 (eISSN)
Vol. 118 8 4553-4566Subject Categories (SSIF 2011)
Physical Chemistry
DOI
10.1021/jp500624q