Convergent synthesis and photoinduced processes in multi-chromophoric rotaxanes
Megiatto JD, Li K, Schuster DI, Palkar A, Herranz MA, Echegoyen L, Abwandner S, De Miguel Rojas G, Guldi DM (2010)
Publication Type: Journal article, Original article
Publication year: 2010
Journal
Original Authors: Megiatto Jr. J.D., Li K., Schuster D.I., Palkar A., Herranz M.A., Echegoyen L., Abwandner S., De Miguel G., Guldi D.M.
Publisher: American Chemical Society
Book Volume: 114
Pages Range: 14408-14419
Journal Issue: 45
DOI: 10.1021/jp101154k
Abstract
A series of [2]rotaxane materials, in which [60]fullerene is linked to a macrocycle and ferrocene (Fc) moieties are placed at the termini of a thread, both of which possess a central Cu(I)-1,10-phenanthroline [Cu(phen) ] complex, were synthesized by self-assembly using Sauvage metal template methodology. Two types of threads were constructed, one with terminal ester linkages, and a second with terminal 1,2,3-triazole linkages derived from Cu(I)-catalyzed "click" 1,3-cycloaddition reactions. Model compounds lacking the fullerene moiety were prepared in an analogous manner. The ability of the interlocked Fc-[Cu(phen)2]+-Cgo hybrids to undergo electron transfer upon photoexcitation in benzonitrile, dichloromethane, and oritho-dichlorobenzene was investigated by means of time-resolved fluorescence and transient absorption spectroscopy, using excitation wavelengths directed at the fullerene and [Cu(phen) ] subunits. The energies of the electronic excited states and charge separated (CS) states that might be formed upon photoexcitation were determined from spectroscopic and electrochemical data. These studies showed that MLCT excited states of the copper complex in the fullerenerotaxanes were quenched by electron transfer to the fullerene in benzonitrile, resulting in charge separated states with oxidized copper and reduced fullerene moieties, (Fc) -[Cu(phen)2] -C . Even though electron transfer from Fc to the oxidized copper complex is predicted to be exergonic by 0.16 to 0.20 eV, no unequivocal evidence in support of such a process was obtained. The conclusion that Fc plays no role in the photoinduced processes in our systems rests on the lack of enhancement of the lifetime of the charge separated state, as measured by decay of C at ∼1000 nm, since one-electron oxidized Fc is very difficult to detect spectroscopically in the 500-800 nm spectral region. © 2010 American Chemical Society.
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APA:
Megiatto, J.D., Li, K., Schuster, D.I., Palkar, A., Herranz, M.A., Echegoyen, L.,... Guldi, D.M. (2010). Convergent synthesis and photoinduced processes in multi-chromophoric rotaxanes. Journal of Physical Chemistry B, 114(45), 14408-14419. https://doi.org/10.1021/jp101154k
MLA:
Megiatto, Jackson D., et al. "Convergent synthesis and photoinduced processes in multi-chromophoric rotaxanes." Journal of Physical Chemistry B 114.45 (2010): 14408-14419.
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