TY - JOUR
T1 - Photoinitiated long-lived charge separation with near-unity quantum yield in donor-acceptor1-acceptor2 systems for artificial photosynthesis
AU - Han, Won Sik
AU - Veldkamp, Brad S.
AU - Dyar, Scott M.
AU - Eaton, Samuel W.
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, an Office of Basic Energy Sciences, DOE under grant no. DE-FG02-99ER14999. B.S.V. is supported by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under contract no. DE-AC05-06OR23100. S.W.E. acknowledges support from the International Materials Institute for Solar Energy and Environment funded by National Science Foundation under grant no. DMR-0843962. W.S.H. acknowledges funding from National Research Foundation of Korea Grant funded by the Korean Government (NRF-2011-C00053) and funding from Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2014R1A1A1005982).
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017
Y1 - 2017
N2 - We report the synthesis and photophysical characterization of isomeric donor-acceptor1-acceptor2 (D-A1-A2) triads each comprising a perylene donor (D) connected by a xylene bridge to a naphthalene-1,8-dicarboximide primary acceptor (NMI, A1) that is, in turn, covalently linked to a naphthalene-1,4:5,8-bis(dicarboximide) secondary acceptor (NDI, A2) through a benzene ring at its ortho, meta or para positions (Per-Xy-NMI-x-NDI). Selective photoexcitation of Per produces both Per+• and NDI‒• simultaneously with time constants of ∼50 ps in benzonitrile and ∼80 ps in toluene with a >98% yield. This is much faster than expected for single-step electron transfer from 1*Per to NDI and is consistent with a two-step mechanism, 1*Per-Xy-NMI-x-NDI → Per+•-Xy-NMI‒•-x-NDI → Per+•-Xy-NMI-x-NDI‒•, in which the second step is much faster than the first step. In addition, preserving long-lived charge separation in these systems is found to depend on inhibiting charge recombination by a triplet radical ion pair recombination pathway.
AB - We report the synthesis and photophysical characterization of isomeric donor-acceptor1-acceptor2 (D-A1-A2) triads each comprising a perylene donor (D) connected by a xylene bridge to a naphthalene-1,8-dicarboximide primary acceptor (NMI, A1) that is, in turn, covalently linked to a naphthalene-1,4:5,8-bis(dicarboximide) secondary acceptor (NDI, A2) through a benzene ring at its ortho, meta or para positions (Per-Xy-NMI-x-NDI). Selective photoexcitation of Per produces both Per+• and NDI‒• simultaneously with time constants of ∼50 ps in benzonitrile and ∼80 ps in toluene with a >98% yield. This is much faster than expected for single-step electron transfer from 1*Per to NDI and is consistent with a two-step mechanism, 1*Per-Xy-NMI-x-NDI → Per+•-Xy-NMI‒•-x-NDI → Per+•-Xy-NMI-x-NDI‒•, in which the second step is much faster than the first step. In addition, preserving long-lived charge separation in these systems is found to depend on inhibiting charge recombination by a triplet radical ion pair recombination pathway.
KW - Donor-acceptor
KW - Photochemistry
KW - Radical pairs
KW - Transient absorption spectroscopy
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U2 - 10.1016/j.tet.2017.06.021
DO - 10.1016/j.tet.2017.06.021
M3 - Article
AN - SCOPUS:85020876140
VL - 73
SP - 4925
EP - 4935
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 33
ER -