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Syntheses and Properties of Two-Dimensional, Dicationic Nonlinear Optical Chromophores Based on Pyrazinyl Cores

Coe, Benjamin J. and Fielden, John and Foxon, Simon P. and Helliwell, Madeleine and Asselberghs, Inge and Clays, Koen and De Mey, Kurt and Brunschwig, Bruce S. (2010) Syntheses and Properties of Two-Dimensional, Dicationic Nonlinear Optical Chromophores Based on Pyrazinyl Cores. Journal of Organic Chemistry, 75 (24). pp. 8550-8563. ISSN 0022-3263.

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Six new dicationic 2D nonlinear optical (NLO) chromophores with pyrazinyl-pyridinium electron acceptors have been synthesized by nucleophilic substitutions of 2,6-dichloropyrazine with pyridyl derivatives. These compounds have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Large red shifts in the intense, π → π* intramolecular charge-transfer (ICT) transitions on replacing −OMe with –Nme_2 substituents arise from the stronger π-electron donor ability of the latter. Each compound shows a number of redox processes which are largely irreversible. Single crystal X-ray structures have been determined for five salts, including two nitrates, all of which adopt centrosymmetric packing arrangements. Molecular first hyperpolarizabilities β have been determined by using femtosecond hyper-Rayleigh scattering at 880 and 800 nm, and depolarization studies show that the NLO responses of the symmetric species are strongly 2D, with dominant “off-diagonal” β_(zyy) components. Stark (electroabsorption) spectroscopic measurements on the ICT bands afford estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large, and the Stark-derived β_0 response for one of the new salts is several times greater than that determined for (E)-4′-(dimethylamino)-N-methyl-4-stilbazolium hexafluorophosphate. These Stark spectroscopic studies also permit quantitative comparisons with related 2D, binuclear RuII ammine complex salts.

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URLURL TypeDescription DOIArticle
Coe, Benjamin J.0000-0002-5998-3895
Fielden, John0000-0001-5963-7792
Brunschwig, Bruce S.0000-0002-6135-6727
Additional Information:© 2010 American Chemical Society. Received October 5, 2010. Publication Date (Web): November 16, 2010. We thank the EPSRC for support (grants EP/E000738 and EP/D070732) and also the Fund for Scientific Research-Flanders (FWO-V, G.0312.08), the University of Leuven (GOA/2006/3), and the NSF (grant CHE-0802907, Powering the Planet: an NSF Center for Chemical Innovation). I.A. is a postdoctoral fellow of the FWO-V. We thank Dr. Daniela Rusanova-Naydenova for obtaining some of the data presented in Figure 4, and are grateful to Dr Robin Pritchard of the University of Manchester for assistance with solving the crystal structure of salt [2][PF6]2.
Group:CCI Solar Fuels
Funding AgencyGrant Number
Engineering and Physical Sciences Research Council (EPSRC)EP/E000738
Engineering and Physical Sciences Research Council (EPSRC)EP/D070732
Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO)FWO-V G.0312.08
University of LeuvenGOA/2006/3
Issue or Number:24
Record Number:CaltechAUTHORS:20110110-090253636
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Official Citation:Syntheses and Properties of Two-Dimensional, Dicationic Nonlinear Optical Chromophores Based on Pyrazinyl Cores Benjamin J. Coe, John Fielden, Simon P. Foxon, Madeleine Helliwell, Inge Asselberghs, Koen Clays, Kurt De Mey, Bruce S. Brunschwig The Journal of Organic Chemistry 2010 75 (24), 8550-8563
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21660
Deposited By: Tony Diaz
Deposited On:31 Jan 2011 23:32
Last Modified:03 Oct 2019 02:27

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