A Caltech Library Service

Quadratic and Cubic Nonlinear Optical Properties of Salts of Diquat-Based Chromophores with Diphenylamino Substituents

Coe, Benjamin J. and Fielden, John and Foxon, Simon P. and Helliwell, Madeleine and Brunschwig, Bruce S. and Asselberghs, Inge and Clays, Koen and Olesiak, Joanna and Matczyszyn, Katarzyna and Samoc, Marek (2010) Quadratic and Cubic Nonlinear Optical Properties of Salts of Diquat-Based Chromophores with Diphenylamino Substituents. Journal of Physical Chemistry A, 114 (45). pp. 12028-12041. ISSN 1089-5639.

PDF - Supplemental Material
See Usage Policy.

[img] Crystallographic Info File (CIF) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


A series of chromophoric salts has been prepared in which 4-(diphenylamino)phenyl (Dpap) electron donor groups are connected to electron-accepting diquaternized 2,2′-bipyridyl (diquat) units. The main aim is to combine large quadratic and cubic nonlinear optical (NLO) effects in potentially redox-switchable molecules with 2D structures. The chromophores have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. The visible absorption spectra are dominated by intense π → π* intramolecular charge-transfer (ICT) bands, and all of the compounds show two reversible or quasireversible diquat-based reductions and partially reversible Dpap oxidations. Single crystal X-ray structures have been obtained for one salt and for the precursor compound (E)-4-(diphenylamino)cinnamaldehyde, both of which adopt centrosymmetric space groups. First hyperpolarizabilities β have been measured by using hyper-Rayleigh scattering (HRS) with a 800 nm laser, and Stark (electroabsorption) spectroscopy of the ICT bands affords estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large and generally increased substantially for the bis-Dpap derivatives when compared with their monosubstituted analogues. Polarized HRS studies show that the NLO responses of the disubstituted species are dominated by “off-diagonal” β_(zyy) components. Lengthening the diquaternizing alkyl unit lowers the electron-acceptor strength and therefore increases the ICT energies and decreases the E_(1/2) values for diquat reduction. However, compensating increases in the ICT intensity prevent significant decreases in the Stark-based β_0 responses. Cubic NLO properties have been measured by using the Z-scan technique over a wavelength range of 520−1600 nm, revealing relatively high two-photon absorption cross-sections of up to 730 GM at 620 nm for one of the disubstituted chromophores.

Item Type:Article
Related URLs:
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: July 13, 2010. Publication Date (Web): October 26, 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), the NSF (grant CHE-0802907, “Powering the Planet: an NSF Center for Chemical Innovation”), and the Foundation for Polish Science. I. A. is a postdoctoral fellow of the FWO-V, and M. S. is a Laureate and J. O. is a Ph.D. scholar of the FNP Welcome programme.
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)G.0312.08
University of LeuvenGOA/2006/3
Foundation for Polish ScienceUNSPECIFIED
Issue or Number:45
Record Number:CaltechAUTHORS:20101208-133020453
Persistent URL:
Official Citation:Quadratic and Cubic Nonlinear Optical Properties of Salts of Diquat-Based Chromophores with Diphenylamino Substituents Benjamin J. Coe, John Fielden, Simon P. Foxon, Madeleine Helliwell, Bruce S. Brunschwig, Inge Asselberghs, Koen Clays, Joanna Olesiak, Katarzyna Matczyszyn, Marek Samoc The Journal of Physical Chemistry A 2010 114 (45), 12028-12041
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21249
Deposited By: Tony Diaz
Deposited On:14 Dec 2010 17:07
Last Modified:03 Oct 2019 02:21

Repository Staff Only: item control page