Thomas H. Baum, Carl E. Larson, et al.
Journal of Organometallic Chemistry
We have described the synthesis of a variety of 1,3, 1,4, and 1,5 donor-acceptor conjugation extended substituted pyrazole derivatives and have studied their spectroscopic and nonlinear optical properties. These materials are thermally stable and absorb strongly in the UV-visible region, albeit at much shorter wavelengths than comparably substituted cyclic azapolyenes such as 2-pyrazolines. Quadratic hyperpolarizability measurements suggest that the pyrazoles are significantly nonlinear, and that 1,3 and 1,4 substitution is preferred. 1,5 substitution causes a significant drop in the nonlinearity and a blue shift in the long-wavelength absorption maximum, presumably due to a twisting and partial deconjugation of the substituents to relieve unfavorable steric interactions. The experimental results are compared with those predicted by simple “finite field” computational procedures. © 1993, American Chemical Society. All rights reserved.
Thomas H. Baum, Carl E. Larson, et al.
Journal of Organometallic Chemistry
I. Morgenstern, K.A. Müller, et al.
Physica B: Physics of Condensed Matter
Ming L. Yu
Physical Review B
M. Hargrove, S.W. Crowder, et al.
IEDM 1998