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Azo‐Azulene Derivatives as Second‐Order Nonlinear Optical Chromophores
Author(s) -
Lacroix Pascal G.,
Malfant Isabelle,
Iftime Gabriel,
Razus Alexandru C.,
Nakatani Keitaro,
Delaire Jacques A.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000717)6:14<2599::aid-chem2599>3.0.co;2-g
Subject(s) - azulene , hyperpolarizability , monoclinic crystal system , chromophore , second harmonic generation , nonlinear optical , nonlinear optics , chemistry , formalism (music) , crystal structure , computational chemistry , crystallography , molecule , materials science , nonlinear system , polarizability , photochemistry , optics , physics , organic chemistry , quantum mechanics , art , musical , laser , visual arts
The molecular and solid state nonlinear optical (NLO) properties of several (phenylazo)‐azulenes are investigated. In particular, (4‐nitrophenylazo)‐azulene ( 2 b ) exhibits a quadratic hyperpolarizability ( β vec ) of 80×10 −30 cm 5 esu recorded at 1.907 μ m by the electric field‐induced second‐harmonic (EFISH) technique. This molecular material, which crystallizes in the monoclinic noncentrosymmetric space group P c, exhibits an efficiency 420 times that of urea in second‐harmonic generation. The origin of the optical nonlinearity in azo‐azulene is discussed in relation with crystal structures and semiempirical calculations within the INDO/SOS formalism, and compared with that of the well known disperse red one (DR1) organic dye.