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Third‐order Nonlinear Optical Properties of Organoboron Compounds: Molecular Structures and Second Hyperpolarizabilities
Author(s) -
Yuan Zheng,
Taylor Nicholas J.,
Ramachandran Ravi,
Marder Todd B.
Publication year - 1996
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199604)10:3/4<305::aid-aoc463>3.0.co;2-g
Subject(s) - chemistry , molecule , anthracene , stereochemistry , benzene , crystallography , acceptor , photochemistry , organic chemistry , physics , condensed matter physics
The third‐order nonlinear optical properties (second molecular hyperpolarizabilities, γ), of a series of organoboron compounds containing dimesitylboron moieties have been investigated by third harmonic generation (THG) measurements at 1.907 μm. Symmetric systems with B(mes) 2 groups (mes=2,4,6–Me 3 C 6 H 2 ) at both ends, e.g. (mes) 2 B–Y–B(mes) 2 where Y=(C 6 H 4 ) n ( n =1,2) or trans‐trans ‐CH=CH–(C 6 H 4 ) n –CH=CH– ( n =1,2), were prepared as well as push– pull systems of the form D–Y–B(mes) 2 where D=MeS, Me 2 N, H 2 N, etc., and Y=C 6 H 4 , C 6 H 4 –C≅C–, C 6 H 4 –CH=CH–, C 6 H 4 –CH=CH–C 6 H 4 . The B(mes) 2 group compares favorably with the more commonly used NO 2 acceptor function for enhancing γ. Values of γ increase significantly with increasing length of π‐conjugation for both symmetric and unsymmetric molecules. The MeS group is much more efficient than MeO for enhancing γ. Values as high as 22910 –36 esu are reported for trans‐trans ‐(mes) 2 ‐B–CH=CH–(C 6 H 4 ) 2 –CH=CH–B(mes) 2 which has a l max for absorption of 370 nm. Crystal and molecular structures of the bis(dimesitylboryl) benzene and anthracene compounds 1,4‐C 6 H 4 ‐{B(mes) 2 } 2 and 9,10‐C 14 H 8 {B(mes) 2 } 2 are reported, as are fluorescence maxima for the symmetric molecules.