ISSN:
0268-2605
Schlagwort(e):
boron
;
nonlinear optics
;
third-order
;
hyperpolarizability
;
organic material
;
fluorescence
;
molecular structure
;
benzene
;
anthracene
;
stilbene
;
Chemistry
;
Industrial Chemistry and Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
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-Me3C6H2) at both ends, e.g. (mes)2B-Y-B(mes)2 where Y=(C6H4)n (n=1,2) or trans-trans-CH=CH-(C6H4)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, Me2N, H2N, etc., and Y=C6H4, C6H4-C≅C-, C6H4-CH=CH-, C6H4-CH=CH-C6H4. The B(mes)2 group compares favorably with the more commonly used NO2 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-(C6H4)2-CH=CH-B(mes)2 which has a lmax for absorption of 370 nm. Crystal and molecular structures of the bis(dimesitylboryl) benzene and anthracene compounds 1,4-C6H4-{B(mes)2}2 and 9,10-C14H8{B(mes)2}2 are reported, as are fluorescence maxima for the symmetric molecules.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
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