Third-order Nonlinear Optical Properties of Organoboron Compounds: Molecular Structures and Second Hyperpolarizabilities

✍ Scribed by Zheng Yuan; Nicholas J. Taylor; Ravi Ramachandran; Todd B. Marder

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 917 KB
• Volume: 10
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199604)10:3/4<305::aid-aoc463>3.0.co;2-g

✦ Synopsis

The third-order nonlinear optical properties (second molecular hyperpolarizabilities, y), of a series of organoboron compounds containing dimesitylboron moieties have been investigated by third harmonic generation (THG) measurements at 1.907 pm. Symmetric systems with B(mes), groups (mes = 2,4,6-Me,Ca2) at both ends, e.g. (mes),B-Y-B(mes), where Y = (C6H4), (n= 1,2) or t r a n s -t r u n s -C H --C H -( c 6 H 4 ) , ~H ~H -(n=1,2), were prepared as well as pushpull systems of the form I)-Y-B(mes), where D=MeS, Me,N, H2N, etc., and c 6 H A H = c H -c , & . The B(mes), group compares favorably with the more commonly used NO, acceptor function for enhancing y. Values of y increase significantly with increasing length of JEconjugation for both symmetric and unsymmetric molecules. The MeS group is much more efficient than Me0 for enhancing y. Values as high as 229 X lo-J6 esu are reported for trans-trans-(mes),-B-CH=CH-(C,&)&H=CH-B(mes), which has a A, for absorption of 370 nm. Crystal and molecular structures of the bis(dimesitylbory1) benzene and anthracene compounds 1 ,4-C6H4-{B(mes),}, and 9,10-C,,H8{B(mes),}, are reported, as are fluorescence maxima for the symmetric molecules.