Synthesis of icosahedral carboranes for second-harmonic generation. Part 1

The synthesis and non-linear optical properties of a series of Icosahedral carboranes are described. The carboranes are substituted on one carbon atom, one boron atom or on mutually para carbon and boron atoms. The single-crystal X-ray structure of one of the series, 1,12-diphenyl-1,2-dicarba-closo-dodecaborane(12) is presented. It crystallises in the orthorhombic space group Pcab(no. 61), with four molecules per unit cell, with dimensions of a = 8.374(3)Å, b= 10.973(4)Å, c= 18.447(2)Å. The second-harmonic generation (SHG) properties of all of the compounds prepared are described, as are the electric-field-induced second-harmonic (EFISH) measurements of selected examples.