SYNTHESIS,CRYSTAL STRUCTURE AND NONLINEAR OPTICAL PROPERTIES OF THIOSEMICARBAZONE ZINC COMPLEX

Abstract

A new zinc bromide complex of a Schiff-base ligand derived from thiosemicarbazide and 4-methoxylphenyldehyde, which shows ca 13 times better SHG efficiency than urea, has been prepared and characterized. Single crystal X-ray diffraction analysis established that the coordination geometry about the zinc atom is tetrahedral with two equivalent Zn-Br and Zn-S bonds. The Schiff-base ligand is coordinated to the Zn(II) via the monodentate mercapto sulfur atom. The polar structure (space group Aba2) is stabilized by hydrogen bonds between the oxygen atom and the amino nitrogen atoms N(l).

The complex crystallizes in the orthorhombic space group Aba2 with cell parameters a=11.970(2), b = 21.888(2), c= 9.157(2)Å and Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0.065 and R _w = 0.117 for the 722 observed reflections with I > 2[sgrave](I).