NMR, X-Ray Crystal Structure Studies and Mechanism for Formation of a Novel Di-gallium Complex and 5-Methoxy-4,5,6-triphenyl-4,5-dihydro-1,2,4-triazene-3(2H)-thione

Abstract

Gallium complexes of bis-thiosemicarbazones were prepared and characterized using NMR and X-ray crystallography. Formation of a gallium nitrate complex was proven by NMR spectroscopy. Surprisingly, this complex was found to convert on standing to a new hydroxido-bridged di-gallium complex. The X-ray crystal structure of the digallium complex is described. Similarly, a triazene compound was formed during the preparation of the gallium complex comprising a tetraphenyl unit in the bis-thiosemicarbazone structure. We propose a mechanism for the formation of both the di-gallium species as well as triazene compound in solution. The lattice parameters for the digallium complex is as follows: a: 17.6854(13) A, b:16.6492(7) A, c: 21.4659(14) A, β = 112.383(8)°.