COMPLEX SALTS DERIVED FROM THE REACTIONS OF lnBr 3 AND lnCI 3 WITH SOME AROMATIC SCHIFF BASES: X-RAY CRYSTAL STRUCTURE OF BIS[N-(2-HYDROXY- BENZALIDENE)-2-METHOXYANILINIUM] TETRABROMOINDATE(III) Guan-Yeow Yeap 1 *, Siang-Guan Teoh 1 , Chen Wei 2 and Jean-Paul Declercq 3 1 School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia 2 Department of Chemistry, Universiti Malaya, Lembah Pantai, 59100 Kuala Lumpur, Malaysia 3 Laboratoire de Chimie Physique et de Cristallographie, Universite Catholique de Louvain, Place L. Pasteur, 1, B-1348, Louvain-la-Neuve, Belgium Abstract The reactions of indium(lll) tribromide and trichloride with the Schiff bases N-(2-hydroxybenzalidene)-2-methoxyaniline, N-(2-hydroxynaphthalidene)-3-bromoaniline and N-(2-hydroxynaphthalidene)-4-methoxyaniline yield complex salts with general formula [L 2 H]*[lnXJ' (where L = Schiff base and X = Br and CI). X-ray structural analysis has been carried out on [L 2 H] + [lnBrJ" where L = N-(2-hydroxybenzalidene)-2-methoxyaniline resulting from the reaction of InBr, with N-(2-hydroxybenzalidene)-2-methoxyaniline in ethanol. All synthesized compounds were characterized by microanalysis, IR and 1 H-NMR spectroscopy. Introduction Extensive studies on indium(lll) compounds have been carried out in the last few decades. (1M17) Almost all of the indium(lll) compounds derived from the reactions of inorganic indium(lll) haiides and organoindium(lll) halides with the respective ligands having Ο, Ν and S atoms display a variety of coordination numbers and stereochemistries at the indium atom. However, very little work has been published on the reactions of indium halides with Schiff bases. A few reports have appeared concerning the indium(lil) complexes of the Schiff bases obtained from 2-hydroxy-1-naphthaldehyde and salicylaldehyde with various substituted anilines but the structural characterization based on infrared spectral evidence are filled with ambiguities wherein the coordination between the indium atom and Schiff bases has not well been established. Whilst indium(lll) molecular adducts derived from the reactions of indium(lll) chloride with salicylidene Schiff bases have been found to exhibit In-O coordination mode, 116 ' in the indium(lli) complexes synthesized from indium(lll) isopropoxide with salicylidene and naphthalidene Schiff bases, the ligands were found to coordinate to In via the imine Ν atom.' 175 In this paper, we report for the first time that the reactions of lnBr 3 and lnCI 3 with N-(2-hydroxybenzalidene)-2-methoxyaniline (1a), N-(2-hydroxynaphthalidene)-3-bromoaniline (2a) and N-(2-hydroxynaphthalidene)-4-methoxyaniline (3a) lead to the formation of indium(lll) complex salts 1b-3b. The ligands (1a-3a) used were obtained by adding equimolar amounts of the appropriate aniline to aldehyde in 96% ethanol. The complex salts were synthesized from the reactions of lnBr 3 and lnCI 3 with the corresponding ligands in the mixed solvent system of dichloromethane and ethanol (1:1). The mixture was left standing at room temperature overnight whereupon orange crystals were obtained. All compounds 1b-3b thus obtained have been 245