2013. 54, 4 UDC 548.737:541.67 CHARACTERIZATION OF SCHIFF BASES DERIVED FROM 3,4-DIMETHOXYBENZALDEHYDE: THE CRYSTAL STRUCTURE OF N,N-BIS(3,4-DIMETHOXYBENZYLIDENE)-2,2-DIMETHYLPROPANE1,3-DIAMINE HYDRATE A.D. Khalaji1, A. Foroghnia2, K. Fejfarova3, M. Dusek3 1Department of Chemistry, Faculty of Science, Golestan University, Gorgan, Iran E-mail: alidkhalaji@yahoo.com. & ad.khalaji@gu.ac.ir Received March, 4, 2012 The Schiff base compounds N,N-bis(3,4-dimethoxybenzylidene)-2,2-dimethylpropane-1,3diamine hydrate, (3,4-MeO-ba)2Mepn.H2O (1), and N,N-bis(3,4-dimethoxybenzylidene)butane-1,4-diamine, (3,4-MeO-ba)2bn (2), with different central groups derived from 3,4dimethoxybenzaldehyde are synthesized and characterized by elemental analysis, FT—IR and 1H NMR spectroscopy. <...> The crystal structure of 1 is determined by single crystal X-ray diffraction. <...> Each imino functional group (—C=N—) is coplanar with its adjacent benzene ring and the two benzene rings form a dihedral angle of 86.868(27). <...> INTRODUCTION Schiff bases are widely used ligands in transition metal complexes and generally in inorganic chemistry [ 1, 2 ]. <...> The most common examples of these compounds are prepared from salicylaldehyde derivatives to form a Schiff base ligand [ 9, 10 ]. <...> Our group is interested in the synthesis, characterization and crystal structure of new Schiff base compounds and their transition metal complexes [11—14 ]. <...> As a part of our ongoing studies, we report the synthesis and spectral characterization of Schiff bases prepared by the condensation of 3,4-dimethoxybenzaldehyde and two diamine derivatives (Scheme 1). 2Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran 3Institute of Physics, Czech Academy of Sciences, Prague 8, Czech Republic – . 728 – 732 Scheme 1. <...> All chemical shifts are reported in q units downfield from TMS. <...> General procedure for the synthesis of 1 and 2. 3,4-Dimethoxybenzaldehyde (0.4 mmol) and Infrared spectra were recorded using KBr disks on a FT—IR Perkin–Elmer spectrophotometer. 2,2-dimethylpropane-1,3-diamine (0.2 mmol) or butane-1,4-diamine (0.2 mmol) were dissolved in a mixture of methanol:chloroform (1:1 v/v, 20 ml) at room temperature. <...> After cooling the product was allowed to crystallize at room temperature. <...> Colorless crystals were formed at the bottom of the vessel after 5 <...>