Synthesis and characterization of tetra-armed-thiosemicarbazone and its salen/salophen capped transition metal complexes: Investigation of their thermal and magnetic properties

2016-10-27T17:10:11Z (GMT) by Şaban Uysal Mustafa Er Hakan Tahtaci
<p>In this work, we aimed to synthesize and characterize a novel tetra-directional ligand, (2<i>E</i>,2′<i>E</i>)-2,2′-((((2-(1,3-bis(4-((<i>E</i>)-(2-carbamothioylhydrazono)methyl)phenoxy)propan-2-ylidene)propane-1,3-diyl)bis(oxy))bis(4,1-phenylene))bis(methanylylidene))bis(hydrazinecarbothioamide) <b>(5),</b> including thiosemicarbazone group and its novel tetra-directional-tetra-nuclear Schiff base complexes. For this purpose, we used 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene <b>(2)</b> as starting material. 4,4′-((2-(1,3-Bis(4-formylphenoxy)propan-2-ylidene)propane-1,3-diyl) bis(oxy))dibenzaldehyde <b>(3)</b> was synthesized by the reaction of an equivalent 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene<b> (2)</b> and 4 equivalents of 4-hydroxybenzaldehyde. Then, compound <b>5</b> was synthesized in high yield (86%) by a condensation reaction of compound <b>3</b> with thiosemicarbazide <b>(4)</b>. Finally, four novel tetra-nuclear Cr(III) or Fe(III) complexes of compound <b>5</b> were synthesized. The synthesized compounds were characterized using elemental analyses, <sup>1</sup>H NMR, Fourier transform–infrared spectrometry, liquid chromatography–mass spectrometry (ESI<sup>+</sup>), and thermal analyses. The metal ratios of the prepared complexes were determined using an atomic absorption spectrophotometer. We also investigated their effects on the magnetic behaviors of [salen, salophen, Cr(III)/Fe(III)] capped complexes. The complexes were found to be low-spin distorted octahedral Fe(III) and distorted octahedral Cr(III), all bridged by thiosemicarbazone.</p>