Synthesis, characterisation and structural aspects of some symmetrical organotellurium halides based on <i>Bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride

<p><i>Bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (<b>2</b>) has been synthesised in good yield by reacting 1-(2-chloroethyl)-3,5-dimethylpyrazole with <i>in situ</i> prepared sodium telluride, Na<sub>2</sub>Te in an aqueous solution. A number of new organotellurium halides from <i>bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride have been synthesised by using different halogenating reagents. Reaction of <b>2</b> with bromine gave <i>bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride dibromide <b>(5a)</b> in addition to unexpected product <i>bis</i>(2-(4-bromo-3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride dibromide <b>(5b)</b>. All compounds were characterized by different spectroscopic techniques viz., <sup>1</sup>H, <sup>13</sup>C, <sup>125</sup>Te NMR, Mass spectroscopy, IR and CHN analysis. EDXRF studies have also been employed to confirm the identity of <b>5a</b> and <b>5b</b>. Thermal gravimetric analysis of <i>bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (IV) chloride (<b>4)</b> and <i>bis</i>(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (IV) iodide <b>(5c)</b> reveals the thermal stability of these molecules above 100°C. The X-ray studies of <b>5c</b> shows trigonal bipyramidal geometry around tellurium atom and intermolecular secondary interaction <i>viz.,</i> C-H π stacking between H23A and C22 showing a supramolecular packing between two molecules.</p>