Synthesis and reactivity of para-substituted benzoylmethyltellurium(II and IV) compounds: observation of intermolecular C-H-O hydrogen bonding in the crystal structure of (p-MeOC6H4COCH2)2TeBr2

Bis(<i>p</i>-substituted benzoylmethyl)tellurium dibromides, (<i>p</i>-YC₆H₄COCH₂)₂TeBr₂, (y=H (<b>1a</b>), Me (<b>1b</b>), MeO (<b>1c</b>)) can be prepared<br>either by direct insertion of elemental Te across CRf-Br bonds (where C_Rf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (<i>p</i>-YC₆H₄COCH₂)₂Te (y = H (<b>2a</b>), Me (<b>2b</b>), MeO (<b>2c</b>)). Bis(<i>p</i>-substituted benzoylmethyl)tellurium dichlorides, (<i>p</i>-YC₆H₄COCH₂)₂TeCh (y = H (<b>3a</b>), Me (<b>3b</b>), MeO (<b>3c</b>)), are prepared by the reaction of the bis(<i>p</i>-substituted benzoylmethyl)tellurides <b>2a</b><b>--c </b>with S0₂Cl₂, whereas the corresponding diiodides (<i>p</i>-YC₆H₄COCH₂)₂Teh (y = H<br>(<b>4a</b>), Me (<b>4b</b>), MeO (<b>4c</b>)) can be obtained by the metathetical reaction of <b>la--c</b> with KI, or alternatively, by the oxidative addition of<br>iodine to <b>2a--c</b>. The reaction of <b>2a--c</b> with allyl bromide affords the diorganotellurium dibrornides <b>la--c</b>, rather than the expected<br>triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, ¹H, ^l3C and ¹²⁵Te<br>NMR spectroscopy (solution and solid-state) and in case of Ie also by X-ray crystallography. (<i>p</i>-MeOC₆H₄COCH₂)₂TeBr₂ (<b>1c</b>) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.<br>