Functionalized Organotellurium Halides: Synthesis, Characterization, and Observation of Intra- and Intermolecular Secondary Bonding

Activated tellurium, but not selenium., reacts with para-substituted benzoyl-methyl bromides as well as with iodoacetamide at their melting points in absence of a solvent to give bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC6H4COCH2)(2)TeBr2, (Y = H, Me, and MeO) and bis(acetamido)tellurium diiodide, (H2NCOCH2)(2)Tel(2), respectively. Quicle reduction of (p-YC6H4COCH2)(2)TeBr2, with sodium. metabisulphite in a two-phase system yields crystalline (p-YC6H4COCH2)(2)Te. These tellurides undergo smooth oxidative addition of halogens, interhalogen ICl or a pseudohalogen (SCN)(2), Intramolecular coordination of the carbonyl group in these functionalized diorganotellurium. dillalides is evident from IR spectra and shorter (TeO)-O-... (carbonyl) distances in comparison to the sum of van der Waals radii and completes six coordination around Te atom. Not unexpectedly, therefore, intermolecular secondary bonding effects of the type (TeO)-O-..., (TeX)-X-... and (XX)-X-... are missing in (PhCOCH2)(2)TeBr2, (p-MeOC6H4COCH2)TeBr2 and (PhCoCH2)(2)TeI2. Instead, these compounds provide rare examples, among organotellurium compounds, of supramolecular architecture, where C-H.. Br and C-(HO)-O-... hydrogen bonds and pi-pi (phenyl ring) interactions appear to be the non-covalent intermolecular associative forces that dominate the crystal packing.