摘要
Chlorotelluration of terminal acetylenes, RCHCH (R聽=聽Ph, rong class="boldFont">1rong>; 4-MeC6H4, rong class="boldFont">2rong>; t-Bu, rong class="boldFont">3rong>) with aryltellurium trichlorides and TeCl4 in refluxing toluene affords (2-chloro-2-organylvinyl)tellurium(IV) dichlorides, Ar[R(Cl)CCH]TeCl2 (Ar聽=聽1-C10H7, rong class="boldFont">1Aarong>-rong class="boldFont">3Aarong>; 2,4,6-Me3C6H2, rong class="boldFont">1Ba-3Barong>; 4-MeOC6H4, rong class="boldFont">1Carong>) and [t-Bu(Cl)CCH]2TeCl2, rong class="boldFont">3arong> respectively. These Te(IV) derivatives on reduction with Na2S2O5 give the corresponding vinyltellurides as oils, except (2,4,6-Me3C6H2)[Ph(Cl)CCH]Te (rong class="boldFont">1Brong>) which is a crystalline solid. The dibromides (rong class="boldFont">1Abrong>-rong class="boldFont">3Abrong>, rong class="boldFont">1Bbrong>-rong class="boldFont">3Bbrong>, rong class="boldFont">3brong>) and diiodides (rong class="boldFont">1Acrong>-rong class="boldFont">3Acrong>, rong class="boldFont">1Bcrong>-rong class="boldFont">3Bcrong>, rong class="boldFont">1Ccrong>) were obtained by the oxidative addition of dihalogens to the tellurides. The stereochemistry of the products has been established with the help of X-ray diffraction studies of rong class="boldFont">1Aarong>, rong class="boldFont">1Barong>, rong class="boldFont">1Bcrong>, rong class="boldFont">1Ccrong>, rong class="boldFont">3Aarong>, rong class="boldFont">3arong> and rong class="boldFont">1Brong>. Intramolecular Te鈰疌l attractive interactions appear to favor the (Z) conformation adopted by the 2-chloro-2-organylvinyltellurium group irrespective of the steric demand of the aryl ligand of the Te(IV) electrophile and the terminal acetylene substituent. The intermolecular Te鈰疿 secondary bonding interactions give rise to dimeric units in the lattices of 1-naphthyl- and anisyltellurium(IV) derivatives, but are absent among the mesityl analogues, consistent with the larger steric requirement of the latter ligand.