Funktionalisierte Alkinkomplexe von Wolfram(VI). Synthese und Kristallstrukturen von [WCl4(Et?Se?CC?Se?Et)(THF)] und [WCl4(Et?Te?CC?Te?Et)(THF)]

Functionalized Alkyne Complexes of Tungsten(VI). Syntheses and Crystal Structures of [WCl₄(Et? Se? C?C? Se? Et)(THF)] and [WCl₄(Et? Te? C?C? Te? Et)(THF)] The title compounds have been prepared by reactions of [WCl₄(SEt₂)₂] with the alkynes Et? X? C?C? X? Et (X = Se, Te) in CCl₄ solution and subsequent addition of tetrahydrofurane. Both complexes were characterized by crystal structure determinations. [WCl₄(Et? Se? C?C? Se? Et)(THF)]: Space group P2₁/n, Z = 4, structure determination with 2942 unique reflections, R = 0.038. Lattice dimensions at 20°C: a = 934.2, b = 1639.5, c = 1189.5 pm, β = 96.497°. [WCl₄(Et? Te? C?C? Te? Et)(THF)]: Space group P2₁/n, Z = 4, structure determination with 4097 unique reflections, R = 0.067, Lattice dimensions at ?70°C: a = 899.2, b = 1691.9, c = 1213.3 pm, β = 96.82°. The complexes have monomeric molecular structures with the oxygen atom of the THF molecules in trans-position to the side-on bound alkyne ligands.