Synthesis and crystal structures of oxonium ion complexes of 21-crown-7 and dibenzo-30-crown-10

Abstract

The reactions of [W(CO)₆] with 21-crown-7 (1,4,7,10,13,16,19-heptaoxacyclohenicosane) or dibenzo-30-crown-10 (6,7,9,10,12,13,15,16,23,24,26,27,29,30,32,33-hexadecahydrodibenzo[b,q][1,4,7,10,13,16,19,22,25,28]decaoxacyclotriacontine) in the presence of water and HCl(g) in toluene have been explored. They were promoted by the use of UV radiation and formed liquid clathrates almost immediately. In each case, oxidation of the tungsten center from either 0 to +2, +5 or +6 occurred. In the reaction of 21-crown-7 with [W(CO)₆] structural data suggest that the H₅O₂⁺ ion is selectively co-ordinated through hydrogen bonds to the 21-crown ether, in the tungsten(VI) complex, [H₅O₂⁺·21-crown-7][WOCl₅^–] 1, which crystallized from the liquid clathrate layer. For the reaction of dibenzo-30-crown-10 with [W(CO)₆] initially the tungsten(II) complex [2H₃O⁺·dibenzo-30-crown-10][W(CO)₄Cl₃^–]₂·2C₆H₅Me 2 formed. Upon exposure of 2 to the atmosphere for ca. 30 min the tungsten(V) complex [2H₃O⁺·dibenzo-30-crown-10][WOCl₄(H₂O)^–]₂ 3 was produced. The structures of each of these complexes were established by X-ray crystallography.