Isolierung und struktur des dreikernigen hexamethylbenzolzirkonium-komplexes [(Me6C6)3Zr3Cl6]2+ [(Al2Cl7)?]2

Crystals of the trinuclear complex (Me₆C₆)₃Zr₃Cl₆]Al₂Cl₇]₂ have been obtained from the reaction of ZrCl₄, hexamethylbenzene, AlCl₃, and Al in benzene. They are monoclinic, space group C2/2, with Z  4 and lattice parameters a 14.167(3), b 27.779(7), c 15.721(3) Å and β 94.27(4)°. The Zr atoms form a regular triangle. Each pair of Zr atoms is bridged by two Cl atoms. The fifth coordination site of each Zr atom is occupied by a h⁶-Me₆C₆ group. The cation is almost isostructural with the known trinuclear cation (Me₆C₆)₃Nb₃Cl₆]²⁺. Important distances are: ZrZr 3.35, ZrCl 2.56, and Zrcenter of C₆ ring 2.17 Å. One of the two independent Al₂Cl₇]^? anions occurs in a staggered conformation and one occurs in an eclipsed conformation.