REACTIONS OF ZR(ETA-6-BENZENE)(ALCL4)2 WITH ALKYNES - CYCLOOLIGOMERIZATION REACTIONS AND CRYSTAL AND MOLECULAR-STRUCTURE OF THE 7-MEMBERED METALLACYCLE [ZRCPH(CPH)4CPH][(MU-CL)2ALCL2]2

Abstract: Benzene solutions of the Zr(II) complex Zr(eta-6-benzene)(AlCl4)2 (1) catalyze the cyclotrimerization of 2-butyne to hexamethyl Dewar benzene (HMDB) and hexamethylbenzene (HMB) at room temperature. HMDB is the predominant initial product, followed by its isomerization to HMB. When diphenylacetylene was reacted with the (arene)zirconium(II) complex, the title metallacycle derivative was obtained, whose crystal and molecular structure was studied by X-ray diffraction methods. For [activated ZrCPh(CPh)4CPh][(mu-Cl)2AlCl2]2, C42H30Al2Cl8Zr.0.5C7H16, M(r) = 1013.6, monoclinic, space group P2(1)/n, a = 14.784 (2) angstrom, b = 16.390 (2) angstrom, c = 22.984 (2) angstrom, beta = 107.17 (1)-degrees, Z = 4, V = 5321 (14) angstrom 3, D(calc) = 1.265 g cm-3, average transmission factor 0.989, and mu = 60.5 cm-1. The structure consists of a seven-membered cycle including zirconium, the coordination sphere of the latter being completed by four chlorine atoms from the two AlCl4 groups