THE SOLID-STATE STRUCTURE OF BIS(PENTAFLUOROPHENYL)ZINC

Using the published method of Wiedenbruch, bis(pentafluorophenyl)zinc, 1, was prepared from anhydrous ZnCl2 and 2 equiv. of LiC6F5 in diethy l ether. Base-free 1 was obtained in 60-65% yield by repeated distilla tion of the initially formed bis(diethyl) ether adduct of 1. The X-ray quality crystals of 1 were obtained from benzene solution. The molecu lar structure of 1 revealed a near linear geometry for the two-coordin ate zinc center (C(1)-Zn-C(7) = 172.6(2)degrees), typical of monomeric ZnR2 derivatives. In the crystal structure, stacking interactions bet ween C6F5 rings on adjacent molecules is a dominant motif, with ring c entroid to ring centroid distances of 3.503 and 3.563 Angstrom observe d. A weak intermolecular C-F ... Zn interaction between F(2) and an ad jacent zinc center, as judged by the close contact of 2.849(2) Angstro m, also appears to be an important aspect of the crystal structure. Co mpound 1 is an effective but nonselective C6F5 transfer agent to BCl3; 1: monoclinic, space group P2(1)/n, a = 11.902(2) Angstrom, b = 7.732 (2) Angstrom, c = 13.735(2) Angstrom, beta = 110.58(1)degrees, V = 118 3.4(4) Angstrom(3), Z = 4, R = 0.048, R-w = 0.069.