The solid-state structure of bis(pentafluorophenyl)zinc

Abstract

Using the published method of Wiedenbruch, bis(pentafluorophenyl)zinc, 1, was prepared from anhydrous ZnCl2 and 2 equiv. of LiC6F5 in diethyl ether. Base-free 1 was obtained in 60-65% yield by repeated distillation of the initially formed bis(diethyl) ether adduct of 1. The X-ray quality crystals of 1 were obtained from benzene solution. The molecular structure of 1 revealed a near linear geometry for the two-coordinate zinc center (C(1)-Zn-C(7) = 172.6(2)°), typical of monomeric ZnR2 derivatives. In the crystal structure, stacking interactions between C6F5 rings on adjacent molecules is a dominant motif, with ring centroid to ring centroid distances of 3.503 and 3.563 Å observed. A weak intermolecular C-F ...Zn interaction between F(2) and an adjacent zinc center, as judged by the close contact of 2.849(2) Å, also appears to be an important aspect of the crystal structure. Compound 1 is an effective but nonselective C6F5 transfer agent to BCl3; 1: monoclinic, space group P21/n, a = 11.902(2) Å, b = 7.732(2) Å, c = 13.735(2) Å, β = 110.58(1)°, V = 1183.4(4) Å3, Z = 4, R = 0.048, Rw = 0.069.Key words: organozinc complex, pentafluorophenyl transfer agent.