STRUCTURE OF A ZIRCONOXYBORANE HAVING A ZR-F-C BRIDGE

Reaction of [Et3NH][(C6F5)3BOH] with (Me5C5)2ZrMe2 produces methane an d (Me5C5)2ZrOB-(C6F5)3. Crystal data (at -175-degrees-C): P2(1)/n, a = 11.197(2) angstrom, b = 16.076(4) angstrom, c = 19.598(5) angstrom, b eta = 93.90(0)-degrees, Z = 4. The structure reveals a (C6F5)3B-O moie ty coordinated to zirconium. One of the C6F5 groups is oriented so tha t its ortho fluorine form a Zr-F-C bridge. The F-19 NMR spectrum at -8 8-degrees-C reveals a static structure in which the shielded Zr-F-C fl uorine resonates at -190.3 ppm. As the temperature is raised, all thre e C6F5 rings interconvert at the same rate in a process for which DELT AG(double dagger) = 10 +/- 0.5 kcal mol-1.