Peihua Yu

Synthesis and spectroscopic characterization of a series of substituted cyclopentadienyl Group 4 fluorides; crystal structure of the acetylacetonato complex [(acac)2(η-C5Me5)Zr(µ-F)SnMe3Cl]

A series of mono- and di-substituted cyclopentadienyl Group 4 fluorides [Ti{η-C5H3R(R′)-1,3}nFm], (n=m= 2 and n= 1, m= 3; R = H or SiMe3; R′= H, Me or SiMe3), [Ti(η-C5Me5)2F2] and [Zr(η-C5H5)2F2] have been prepared via the reaction of the corresponding chlorides with SnMe3F. The compounds have been characterized by means of 1H and 19F NMR, IR and mass spectroscopy and chemical analyses. The solvent dependence of the reactions using SnMe3F is discussed. To demonstrate the wide applicability of this fluorinating system the acetylacetonatofluoro complex [(acac)2(η-C5Me5)Zr(µ-F)SnMe3Cl] has been prepared and its crystal structure determined.

Organotitanium Fluorides as Matrices for Trapping Molecular ZnF2 and MeZnF

Trapped as molecular solids, the transition metal fluorides ZnF(2) and MeZnF-the latter isolated for the first time-exist as adducts in [(Cp*TiF(3))(8)(ZnF(2))(3)] (1) and [(Cp*TiF(3))(4)(MeZnF)(2)] (2), respectively. Compounds 1 and 2 were obtained in reactions of [Cp*TiF(3)] (Cp*=C(5)Me(5)) with ZnMe(2) and Me(3)SnF in various molar ratios. The single-crystal structure of 1 is shown here; the unlabeled circles are F atoms.

Formation of Adamantane‐Like Structures by Reaction of Titanocene Fluorides with an Iminoalane

Fluorine-nitrogen metathesis in the reaction of a cyclic iminoalane with titanocene fluorides results in unexpected cage compounds. Treatment of one of these compounds with diethyl ether leads to 1, which contains a titanium-nitrogen double bond stabilized intramolecularly by fluorine.

The Activation of Metal-Fluorine Bonds in Compounds of Group 4 by Aluminum Alkyls

In recent years we have developed the facile preparation of group 47#x2013;6 and main-group fluorides from the corresponding chlorides using Me3SnF as a fluorinating reagent. Reactions of group 4 organometallic fluorides with alkyls of group 13 elements, especially those of aluminum, are of particular interest with regard to the mechanism of homogeneous catalysis for the polymerization of olefins. The formation of adducts of group 4 metallocene halides with AlMe3 is assumed to be the first step of activation of a polymerization catalyst when AlMe3 containing methylaluminoxane (MAO) is used. The following methylation of the metallocene centers is markedly facilitated by this electrophilic support. In order to understand the catalytic activity of those compounds, it is neccessary to examine whether a selective coordination of the fluorine atoms and an exchange for alkyl and amino groups, respectively, is possible using aluminum compounds.