Reactions of SF6 with organotitanium and organozirconium complexes: the "inert" SF6 as a reactive fluorinating agent.

The normally remarkably inert SF6 has been found to be quite reactive toward low valent organometallic compounds, under conditions in which usually powerful fluorinating agents may be less reactive. Reaction of SF6 with Ti[1,3-C5H3(t-Bu)2](6,6-dmch)(PMe3), for example, leads to {Ti[1,3-C5H3(t-Bu)2]F2}4 (dmch = dimethylcyclohexadienyl), whose structure is based on a cube of fluoride ions with the ligated titanium centers situated above four coplanar face centers.

Pentadienyls vs cyclopentadienyls and reversal of metal-ligand bonding affinity with metal oxidation state: synthesis, molecular structures, and electronic structures of high-valent zirconium pentadienyl complexes.

Molecules of the form Cp(6,6-dmch)ZrX(2) (Cp = eta(5)-cyclopentadienyl, X = Cl, Br, I; 6,6-dmch = eta(5)-6,6-dimethylcyclohexadienyl) have been synthesized, and the molecular and electronic structures have been investigated. These molecules allow direct comparison of the bonding and properties of pentadienyl and cyclopentadienyl ligands in the same high-oxidation-state metal complexes. Unlike the well-known Cp(2)ZrX(2) analogues, these Cp(6,6-dmch)ZrX(2) molecules are intensely colored, indicating significantly different relative energies of the frontier orbitals.

Syntheses and structural systematics of trialkylphosphine complexes of open titanocenes, zirconocenes and hafnocenes.

The synthesis and characterization of the open hafnocene, Hf(2,4-C7H11)2(PMe3)(C7H11 = dimethylpentadienyl), is reported. Additionally, a much improved synthetic procedure has been developed for Hf(2,4-C7H11)2(PEt3). Structural data have been obtained for these complexes, and for Ti(2,4-C7H11)2(PEt3) and Zr(2,4-C7H11)2(PMe3), thereby allowing for detailed comparisons between all M(2,4-C7H11)2(PX3) species (M = Ti, Zr, Hf; X = Me, Et).

Synthesis of Bridged Bicyclic Ethers and Fused Oxetanes from Pyran-4-ones via Tandem Solvent Trapping and Norrish Type II Cyclization(1).

Polyalkyl pyran-4-ones 1a-c were irradiated in methanol or ethanol. Although the expected solvent trapping products 3 could be observed, extended irradiation times allowed exclusive formation of secondary photoproducts 4 and 5 in combined yields of 37-64%. These bicyclic compounds are believed to arise from gamma-hydrogen abstraction by the excited enone chromophore of 3, followed by closure of the resulting biradical through one of two possible pathways.