Lawrence B. Kool

Preparation, characterization and reactivity of Cp2M(PMe3)2 complexes (M = Ti, Zr): the molecular structure of Cp2Zr(PMe3)2

Abstract The reduction of Cp2MCl2 (M = Ti, Zr) with magnesium in THF in the presence of PMe3 affords the complexes Cp2M(PMe3)2 in high yields. These compounds lose one or both PMe3 ligands under very mild conditions. Cp2Ti(PMe3)2 reacts readily with CH3I, CH3C(O)Cl, PhSSPh, Me2PCH2CH2PMe2, CO, RCN (R = Me, t-Bu) or (RN)2S (R = t-Bu, Me3Si) to give the corresponding titanocene products. The structure of Cp2Zr(PMe3)2 has been determined by X-ray diffraction; the structural parameters are similar to those of the titanium analog Cp2Ti(PMe3)2 except that the Zr-P and Zr-C distances are longer.

Reactions of Cp2M(PMe3)2 complexes (M = Ti, Zr) with acetylenes. Selective formation of trans-polyacetylene at low temperatures

Abstract The reaction of Cp2Ti(PMe3)2 with C2H2 gives the substitution product Cp2Ti(C2H2)(PMe3), the titanacyclopentadiene Cp2Ti(C4H4), and trans-polyacetylene. A mechanism for the catalytic formation of polyacetylene is proposed. Substituted acetylens R1C2R2 (R1 ≠ R2 = H, Me, Ph) react with Cp2Ti(PMe3)2 in an analogous manner except that no polyalkynes are produced. The Zr derivative Cp2Zr(PMe3)2 and C2H2 yield the labile Cp2Zr(C2H2) (PMe3).

Synthesis and characterization of (η1:η5-C5H4)-bridged group IV metallocene derivatives. X-ray structure of {Cp(μ-[η1:η5-C5H4])Ti[PMe3]}2

Abstract Reduction of Cp2MCl2 (M = Ti, Zr and Hf) with magnesium in the presence of one equivalent of PMe3 gives the dimeric (η1 : η5-C5H4)-bridged complexes {Cp(μ-[η1 : η5-C5H4])M[PMe3]}2 in excellent yields. The 1H, 13C and 31P NMR spectra are presented, together with the results of an X-ray structure determination of the titanium derivative.

Structural and spectroscopic comparison of the complexes Cp2M(PMe3)(CO) (M = Ti, Zr, Hf), (C9H7)2Ti(PMe3)(CO) and Cp2TiCl(PMe3); X-ray structures of Cp2Ti(PMe3)(CO) and Cp2TiCl(PMe3)

Abstract The photo-induced reaction of Cp′ 2 M(CO) 2 complexes (Cp′ = C 5 H 5 , C 5 H 5 ; M = Ti, Zr, Hf) with trimethylphosphine provides the substitution products Cp′ 2 M(PMe 3 )(CO) in high yields. Cp 2 TiCl(PMe 3 ) is obtained by the reduction of Cp 2 TiCl 2 with magnesium in the presence of PMe 3 . The spectroscopic data for these complexes and the X-ray structures of Cp 2 Ti(PMe 3 )(CO) and Cp 2 TiCl(PMe 3 ) are compared.

Zweikernige Dicyclopentadienyltitan-Komplexe mit Sauerstoff-Brücke. Die Struktur von [Cp2Ti]2(μ-O)

Abstract In the presence of traces of oxygen, the tetramethylethylenediamine-stabilized fragment [Cp 2 Ti] is converted into the oxo-bridged titanium(III) complex [Cp 2 Ti] 2 (μ-O). According to the X-ray crystallographic structure determination, the molecule [Cp 2 Ti] 2 (μ-O) posseses (crystallographic) C 2 symmetry with Ti-O distances of 1.838(1) A and a Ti-O angle of 170.9(4)°.

Synthesis and characterization of bis-isonitrile complexes Cp2M(CNR)2 (M = Ti, Zr; R = 2,6-dimethylphenyl)

Abstract Bis-isonitrile complexes Cp 2 M(CNR) 2 (M  Ti, Zr), where RNC is the sterically hindered 2,6-dimethylphenyl isonitrile, can be prepared in high yield by reduction of Cp 2 MCl 2 with magnesium in THF solution in the presence of the isonitrile. 1 H NMR spectroscopy reveals that with the titanium complex dissociation of the isonitrile ligands takes place in solution.

A diazoalkane complex of titanium

(cp)2Ti(PMe3)2(cp =η5-C5H5) and (cp)2Ti(CO)(PMe3) react with diphenyldiazomethane to yield (cp)2Ti(NNCPh2)(PMe3), the crystal structure of which has been determined, containing a monodentate diazoalkane ligand end-on co-ordinated through nitrogen.