291538-16-4

Upstream product

• 291538-06-2 [Ta(C5Me5)(NtBu)Me(η2-C(Me)=N-2,6-Me2C6H3)] 
• 119072-54-7 2,6-dimethylphenyl isonitrile 

Relevant academic research and scientific papers

Insertion of isocyanides into tantalum-methyl and tantalum-amido bonds

The imido-amido complex [TaCp*(NtBu)Cl(NHtBu)], 1, was isolated from the reaction of [TaCp*Cl4] with 3 equiv of LiNHtBu. The dimethyl [TaCp*(NtBu)Me2], 2, and chloro-methyl [TaCp*(NtBu)ClMe], 3, complexes were obtained by methylation of [TaCp*(NtBu)Cl2] with 2 equiv of LiMe and 1 equiv of ZnMe2, respectively. Metathetical reactions of complex 3 with alkali metal salts MX (M = Na, X = OMe; M = Li, X = OtBu, NHtBu) afforded the new imido-methyl compounds [TaCp*(NtBu)MeX] (X = OMe 4, OtBu 5, NHtBu 6). Insertion of CNR (R = 2,6-Me2C6H3) into the Ta-NHtBu and Ta-Me bonds of the imido-pentamethylcyclopentadienyl complexes 1-6 gave the η2-iminocarbamoyl compound [TaCp*(NtBu)Cl-{η2-C(NHtBu)=NR}], 7, and the η2-iminoacyl compounds [TaCp*(NtBu)X{η2-C(Me)=NR}] (X = Me 8, Cl 9, OMe 10, OtBu 11, NHtBu 12), which under appropriate thermal conditions react with a second equivalent of CNR (R = 2,6-Me2C6H3) to give the double insertion imine-η2-iminoacyl products [TaCp*(NtBu)X{η2-C[C(Me)=NR]=NR}] (X = Me 13, Cl 14, OMe 15, OtBu 16, NHtBu 17). When compound 17 was heated at 140 °C for 3 days, an intramolecular proton migration occurred to give the η2-diamidoalkene complex [TaCp*(NtBu){η-NtBu-C(NHR)=C(Me)-η-NR}], 18. All of the new compounds were characterized by IR, 1H NMR, and 13C NMR spectroscopy, and the molecular structures of 14 and 18 were studied by X-ray diffraction methods.

Methyl(2-phosphanylphenolato[P,O])nickel(II) complexes - Synthesis, structure, and activity as ethene oligomerization catalysts

Reactions of various substituted 2-phosphanylphenols 1a-f with half- molar amounts of cis-[MeNi(μ-OMe)(PMe3)]2 have been found to yield square- planar methyl(2-phosphanylphenolato)(trimethylphosphane)nickel(II) complexes 2a-f. 2J(PP) coupling constants of 305-316 Hz at low temperature indicate a trans-configuration for the products, while broad 31P-NMR signals at room temperature can be attributed to rapid dissociation of PMe3. Reaction with excess 1 gave rigid bis(2-phosphanylphenolato)nickel(II) complexes as exemplified by 3e, whereas addition of PMe3 to 2a led to the penta- coordinate methyl(2-phosphanylphenolato)bis(trimethylphosphane)nickel(II) complex 4a. Higher yields of 4a and 4d were obtained by reactions of 1a and 1d with Me2Ni(PMe3)3. Single-crystal X-ray diffraction analyses of 3e and 4a have revealed the structures as square-planar trans-bis- and trigonal- bipyramidal mono(2-phosphanylphenolato)nickel(II) P(intersection set)O- chelate complexes, respectively. The methylnickel complexes 2 and 4 have been found to be effective one-component catalysts for the oligomerization of ethene. High conversions (> 96%) were achieved with the P-basic derivatives 2e, 2f, and 4d bearing one or two branched alkyl groups (isopropyl, tert- butyl), whereas the diphenylphosphanyl derivatives were less active; 4d gave shorter oligomers than 2e or 2f.