252334-18-2

Upstream product

• 28069-69-4 tetrakis(trimethylphosphine)nickel⁽⁰⁾ 
• 185509-31-3 rac-4,6-di-tert-butyl-2-(tert-butyl(phenyl)phosphino)phenol 
• 264258-95-9 trans-[4,6-di-tert-butyl-2-(tert-butylphenylphosphanyl)phenolato[P,O]]methyl(trimethylphosphane)nickel(II) complex 

Relevant academic research and scientific papers

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.

Formation of η1-P-(2-phosphinophenol)Ni(0)(PMe3)3 and oxidation to cis/trans-bis(2-phosphinophenolato)nickel(II) complexes

o-Phosphinophenols 1 (P∩OH) react with equimolar amounts of Ni(PMe3)4 at low temperatures to give yellow Ni(0) complexes such as [(HO～P)Ni(PMe3)3] 2a with only P coordination of the P∩OH ligand. Oxidation of solutions of 1 and Ni(PMe3)4 by dioxygen leads to brown bis(o-phosphinophenolato-P∩O)nickel chelate complexes 3a-d. Structure elucidation by NMR is consistent with a cis-square planar geometry for 3a-c and a trans-square planar solution structure of the tert-butylphenylphosphino derivative 3d. The geometric isomers were distinguished by different ranges of phosphorus coordination shifts and 31P-13C-2 and 31P-13C-1 coupling constants. In the solid state, 3d adopts also a cis-square planar geometry. The steric stress of the substituents causes anti-orientation of the tert-butyl groups at phosphorus (R,R and S,S diastereoisomers) and a significant distorsion (22°) of the planes of the two five-membered rings. With less bulky substituents the R,S and S,R diastereoisomers are preferred as in the cis-square planar complex 3c with syn-orientation of the two isopropyl and phenyl groups, respectively.