Alkylcobalt Carbonyls. 7. (η1-Benzyl)-, (η3-Benzyl)-, and (η1-Phenylacetyl)cobalt Carbonyls

Article abstract of DOI:10.1021/ja00272a031

Benzyl- or phenylacetyl halides react with Na to yield an equilibrium mixture of (η¹-benzyl)-, (η³-benzyl)-, and (η¹-phenylacetyl)cobalt carbonyls.The equilibria are reversible and can be shifted by bubbling Ar or CO through the reaction mixture, resulting in enrichment of the CO-deficient and -rich derivatives, respectively.The mono-PPh3 derivatives of the η¹ complexes show similar behavior.Styrenes react with HCo(CO)4 to α-methyl derivatives of the former compounds and (β-phenylpropionyl)cobalt tetracarbonyls. 2,6-Cl2C6H3CH2COCo(CO)3PPh3 (VIIh) and η¹-<η⁶-(4-MeC6H4CH2)Cr(CO)3>Co(CO)4 (XIb) were characterized by X-ray crystallography as first examples of a nonfluorinated alkylcobalt tetracarbonyl and an alkylcobalt carbonyl.Complex VIIh crystallizes in a triclinic cell of dimensions a = 8.866 (2) Angstroem, b = 11.525 (4) Angstroem, and c = 14.338 (3) Angstroem, α = 74.74 (2) deg, β = 83.42 (2) deg, and γ = 80.84 (2) deg, Z = 2, space group <*>, and R = 0.052.The molecule consists of a trigonal bipyramid with axial acyl and PPh3 groups.Crystals of compound XIb show a monoclinic cell of dimensions a = 12.365 (2) Angstroem, b = 7.031 (1) Angstroem, c = 19.656 (3) Angstroem, β = 97.68 (1) deg, Z = 4, space group P2₁/c, and R = 0.077.The molecule shows a trigonal-bipyramidal geometry.