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β-Keto phosphines derived from ferrocene. Syntheses and structures of [Ph2PCH2C(O)(η5-C5H4)Fe(η5-C5H5)] (L1) and trans-[PdCl2L12]

1989; Elsevier BV; Volume: 367; Issue: 1-2 Linguagem: Inglês

10.1016/0022-328x(89)87213-4

1872-8561

Pierre Braunstein, Tânia Mara Gomes Carneiro, Dominique Matt, F. Balegroune, Daniel Grandjean,

Carbon dioxide utilization in catalysis

The keto-phosphines [Ph2PCH2C(O)(η5-C5H4)Fe(η5-C5H5)] (L1), [{Ph2PCH2C(O)(η5-C5H4)}2Fe] (L2) and [{Ph2PCH2C(O)(η5-C5H4)}Fe{(η5-C5H4)C(O)Ch3}] (L3) were respectively prepared by the reaction of Ph2PCl with the lithium enolates derived from acetylferrocene for L1, and 1, 1′-bis(acetyl)ferrocene for L2 and L3. Ligand L1 crystallizes in the space group P1 with a 8.526(2), b 10.915(3), c12.822(3) Å, α 63.75(2), β 69.04(2), γ 70.77(2)°, V 978.4 Å3 and Z 2. The structure was solved and refined to R = 0.034 and Rw = 0.042. The C5-rings are eclipsed (3.2°) and the plane of the keto group forms a dihedral angle of 13.1° with the C5H4 plane. In the complexes cis- and trans-[PdCl2L12] (cis-1 and trans-1), [(o-C6H4CH2NMe2)PdC1L1] (2), cis-[PtCl2L12] (3), and [AuC1L1] (4) the phosphine ligand(s) behave as P-monodentate(s). The structure of rans-1 has been determined by X-ray diffraction at −145°C. The complex crystallizes in the monoclinic space group P21/c with a 10.622(7), b 12.647(7), c 15.59(1) Å, β 103.20(6)°, V 2039 Å3 and Z = 2. The structure was solved and refined to R = 0.037 and Rw = 0.053. The palladium atom lies on a centre of symmetry and the PdP and PdCl bond lengths are respectively 2.314(1) and 2.287(1) Å. The C5-rings of each ligand are slightly staggered (10.5°) and, as for L1, each keto group is almost parallel to the C5H4 plane (dihedral angle 8.9°). For the complex [CuL12)]BF4, NMR and IR solution spectroscopy has shown that there is a dynamic exchange between chelating and P-monodentate L1. The possibility of using L2 as a binucleating ligand was demonstrated by the preparation of the trinuclear complex [{(C10H8N)PdCl}2(μ-L2-P,P′)] (6). The enolato complexes cis-[M{Ph2PCHC(O)(η5-C5H4)Fe(η5-C5H5)}2] (M = Pd (7, M = Pt (8)), and [(o-C6H4CH2NMe2)Pd{Ph2PCHC(O)(η5-C5H4)Fe(η5-C5H5)}] (9) were prepared in high yield by the reaction of NaH with complexes 1, 3, and 2, respectively. Complex 9 reacts with dimethylacetylenedicarboxylate to yield the alkenyl complex [(o-C6H4CH2NMe2)Pd{Ph2PCH[C(O)(η5-C5H4)Fe(η5-C5H5)](MeO2CCCCO2M (10), resulting from carboncarbon coupling between the P bound enolate-carbon atom and the alkyne. All the complexes were characterized by elemental analysis, and 1H and 31P{1H} NMR and IR spectroscopy.