The Reaction of 2-C(R)=CHR>(μ-PPh2)(CO)7> (R = H or Ph) with Nucleophiles: X-Ray Crystal Structures of (μ-PPh2)(CO)6>, (CO)9>, , μ-PPh2)(CO)6(CNBut)2>,

DOI: 10.1039/DT9870002669

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 2669 - 2682 (1987)

Update date:2022-07-30

Topics:

Authors:

Henrick, Kim

McPartlin, Mary

Iggo, Jonathan A.

Kemball, Alan C.

Mays, Martin J.

Raithby, Paul R.

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Article abstract of DOI:10.1039/DT9870002669

The reaction of 2-C(R)=CHR>(μ-PPh2)(CO)7> (R = H or Ph) with the nucleophiles H^-, CO, Bu^tNC and PEt3 have been studied and the structures of six of the products of these reactions have been determined by X-ray diffraction.In all of the products the nucleophile is bound to the metal but the course of a given reaction is highly sensitive both to the nature of the nucleophile and to the substituents on the μ-vinyl group.With H^- as the nucleophile and R = Ph the principal products is the μ-acyl complex (μ-PPh2)(CO06> in which the Mn-Mn distance of 2.813(1) Angstroem indicates the presence of a metal-metal bond.With CO as the nucleophile a P-C coupling reaction between the μ-PPh2 and the μ-vinyl ligand is induced (R = H or Ph) leading via (CO)8> to the final product (CO)9> which results from the addition of a second molecule of the nucleophile.The structures of both of these P-C linked complexes have been determined by X-ray diffraction, the former for R = H and the latter for R = Ph.The Mn-Mn separations for these two complexes are 2.957(1) and 2.941(1) Angstroem, respectively.With Bu^tNC as the nucleophile and R = Ph a μ-acyl complex (μ-PPh2)(CO)6(CNBu^t)2>, is also obtained as the principal product but the X-ray diffraction study reveals an Mn-Mn separation of 3.820(2) Angstroem indicating the absence of a metal-metal iteraction.A second product obtained in this reaction has been shown by an X-ray diffraction study to be the Bu^tNC-substituted vinyl derivative 2-C(Ph)=CHPh>(μ-PPh2)(CO)6(CNBu^t)> in which the Mn-Mn distance is 2.758(1) Angstroem.With phosphines as the nucleophiles, complex mixtures of products are, in general, obtained and these products have not all been characterised.With PEt3 and R = H, however, the principal products is the P-C linked complex and this has been isolated and structurally characterised by an X-ray diffraction study which shows that the Mn-Mn distance is 2.989(3) Angstroem.Finally, with Bu^tNC as the nucleophile and R = H a compound is formed which is tentatively assigned a structure analogous to that obtained with PEt3 as the nucleophile.Some reaction pathways which account for the formation of the major products in the above reactions are proposed and discussed.