Stannate complexes

Although many alkali and alkaline earth stannate complexes have been structurally characterized, there are only a few reports of stannyl compounds containing true metal-Sn... 

The reaction is reversible (equation 3, step a) and, furthermore, a mixture of stannate complexes may undergo disproportionation to establish an equilibrium between homo-and mixed-ligand compounds (equation 3, step b). Moreover, the aryloxy mixed ligand stannates 36-38 are more stable than a 1 1 mixture of the corresponding dichloro- and bis(aryloxy)-stannates. Thus, the stability of the TAS stannates with TBP structures is highly affected by the nature of the equatorial organic groups and apical heteroatom substituents. 

The structure of most stannocenes is attributed to an sp hybridized tin atom, with two of the three hybrid orbitals interacting with the tt-systems of the rings and the third hybrid orbital containing the unshared electron pair. A tris(cyclopentadienyl)stannate complex (93) has been characterized it has a trigonal planar paddle-wheel geometry. ... 

Stille coupling of alkyl halides with alkenyl stannanes can be achieved using electron-rich alkyl phosphines ligands, combined with the addition of a fluoride source as a nucleophilic promoter (Scheme 2.69). ° This probably works by generating a stannate complex 2.201 that participates in transmetallation more readily than the original stannane, in a similar manner to the addition of Lewis bases to Suzuki reactions (Section 2.6). 

The pentacoordinate stannate complexes LiSnMe5 Ph [Pg.104]

The hydroformylation of 1-octene and the i-octenes was performed with the precursor [Pt(sixantphos)Cl2]. For the internal alkenes, selective tandem isomeriza-tion/hydroformylation toward n-nonanal was observed. In situ UV-Vis spectroscopic studies revealed rapid formation of the corresponding Pt-stannate complex upon reaction with SnCl2, whereas high-pressure in situ IR spectroscopy showed the formation of a Pt—CO species and a short-lived Pt— H species under syngas, as well as a rapid evolution of aldehyde product upon addition of 1-octene to the preformed catalyst in the IR autoclave [73]. 

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