Tin(IV) Compounds with 2-C 6 F 4 PPh 2 Substituents and Their Reactivity toward Palladium(0): Formation of Tin-Palladium Complexes via Oxidative Addition.

The tin(IV) compounds Mex Sn(2-C6 F4 PPh2 )4-x (1, x = 1; 2, x = 2) and ClSn(2-C6 F4 PPh2 )3 (3) were obtained from the reactions of 2-LiC6 F4 PPh2 with MeSnCl3 (3:1), Me2 SnCl2 (2:1), or SnCl4 (3:1), respectively. The reactions of 2-LiC6 F4 PPh2 with SnCl4 in different stoichiometric ratios (4:1-1:1) gave 3 as the main product. Compound Cl2 Sn(2-C6 F4 PPh2 )2 (4) was formed in the transmetalation reaction of 3 and [AuCl(tht)] but could not be isolated. 1 and 2 react with palladium(0) sources {[Pd(PPh3 )4 ] and [Pd(allyl)Cp]} by the oxidative addition of one of their Sn-CAryl bonds to palladium(0) with formation of the heterobimetallic complexes [MeSn(μ-2-C6 F4 PPh2 )2 Pd(κC-2-C6 F4 PPh2 )] (5) and [Me2 Sn(μ-2-C6 F4 PPh2 )Pd(κ2 -2-C6 F4 PPh2 )] (6) featuring Sn-Pd bonds. The reaction of 3 with palladium(0) proceeds via the oxidative addition of the Sn-Cl bond to palladium(0), thus furnishing the complex [Sn(μ-2-C6 F4 PPh2 )3 PdCl] (7) featuring a Sn-Pd bond and a pentacoordinate Pd atom. Transmetalation of Mex Sn(2-C6 F4 PPh2 )4-x (x = 1-3) with [Pd(allyl)Cl]2 gave Mex ClSn(2-C6 F4 PPh2 )3-x and [Pd(allyl)(μ-2-C6 F4 PPh2 )]2 . For x = 1, the compound MeClSn(2-C6 F4 PPh2 )2 (generated in situ) reacted with another 1 equiv of [Pd(allyl)Cl]2 by the oxidative addition of the Sn-Cl bond to palladium(0) and the reductive elimination of allyl chloride, thus leading to [MeSn(μ-2-C6 F4 PPh2 )2 PdCl] (8). The reductive elimination of allyl chloride was also observed in the reaction of 3 with [Pd(allyl)Cl]2 , giving [Sn(μ-2-C6 F4 PPh2 )3 PdCl] (7). All compounds have been characterized by means of multinuclear NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and selected compounds by119 Sn Mössbauer spectroscopy. Computational analyses (natural localized molecular orbital calculations) have provided insight into the Sn-Pd bonding of 5-8.