Tin(IV) Compounds with 2-C6F4PPh2 Substituents and Their Reactivity toward Palladium(0): Formation of Tin–Palladium Complexes via Oxidative Addition

The tin(IV) compounds Me x Sn(2-C 6 F 4 PPh 2 ) 4– x ( 1, x = 1; 2, x = 2) and ClSn(2-C 6 F 4 PPh 2 ) 3 ( 3 ) were obtained from the reactions of 2-LiC 6 F 4 PPh 2 with MeSnCl 3 (3:1), Me 2 SnCl 2 (2:1), or SnCl 4 (3:1), respectively. The reactions of 2-LiC 6 F 4 PPh 2 with SnCl 4 in different stoichiometric ratios (4:1–1:1) gave 3 as the main product. Compound Cl 2 Sn(2-C 6 F 4 PPh 2 ) 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(PPh 3 ) 4 ] and [Pd(allyl)Cp]} by the oxidative addition of one of their Sn–C Aryl bonds to palladium(0) with formation of the heterobimetallic complexes [MeSn(μ-2-C 6 F 4 PPh 2 ) 2 Pd( κC -2-C 6 F 4 PPh 2 )] ( 5 ) and [Me 2 Sn(μ-2-C 6 F 4 PPh 2 )Pd(κ 2 -2-C 6 F 4 PPh 2 )] ( 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-C 6 F 4 PPh 2 ) 3 PdCl] ( 7 ) featuring a Sn–Pd bond and a pentacoordinate Pd atom. Transmetalation of Me x Sn(2-C 6 F 4 PPh 2 ) 4– x ( x = 1–3) with [Pd(allyl)Cl] 2 gave Me x ClSn(2-C 6 F 4 PPh 2 ) 3– x and [Pd(allyl)(μ-2-C 6 F 4 PPh 2 )] 2 . For x = 1, the compound MeClSn(2-C 6 F 4 PPh 2 ) 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-C 6 F 4 PPh 2 ) 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-C 6 F 4 PPh 2 ) 3 PdCl] ( 7 ). All compounds have been characterized by means of multinuclear NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and selected compounds by 119 Sn Mössbauer spectroscopy. Computational analyses (natural localized molecular orbital calculations) have provided insight into the Sn–Pd bonding of 5 – 8 .