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 MexSn­(2-C6F4PPh2)4–x (1, x = 1; 2, x = 2) and ClSn­(2-C6F4PPh2)3 (3) were obtained from the reactions of 2-LiC6F4PPh2 with MeSnCl3 (3:1), Me2SnCl2 (2:1), or SnCl4 (3:1), respectively. The reactions of 2-LiC6F4PPh2 with SnCl4 in different stoichiometric ratios (4:1–1:1) gave 3 as the main product. Compound Cl2Sn­(2-C6F4PPh2)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-C6F4PPh2)2Pd­(κC-2-C6F4PPh2)] (5) and [Me2Sn­(μ-2-C6F4PPh2)­Pd­(κ2-2-C6F4PPh2)] (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-C6F4PPh2)3PdCl] (7) featuring a Sn–Pd bond and a pentacoordinate Pd atom. Transmetalation of MexSn­(2-C6F4PPh2)4–x (x = 1–3) with [Pd­(allyl)­Cl]2 gave MexClSn­(2-C6F4PPh2)3–x and [Pd­(allyl)­(μ-2-C6F4PPh2)]2. For x = 1, the compound MeClSn­(2-C6F4PPh2)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-C6F4PPh2)2PdCl] (8). The reductive elimination of allyl chloride was also observed in the reaction of 3 with [Pd­(allyl)­Cl]2, giving [Sn­(μ-2-C6F4PPh2)3PdCl] (7). All compounds have been characterized by means of multinuclear NMR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and selected compounds by 119Sn Mössbauer spectroscopy. Computational analyses (natural localized molecular orbital calculations) have provided insight into the Sn–Pd bonding of 5–8.