Supported by excess triethylamine, 7-azaindole (H L ) and dichlorodimethylsilane (Me2SiCl2), methyltrichlorosilane (MeSiCl3), and tetrachlorosilane (SiCl4) react, respectively, with formation of the 7-azaindol-1-yl-substituted silanes Me 2 Si L 2 , MeSi L 3 , and Si L 4 . In these compounds the silicon atom adopts [4+2], [4+3], and [4+4] coordination, respectively, with the pyridine N atoms of the 7-azaindol-1-yl groups capping the tetrahedral Si coordination sphere from distances of >3 Å. Two pyridine nitrogen atoms of these silanes replace the acetonitrile ligands of [PdCl2(NCMe)2], thus forming the complexes Me 2 Si( μ-L ) 2 PdCl 2 , MeSi L ( μ-L ) 2 PdCl 2 , and Si L 2 ( μ-L ) 2 PdCl 2 . In addition to capping of the silicon coordination sphere by the pyridine N atoms of the dangling 7-azaindol-1-yl groups (in MeSi L ( μ-L ) 2 PdCl 2 and Si L 2 ( μ-L ) 2 PdCl 2 ), these three palladium complexes exhibit capping of one tetrahedral face of the Si coordination sphere by the palladium atom (with Si···Pd separations of 3.34, 3.43, and 3.31 Å, respectively). According to computational analyses, the paddlewheel complex ClSi( μ-L ) 4 PdCl should be energetically favored over its isomer Si L 2 ( μ-L ) 2 PdCl 2 ; however, isomerization into this paddlewheel compound requires higher temperatures (150 °C) or the addition of a Lewis acid (such as GaCl3).

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