On the silicon-silicon bonds σ-coordinated to group 10 transition metals

• Published in: Inorganica Chimica Acta 2019-02, Vol.486, p.449-457
• Main Author: Aullón, Gabriel
• Format: Article
• Language: English
• Subjects: Chemical bonds; Hydrogen atoms; Infrared analysis; NMR; Nuclear magnetic resonance; Palladium; Silanes; Silicon; Silicon compounds; Transition metals
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2018.10.056

A theoretical study predicts the different behavior of group 10 metals toward a disilane bond: nickel and palladium compounds prefer σ(Si-Si) coordination to transition metal center, platinum ones stabilize bis(silyl) complexes. [Display omitted] •Polysilyl-palladium systems are unstable and evolve to give silicon-silicon bonds.•Agostic interactions compete with the coordination of σ(SiSi) bonds to late transition metals.•Pd cannot be replaced by Pt, whereas Ni may be a good candidate for these reactions.•IR and 29Si NMR spectroscopies can identify σ(SiSi) bonds coordinated to metals.•A peculiar behaviour of the Si-Si single bond is found by structural analysis. A theoretical study of silicon-group 10 compounds containing coordinated σ-bonds is presented. The hexacoordinated {Pd(SiR3)6} unit is unstable and it evolves to different cores having silicon–silicon bonds, in which there are two disilane fragments and two silyl-palladium bonds. However, the coordination of σ(Si-Si) is difficult due competitive interactions involving agostic hydrogen atoms of silanes, and they should be avoided by blocking its positions, such as substituents or polymetallic species. All minima have been characterized by vibrational analysis, and can allow us to understand experimental infrared spectroscopy. Moreover, unexpected experimental data for 29Si nuclear magnetic resonance are confirmed and reproduced by theoretical calculations.