The first SiH22+ complex, dihydridotetrakis(3-picoline)silicon dichloride-tetrakis(chloroform), [H2Si(3pic)(4)]Cl-2 center dot 4 CHCl3: Formation, chemical equilibria, and structural investigation by NMR spectroscopy and single-crystal X-ray diffraction

Bis(dichlorosilyl) amine reacts in chloroform solution with 2-picoline to give H3SiCl, H2SiCl2, and HSiCl3, whereas with 3-picoline the two hypervalent silicon compounds H2SiCl2-(3pic)(2) and [H2Si(3pic)(4)]Cl-2 . 4 CHCl3 containing hexacoordinated Si atoms are formed. These complexes are in a chemical equilibrium with each other in chloroform solution, from which crystals of [H2Si(3pic)(4)]Cl-2 . 4 CHCl3 could be isolated. The crystal structure of the latter was determined by single-crystal X-ray diffraction. The complex can be regarded as an ''contact ion trio'' of [H2Si(3pic)(4)](2+) and two Cl- ions. The N-->Si bond lengths, r(Si-N) = 196.9(3) and 197.5(3) pm, are similar to those found in neutral hexacoordinated Si complexes. The data obtained from a (HH)-H-1-H-1 ROESY experiment suggest that dissolution has no significant impact on the molecular structure of [H2Si(3pic)(4)]Cl-2 . 4 CHCl3.