Beiträge zur Chemie der Halogensilan-Addukte. XVI. Darstellung,Eigenschaften, Kristall- und Molekülstruktur von Hexa(N,N-dimethylformamid)silicium(IV)-tetraiodid, [Si(OCHN(CH3)2)6]I4

Contributions to the Chemistry of Halosilane Adducts. XVI. Synthesis, Properties, Crystal and Molecular Structure of Hexa(N,N-dimethylformamide)silicon(IV)-tetraiodide When SiI₄ is reacted with DMF ionization of all SiI bonds occurs to give ( 2 ) (reaction of pure components) or ( 1 ) (CHCl₃ solution). IR and ¹H-NMR spectra are in accordance with the formation of the octahedral cation Si · 6 DMF]⁴⁺, DMF being coordinated through the CO group. 1 is only slowly attacted by methanol or water DMF being liberated. 1 crystallizes in the monoclinic space group C2/c with 4 formula units per unit cell. The cation Si · 6 DMF]⁴⁺ has 1 symmetry. DMF is coordinated to Si in trans-configuration with respect to NMe₂ with donation by oxygen. SiO bond distances (175.4–177.2 pm) correspond to those of Si(O₂C₆H₄)₃]^2? and Si(acac)₃]⁺; an increase of the CO distances (126.1–128.9 pm) and decrease of the CN distances (126.4–129.1 pm) as compared to free DMF is observed. These changes and structural data are discussed.