title: Stabilization of low valent silicon fluorides in the coordination sphere of transition metals.
abstract: Silicon(II) fluoride is unstable; therefore, isolation of the stable species is highly challenging and was not successful during the last 45 years. SiF(2) is generally generated in the gas phase at very high temperatures (~1100-1200 °C) and low pressures and readily disproportionates or polymerizes. We accomplished the syntheses of stable silicon(II) fluoride species by coordination of silicon(II) to transition metal carbonyls. Silicon(II) fluoride compounds L(F)Si·M(CO)(5) {M = Cr (4), Mo (5), W(6)} (L = PhC(NtBu)(2)) were prepared by metathesis reaction from the corresponding chloride with Me(3)SnF. However, the chloride derivatives L(Cl)Si·M(CO)(5) {M = Cr (1), Mo (2), W(3)} (L = PhC(NtBu)(2)) were prepared by the treatment of transition metal carbonyls with L(Cl)Si. Direct fluorination of L(Cl)Si with Me(3)SnF resulted in oxidative addition products. Compounds 4-6 are stable at ambient temperature under an inert atmosphere of nitrogen. Compounds 4-6 were characterized by NMR spectroscopy, EI-MS spectrometry, and elemental analysis. The molecular structures of 4 and 6 were unambiguously established by single-crystal X-ray diffraction. Compounds 4 and 6 are the first structurally characterized fluorides, after the discovery of SiF(2) about four and a half decades ago.
authors.affiliation: Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany.
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Azhakar
authors.forename: Rajendra S
authors.initials: RS
authors.lastname: Ghadwal
authors.forename: Herbert W
authors.initials: HW
authors.lastname: Roesky
authors.forename: Hilke
authors.initials: H
authors.lastname: Wolf
authors.forename: Dietmar
authors.initials: D
authors.lastname: Stalke
mesh_terms: D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D017655:Silicon Compounds; D028561:Transition Elements; C054375:silicon fluoride; D005459:Fluorides