Kristallstrukturen,Schwingungsspektren und Normalkoordinatenanalyse von fac‐(Et4N)[OsF3Cl3] und fac‐(Et4N)[IrF3Cl3]

Crystal Structures, Vibrational Spectra and Normal Coordinate Analysis of fac ‐(Et₄N)OsF₃Cl₃] and fac ‐(Et₄N)IrF₃Cl₃] By careful oxidation of the pure fluorochloroosmates(IV) or ‐iridates(IV) with BrF₃ or KBrF₄ in dichloromethane the mixed pentavalent complex anions fac‐OsF₃Cl₃]^– and fac‐IrF₃Cl₃]^– are formed. X‐ray structure determinations on single crystals have been performed of cis‐(Et₄N)OsF₃Cl₃] ( 1 ) (orthorhombic, space group Pbca, a = 11.225(5), b = 12.020(5), c = 21.873(5) Å, Z = 8) and fac‐(Et₄N)IrF₃Cl₃] ( 2 ) (orthorhombic, space group Pbca, a = 11.269(10) b = 12.049(1), c = 21.801(3) Å, Z = 8). Based on the molecular parameters of the X‐ray determinations the IR and Raman spectra for the anion of 1 and 2 have been assigned by normal coordinate analysis. The Osmium compound exhibits slightly higher valence force constants as compared with the Iridium complex: f_d(OsF) = 3.25, f_d(IrF) = 3.25, f_d(OsCl) = 2.35 and f_d(IrCl) = 2.25 mdyn/Å.