The syntheses and vibrational spectra of tetrakis(carbonyl) palladium(II) and platinum(II) undecafluorodiantimonate(V), [Pd(CO)₄][Sb₂F₁₁]₂, and [Pt(CO)₄][Sb₂F₁₁]₂

Abstract

The reductive carbonylation of either platinum(1V) fluorosulfate, Pt(SO,F),, or palladium(II1) fluorosulfate, Pd(S03F),, either in solution of fluorosulfuric acid, HS03F, or in the solid state with CO at pressures of 0.5 to 2 atmospheres and at 25"C, affords in high yield complexes of the type M(C0)2(S03F),, M = Pd or Pt. The square-planar complexes are readily converted by solvolysis in liquid antimony(V) fluoride in the presence of CO at a pressure of about I atmosphere to white, thermally stable, salts of the composition [M(CO)4][Sb2F11]2r M = Pd or Pt, which contain the novel, square-planar cations [Pd(C0)4]Z+ and [Pt(CO),12+. The two cations exhibit the highest C O stretching frequencies reported so far, about 120 cm-' higher than in free CO, which suggests the absence or near absence of =-back donation for the M-CO bond.

Carbon Monoxide and Isocyanide Complexes of Trivalent Uranium Metallocenes

“…[1] In d-block transition metal compounds the extent of p backbonding decreases as the net positive charge on the complex or the oxidation state of the metal center increases, which gives rise to the general view that metals in high oxidation state cannot bind to carbon monoxide. This perception has changed with the recent isolation of cationic carbonyl species such as [Ir(CO) 6 ] 3 [2] and [M(CO) 4 ] 2 (M Pd, Pt) [3] in which little p backbonding appears to exist.…”

“…The traditional view that actinide metals (An) cannot bind to carbon monoxide has changed recently [4] with the development of the chemistry of trivalent [Cp' 3 An] derivatives of sterically demanding cyclopentadienyl ligands. [5] A monocarbonyl complex of composition [(Me 3 SiC 5 H 4 ) 3 U(CO)] has been detected in the solid state and in hexane [6] and, although it loses the coordinated CO when exposed to vacuum, the n Ä CO value of 1976 cm À1 suggests that the U III metallocene, of f 3 electron configuration, [7] acts as a p donor.…”

Synthesen und Schwingungsspektren der homoleptischen Acetonitrilkomplex-Kationen [Au(NCCH3)2]+, [Pd(NCCH3)4]2+, [Pt(NCCH3)4]2+ und des Adduktes CH3CN · SbF5. Kristallstrukturen der Salze [M(NCCH3)4][SbF6]2 · CH3CN, M = Pd, Pt

“…Eine interessante Korrelation wird erkennbar, wenn die Verschiebungen der CN-Streckschwingung m 2 zu freiem CH 3 CN, aufgefu È hrt in Tabelle 3 als Dm 2 (CN), mit der entsprechenden Dm (CO) fu È r die korrespondierenden Metall-Carbonylkationen [8,26] zu CO (2143 cm ±1 ) verglichen werden. Fu È r Pt 2+ ist Dm 2 (CN) + 89 cm ±1 und Dm (CO) + 146 cm ±1 .…”

Das Tetrakis(carbonyl)dioxoosmium(VI)-Kation:trans-[OsO2(CO)4]2+

“…[14,15] 1) Wie bei anderen Metallcarbonyl-Kationen [3] sind die Wellenzahlen der CO-Streckschwingungen ungewöhnlich hoch. Die nach Cotton und Kraihanzel [16] berechnete Kraftkonstante beträgt 20.7 Â 10 2 Nm À1 und ähnelt damit dem f co -Wert von 20.64 Â 10 2 Nm À1 des planar-quadratischen [Pt(CO) 4 ] 2 -Ions, [17] das ebenfalls mit dem [Sb 2 F 11 ] À -Gegenion im Komplexsalz vorliegt. Hieraus kann geschlossen werden, dass die Kationen Pt 2 und trans-OsO 2 2 gegenüber CO ähnliche Lewis-Säurestärken aufweisen.…”

“…45 cm À1 für [Pt(CO) 4 ] 2 . [17] Bei den CN-Streckschwingungen des trans-[OsO 2 (CN) 4 ] 2À -Ions [12] sind diese Abstände mit 6 bzw. 19 cm À1 noch kleiner, und beim linearen [Hg(CO) 2 ] 2 liegen die Banden der n s (CO)-und der n as (CO)-Schwingung sogar nur 3 cm À1 auseinander.…”