Hexakis(carbonyl)iron(II) undecafluorodiantimonate(V), [Fe(CO)6][Sb2F11]2, is conveniently prepared by the oxidative carbonylation of Fe(CO)5 with XeF2 as external oxidizer in the conjugate Brønsted-Lewis superacid HF−SbF5. The colorless compound crystallizes from the reaction medium in high purity. The molecular structure is obtained by single-crystal X-ray diffraction. The cation is a regular octahedron, while the vertex-shared di-octahedral [Sb2F11]- anion is distorted from D 4 h symmetry by bending and rotational processes, due to significant interionic interactions, primarily of the F···C type. Washing of [Fe(CO)6][Sb2F11]2 with anhydrous HF results in an unusual elution of SbF5 and the quantitative conversion to hexakis(carbonyl)iron(II) hexafluoroantimonate(V) [Fe(CO)6][SbF6]2. The molecular structure of the salt shows octahedral ions with slight tetragonal distortions for the cation (elongation) and the anion (compression). Both salts are thermally stable up to 150 °C. The averaged bond distances and the vibrational wavenumbers of [Fe(CO)6]2+ are nearly identical in both compounds. The [Fe(CO)6]2+ cation, the first and so far only isolated and structurally characterized dipositive, superelectrophilic carbonyl cation formed by a 3d-metal, is further characterized by a normal coordinate analysis (NCA). The obtained force constants are compared to those of the isoelectronic molecule Cr(CO)6. Changes in π-back-bonding affect the F CO/CO and F CO/MC interaction force constants more strongly than the stretching force constants F CO and F MC. All 13 fundamentals of [Fe(CO)6]2+ are detected and assigned with the help of the data obtained from the normal coordinate analysis and density functional calculations published previously. The electronic ground state 1A1g of the [Fe(CO)6]2+ cation is established by magnetic susceptibility measurements of polycrystalline [Fe(CO)6][SbF6]2 and [Fe(CO)6][Sb2F11]2 between 2 and 300 K. The magnetic impurity formed during synthesis is identified as Fe[SbF6]2 which has iron(II) in high spin (5T2g) ground state. Consistent with a diamagnetic ground state are the single line in the 57Fe Mössbauer spectrum (i.s. = −0.003(8) mm s-1 relative to α-Fe), obtained on polycrystalline samples and the single sharp line in the 13C NMR spectrum in DF solution at 178 ppm with J (57Fe-13C) of 19.2 Hz.

The crystal structures and photophysical properties of mononuclear [(RC N N)PtX](ClO4)n ((RC N N)=3-(6'-(2''-naphthyl)-2'-pyridyl)isoquinolinyl and derivatives; X=Cl, n=0; X=PPh(3) or PCy(3), n=1), dinuclear [(RC N N)2Pt2(mu-dppm)](ClO4)2 (dppm=bis(diphenyphosphino)methyl) and trinuclear [(RC N N)3Pt3(mu-dpmp)](ClO4)3 (dpmp=bis(diphenylphosphinomethyl)phenylphosphine) complexes are presented. The crystal structures show extensive intra- and/or intermolecular pipi interactions; the two (RC N N) planes of [(RC N N)2Pt2(mu-dppm)](ClO4)2 (R=Ph, 3,5-tBu2Ph or 3,5-(CF3)2Ph) are in a nearly eclipsed configuration with torsion angles close to 0 degrees. [(RC N N)PtCl], [(RC N N)2Pt2(mu-dppm)](ClO4)2, and [(RC N N)3Pt3(mu-dpmp)](ClO4)3 are strongly emissive with quantum yields of up to 0.68 in CH2Cl2 or MeCN solution at room temperature. The [(RC N N)PtCl] complexes have a high thermal stability (T(d)=470-549 degrees C). High-performance light-emitting devices containing [(RC N N)PtCl] (R=H or 3,5-tBu2Ph) as a light-emitting material have been fabricated; they have a maximum luminance of 63,000 cd m(-2) and CIE 1931 coordinates at x=0.36, y=0.54.

The reaction of tungsten hexacarbonyl, W(CO)6, with antimony(V) fluoride, SbF5, in the conjugate Brønsted-Lewis superacid HF-SbF5 at 40 degrees C produces quantitatively the salt [W(CO)6(FSbF5)][Sb2F11] as the main product. The observed 2e- oxidation without any loss of CO is unprecedented. The cation [W(CO)6(FSbF5)]+ is seven coordinated with a distorted C2v capped trigonal prismatic structure. [W(CO)6(FSbF5)][Sb2F11] crystallizes in the monoclinic space group P21 (No. 4). a = 8.2051(12) A, b = 16.511(3) A, c = 8.1432(2) A, beta = 111.5967(6) degrees, V = 1025.8(2) A3, Z = 2. Number of reflections measured = 9112, unique 4410. Residuals on F, I > 3 sigma (I): R (Rw) = 0.023 (0.023). In the [W(CO)6(FSbF5)]+ cation the FSbF5 group is very tightly coordinated to tungsten with the bridging fluorine nearly equidistant from W and Sb. The details of the molecular structure are compared to those to polymeric [[Mo(CO)4]2(cis-mu-F2SbF4)3]x[Sb2F11]x reported by us very recently.

The oxidation of molybdenum hexacarbonyl, Mo(CO)(6), by antimony(V) fluoride, SbF(5), at 60 degrees C in an excess of liquid SbF(5), produces polymeric [{Mo(CO)(4)}(2)(cis-&mgr;-F(2)SbF(4))(3)](x)()[Sb(2)F(11)](x)() as the main product. Recrystallization from HF-SbF(5) produces orange prismatic crystals, suitable for a single-crystal X-ray diffraction study. Crystals of [{Mo(CO)(4)}(2)(cis-&mgr;-F(2)SbF(4))(3)](x)()[Sb(2)F(11)](x)() are monoclinic, space group P2(1)/c (No. 14), a = 9.234(4) Å, b = 13.858(3) Å, c = 25.790(3) Å, beta = 90.532(2) degrees, V = 3300.1(12) Å(3), and Z = 4. The structure was solved by the Patterson method and refined with anisotropic thermal parameters to R = 0.048 and R(w)() = 0.047 (on F, 472 variables, 5116 observations with I >/= 3sigma(I)). In the polymeric cation, two pyramidal Mo(CO)(4) groups are linked by bridging, iso-bidentate F(2)SbF(4) groups first into eight-membered rings, which are then further linked into polymeric chains. The bridging F(2)SbF(4) groups and the [Sb(2)F(11)](-) anion are involved in significant intermolecular and interionic F.C contacts to the C atoms of the Mo(CO)(4) groups.