The Binary Group 4 Azides [PPh4]2[Zr(N3)6] and [PPh4]2[Hf(N3)6]

The binary zirconium and hafnium polyazides [PPh₄]₂[M(N₃)₆] (M=Zr, Hf) were obtained in near quantitative yields from the corresponding metal fluorides MF₄ by fluoride–azide exchange reactions with Me₃SiN₃ in the presence of two equivalents of [PPh₄][N₃]. The novel polyazido compounds were characterized by their vibrational spectra and their X‐ray crystal structures. Both anion structures provide experimental evidence for near‐linear M‐N‐N coordination of metal azides. The species [M(N₃)₄], [M(N₃)₅]^? and [M(N₃)₆]^2? (M=Ti, Zr, Hf) were studied by quantum chemical calculations at the electronic structure density functional theory and MP2 levels.     

Oligonuclear Molecular Models of Intermetallic Phases: A Case Study on [Pd2Zn6Ga2(Cp*)5(CH3)3]

The synthesis, characterization, and theoretical investigation by means of quantum‐chemical calculations of an oligonuclear metal‐rich compound are presented. The reaction of homoleptic dinuclear palladium compound [Pd₂(μ‐GaCp*)₃(GaCp*)₂] with ZnMe₂ resulted in the formation of unprecedented ternary Pd/Ga/Zn compound [Pd₂Zn₆Ga₂(Cp*)₅(CH₃)₃] ( 1 ), which was analyzed by ¹H and ¹³C NMR spectroscopy, MS, elemental analysis, and single‐crystal X‐ray diffraction. Compound 1 consisted of two C_s‐symmetric molecular isomers, as revealed by NMR spectroscopy, at which distinct site‐preferences related to the Ga and Zn positions were observed by quantum‐chemical calculations. Structural characterization of compound 1 showed significantly different coordination environments for both palladium centers. Whilst one Pd atom sat in the central of a bi‐capped trigonal prism, thereby resulting in a formal 18‐valence electron fragment, {Pd(ZnMe)₂(ZnCp*)₄(GaMe)}, the other Pd atom occupied one capping unit, thereby resulting in a highly unsaturated 12‐valence electron fragment, {Pd(GaCp*)}. The bonding situation, as determined by atoms‐in‐molecules analysis (AIM), NBO partial charges, and molecular orbital (MO) analysis, pointed out that significant Pd? Pd interactions had a large stake in the stabilization of this unusual molecule. The characterization and quantum‐chemical calculations of compound 1 revealed distinct similarities to related M/Zn/Ga Hume–Rothery intermetallic solid‐state compounds, such as Ga/Zn‐exchange reactions, the site‐preferences of the Zn/Ga positions, and direct M? M bonding, which contributes to the overall stability of the metal‐rich compound.     

Synthesis and Reactivity of Functionalized Binary and Ternary Thiometallate Complexes [(RT)4S6], [(RSn)3S4]2−, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4− (R=C2H4COOH,CMe2CH2COMe; T=Ge,Sn)

Caged chalcogens : A series of novel, functionalized T_nS_m cages (T=Ge, Sn; n/m=4:6, 3:4) with terminal COO(H) or COMe groups were synthesized and show further reactivity toward Cu^I complexes (an example of which is shown here) and to hydrazines. This led to the generation of functionalized Cu/T/S clusters or the formation of Schiff bases at the C?O groups, respectively, with or without further fragmentation of the T/S core.

     

Cover Picture: Synthesis and Reactivity of Functionalized Binary and Ternary Thiometallate Complexes [(RT)4S6], [(RSn)3S4]2−, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4− (R=C2H4COOH,CMe2CH2COMe; T=Ge,Sn) (Chem. Eur. J. 27/2009)

Proof‐of‐principle is reported for a directed functionalization and derivatization of chalcogenidometallate cages with respect to the formation of hybrid compounds containing (M)/T/E semi‐conductor nodes (M=Cu; T=Ge, Sn; E=S). In their Full Paper on page 6595 ff. , S. Dehnen et al. show how it is possible to generate functionalized ternary CuSnS or CuGeS clusters and to transfer COMe ligands into CR(N–NH₂) or CR(N–NHPh) terminal groups by reaction of a series of novel, functionalized thiometallate cages [(RT)_nS_m] (n/m=4/6, 3/4), the R ligands of which are terminated by COO(H) or COMe.

     

The Vanadium(V) Oxoazides [VO(N3)3], [(bipy)VO(N3)3], and [VO(N3)5]2−

Vanadium(V) oxoazide [VO(N₃)₃] was prepared through a fluoride–azide exchange reaction between [VOF₃] and Me₃SiN₃ in acetonitrile solution. When the highly impact‐ and friction‐sensitive compound [VO(N₃)₃] was reacted with 2,2′‐bipyridine, the adduct [(bipy)VO(N₃)₃] was isolated. The reaction of [VO(N₃)₃] with [PPh₄]N₃ resulted in the formation and isolation of the salt [PPh₄]₂[VO(N₃)₅]. The adduct [(bipy)VO(N₃)₃] and the salt [PPh₄]₂₃[VO(N₃)₅] were characterized by vibrational spectroscopy and single‐crystal X‐ray structure determination, making these compounds the first structurally characterized vanadium(V) azides.     

Gas-Phase Structures of Potassium Tetrakis(hexafluoro- acetylacetonato) Lanthanide(III) Complexes [KLn(C5HF6O2)4] (Ln=La,Gd, Lu)

The molecular structures of potassium tetrakis(hexafluoroacetylacetonato)lanthanide(III) complexes [KLn(hfa)₄] (Ln=La, Gd, Lu; hfa=C₅HF₆O₂,) were studied by synchronous gas-phase electron diffraction/mass spectrometry (GED/MS) supported by quantum-chemical (DFT/PBE0) calculations. The compounds sublime congruently and the vapors contain a single molecular species: the heterobinuclear complex [KLn(hfa)₄]. All molecules are of C₁ symmetry with the lanthanide atom in the center of an LnO₈ coordination polyhedron, while the potassium atom is coordinated by three ligands with formation of three K−O and three K−F bonds. One hfa ligand is not bonded to the potassium atom. Topological analysis of the electron-density distributions confirmed the existence of ionic-type K−O and K−F bonding. The structures of the free [KLn(hfa)₄] molecules are compared with those of the related compounds [KDy(hfa)₄] and [KEr(hfa)₄] in their crystalline state. The complex nature of the chemical bonding is discussed on the basis of electron-density topology analyses.