Consecutive fragmentations of the cubane-like zinc cluster [CH3Zn(O-i-C3H7)]4 upon electron ionization.

The sequential dissociations of the tetranuclear zinc cluster-ion [(CH3)3Zn4(O-i-C3H7)4]+ obtained by dissociative electron ionization of neutral [(CH3)Zn(O-i-C3H7)]4 are investigated by tandem mass spectrometry. After initial loss of a neutral (CH3)Zn(O-i-C3H7) unit to afford [(CH3)2Zn3(O-i-C3H7)3]+, hydrogen migration leads to the expulsion of neutral acetone concomitant with [(CH3)2Zn3(O-i-C3H7)2(H)]+ as ionic fragment. Unimolecular dissociation of the latter gives rise to [(CH3)2Zn2(O-i-C3H7)]+ and neutral HZn(O-i-C3H7).

Novel hypervalent complexes of main-group metals by intramolecular ligand-->metal electron transfer.

New fascinating electronic features of the simple diketoamine chelate ligand HN[CH2C(tBu)=O]2 (1) are described. Unexpectedly, the corresponding trianionic amido-dienolate form of 1 is capable of reducing main-group metal atoms M after initial coordination and intramolecular L-->M two-electron transfer and of stabilizing main-group elements in unusual low oxidation states. This is impressively shown by the synthesis and structural characterization of the novel Ge and Sn complexes 4-6 by redox reactions of lithiated 1 with the corresponding metal halides GeCl4 and MCl2 (M=Ge, Sn).

Metal-induced formation of a new chiral bidentate N,O ligand and the synthesis of novel monomeric germylenes.

Lithiation of the N-benzyl substituted diketoamine ligand PhCH(2)-N[CH(2)C(tBu=O](2) with lithium diisopropylamide (LDA) affords a novel chiral anionic N,O-ligand L; LiL reacts with GeCl(2).dioxane to give the corresponding new monomeric germylenes LGeCl and L(2)Ge.

First preparation of nanocrystalline zinc silicate by chemical vapor synthesis using an organometallic single-source precursor.

A method is presented to prepare nanocrystalline alpha-Zn(2)SiO(4) with the smallest crystal size reported so far for this system. Our approach combines the advantages of organometallic single-source precursor routes with aerosol processing techniques. The chemical design of the precursor enables the preferential formation of pure zinc silicates.

Synthesis of the first fluoro(phosphanyl)- and diphosphanyl-stannanes and surprising formation of [P(SnMe3)4]+ SiF5-.

Monophosphanylation of the difluorostannane Is2SnF2 (Is = 2,4,6-triisopropylphenyl) with Si(PH2)4 furnishes the first isolable fluoro(phosphanyl)stannane Is2Sn(F)PH2 1, which readily undergoes unique SiO2-assisted decompostion to [Is2Sn(PH)]2 2 and HF, while further phosphanylation of 1 leads to the remarkably stable diphosphanylstannane Is2Sn(PH2)2 3; the latter reacts with Me3SnF at the glass-wall to give the first perstannylphosphonium pentafluorosilicate [P(SnMe3)4]+ SiF5- 4.

Germanium(IV) chloride at 193 K.

Single crystals of germanium(IV) tetrachloride, GeCl(4), were grown at 193 K. In the crystal structure, the isolated molecules have very well realised tetrahedral geometry.

E(SiMe ) Ions (E=P, As): Persilylated Phosphonium and Arsonium Ions.

Only strong Lewis acidic, arene-solvated Me Si ions react with E(SiMe ) compounds (E=P, As) to give the crystallographically characterized E(SiMe ) onium ions 1 (left hand picture), which contain highly negative polarized P and As atoms, respectively. The masked Me Si ions in 1 can be easily transferred to Et O, to give the first structurally characterized planar silyloxonium ion [Et (Me Si)O] 2 (right hand picture).

Modular chemistry with aluminum phosphanides: cluster formation of (AlP)n (n=3,6,7), Al4P3, and Al4Li4P6 frameworks.

The Al3P3 heterocycle 1 is formed in 94% yield by the reaction of the primary silylphosphane 6a with Me3Al in toluene at 70 degrees C. While 1 crystallizes in an isomerically pure form, in which the six-membered Al3P3 ring prefers the chair conformation and the P-H hydrogen atoms adopt exo positions, it isomerizes in solution to give different diastereomers as shown by 1H and 31P NMR spectroscopy. Intermolecular cyclocondensation of 1 at 110 degrees C in toluene leads, under liberation of methane, to the distorted hexameric-prismatic (AlP)6 cluster 2 in 98% yield.

van't Hoff-Le Bel Stranger: Formation of a Phosphonium Cation with a Planar Tetracoordinate Phosphorus Atom.

A novel intriguing type of coordination mode in phosphorus chemistry has been established that is of fundamental interest in the understanding of chemical bonding. Besides the synthesis of the first planar phosphonium cation PR(4)(+) 1 by a surprisingly simple metathesis reaction, a potentially general experimental method that reaches the seemingly impossible high-energy region of basic molecular and isoelectronic ER(4) systems (E=B(-), C, N(+), Al(-), Si, P(+)) is provided.

Lithiated Clusters from Primary Silylphosphanes and Silylarsanes: Spherical Bodies with and without Li(2)O Filling.

Molecular clusters with archimedean and platonic shape, which in order to build a closed polyhedron, spontaneously eliminate H(2) or voluntarily encapsulate Li(2)O as a "cluster nucleus", result from the dilithiation of primary silylphosphanes and silylarsanes with BuLi. Thus, the first mixed-valent, decameric P(10)Li(16) cluster 1 was obtained from iPr(3)SiPH(2) and tBuLi (molar ratio 1:2) with strict exclusion of LiOH and Li(2)O, whereas partial metalation in the presence of LiOH initially leads to a dodecameric, Li(2)O-containing cluster 2, from which the three-shell cluster 3 with a [Li(6)O](4+) core is obtained.

Synthesis and Crystal Structure Analysis of Tetraphosphanylsilane and Identification of Tetraphosphanylgermane.

Inversion-symmetric pairs, each with two weak P-H⋅⋅⋅P interactions, form molecules of Si(PH ) in the crystal (see drawing). The title compounds are formed from ECl (E=Si,Ge) on reaction with [LiAl(PH ) ] and could serve as single-source CVD precursors for phosphides.

29Si CP/MAS NMR of phosphorus-bearing organosilicon compounds.

While liquid-state 29Si NMR of phosphorus-bearing organosilicon compounds with more than one phosphorus per molecule can take advantage of the presence of J-coupling nJ(31P29Si) for purposes of structural assignment from J-coupling patterns, conventional 29Si CP/MAS spectra of such molecular solids do not reveal structural details in a straightforward manner. For such compounds it is necessary to obtain 29Si CP/MAS spectra under conditions of simultaneous 1H- and 31P-high power decoupling in order to derive reliable 29Si chemical shift information. 29Si CP/MAS NMR spectra, obtained with and without 31P high power decoupling during the acquisition time, of several organosilicon compounds containing SixPy (x = 1-10, y = 1-10) moieties are reported.