Einfache Synthese von Alkylaluminium‐ und Alkylgalliumhydriden – Kristallstrukturen von [(Me3C)2GaH]3 und den neuartigen Sesquihydriden [(Me3C)2EH]2[EH2CMe3]2 (E = Al,Ga)

Facile Syntheses of Alkylaluminium and Alkylgallium Hydrides – Crystal Structures of [(Me₃C)₂GaH]₃ and the Novel Sesquihydrides [(Me₃C)₂EH]₂[EH₂CMe₃]₂ (E = Al, Ga) The facile syntheses of some important, sterically highly shielded dialkylaluminium hydrides R₂AlH [R = CMe₃, CH(SiMe₃)₂] succeeded by the reaction of the corresponding trialkylaluminium compounds with the alane adduct AlH₃ × NMe₂Et in a 2 to 1 molar ratio. This route is not suitable for the synthesis of monoalkylaluminium dihydrides. An excess of AlH₃ yielded the novel sesquihydride [(Me₃C)₂AlH]₂[AlH₂CMe₃]₂ ( 3 ) as the hydride richest compound which possesses an unprecedented heterocycle comprising four aluminium and four hydrogen atoms in the solid state. The dialkylgallium hydride (Me₃C)₂GaH ( 4 ) was formed on a similar route by the treatment of tri(tert‐butyl)gallane with the adduct GaH₃ · NMe₂Et. As shown by a crystal structure determination, compound 4 is a trimer in the solid state possessing a Ga₃H₃ heterocycle. A gallium sesquihydride analogous to compound 3 , [(Me₃C)₂GaH]₂[GaH₂CMe₃]₂ ( 5 ), was formed on employing an excess of GaH₃.     

Synthese und Kristallstruktur von [(Me3Si)2BiCu(PMe3)3], dem ersten Komplex mit einer Bismut—Kupfer‐Bindung

Synthesis and Crystal Structure of [(Me₃Si)₂BiCu(PMe₃)₃] — the First Complex with a Bismuth—Copper Bond The reaction of CuO^t Bu with PMe₃ and Bi(SiMe₃)₃ in hexane yields the phosphine‐stabilized complex [(Me₃Si)₂Bi‐Cu( PMe₃)₃]. This synthesis gave rise to the first binuclear Bi—Cu compound to be structurally characterized by X‐ray crystallography.     

The First Orthotelluric Acid Polysilylesters: Synthesis and Crystal Structure of [(Me3SiO)8Te2O2] and [(Me4Si2O2)3Te]

The compounds [(Me₃SiO)₈Te₂O₂] ( 1 ) and [(Me₄Si₂O₂)₃Te] ( 2 ) have been prepared in good yields through Bronsted acid‐base reaction of Te(OH)₆ with Me₃SiNEt₂ and Me₄Si₂(NEt₂)₂, respectively. They have been characterised by multinuclear NMR spectroscopy and single crystal X‐ray diffraction analyses. The formation of dinuclear 1 is the result of fast intermolecular condensation of two partially silylated orthotelluric acid units during the esterification process. Its structure consists of two edge‐fused TeO₆‐octahedra, bearing a four‐membered Te₂O₂ ring as central motif. In contrast, the main structural feature of chiral 2 is a TeO₆ octahedron which is fully silylated by three bidentate 1,1,2,2‐tetramethyldisilanediyl units, resulting in a racemic mixture. The metastability of 2 is remarkable since the Te(+ 6) center usually acts as a strong oxidation reagent toward the Si–Si bond in disilanes. 1 and 2 represent potential starting compounds for molecular Te_xO_y aggregates as hybrid components for new glasses by sol‐gel procedure.     

Reaktionen eines Dibismutans und von Cyclobismutanen mit Metallcarbonylen ‐ Synthesen von Komplexen mit R2Bi‐, RBi‐, Bi2‐ und Bin‐Liganden (R = Me3CCH2, Me3SiCH2)

Reactions of a Dibismuthane and of Cyclobismuthanes with Metal Carbonyls ‐ Syntheses of Complexes with R₂Bi‐, RBi‐, Bi₂‐ and Bi_n‐ligands (R = Me₃CCH₂, Me₃SiCH₂) Reactions of [Fe₂(CO)₉] with [(Me₃CCH₂)₄Bi]₂ or cyclo‐(Me₃SiCH₂Bi)_n (n = 3 ‐ 5) lead to the complexes [(R₂Bi)₂Fe(CO)₄], [RBiFe(CO)₄]₂[R = Me₃CCH₂, Me₃SiCH₂] and [Bi₂Fe₃(CO)₉]. [Bi₂{Mn(CO)₂C₅H₄CH₃}₃] forms in a photochemical reaction of [Mn(CO)₃C₅H₄CH₃] with cyclo‐(Me₃SiCH₂Bi)_n.     

Darstellung,Charakterisierung und Reaktionsverhalten von Natrium‐ und Kaliumhydridosilylamiden R2(H)Si—N(M)R′ (M = Na,K) — Kristallstruktur von [(Me3C)2(H)Si—N(K)SiMe3]2·THF

Preparation, Characterization and Reaction Behaviour of Sodium and Potassium Hydridosilylamides R₂(H)Si—N(M)R′ (M = Na, K) — Crystal Structure of [(Me₃C)₂(H)Si—N(K)SiMe₃]₂ · THF The alkali metal hydridosilylamides R₂(H)Si—N(M)R′ 1a‐Na — 1d—Na and 1a‐K — 1d‐K ( a : R = Me, R′ = CMe₃; b : R = Me, R′ = SiMe₃; c : R = Me, R′ = Si(H)Me₂; d : R = CMe₃, R′= SiMe₃) have been prepared by reaction of the corresponding hydridosilylamines 1a — 1d with alkali metal M (M = Na, K) in presence of styrene or with alkali metal hydrides MH (M = Na, K). With NaNH₂ in toluene Me₂(H)Si—NHCMe₃ ( 1a ) reacted not under metalation but under nucleophilic substitution of the H(Si) atom to give Me₂(NaNH)Si—NHCMe₃ ( 5 ). In the reaction of Me₂(H)Si—NHSiMe₃ ( 1b ) with NaNH₂ intoluene a mixture of Me₂(NaNH)Si—NHSiMe₃ and Me₂(H)Si—N(Na)SiMe₃ ( 1b‐Na ) was obtained. The hydridosilylamides have been characterized spectroscopically. The spectroscopic data of these amides and of the corresponding lithium derivatives are discussed. The ²⁹Si‐NMR‐chemical shifts and the ²⁹Si—¹H coupling constants of homologous alkali metal hydridosilylamides R₂(H)Si—N(M)R′ (M = Li, Na, K) are depending on the alkali metal. With increasing of the ionic character of the M—N bond M = K > Na > Li the ²⁹Si‐NMR‐signals are shifted upfield and the ²⁹Si—¹H coupling constants except for compounds (Me₃C)(H)Si—N(M)SiMe₃ are decreased. The reaction behaviour of the amides 1a‐Na — 1c‐Na and 1a‐K — 1c‐K was investigated toward chlorotrimethylsilane in tetrahydrofuran (THF) and in n‐pentane. In THF the amides produced just like the analogous lithium amides the corresponding N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2a — 2c ) in high yields. The reaction of the sodium amides with chlorotrimethylsilane in nonpolar solvent n‐pentane produced from 1a‐Na the cyclodisilazane [Me₂Si—NCMe₃]₂ ( 8a ), from 1b‐Na and 1‐Na mixtures of cyclodisilazane [Me₂Si—NR′]₂ ( 8b , 8c ) and N‐silylation product 2b , 2c . In contrast to 1b‐Na and 1c‐Na and to the analogous lithium amides the reaction of 1b‐K and 1c‐K with chlorotrimethylsilane afforded the N‐silylation products Me₂(H)Si—N(SiMe₃)R′ ( 2b , 2c ) in high yields. The amide [(Me₃C)₂(H)Si—N(K)SiMe₃]₂·THF ( 9 ) crystallizes in the space group C2/c with Z = 4. The central part of the molecule is a planar four‐membered K₂N₂ ring. One potassium atom is coordinated by two nitrogen atoms and the other one by two nitrogen atoms and one oxygen atom. Furthermore K···H(Si) and K···CH₃ contacts exist in 9 . The K—N distances in the K₂N₂ ring differ marginally.     

Komplexchemie P-reicher Phosphane und Silylphosphane. X [1] Zum Einfluß der Komplexierung auf die Reaktivität des [(Me3Si)2P]2PH

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. X. The Influence of the Formation of Complex Compounds on the Reactivity of [(Me₃Si)₂P]₂PH Whereas [(Me₃Si)₂P]₂PH 1 by BuLi is attacked at the PH group to give [(Me₃Si)₂P]₂PLi 2 , the related chromium carbonyl complex (Me₃Si)P^IV ? ²P^IV(H) ? ³P^III(Si? Me₃)₂ · Cr(CO)₄ 3 with BuLi yields Li(Me₃Si)¹P^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂ · Cr(CO)₄ 4 by cleaving a Si? P bond at the chromium substituted ¹P atom. Dissolved in ether, 4 is stable for a longer time, while under comparable conditions 2 forms Li₃P₇ which is not obtained from 4 . MeOH in 3 cleaves selectively the Me₃Si groups from the complex substituted P atom yielding (Me₃Si)(H)¹P^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂ · Cr(CO)₄ 5 and HP^IV ? ²P^IV(H) ? ³P^III(SiMe₃)₂Cr(CO)₄ 6. 5 and 6 seem to be stable in contrast to the uncoordinated triphosphanes which are not known.     

Neue Synthesen von Me2SbX (X = Cl,I) und Kristallstrukturen von Me2SbI und [(Me3Si)2CH]2SbCl

Novel Syntheses of Me₂SbX (X = Cl, I) and Crystal Structures of Me₂SbI and [(Me₃Si)₂CH]₂SbCl The crystal structures of Me₂SbI (Me = CH₃) and [(Me₃Si)₂CH]₂SbCl have been determined by X‐ray methods. Both molecules are pyramidal. The Me₂SbI molecules are associated to chains through short intermolecular Sb…I distances (366,7(1) pm) with linear I–Sb…I units (171,87(4)°) and bent Sb–I…Sb bridges (116,83(3)°).     

Synthese und Struktur von η1‐Phosphaallyl‐, η1‐Arsaallylund η1‐Stibaallyleisen‐Komplexen [(η5‐C5Me5)(CO)2Fe–E(SiMe3)C(OSiMe3)=CPh2] (E = P,As, Sb)

Syntheses and Structures of η¹‐Phosphaallyl, η¹‐Arsaallyl, and η¹‐Stibaallyl Iron Complexes [(η⁵‐C₅Me₅)(CO)₂Fe–E(SiMe₃)C(OSiMe₃)=CPh₂] (E = P, As, Sb) The reaction of equimolar amounts of [(η⁵‐C₅Me₅)(CO)₂Fe–E(SiMe₃)₂] ( 1 a : E = P; 1 b : As; 1 c : Sb) and diphenylketene afforded the η¹‐phosphaallyl‐, η¹‐arsaallyl‐, and η¹‐stibaallyl complexes [(η⁵‐C₅Me₅)(CO)₂Fe–E(SiMe₃)C(OSiMe₃)=CPh₂] ( 2 a : E = P; 2 b : As; 2 c : Sb). The molecular structures of 2 b and 2 c were elucidated by single crystal X‐ray analyses.     

Einfluß der Ringatome auf die Struktur von Triel‐Pentel‐Heterozyklen – Synthese und Molekülstrukturen von [Me2InAs(SiMe3)2]2 und [Me2InSb(SiMe3)2]3

Influence of the Ring Atoms on the Structure of Triel‐Pentel Heterocycles – Synthesis and X‐Ray Crystal Structures of [Me₂InAs(SiMe₃)₂]₂ and [Me₂InSb(SiMe₃)₂]₃ Triel‐pentel heterocycles [Me₂InE(SiMe₃)₂]_x have been prepared by dehalosilylation reactions from Me₂InCl and E(SiMe₃)₃ (E = As, x = 2; E = Sb, x = 3) and characterised by NMR spectroscopy and by X‐ray crystal structure analyses. In addition the X‐ray crystal structures of [Me₂GaAs(SiMe₃)₂]₂ and [Me₂InP(SiMe₃)₂]₂ are reported. The compounds complete a family of 13 identically substituted heterocycles [Me₂ME(SiMe₃)₂]_x (M = Al, Ga, In; E = N, P, As, Sb, Bi; x = 2, 3), whose structures were investigated depending on the ring atoms M and E. The tendencies that have been observed concerning the ring sizes can be explained by the interplay of the atomic radii of the central atoms and the sterical demand of the ligands. After a formal separation of the M–E bonds in σ bonds and dative bonds the characteristic differences and trends in the endocyclic and exocyclic bond angles of both centres M and E can be interpreted on the basis of a simple Lewis acid/base adduct model.     

[Bi4]6– – The Zintl Anion with the Highest Charge per Atom Obtained from Solution

From the dark‐purple solution of the Zintl phase KBi in liquid ammonia dark‐blue crystals of the ammonia solvate K₆[Bi₄](NH₃)₈ were obtained. In contrast to known Bi_n polyanions the chemical bond in the anion [Bi₄]^6– is in accordance with the (8‐N) rule featuring solely Bi–Bi single bonds. [Bi₄]^6– is a butane‐analog valence compound, and with 6 negative charges per 4 atoms it is the anion with the highest known charge per atom obtained from solution. The planarity of the trans‐[Bi₄]^6– unit hints at π orbital contributions of the bismuth atoms. The corresponding reactions of the phases K₅Bi₄ and K₃Bi₂ in liquid ammonia in the presence of [2.2.2]crypt(4, 7, 13, 16, 21, 24‐hexaoxa‐1, 10‐diazabicyclo‐[8.8.8]hexacosane) lead to the salt [K([2.2.2]crypt)]₂[Bi₂](NH₃)₄ with the known electron‐deficient [Bi₂]^2– polyanion and a Bi=Bi double bond.     

Die Reaktion des [(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2 mit Neopentyllithium: Bildung des {[(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2CH2CMe3}⊖ [Li(TMEDA)2]⊕

Reaction of [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ with Neopentyllithium: Formation of {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂CMe₃} ? [Li(TMEDA)₂]⊕ The recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ reacts with neopentyl lithium in the presence of TMEDA to give the stable {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂ · CMe₃}? [Li(TMEDA)₂]⊕ decomposing at 115°C. The aluminium atoms therein are not additionally bridged, but the new substituent is occupying a terminal position as detected by crystal structure determination. A compound is formed containing a saturated, fourfold coordinated neighbouring a formally unsaturated, threefold coordinated aluminium atom. Due to high sterical restrictions the Al? C bonds are lengthened up to 209.0(3) pm at the alanate site and the Al? C? Al angle in the methylene bridge is extraordinarily enlarged to 144.4(2)°.     

Bi53+‐Polykationen in geordneten und plastischen Kristallen von Bi5[AlI4]3 und Bi5[AlBr4]3

Bi₅³⁺ Polycations in Ordered and Plastic Crystals of Bi₅[AlI₄]₃ and Bi₅[AlBr₄]₃ Dark‐red air‐sensitive crystals of pentabismuth‐tris(tetrabromoaluminate) Bi₅[AlBr₄]₃ and black crystals of Bi₅[AlI₄]₃ have been crystallized from melts of Bi, BiX₃ and AlX₃ (X = Br, I). X‐ray diffraction on a single crystal of Bi₅[AlI₄]₃ (T = 293(2) K; space group Pnma; a = 2143.6(3) pm, b = 1889.1(1) pm, c = 811.74(5) pm) revealed an ordered packing of Bi₅³⁺ trigonal bipyramids and [AlI₄]^? tetrahedra that corresponds to the PuBr₃ structure type. Contrary to the so far known Bi₅³⁺ polycations with accurate D_3h symmetry, the bismuth cluster found in Bi₅[AlI₄]₃ holds only C_s symmetry. The room temperature structure of the tetrabromoaluminate Bi₅[AlBr₄]₃, which is related to the AuCu₃ type, shows a dynamic disorder of the Bi₅³⁺ polycations (T = 293(2) K; space group ; a = 1766.2(3) pm). Slight cooling induces the transition into an ordered rhombohedral phase isostructural to Bi₅[AlCl₄]₃ (T = 260(2) K; space group a = 1241.5(8) pm, c = 3041(2) pm).     

Studien zur Reaktion von [Me2AlP(SiMe3)2]2 mit basenstabilisierten Organogalliumchloriden und ‐hydriden

Investigations on the Reactivity of [Me₂AlP(SiMe₃)₂]₂ with Base‐stabilized Organogalliumhalides and ‐hydrides [Me₂AlP(SiMe₃)₂]₂ ( 1 ) reacts with dmap?Ga(Cl)Me₂, dmap?Ga(Me)Cl₂, dmap?GaCl₃ and dmap?Ga(H)Me₂ with Al‐P bond cleavage and subsequent formation of heterocyclic [Me₂GaP(SiMe₃)₂]₂ ( 2 ) as well as dmap?AlMe_xCl_3?x (x = 3 8 ; 2 3 ; 1 4 ; 0 5 ). The reaction between equimolar amounts of dmap?Al(Me₂)P(SiMe₃)₂ and dmap?Ga(t‐Bu₂)Cl yield dmap?Ga(t‐Bu₂)P(SiMe₃)₂ ( 6 ) and dmap?AlMe₂Cl ( 3 ). 2 – 8 were characterized by NMR spectroscopy, 2 and 6 also by single crystal X‐ray diffraction.     

Transients from a mixture of [(R(O)Sn)2C(CH3)2]2 and (RCl2Sn)2C(CH3)2 [R = (SiMe3)2CH]: an identification in situ by 1D 119Sn and 2D 1H?119Sn HMQC NMR spectroscopy and electrospray mass spectrometry

The reaction of the 2,2‐bis(organodichlorostannyl)propane [(Me₃Si)₂CH(Cl₂)Sn]₂CMe₂ (A) with the corresponding organotin oxide {[(Me₃Si)₂CH(O)Sn]₂CMe₂}₂ (B) does not provide the corresponding normally expected tetraorganodistannoxane {[(Me₃Si)₂CH(Cl)SnCMe₂Sn(Cl)CH(SiMe₃)₂]O}_n but a complex reaction mixture. One major product, namely the 2,4,6,8‐tetraorgano‐2,6‐dichloro‐1,5,9‐trioxa‐2,4,6,8‐tetrastannabicyclo[3.3.1]nonane derivative [(Me₃Si)₂CHSnCMe₂Sn(Cl)CH(SiMe₃)₂]₂O₃ (C) was identified in situ by 2D ¹H? ¹¹⁹Sn and ¹H? ¹³C heteronuclear multiple quantum coherence and heteronuclear multiple bond correlation NMR spectroscopy as well as electrospray mass spectrometry. Compound C is proposed to be in equilibrium with an ionic species C′, the cation of which has an adamantane‐type structure. Copyright © 2003 John Wiley & Sons, Ltd.     

Komplexchemie P‐reicher Phosphane und Silylphosphane. XXII. Die Bildung von [η2‐{tBu–P=P–SiMe3}Pt(PR3)2]aus (Me3Si)tBuP–P=P(Me)tBu2 und [η2‐{C2H4}Pt(PR3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXII. The Formation of [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂] from (Me₃Si)^tBuP–P=P(Me)^tBu₂ and [η²‐{C₂H₄}Pt(PR₃)₂] (Me₃Si)^tBuP–P = P(Me)^tBu₂ reacts with [η²‐{C₂H₄}Pt(PR₃)₂] yielding [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂]. However, there is no indication for an isomer which would be the analogue to the well known [η²‐{^tBu₂P–P}Pt(PPh₃)₂]. The syntheses and NMR data of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] and [η²‐{^tBu–P=P–SiMe₃}Pt(PMe₃)₂] as well as the results of the single crystal structure determination of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] are reported.     

Synthese,Struktur und Reaktivität des Ferrioarsaalkens [(η5‐C5Me5)(CO)2FeAs=C(Ph)NMe2]

Synthesis, Structure, and Reactivity of the Ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂] Reaction of equimolar amounts of the carbenium iodide [Me₂N(Ph)CSMe]I and LiAs(SiMe₃)₂ · 1.5 THF afforded the thermolabile arsaalkene Me₃SiAs = C(Ph)NMe₂ ( 1 ), which in situ was converted into the black crystalline ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂)] ( 2 ) by treatment with [(η⁵‐C₅Me₅)(CO)₂FeCl]. Compound 2 was protonated by ethereal HBF₄ to yield [(η⁵‐C₅Me₅)(CO)₂FeAs(H)C(Ph)NMe₂]BF₄ ( 3 ) and methylated by CF₃SO₃Me to give [(η⁵‐C₅Me₅)(CO)₂FeAs(Me)C(Ph)NMe₂]‐ SO₃CF₃ ( 4 ). [(η⁵‐C₅Me₅)(CO)₂FeAs[M(CO)_n]C(Ph)NMe₂] ( 5 : [M(CO)_n] = [Fe(CO)₄]; 6 : [Cr(CO)₅]) were isolated from the reaction of 2 with [Fe₂(CO)₉] or [{(Z)‐cyclooctene}Cr(CO)₅], respectively. Compounds 2 – 6 were characterized by means of elemental analyses and spectroscopy (IR, ¹H, ¹³C{¹H}‐NMR). The molecular structure of 2 was determined by X‐ray diffraction analysis.     

Synthetic and Structural Studies on the Cyclic Bis(amino)stannylenes Sn[(NR)2C10H6‐1, 8] and their Reactions with SnCl2 or Si[(NCH2But)2C6H4‐1, 2] (R = SiMe3 or CH2But)

Treatment of {HNR}₂C₁₀H₆‐1, 8 [R = SiMe₃ ( 1 ), CH₂Bu^t ( 2 )] with Sn[N(SiMe₃)₂]₂ afforded the cyclic stannylene Sn[{NR}₂C₁₀H₆‐1, 8] [R = SiMe₃ ( 3 ), CH₂Bu^t ( 4 )]. From 3 and SnCl₂ in THF and crystallisation from toluene, the product was the crystalline tetracyclic compound ( 5 ) as the (toluene)_0.5‐solvate. Reaction of 4 with the silylene Si[(NCH₂Bu^t)₂C₆H₄‐1, 2] ( 6 ) [abbreviated as Si(NN)] in benzene and crystallisation in presence of Et₂O furnished the crystalline tricyclic complex Sn[{Si(NCH₂Bu^t)₂C₆H₄‐1′, 2′}₂‐{(NCH₂Bu^t)₂C₁₀H₆‐1, 8}] ( 7 ) as the Et₂O‐solvate. Complex 5 slowly dissociated into its factors 3 and SnCl₂ in toluene, but rapidly in THF. Solutions of 7 in C₆D₆, C₇D₈ or THF‐d₈, studied by multinuclear, variable temperature NMR spectroscopy, revealed the presence of an equilibrium between 8 (an isomer of 7 , in which the skeletal atoms of the eight‐membered ring were , rather than the of 7 ) and 4 + 2 Si(NN), with 8 dominant in PhMe but not in THF; additionally 8 was shown to be fluxional and solutions of 8 in C₆D₆ or C₇D₈ decomposed to give the silane Si(NN)[(NCH₂Bu^t)₂C₁₀H₆‐1, 8], 6 and Sn metal. The X‐ray structures of 3 , 5 and 7 are presented.     

Die Cluster‐Salze Bi14Si2MI12 (M = Rh,Ir): [Bi8Si2]‐ und [MBi6I12]‐Baugruppen in CsCl‐analoger Anordnung

The Cluster Salts Bi₁₄Si₂MI₁₂ (M = Rh, Ir): [Bi₈Si₂] and [MBi₆I₁₂] Building Groups in CsCl‐like Structure The reaction of bismuth and iridium with iodine in evacuated quartz ampoules at 1320 K yields black, air insensitive crystals of Bi₁₄Si₂IrI₁₂. The silicon therein is abstracted from the ampoule material whereby the oxygen is gettered in BiOI. The synthesis of Bi₁₄Si₂RhI₁₂ requires the addition of niobium, which gives NbOI₂ with the oxygen originating from the SiO₂. X‐ray diffraction on single crystals showed that the two isotypic compounds crystallize in the space groups P 4/m c c with a = 1018.3(1), c = 2020.1(4) pm for M = Ir, and a = 1019.0(1), c = 2018.7(4) pm for M = Rh. The crystal structures consist of two types of isolated clusters, which form a CsCl‐like packing. In the [MBi₆I₁₂] cuboctahedron the central transition metal atom is octahedrally surrounded by bismuth atoms, and the iodine atoms bridge the edges of the octahedron. The [Bi₈Si₂] polyhedron is a tetragonal antiprism of bismuth atoms of which square faces are capped by silicon atoms. Based on crystal chemistry and band structure calculations the compounds may be formulated as cluster salts [Bi₈Si₂]³⁺[MBi₆I₁₂]^3–. Measurements of the electrical conductivity showed that Bi₁₄Si₂IrI₁₂ is a semiconductor with a band gap of about 0.1 eV. A single unpaired electron out of 1903 electrons per formula causes paramagnetic behaviour that is superposed by strong diamagnetic contributions.     

Zur Chemie des Titan(III)-Komplexes [{(Me3Si)2N}2TiCH2SiMe2NSiMe3]–. Insertions-Reaktionen in die Ti–C-Bindung und Redox-Reaktionen

On the Chemistry of the Titanium(III) Complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃]^–. Insertion Reactions into the Ti–C Bond and Redox Reactions [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 1 ) reacts with CO and the isonitrile CNCy (Cy = Cyclohexyl) under insertion into the Ti–C bond. After rearrangement planar five-membered titana(III)-heterocycles TiOCSiN and TiNCSiN with exocyclic C=CH₂ groups are formed. On the other hand, the insertion of CNBu^t leads to the primary insertion product [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiC(NBu^t)CCH₂SiMe₂NSiMe₃] ( 4 ) forming a new Ti(III)–C-bond. With NOBF₄ the anion of 1 can be oxydized to form the molecular complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 5 ), while with phenylacetylene redox disproportionation occurs, in the course of which the mixed ligand complex [Na(12-crown-4)₂][{(Me₃Si)₂N}₂Ti(NSiMe₃)(CH₂SiMe₂C≡C–Ph)] ( 6 ) can be isolated. 6 and the insertion products [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiOC(CH₂)SiMe₂NSiMe₃] ( 2 ) and [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiNCyC(CH₂)SiMe₂NSiMe₃] ( 3 ) are characterized by crystal structure determinations.     

[μ‐(Me3SiCH2Sb)5–Sb1,Sb3–{W(CO)5}2] und [{(Me3Si)2CHSb}3Fe(CO)4] – zwei cyclische Komplexe mit Antimon‐Liganden

Syntheses and Crystal Structures of [μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] and [{(Me₃Si)₂CHSb}₃Fe(CO)₄] – Two Cyclic Complexes with Antimony Ligands cyclo‐(Me₃SiCH₂Sb)₅ reacts with [(THF)W(CO)₅] (THF = tetrahydrofuran) to form cyclo‐[μ‐(Me₃SiCH₂Sb)₅–Sb¹,Sb³–{W(CO)₅}₂] ( 1 ). The heterocycle cyclo‐ [{(Me₃Si)₂CHSb}₃Fe(CO)₄] ( 2 ) is formed by an insertion reaction of cyclo‐[(Me₃Si)₂CHSb]₃ and [Fe₂(CO)₉]. The crystal structures of 1 and 2 are reported.