Synthese und Kristallstruktur eines μ-Methylen-μ-hydrido-dialanats [R2Al(μ-CH2)(μ-H)AlR2]− (R = CH(SiMe3)2)

Synthesis and Crystal Structure of a μ-Methylene-μ-hydrido-dialanate [R₂Al(μ-CH₂)(μ-H)AlR₂]^? (R = CH(SiMe₃)₂) tert-Butyl lithium reacts with the recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al[CH(SiMe₃)₂]₂ 2 in the presence of TMEDA under β-elimination; the thereby formed hydride anion is bound in a chelating manner by both unsaturated aluminium atoms forming a 3c–2e–Al? H? Al bond. The crystal structure of the product shows two independent molecules differing only slightly in bond lengths and angles, but significantly in conformation. While one of the Al₂CH heterocycles deviates little from planarity with a rough C₂ symmetry for the whole anion, the other one is folded with an angle of 21.1° and the arrangement of the substituents is best described by C_s symmetry.     

Nitrido-Sodalithe. III [1]. Synthese,Struktur und Eigenschaften von Zn8[P12N24]X2 mit X = O,S, Se,Te

Nitrido-Sodalites. III. Synthesis, Crystal Structure, and Properties of Zn₈[P₁₂N₂₄]X₂ with X = O, S, Se, Te The P? N-sodalites Zn₈[P₁₂N₂₄]X₂ with X = O, S, Se, Te are obtained by the reaction of HPN₂ with the corresponding zinc chalcogenide ZnX at 750°C. They crystallize in a filled up variant of Zn₇[P₁₂N₂₄]Cl₂ and are isotypic to Zn₈[B₁₂O₂₄]O₂ (I4 3m, a = 823 to 830 pm, Z = 1). The P? N-sodalites contain in the center of their β-cages XZn₄⁶⁺ units which can be described as sections of II/VI-semiconductors. The UV/Vis-spectra of the compounds show in comparison with binary bulk zinc chalcogenides a blue shift of the absorption edge according to the size quantization effect.     

Synthese und Kristallstruktur des trimeren [(Me3Si)2CH]2Al?CN

Synthesis and Crystal Structure of the Trimeric [(Me₃Si)₂CH]₂Al? CN Tetrakis[bis(trimethylsilyl)methyl]dialane(4) 1 with an Al? Al bond reacts with tert-butyl isocyanide in the molar ratio of 1:2 within three days to give a mixture of several unknown products, from which the title compound 4 is isolated in a 26% yield by recrystallization from n-pentane. 4 is a trimer in the solid state via Al? C?N? Al bridges showing a nine-membered Al₃C₃N₃ heterocycle in a boat conformation. In contrary to the reaction with phenyl isocyanide the expected dark red product of the twofold insertion into the Al? Al bond under formation of a carbon-carbon single bond is detected only spectroscopically as a minor by-product.     

Die Kristallstruktur des Tetrakis(di-tert.-butylphosphino)diphosphans. [(tBu)2P]2P?P[P(tBu)2]2

The Crystal Structure of Tetrakis(di-tert.-butylphosphino)diphosphane [(tBu)₂P]₂P? P[P(tBu)₂]₂ [(tBu)₂P]₂P? P[P(tBu)₂]₂ 1 obtained at ?20°C from a solution of (tBu)₂P? P=P(Br)tBu₂ forms yellow crystals (regular hexagons). 1 crystallizes monoclinic in the space group C2/c with a = 2145.6pm, b = 1137pm, c = 1696.1pm, β = 110.075° and Z = 4 formula units in the elementary cell. Due to high steric load the bond angles at the tertiary P atoms with δ = 115.7° are significantly larger than those at the primary P atoms with δ = 108.6°.     

Periphere Anbindung von Quecksilber(II)-iodid an dreikernige Molybdän-Schwefel-Dithiophosphinatocluster: [Mo3S4(R2PS2)4HgI2] (R = Et,Pr)

Peripheral Bonding of Mercury(II) Iodide to Trinuclear Molybdenum-Sulfur-Dithiophosphinato Clusters: [Mo₃S₄(R₂PS₂)₄HgI₂] (R = Et, Pr) Reaction of Mo₃S₄(R₂PS₂)₄ 1 (a : R = Et, b : R = Pr) with HgI₂ in THF yields the diamagnetic title complexes [Mo₃S₄(R₂PS₂)₄HgI₂] 3 . The crystal structure of [ 3a (H₂O)] · 2 CH₂Cl₂ shows the complexes to consist of a triangular array of Mo atoms which are bridged by μ₂? S atoms and capped by a μ₃? S atom. Each of the Mo atoms is chelated by a dithiophosphinato ligand Et₂PS₂^? and in addition two Mo atoms are bridged by a Et₂PS₂^? ligand while the H₂O molecule is bonded weakly to the third Mo atom. Thus, all Mo atoms reveal a distorted octahedral coordination sphere. HgI₂ is ?peripherally”? bonded to the cluster via two S atoms, one of which belongs to a chelating ligand and the other one to the bridging ligand. Space group P1 , lattice constants a = 12.157(2), b = 15.284(3), c = 16.049(3) Å, α = 115.56(1), β = 107.35(1), and γ = 94.62(1)°; Z = 2, d_calc = 2.23 mg/mm³; 4 236 observed reflections, R = 0.068. In organic solvents complexes 3 are strong electrolytes. VT-³¹P NMR data suggest a stepwise dissociation of 3 with formation of [Mo₃S₄(R₂PS₂)₃] ⁺[(R₂PS₂)HgI₂]^? and elimination of the bridging ligand from the cluster.     

SnCl2 als Brückenligand in [{(CO)5M}2Sn(Cl)2]2− (M = Cr,Mo, W) — Synthese,Struktur und Reaktivität

SnCl₂ as a Bridging Ligand in [{(CO)₅M}₂Sn(Cl)₂]^2? (M = Cr, Mo, W) — Synthesis, Structure, and Reactivity [{(CO)₅Cr}₂Sn(Cl)₂]^2?, 1 , may be obtained from [(CO)₅Cr]^2? or [(CO)₅CrSnCl₂ · THF] in fair yields. Alternatively, 1 is accessible by the reaction of [Cr₂(CO)₁₀]^2? with SnCl₂. This procedure may be extended to the synthesis of [{(CO)₅M}₂Sn(Cl)₂]^2? (M = Mo, 2 ; M = W, 3 ). The compounds 1–3 are crystallized as their alkalimetal (12-crown-4)₂ or [2,2,2]cryptand salts. X-ray analyses demonstrate bridging SnCl₂-moieties with M? Sn? M-angles close to 130° in each case. The relation of the bonding situation in 1–3 to the ones observed for stannylene or ?inidene”? complexes, respectively, is discussed. The transformation of 1 into the rhombododecahedral (X-ray analysis) Sn? O-cage compound [{(CO)₅CrSn}₆(μ₃-O)₄(μ₃-OH)₄], 4 , demonstrates the reactivity of the dianions 1–3 .     

[iPr2P]2P?SiMe3 und [iPr2P]2PLi – Synthese und Reaktionen Struktur des [iPr2P]2P?P[PiPr2]2

[iPr₂P]₂P? SiMe₃ and [iPr₂P]₂PLi – Synthesis and Reactions Structure of [iPr₂P]₂P? P[PiPr₂]₂ [iPr₂P]₂P? SiMe₃ 1 and [iPr₂P]₂PLi 2 were prepared to investigate the influence of the bulky alkyl groups on formation and properties of the ylides R₂P? P?P(X)R₂ (R = iPr, tBu; X = Br, Me) in reactions of 1 with CBr₄ and of 2 with 1,2-dibromoethane or MeCl, resp. Compared to the iPr groups the tBu groups favour the formation of ylides. With CBr₄ 1 forms iPr₂P? P?P(Br)iPr₂ 5 just as a minor product which decomposes already below ?30°C. With 1,2-dibromoethane 2 yields only traces of 5 but [iPr₂P]P? P[P(iPr)₂]₂ 7 as main product. With MeCl 2 gives iPrP? P?P(Me)iPr₂ 9 and [iPr₂P]₂PMe 10 in a molar ratio of 1:1. 9 is considerably more stable than 5. 7 crystallizes triclinic in the space group P1 (No. 2) with a = 10.813 Å, b = 11.967 Å, c = 15.362 Å, α = 67.90°, β = 71.36°, γ = 64.11° and two formula units in the unit cell.     

Untersuchungen zum Zustandsbarogramm und Schmelzdiagramm der Systeme BiI3?HgI2 und BiI3?I2

Investigations on the Barogram and Melting Diagram of the Systems BiI₃? HgI₂ and BiI₃? I₂ The barograms of the systems BiI₃? HgI₂ and BiI₃? I₂ are determined by total pressure measurements in a membrane manometer. The melting diagrams follow from DTA measurements and the barogram. Both systems are eutectic with eutectica at 1.5 mol% BiI₃ and 110°C for BiI₃? I₂ and 9 mol% BiI₃ and 243°C for BiI₃? HgI₂.     

Reaktionen des tBu(Me3Si)P?P(Li)?P(tBu)2 mit CH3Cl und 1,2-Dibromethan

Reactions of tBu(Me₃Si)P? P(Li)? P(tBu)₂ with CH₃Cl and 1,2-Dibromoethane tBu(Me₃Si)P? P(Li)? P(tBu)₂ · 0.95 THF 1 with CH₃Cl (?70°C) yields tBu(Me₃Si)P? P = P(Me)(tBu)₂ 2 at ?70°C, with 1,2-Dibromoethane tBu(Me₃Si)P? PBr? P(tBu)₂ 3 (main product) and tBu(Me₃Si)P? P?P(Br)tBu₂ 4. 3 eliminates Me₃SiBr yielding the cyclotetraphosphane {tBuP? P[P(tBu)₂]}₂ 5 .     

Neue phosphidoverbrückte Mehrkernkomplexe des Ag und Zn. Die Kristallstrukturen von [Ag3(PPh2)3(PnBu2tBu)3], [Ag4(PPh2)4(PR3)4] (PR3 = PMenPr2, PnPr3), [Ag4(PPh2)4(PEt3)4]n, [Zn4(PPh2)4Cl4(PRR2)2] (PRR′2 = PMenPr2, PnBu3, PEt2Ph), [Zn4(PhPSiMe3)4Cl4(C4H8O)2] und [Zn4(PtBu2)4Cl4]

New Phosphido-bridged Multinuclear Complexes of Ag and Zn. The Crystal Structures of [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃], [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂, PⁿPr₃), [Ag₄(PPh₂)₄(PEt₃)₄]_n, [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂, PⁿBu₃, PEt₂Ph), [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] and [Zn₄(P^tBu₂)₄Cl₄] AgCl reacts with Ph₂PSiMe₃ in the presence of tertiary Phosphines (PⁿBu₂^tBu, PMeⁿPr₂, PⁿPr₃ and PEt₃) to form the multinuclear complexes [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃] 1 , [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂ 2 , PⁿPr₃ 3 ) and [Ag₄(PPh₂)₄(PEt₃)₄]_n 4 . In analogy to that ZnCl₂ reacts with Ph₂PSiMe₃ and PRR′₂ to form the multinuclear complexes [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂ 5 , PⁿBu₃ 6 , PEt₂Ph 7 ). Further it was possible to obtain the compounds [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] 8 and [Zn₄(P^tBu₂)₄Cl₄] 9 by reaction of ZnCl₂ with PhP(SiMe₃)₂ and ^tBu₂PSiMe₃, respectively. The structures were characterized by X-ray single crystal structure analysis. Crystallographic data see “Inhaltsübersicht”.     

Zur Bildung und Struktur der Phosphinophosphiniden-phosphorane tBu2P?PP(Me)tBu2 1, tBu(Me3Si)P?PP(Me)tBu2 2 und tBu2P?PP(Br)tBu2 3

Synthesis and Structure of Phosphinophosphinidene-phosphoranes tBu₂P? P?P(Me)tBu₂ 1, tBu(Me₃Si)P? P?P(Me)tBu₂ 2, and tBu₂P? P?P(Br)tBu₂ 3 A new method for the synthesis of 1 and 2 (Formulae see ?Inhaltsübersicht”?) is reported based on the reaction of 5 with substitution reagents (Me₂SO₄ or CH₃Cl). The results of the X-ray structure determination of 1 and 2 are given and compared with those of 3 . While in 3 one P? P distance corresponds to a double bond and the other P? P distance to a single bond (difference 12.5 pm) the differences of the P? P distances in 1 and 2 are much smaller: 5.28 pm in 1 , 4.68 pm in 2 . Both 1 and 2 crystallize monoclinic in the space group P2₁/n (Z = 4). 2 additionally contains two disordered molecules of the solvent pentane in the unit cell. Parameters of 1 : a = 884.32(8) pm, b = 1 924.67(25) pm, c = 1 277.07(13) pm, β = 100.816(8)°, and of 2 : a = 1 101.93(12) pm, b = 1 712.46(18) pm, c = 1 395.81(12) pm, β = 111.159(7)°, all data collected at 143 K. The skeleton of the three P atoms is bent (PPP angle 100.95° for 1 , 100.29° for 2 and 105.77° for 3 ). Ab initio SCF calculations are used to discuss the bonding situation in the molecular skeleton of the three P atoms of 1 and 3 . The results show a significant contribution of the ionic structure R₂P? P(^?)? P(⁺)(X)R₂. The structure with (partially) charged P atoms is stabilized by bulky polarizable groups R (as tBu) as compared to the fully covalent structure R₂P? P(X)? PR₂.     

Phosphinophosphiniden-Phosphorane tBu2P?P = P(R)tBu2 aus Li(THF)2[η2-(tBu2P)2P] und Alkylhalogeniden

The Phosphinophosphinidene-phosphoranes ^tBu₂P? P = P(R)^tBu₂ from Li(THF)₂[η²-(^tBu₂P)₂P] and Alkyl Halides We report the formation of ^tBu₂P? P = P(R)^tBu₂ a and (^tBu₂)₂PR b (with R = Me, Et, ⁿPr, ⁱPr, ⁿBu, PhCH₂, H₂C = CH? CH₂ and CF₃) reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 2 with MeCl, MeI, EtCl, EtBr, ⁿPrCl, ⁿPrBr, ⁱPrCl, ⁿBuBr, PhCH₂Cl, H₂C = CH? CH₂Cl or CF₃Br. In THF solutions the ylidic compounds a predominate, whereas in pentane the corresponding triphosphanes b are preferrably formed. With ClCH₂? CH = CH₂ only b is produced; CF₃Br however yields both ^tBu₂P? P = P(Br)^tBu₂ and ^tBu₂P? P = P(CF₃)^tBu₂, but no b . The ratio of a:b is influenced by the reaction temperature, too. The compounds ^tBu₂P? P = P(Et)^tBu₂ 4a and (^tBu₂P)₂PEt 4 b , e. g., are produced in a ratio of 4:3 at ?70°C in THF, and 1:1 at 20°C; whereas 1:1 is obtained at ?70°C in pentane, and 1:2 at 20°C. Neither ^tBuCl nor H₂C = CHCl react with 2 . The compounds a decompose thermally or under UV irradiation forming ^tBu₂PR and the cyclophosphanes (^tBu₂P)_nP_n.     

Synthese und Molekülstruktur des (N,N′ -Dimethylpiperazin)lithium-(μ-hydrido)(tert-butyl)bis[bis(trimethylsilyl)methyl]alanats mit intramolekularer Wechselwirkung zwischen Lithium und C?H?σ-Bindungen

Synthesis and Molecular Structure of (N,N′-Dimethyl-piperazine)lithium-(·-hydrido)(tert-butyl)bis[bis(trimethylsilyl)methyl]alanate with an Intramolecular Interaction between Lithium and C? H-σ-Bonds Syntheses and properties of the starting compounds bis[bromo-di(tert-butyl)alane] 3 , bis[dibromo-tert-butyl-alane] 4 , and (tert-butyl)bis[bis(trimethylsilyl)methyl]alane 5 are described. In the presence of 5 and the chelating amine N,N′-dimethylpiperazine lithium tert-butyl gives via μ-elimination isobutene and LiH, which is taken up by the starting alane 5 to give the title compound 6 . No attack of the strong base (lithium alkyl/amine) to the bis(trimethylsilyl) methyl substituent is observed as recently occured for the sterically more crowded tris[bis(trimethylsilyl)methyl]alane. Crystal structure of 6 shows a angled Li? H? Al bridge and a short intramolecular contact between Li and C? H-σ-bonds of a trimethylsilyl group.     

Synthese und Struktur eines Molybdän–Gadolinium-Heterometall-Komplexes Die Struktur von [Li(thf)4]2[Cp2MoSGdBr4(thf)]2

Synthesis and structure of a Molybdenum–Gadolinium Heterometallic Complex. The Structure of [Li(thf)₄]₂[Cp₂MoSGdBr₄(thf)]₂ [Cp₂MoHLi] reacts in THF with S and GdBr₃ to yield the tetranuclear heterobimetallic complex [Li(thf)₄]₂[Cp₂MoSGdBr₄(thf)]₂. The bonding situation and the structure of this compound were characterized by X-ray structure analysis (space group P1 (No. 2), Z = 1, a = 10.845(2) Å, b = 12.166(2) Å, c = 15.881(2) Å, α = 101.74(2)°, β = 97.62(2)°, γ = 103.97(2)°). Each S atom of the central Mo₂S₂-ring is coordinated by a GdBr₄(thf) fragment. Additionally each Mo atom is connected to two Cp ligands. This leads to a tetrahedral coordination of the Mo atoms and a octahedral coordination of the Gd ions.     

Die Kristallstruktur des tBu2P?PP(Br)tBu2

The Crystal Structure of tBu₂P? P?P(Br)tBu₂ tBu₂P? P?P(Br)tBu₂ 1 crystallizes in the monoclinic space group P2₁/c with a = 2 888.9(3), b = 972.16(10), c = 1 534.04(14) pm, β = 105.129(8)° and 8 formula units in the unit cell. The two independent P₃-units in 1 form angles of 105.77° or 105.98°, resp. One P? P distance (220,4 pm) corresponds to a single bond, the other one (207.9 pm) to a double bond.     

Komplexchemie P-reicher Phosphane und Silylphosphane. XIV. Phosphinophosphiniden tBu2P?P als Ligand in den Pt-Komplexen [η2-{tBu2P?P}Pt(PPh3)2] und [η2-{tBu2P?P}Pt(PEtPh2)2]

Coordination Chemistry of P-rich Phosphanes and Silylphasphanes. XIV. The Phosphinophosphinidene ^tBu₂P? P as a Ligand in the Pt Complexes [η²-{^tBu₂P? P}Pt(PPh₃)₂] and [η²-{^tBu₂P? P}Pt(PEtPh₂)₂] [η²-{^tBu₂P? P}Pt(PPh₃)₂ 1 and [η²-{^tBu₂P? P}Pt(PEtPh₂)₂] 2 are the first complex compounds of ^tBu₂P? P 5 . They are formed in the reaction of ^tBu₂P? P ? P(Me)^tBu₂ 3 with [η²-{H₂C ? CH₂}Pt(PPh₃)₂] 6 or [η²-{H₂C ? CH₂}Pt(PEtPh₂)₂] 7 , respectively. Compound 1 is less stable than 2 and reacts on to [η²-{^tBu₂P? P} Pt(PPh₃)(P^tBu₂Me)] 10 with the coincidently formed ^tBu₂PMe. The molecular structures of 1 and 2 were derived from their ¹H and ³¹P-NMR spectra, 2 was additionally characterized by a X ray structure determination. 2 crystallizes in the monoclinic space group P2₁/n with a = 1222.36(7) pm, b = 1770.7(1) pm, c = 1729.7(1) pm, β = 108.653(6)°.     

Darstellung von Dithiatetrazocinen und Folgereaktionen

Preparation of Dithiatetrazocine and Secondary Reactions Li[PhCN₂(SiMe₃)₂] ( 1 ) or PhCN₂(SiMe₃)₃ ( 3 ) react with SCl₂ to give in good yields the dithiatetrazocine PhC(NSN)₂CPh ( 2 ). By analogy, p-MeC₆H₄C(NSN)₂CC₆H₄Me-p ( 7 ), p-NO₂C₆H₄C(NSN)₂-CC₆H₄NO₂-p ( 8 ), and p-CF₃C₆H₄C(NSN)₂CC₆H₄CF₃-p ( 9 ) are obtained from the reaction of p-MeC₆H₄CN₂(SiMe₃)₃ ( 4 ), Li[p-NO₂-C₆H₄CN₂(SiMe₃)₂] ( 5 ), und Li[p-CF₃C₆H₄CN₂(SiMe₃)₂] ( 6 ) with SCl₂. Reaction of 2 /LiCl with AgAsF₆ in liquid SO₂ leads to [PhCN₂S₂]⁺[AsF₆]⁻ ( 10 ) and 3[PhCN₂S₂]⁺2[AsF₆]⁻Cl⁻ ( 11 ). The structures of 10 and 11 are confirmed by X-ray analyses.