Das P(SiMe2)3P

P(SiMe₂)₃P Li₃P (produced from the elements) forms with Me₂SiCl₂ at 20°C in toluene the bicyclic compound P(SiMe₂)₃P 4 beside small amounts of ClMe₂Si? P(SiMe₂)₂P? SiMe₂Cl and traces of P₄(SiMe₂)₆ 7. 4 can be transformed into 7 by thermal treatment. With the formation of 4 the existence of a bicyclic silylphosphane is confirmed which has already been mentioned in connection with P(SiEt₂)₃P [1], but could not be proven until now.     

Bildung und Struktur des iso-Tetraphosphans P[P(SiMe3)Me]3

Formation and Structure of iso-Tetraphosphane P[P(SiMe₃)Me]₃ The reaction of MeP(SiMe₃)₂ with PCl₃ (molar ratio 3:1, ?78°C, n-pentane) yields by cleaving of the P? Si bond P[P(SiMe₃)Me]₃ 1 with Cl₂P? P(SiMe₃)Me and ClP[P(SiMe₃)Me]₂ as intermediates. The reaction rate decreases by the increase of phosphorylation. The last reaction step (formation of 1 ) occurs while warming up to room temperature. 1 forms colorless hexagonal crystals, melting point 65 ± 1°C. Tris(trimethylsilyl-methyl-phosphino)phosphane 1 crystallizes monoclinically in the space group Cc (No. 8) with Z = 8 formula units per unit cell. The molecules possess approximated C₃ symmetry and have (RRR) and (SSS) configurations, respectively. The bond distances d?(P? P) = 220.1 pm, d?(P? C) = 186.5 pm, and d?(P? Si) = 225.2 pm are normal and within the expected range of known distances. According to repulsive interactions between the non bonded electron pairs of the terminal P atoms and the protons of the methyl groups the angles at the central and terminal P atoms are enlarged to ? P P P = 105.1° and ? P P C = 106.9°, respectively.     

Bildung und struktur der Cyclophosphane P4(CMe3)2[P(CMe3)2]2 und P4(SiMe3)2[P(CMe3)2]2

Formation and Structure of the Cyclophosphanes P₄(CMe₃)₂[P(CMe₃)₂]₂ and P₄(SiMe₃)₂[P(CMe₃)₂]₂ n-Triphosphanes showing a SiMe₃ and a Cl substituent at the atoms P¹ and P², like (Me₃C)₂P? P(SiMe₃)? P(CMe₃)Cl 3 or (Me₃C)₂P? P(Cl)? P(SiMe₃)₂ 4 are stable only at temperatures below ?30°C. Above this temperature these compounds lose Me₃SiCl, thus forming cyclotetraphosphanes, P₄(CMe₃)₂[P(CMe₃)₂]₂ 1 out of 3 , P₄(SiMe₃)₂[P(SiMe₃)₂]₂ 2a (cis) and 2b (trans) out of 4 . The formation of 1 proceeds via (Me₃C)₂P? P?PCMe₃ 5 as intermediate compound, which after addition to cyclopentadiene to give the Diels-Alder-adduct 6 (exo and endo isomers) was isolated. 6 generates 5 , which then forms the dimer compound 1 . Likewise (Me₃C)₂P? P?P-SiMe₃ 8 (as proven by the adduct 7 ) is formed out of 4 , leading to 2a (cis) and 2b (trans). Compound 1 is also formed out of the iso-tetraphosphane P[P(CMe₃)₂]₂[P(CMe₃)Cl] 9 , which loses P(CMe₃)₂Cl when warmed to a temperature of 20°C. 1 crystallizes monoclinically in the space group P2₁/a (no. 14); a = 1762.0(15) pm; b = 1687.2(18) pm; c = 1170.5(9) pm; β = 109.18(5)° and Z = 4 formula units in the elementary cell. The molecule possesses E conformation. The central four-membered ring is puckered (approx. symmetry 4 2m; dihedral angle 47.4°), thus bringing the substituents into a quasi equatorial position and the nonbonding electron pairs into a quasi axial position. The bond lengths in the four-membered ring of 1 (d (P? P) = 222.9 pm) are only slightly longer than the exocyclic bonds (221.8 pm). The endocyclic bond angles \documentclass{article}\pagestyle{empty}\begin{document}$ \bar \beta $\end{document}(P/P/P) are 85.0°, the torsion angles are ±33° and d (P? C) = 189.7 pm.     

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.     

Kristallstruktur des Zinkamids Zn[N(SiMe3)2]2

Crystal Structure of the Zinc Amide Zn[N(SiMe₃)₂]₂ X‐ray quality crystals of Zn[N(SiMe₃)₂]₂ (monoclinic, P2₁/c) are obtained by sublimation of the zinc amide Zn[N(SiMe₃)₂]₂ at —30 °C in vacuo (300 torr). According to the result of the X‐ray structural analysis, Zn[N(SiMe₃)₂]₂ contains an almost linear N‐Zn‐N unit with two short N‐Zn bonds.     

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.     

Synthesis and P-P cleavage reactions of [P(X)X']2; X-ray structures of [Co[P(X)X'](CO)3] and P4[P(X)X']2[X = N(SiMe3)2, X'= NPri2

Treatment of P(X)(X')Cl with KC8 gave the crystalline diphosphine [P(X)X']2 (1) which dissociated reversibly into the phosphinyl radical *P(X)X' (2), a plausible intermediate in the reaction of with [Cr(CO)6], [Co(NO)(CO)3] or P4, yielding [Cr[P(X)X']2(CO)3] (3), [Co[P(X)X'](CO)3] (4), or 1,4-P4[P(X)X']2 (5); the P(X)X' substituent is pyramidal at P in but planar in [X = N(SiMe3)2, X'= NPri2].     

Crystal and molecular structure of organosilicon titanium(iv) derivatives: (Me3Si)3SiTi(NEt2)3 and ClTi[N(SiMe3)2]3

An X-ray structural study of two titanium-containing organosilicon compounds, (Me₃Si)₃SiTi(NEt₂)₃ (1) and ClTi[N(SiMe₃)₂]₃ (2), has been performed. The conformation of molecule1 in a crystal is staggered (approximate inherentC ₃ symmetry), the Ti-Si and Ti-N bond lengths are 2.671(2) and 1.874–1.890(5) Å, respectively. A crystal of1 consists of one type of enantiomers (the space group is P4₁2₁2; the absolute configuration has been determined). The structure of2 studied previously has been refined to the value of R=0.029 on the basis of 3442 reflections (the absolute structure has been determined), the Ti-Cl and Ti-N bond lengths are 2.260(1) and 1.926(1) Å, respectively. The strong distortions in the symmetry of the valence environment of the N atoms in the molecules of1, 2, and related structures are caused by electronic effects, in which the conformation of the relevant molecular fragments plays a determining role.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1473–1476, August, 1993.     

Neue viergliedrige GaE‐ und InE‐Ringverbindungen: Synthese und Kristallstruktur von [Et2InE(SiMe3)2]2 und [GaCl(PtBu2Me)E(SiMe3)]2 (E = P,As)

New GaE and InE Four Membered Ring Compounds: Syntheses and Crystal Structures of [Et₂InE(SiMe₃)₂]₂ and [GaCl(P t Bu₂Me)E(SiMe₃)]₂ (E = P, As) Et₃In · PR₃ (R = Et, iPr) reacts with H₂ESiMe₃ under liberation of C₂H₆ and EH₃ to form the cyclic compounds [Et₂InE(SiMe₃)₂]₂ ( 1 a : E = P, 1 b : E = As). 1 consists of a planar four membered In₂E₂ ring in which the indium and phosphorus or arsenic atoms are four coordinated. In contrast, the phosphorus/arsenic atoms in [GaCl(PtBu₂Me)E(SiMe₃)]₂ ( 2 a : E = P, 2 b : E = As) only have the coordination number three. 2 results from the reaction of GaCl₃ · PtBu₂Me with As(SiMe₃)₃ or Li₂PSiMe₃ respectively, and displays a folded four membered Ga₂E₂ ring as central structural motif. 1 and 2 have been characterised by single crystal X‐ray diffraction analysis as well as ¹H and ³¹P{¹H} NMR spectroscopy.     

Synthese und Strukturen von [ReNBr2(Me2PhP)3] und (Me2PhPH)[fac‐Re(NBBr3)Br3(Me2PhP)2]

Syntheses and Structures of [ReNBr₂(Me₂PhP)₃] and (Me₂PhPH)[ fac ‐Re(NBBr₃)Br₃(Me₂PhP)₂] [ReNBr₂(Me₂PhP)₃] ( 1 ) has been prepared by the reaction of [ReNCl₂(Me₂PhP)₃] with Me₃SiBr in dichloromethane. The bromo complex reacts with BBr₃ under formation of [Re(NBBr₃)Br₂(Me₂PhP)₃] ( 2 ) or (Me₂PhPH)[fac‐Re(NBBr₃)Br₃(Me₂PhP)₂] ( 3 ) depending on the experimental conditions. The formation of the nitrido bridge leads to a significant decrease of the structural trans influence of the nitrido ligand which is evident by the shortening of the Re‐(trans)Br bond from 2.795(1) Å in [ReNBr₂(Me₂PhP)₃] to 2.620(1) Å in [fac‐Re(NBBr₃)Br₃(Me₂PhP)₂]^– and 2.598(1) Å in [Re(NBBr₃)Br₂(Me₂PhP)₃], respectively.     

Synthesis and Crystal Structure of the two Lithium Hypersilylcuprates LiCu2[Si(SiMe3)3]3 and [Li7(OtBu)6][Cu2{Si(SiMe3)3}3]

The two hypersilylcuprates LiCu₂Hyp₃ ( 2 ) and [Li₇(O^tBu)₆][Cu₂Hyp₃] ( 3 ) (Hyp = Si(SiMe₃)₃) were synthesized by reactions of unsolvated lithium hypersilanide, LiHyp with hypersilylcopper and CuO^tBu, respectively. Both contain the novel A‐frame trihypersilyldicuprate anion [Cu₂Hyp₃]^–. In the former case a molecular compound is produced containing intimate ion pairs. In the latter case the cuprate anion and the unique large [Li₇(O^tBu)₆]⁺ cation form a salt‐like compound, only sparingly soluble in unpolar solvents. According to NBO analyses the bonding within the trihypersilyldicuprate moiety is best described by interaction of a bridging lewis‐basic hypersilanide anion with two lewis‐acidic hypersilyl copper fragments.     

Dihaloheptasilanes X2Si[SiMe(SiMe3)2]2 as potential precursors for silylenes, disilenes and cyclotrisilanes

The synthesis of new dihaloheptasilanes X₂Si[SiMe(SiMe₃)₂]₂ (X=Cl: 2, Br: 3, I: 4) was performed by treating dihydridoheptasilane 1 (X=H) with CCl₄, HCBr₃ or HCI₃. Difluoroheptasilane 6 (X=F) was prepared from either diphenylheptasilane 5 (X=Ph), triflic acid (HOTf), and LiF with concomitant isolation of heptasilanes 7 (X₂=Ph and OTf), 8 (X₂=F and Ph), and 9 (X₂=F and OTf), or by halogen exchange from 2 using ZnF₂. Crystal structures of 2, 3, 4, and 5 are reported. The reduction of 2 with Li, Na or KC₈ resulted in the instantaneous formation of various cyclotrisilanes, while the reduction of 3 gave exclusively the unsymmetrical cyclotrisilane (E)-1-methyl-2,3,3-tris[methylbis(trimethylsilyl)silyl]-1,2-bis(trimethylsilyl)cyclotrisilane 10, which was characterized by X-ray crystallography. A mechanism for the formation of cyclotrisilanes via a silylsilylene-to-disilene rearrangement is proposed. Attempts to prepare the tetradekasilane [(Me₃Si)₂MeSi]₂SiH–SiH[SiMe(SiMe₃)₂]₂ (by reductive dehalogenation of either HClSi[SiMe(SiMe₃)₂]₂ 13 or HISi[SiMe(SiMe₃)₂]₂ 18), or the tetradekasilane [(Me₃Si)₂MeSi]₂SiPh–SiPh[SiMe(SiMe₃)₂]₂ (by reductive dehalogenation of either PhClSi[SiMe(SiMe₃)₂]₂ 14 or PhISi[SiMe(SiMe₃)₂]₂ 19) as precursors for the disilene [(Me₃Si)₂MeSi]₂Si=Si[SiMe(SiMe₃)₂]₂ failed. 14 was characterized by X-ray crystallography. All compounds described were also characterized by multinuclear NMR spectroscopy and elemental analysis.     

Ein- und zweikernige Dinitrosylkomplexe von Molybdän und Wolfram. Die Kristallstrukturen von (PPh3Me)2[WCl4(NO)2], (PPh3Me)2[MoCl3(NO)2]2 und von (PPh3Me)2[WCl3(NO)2]2

Mono- and Binuclear Dinitrosyl Complexes of Molybdenum and Tungsten. Crystal Structures of (PPh₃Me)₂[WCl₄(NO)₂], (PPh₃Me)₂[MoCl₃(NO)₂]₂, and (PPh₃Me)₂[WCl₃(NO)₂]₂ The complexes (PPh₃Me)₂[MCl₄(NO)₂] (M = Mo, W), and (PPh₃Me)₂[MCl₃(NO)₂]₂, respectively, are prepared by reactions of the polymeric compounds MCl₂(NO)₂ with triphenylmethylphosphonium chloride in CH₂Cl₂, forming green crystals. According to the IR spectra the nitrosyl groups are in cis-position in all cases. The tungsten compounds as well as (PPh₃Me)₂[MoCl₃(NO)₂]₂ were characterized by structure determinations with X-ray methods. (PPh₃Me)₂[WCl₄(NO)₂]: space group C2/c, Z = 4. a = 1874, b = 1046, c = 2263 pm, β = 119.99°. Structure determination with 3492 independent reflexions, R = 0.057. The compound consists of PPh₃Me^⊕ ions, and anions [WCl₄(NO)₂]^2? with the nitrosyl groups in cis-position (symmetry C_2v). (PPh₃Me)₂[WCl₃(NO)₂]₂: Space group C2/c, Z = 4. Structure determination with 2947 independent reflexions, R = 0.059. (PPH₃Me)₂[MoCl₃(NO)₂]₂: Space group P1 , Z = 1. a = 989, b = 1134, c = 1186 pm; α = 63.25°, β = 80.69°, γ = 69.94°. Structure determination with 3326 independent reflexions, R = 0.046. The compounds consist of PPh₃Me^⊕ ions, and centrosymmetric anions [MCl₃(NO)₂]₂^2?, in which the metal atoms are associated via MCl₂M bridges of slightly different lengths. One of the NO groups is in an axial position, the other one in equatorial position (symmetry C_2h).     

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)°.     

Silylierte Phosphanimin-Komplexe von Chrom(II), Palladium(II) und Kupfer(II). Die Kristallstrukturen von [CrCl2(Me3SiNPMe3)2], [PdCl2(Me3SiNPEt3)2] und [CuCl2(Me3SiNPMe3)]2

Silylated Phosphaneimine Complexes of Chromium(II), Palladium(II), and Copper(II). The Crystal Structures of [CrCl₂(Me₃SiNPMe₃)₂], [PdCl₂(Me₃SiNPEt₃)₂], and [CuCl₂(Me₃SiNPMe₃)]₂ The title compounds have been prepared by the reaction of the silylated phosphaneimines Me₃SiNPR₃ (R = CH₃, C₂H₅) with CrCl₂(THF)₂, PdCl₂ and CuCl₂, respectively, in dichloromethane suspensions. All donor-acceptor complexes were characterized by IR spectroscopy and by crystal structure determinations. [ CrCl₂(Me₃SiNPMe₃ )₂]: Space group Pccn, Z = 4, structure determination with 2104 observed unique reflections, R = 0.045. Lattice dimensions at ?70°C: a = 1326.3, b = 1562.5, c = 1171.5 pm. Within the monomeric molecular structure the chromium atom is planarly coordinated within the trans-configuration of the Cl atoms and the N atoms with distances of Cr? Cl = 235.94 pm and Cr? N = 211.7 pm. [ PdCl₂(Me₃SiNPEt₃)₂ ]: Space group P2₁/n, Z = 2, structure determination with 2412 observed unique reflections, R = 0.031. Lattice dimensions at 20°C: a = 917.3, b = 1390.2, c = 1161.7 pm, β = 95.80°. Within the monomeric molecular structure the palladium atom is planarly coordinated within the trans-configuration of the Cl atoms and the N atoms with distances of Pd? Cl = 222.9 pm and Pd? N = 209.5 pm. [ CuCl₂(Me₃SiNPMe₃)₂ ]: Space group Pbca, Z = 4, structure determination with 1861 observed unique reflections, R = 0.067. Lattice dimensions at ?70°C: a = 1440.2, b = 1205.1, c = 1536.5 pm. The compound forms centrosymmetric dimeric molecules, in which the Cu atoms are linked via almost symmetrical chloro-bridges with Cu? Cl distances of 231.4 pm. The distance Cu? N is 196.7 pm.