Untersuchungen zur Bildung silylierter iso-Tetraphosphane aus P2-chlorierten Triphosphanen und Li-Phosphiden

Investigations on the Formation of Silylated iso-Tetraphosphanes We investigated the formation of iso-tetraphosphanes by reacting [Me(Me₃Si)P]₂PCl 4 , Me(Me₃Si)P? P(Cl)? P(SiMe₃)₂ 8 , Me(Me₃Si)P? P(Cl)? P(SiMe₃)(CMe₃) 9 , [Me(Me₃Si)P]₂PCl 20 , Me₃C(Me₃Si)P? P(Cl)? P(SiMe₃)₂ 21 , and [MeC(Me₃Si)P]₂PCl 22 with LiP(SiMe₃)Me 1 , LiP(SiMe₃)₂ 2 , and LiP(SiMe₃)CMe₃ 3 , respectively, to elucidate possible paths of synthesis, the influence of substituents (Me, SiMe₃, CMe₃) on the course of the reaction, and the properties of the iso-tetraphosphanes. These products are formed via a substitution reaction at the P²Cl group of the iso-triphosphanes. However, with an increasing number of SiMe₃ groups in the triphosphane as well as in reactions with LiP(SiMe₃)Me, cleaving and transmetallation reactions become more and more important. The phosphides 1,2, and 3 attack the PC1 group of 4 yielding the iso-tetraphosphanes P[P(SiMe₃)Me]₃ 5, [Me(Me₃Si)P]₂P? P(SiMe₃)₂ 6 and [Me(Me₃Si)P]₂P? P(SiMe₃)CMe₃ 7. I n reactions With 8 and 9, LiP(SiMe₃)Me causes bond cleavage and mainly leads to Me(Me₃Si)P? P(Me)? P(SiMe₃)₂ 13 and Me(Me₃Si)P? (Me)? P(SiMe₃)CMe₃ 16, resp., and to monophosphanes; minor products are [Me(SiMe₃)P]₂P? P(SiMe₃)₂ 6 and [Me(Me₂Si)P]₂P? P(SiMe₃)CMe₂ 7. LiP(SiMe₃)₂ 2 and LiP(SiMe₃)CMe₂ 3 with 8 and 9 give Me(Me₃,Si)P? P[P(SiMe₃)₂]₂ 10, Me(Me₂Si)P? P[P(SiMe₃)CMe₂]? P(SiMe₃)₂ 11, and Me(Me₃Si)P? P[P(SiMe₃)CMe₃]₂ 12 as favoured products. With 20, LiP(SiMe₃)₂ 2 forms P[P(SiMe₃)₂]₃ 28. Bond cleavage products are obtained in reactions of 20 with 1 and 2, of 21 with 1, 2, and 3, and of 22 with 1 and 2. P[P(SiMe₃)CMe₃]₃ 23 is the main product in the reaction of 22 with LiP(SiMe₃)CRle₂ 3. In the reactions of 22 with 1, 2, and 3 the cyclophosphanes P₃(CMe₃)₂(SiMe₃)25, P₄[P(SiMe₃)CMe₃]₂(CMe₃)₂ 26, and P₅(CMe₃)₄(SiMe₃) 27 are produced. The formation of these rom- pounds begins with bond cleavage in a P- SiMe, group by means of the phosphides. The thermal stability of the iso-tetraphosphanes decreases with an increasing number of silyl groups in the molecule. At 20O°C compounds 5, 7, and 23 are crystals; also 6 is stable; however, 10, It, 12, and 28 decompose already.     

Kettenverlängerung am P2(SiMe3)4 durch Reaktion mit LiBu

Extension of the Chain Length of P₂(SiMe₃)₄ by Reaction with LiBu The first steps of the reaction of P₂(SiMe₃)₄ 1 with LiBu in THF, which finally yields Li₃P₇ among other P-rich phosphides while P(SiMe₃)₃ and LiP(SiMe₃)₂ are simultaneously split off, were investigated by means of ³¹P-NMR spectroscopy. At ?20°C first of all one Si? P bond is cleaved generating Li(Me₃Si)P? P(SiMe₃)₂ 2 as well as BuSiMe₃. Subsequently 2 forms Li(Me₃Si)P? P(SiMe₃)? P(SiMe₃)₂ 5 and LiP(SiMe₃)₂ 4 in equimolar ratios. This clearly demonstrates that both compounds are generated in one single reaction step. This behaviour is caused by the different basicity of the respective P-atoms in 2 , which necessarily results in a multicentered mechanism.     

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.     

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.     

Synthese und Eigenschaften teilsilylierter Tri- und Tetraphosphane. Reaktionen lithiierter Diphosphane mit Chlorphosphanen

Synthesis and Properties of Partially Silylated Tri- and Tetraphosphanes. Reaction of Lithiated Diphosphanes with Chlorophosphanes The reactions of Li(Me₃Si)P? P(SiMe₃)(CMe₃) 1 , Li(Me₃Si)P? P(CMe₃)₂ 2 , and Li(Me₃C)P? P(SiMe₃)(CMe₃) 3 with the chlorophosphanes P(SiMe₃)(CMe₃)Cl, P(CMe₃)₂Cl, or P(CMe₃)Cl₂ generate the triphosphanes [(Me₃C)(Me₃Si)P]₂P(SiMe₃) 4 , (Me₃C)(Me₃Si)P? P(SiMe₃)? P(CMe₃)₂ 6 , [(Me₃C)₂P]₂P(SiMe₃) 7 , and (Me₃C)(Me₃Si)P? P(SiMe₃)? P(CMe₃)Cl 8 . The triphosphane (Me₃C)₂P? P(SiMe₃)? P(SiMe₃)₂ 5 is not obtainable as easily. The access to 5 starts by reacting PCl₃ with P(SiMe₃)(CMe₃)₂, forming (Me₃C)₂ P? PCl₂, which then with LiP(SiMe₃)₂ gives (Me₃C)₂ P? P(Cl)? P(SiMe₃)₂ 11 . Treating 11 with LiCMe₃ generates (Me₃C)₂P? P(H)? P(SiMe₃)₂ 16 , which can be lithiated by LiBu to give (Me₃C)₂P? P(Li)? P(SiMe₃)₂ 13 and after reacting with Me₃SiCl, finally yields 5 . 8 is stable at ?70°C and undergoes cyclization to P₃(SiMe₃)(CMe₃)₂ in the course of warming to ambient temperature, while Me₃SiCl is split off. 7 , reacting with MeOH, forms [(Me₃C)₂P]₂PH. (Me₃C)₂P? P(Li)? P(SiMe₃)₂ 18 , which can be obtained by the reaction of 5 with LiBu, decomposes forming (Me₃C)₂P? P(Li)(SiMe₃), P(SiMe₃)₃, and LiP(SiMe₃)₂, in contrast to either (Me₃C)₂P? P(Li)? P(SiMe₃)(CMe₃) 19 or [(Me₃C)₂P]₂PLi, which are stable in ether solutions. The Li phosphides 1 , 2 , and 3 with BrH₂C? CH₂Br form the n-tetraphosphanes (Me₃C)(Me₃Si)P? [P(SiMe₃)]₂? P(SiMe₃)(CMe₃) 23 , (Me₃C)₂P? [P(SiMe₃)]₂? P(CMe₃)₂ 24 , and (Me₃C)(Me₃Si)P? [P(CMe₃)]₂? P(SiMe₃)(CMe₃) 25 , respectively. Li(Me₃Si)P? P(SiMe₃)₂, likewise, generates (Me₃Si)₂P? [P(SiMe₃)]₂? P(SiMe₃)₂ 26 . Just as the n-triphosphanes 4 , 5 , 6 , and 7 , the n-tetraphosphanes 23 , 24 , and 25 can be isolated as crystalline compounds. 23 , treated with LiBu, does nor form any stable n-tetraphosphides, whereas 24 yields (Me₃C)₂P? P(Li)? P(SiMe₃)? P(CMe₃)₂, that is stable in ethers. With MeOH, 24 , forms crystals of (Me₃C)₂P? P(H)? P(SiMe₃)? P(CMe₃)₂.     

Zur Bildung der Cyclotetraphosphane cis- und trans-P4(SiMe3)2(CMe3)2 bei der Umsetzung von (Me3C)PCl2 mit LiP(SiMe3)2 · 2 THF

Formation of the Cyclotetraphosphanes cis- und trans-P₄(SiMe₃)₂(CMe₃)₂ in the Reaction of (Me₃C)PCl₂ with LiP(SiMe₃)₂ · 2 THF The mechanism of the reaction of (Me₃C)PCl₂ 1 with LiP(SiMe₃)₂ · 2 THF 2 was investigated. With a mole ration of 1:1 at ?60°C quantitatively (Me₃C)(Cl)P? P(SiMe₃)₂ 3 is formed. This compound eliminates Me₃SiCl on warming to 20°C, yielding Me₃Si? P?P? CMe₃ 4 (can be trapped using 2,3-dimethyl-1,3-butadiene in a 4+2 cycloaddition), which dimerizes to produce the cyclotetraphosphanes cis-P₄(SiMe₃)₂(CMe₃)₂ 5 and trans-P₄(SiMe₃)₂(CMe₃)₂ 6 . Also with a mole ratio of 1:2 initially 3 is formed which remarkably slower reacts on to give [(Me₃Si)₂P]P₂P? CMe₃ 8 . Remaining LiP(SiMe₃)₂ cleaves one Si? P bond of 8 producing (Me₃)₂P? P(CMe₃)? P(SiMe₃)₂Li. Via a condensation to the pentaphosphide 10 and an elimination of LiP(SiMe₃)₂ from this intermediate, eventually trans-P₄(SiMe₃)₂(CMe₃)₂ 6 is obtained as the exclusive cyclotetra-phosphane product.     

Stabilisierung von ?PC〈-Bindungen durch cyclische Silylhydrazone

Stabilization of ? P?C〈 Bonds by Cyclic Silylhydrazones 1,2-Diaza-3-sila-5-cyclopentenes unsubstituted at the 4-position react after lithiation with halophosphanes and -arsanes to give 1 – 4 . The 4-methylated ring 5 reacts analogously with F₂P? N(SiMe₃)₂ to give 6 , but exchanges the dimethylsilyl group of the ring in reaction with PCl₃, to give 1,2-diaza-3-phospha-3,5-cyclopentadien 7 . The phosphaethenes 8 and 9 are formed from 4-trimethylsilylsubstituted lithiated rings by reaction with difluorophosphanes, F₂PR (R = N(SiMe₃) CMe₃, N(SiMe₃)₂) and elimination of LiF and chlorosilane.     

Synthese und Kristallstruktur des Zirkonocen-Alkinyl-Alkenyl-Komplexes (Z)?Cp2Zr(CCPh){C(Ph) = C(H)P(SiMe3)2}

Synthesis and Crystal Structure of the Zirkonocene Alkynyl Alkenyl Complex (Z)? Cp₂Zr(C?CPh){C(Ph) = C(H)P(SiMe₃)₂} The reaction of ( Z )? Cp₂Zr(C(Ph) = C(H)P(SiMe₃)₂}(Cl) with lithium phenylacetylide yields the zirconocene alkynyl alkenyl complex ( Z )? Cp₂Zr(C?CPh){C(Ph) = C(H)P(SiMe₃)₂} ( 1 ). 1 was characterised spectroscopically (IR, NMR, MS) and by X-ray structure determination. The complex crystallises triclinic in the space group P1 with a = 10.561(10), b = 11.226(12), c = 14.274(13) Å, α = 70.87(7), β = 77.70(7), γ = 77.85(7)°. In 1 , there are two different Zr? C bond distances (Zr? C(=C) 2.415(6), Zr? C(?C) 2.309(6) Å). A Zr? P interaction (Zr? P 2.774(3) Å) is observed in the solid state.     

Übergangsmetallphosphidokomplexe. XI. Diphosphenkomplexe des Typs (R3P)2Ni[η2-(PR′)2] und phosphidoverbrückte Nickel(I)-Komplexe des Typs [R3PNiP(SiMe3)2]2 (Ni?Ni)

Transition Metal Phosphido Complexes. XI. Diphosphene Complexes of the Type (R₃P)₂Ni[η²-(PR′)₂] and Phosphido-Bridged Nickel(I) Complexes of the Type [R₃PNiP(SiMe₃)₂]₂(Ni? Ni) From reactions of complexes of the type (R₃P)₂NiCl₂ 1 (R = Me a , Et b , nBu c , iBu d , Ph e , iPr f , Cy g ) with LiP(SiMe₃)₂ in a 1:2 molar ratio the diphosphene complexes (R₃P)₂Ni[η²-(PSiMe₃)₂] 4a–c and the phosphido-bridged nickel(I) complexes [R₃PNiP(SiMe₃)₂]₂ (Ni? Ni) 7a–g are available. Using low temperature n.m.r. measurements the monosubstitution products (R₃P)₂NiClP(SiMe₃)₂ 2a–c and the nickel(0) diphosphane complexes R₃PNi[η¹-P₂(SiMe₃)₄] 6a–g can be detected as intermediates. In reactions in a 1:1 molar ratio the formation of the diphosphorus complexes [(R₃P)₂Ni]₂P₂ 9b, 9c is n.m.r. spectroscopically detectable. 1b reacts with LiP(SiMe₃)CMe₃ to give first the nickel(0) diphosphane complex Et₃PNi[η¹-P(SiMe₃)CMe₃? P(SiMe₃)CMe₃] 10 , which can be isolated at low temperatures, finally yielding (Et₃P)₂Ni[η²-(PCMe₃)₂] 11 and [Et₃PNiP(SiMe₃)CMe₃]₂ (Ni? Ni) 12. 11 as well as (Et₃P)₂Ni[η²-(PPh)₂] 14 can also be obtained reacting 1b with R′P(SiMe₃)₂ (R′ = CMe₃, Ph). The best yields of diphosphene complexes result from [2+1] cyclocondensation reactions of 1a–c with P₂(SiMe₃)₄ to give 4a–c and of 1b with [P(SiMe₃)CMe₃]₂ to give 11 . N.m.r. and mass spectral data are reported.     

Molecular Gallium Arsenide Phosphide Clusters Prepared from AsP3, P4, and [{GaC(SiMe3)3}4]

Treatment of AsP₃ with 0.75 equivalents of [{GaC(SiMe₃)₃}₄] resulted in selective insertion of three equivalents of {GaC(SiMe₃)₃} into the three As? P bonds to give [As{GaC(SiMe₃)₃}₃P₃] ( 1 ‐As) with an intact cyclo‐P₃ ring. This yellow compound has been characterized by NMR spectroscopy, combustion analysis, single‐crystal X‐ray diffraction, UV/Vis spectroscopy, Raman spectroscopy, and cyclic voltammetry (THF, 0.2 M [TBA][B(C₆F₅)₄]; TBA=tetrabutyl ammonium). Computational models of 1 ‐As and the isomeric [P{GaC(SiMe₃)₃}₃AsP₂] ( 1 ‐P) have been investigated as well, revealing several interesting electronic features of these cage molecules. Following from the cyclic voltammetry studies of 1 ‐As that highlight an irreversible two‐electron reduction at ?2.2 V versus Fc/Fc⁺, treatment with one equivalent of [Mg(C₁₄H₁₀)(thf)₃] resulted in two‐electron reduction to provide [As{GaC(SiMe₃)₃}₃P₃Mg(thf)₃] ( 2 ), in which the Mg²⁺ ion has inserted into one of the P? P bonds of the cyclo‐P₃ ring. It was also found that treatment of AsP₃ or P₄ with one equivalent of [{GaC(SiMe₃)₃}₄] resulted in formation of the quadruple insertion products [As{GaC(SiMe₃)₃}₄P₃] ( 3 ) and [P{GaC(SiMe₃)₃}₄P₃] ( 4 ), respectively.     

Zum Thermischen verhalten teilsilylierter Tri- und Tetraphosphane

Concerning the Thermal Behaviour of Partially Silylated Tri- and Tetraphosphanes The influence of Me₃Si- and Me₃C-substituents in the compounds (Me₃Si)P[P(SiMe₃)(CMe₃)]₂ 1 , (Me₃C)₂P-P(SiMe₃)? P(SiMe₃)₂ 2 , (Me₃C)₂P? P(SiMe₃)? P(SiMe₃)(CMe₃) 3 , (Me₃Si)P[P(CMe₃)₂]₂ 4 , (Me₃C)(Me₃Si)P? [P(SiMe₃)]₂? P (SiMe₃)(CMe₃) 5 , (Me₃C)(Me₃Si)P? [P(CMe₃)]₂? P (SiMe₃)(CMe₃) 6 and (Me₃C)₂P? [P(SiMe₃)]₂? P (CMe₃)₂ 7 on their thermal stability as well as on the reactions that occur, when these compounds are exposed to higher temperatures, is investigated. The tetraphosphane 6 , bearing 4 Me₃C and 2 Me₃Si groups (the latter being located at the primary P atoms) hardly shows any changes, when it is exposed to 100°C in toluene (hermetically sealed ampoule) for several days, while the remaining compounds are found to rearrange significantly under similar conditions. Thus 1 [no (Me₃C)₂P-group] forms trans- P₄ (SiMe₃)₂(CMe₃)₂ 9 , while (Me₃C)P(SiMe₃)₂ 8 is being cleaved off, which can be understood easily, assuming the formation of the corresponding linear pentaphosphane (accompanied by the cleave-off of 8 ) and its subsequent cyclisation to 9 (again splitting off 8 ). 5 is found to form cyclophosphanes (tri-, penta-, hexa-), while (Me₃C)P(SiMe₃)₂ and P(SiMe₃)₃ are being cleaved off. All of the remaining compounds mentioned [with (Me₃C)₂P-groups] finally yield, aside of P(SiMe₃)₃ and (Me₃C)P(SiMe₃)₂, the cyclophosphanes P₄[P(CMe₃)₂]₄ 11 and P₃[P(CMe₃)₂]₃ 12 , which can be explained by the formation of the reactive intermediate (Me₃C)₂P? \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits_ - ^ - $\end{document} ( which, however, has not been proven).     

Synthese,Struktur und Reaktivität von Bis(dialkylamino)diphosphanen

Synthesis, Structure, and Reactivity of Bis(dialkylamino)diphosphines Starting with the aminochlorophosphines ⁱPr₂N? PCl₂ 1 and (ⁱPr₂N)₂P? Cl 2 , the synthesis of some new functionalized aminophosphines (ⁱPr₂N)₂P? SiMe₃ 3a , (ⁱPr₂N)₂P? SnMe₃ 3b , (ⁱPr₂N)(DMP)P? Cl 4 , ⁱPr₂N? P(SiMe₃)₂ 5 and ⁱPr₂N? P(SiMe₃)Cl 6 is reported. Reactions of 2 with different phosphides yield the aminodiphosphines (ⁱPr₂N)₂P? P(SiMe₃)₂ 7a , (ⁱPr₂N)₂P? P(SiMe₂^tBu)₂ 7b , (ⁱPr₂N)₂P? PPh₂ 8 and (ⁱPr₂N)₂P? PH₂ 9 . The phosphines 3a/b react with halogenophosphines to the aminohalogenodiphosphines (ⁱPr₂N)₂P? PCl₂ 10 , (ⁱPr₂N)₂P? P^tBuCl 11 and (ⁱPr₂N)₂P? P(NⁱPr₂)Cl 12 . The ambivalente aminophosphine 6 gives the aminotrichlorodiphosphine Cl(ⁱPr₂N)P? PCl₂ 13 after condensation with PCl₃, while the reactions with the corresponding lithiumphosphides yield the aminosilyldiphosphines (ⁱPr₂N)(SiMe₃)P? P(SiMe₃)₂ 14a and (ⁱPr₂N)(SiMe₃)P? P(SiMe₂^tBu)₂ 14b . The aminochlorophosphines 2/4 are reductively coupled with magnesium leading to the symmetrically substituted tetraaminodiphosphines (ⁱPr₂N)₂P? P(ⁱPr₂N)₂ 15a and DMP(ⁱPr₂N)P? P(ⁱPr₂N)DMP 15b . The functionalized aminosilyldiphosphine 7a is treated with methanol to yield the diphosphine (ⁱPr₂N)₂P? PH(SiMe₃) 16 and gives the lithium phosphinophosphide (ⁱPr₂N)₂P? PLi(SiMe₃) 17 after metallation with n-BuLi. The compounds are characterized by their NMR and mass spectra and the ³¹P-NMR values of the diphosphines are discussed according to their substituents. The crystal structures of 7b, 8 and 15b showing significantly differing conformations are presented.     

Bildung und Reaktionen silylierter Diphosphane

Preparation and Reactions of Silylated Diphosphanes The preparation of previously not available silylated diphosphanes is reported, i. e. the compounds (Me₃Si)₂P? P(SiMe₃)(CMe₃) 1 , (Me₃Si)₂P? P(CMe₃)₂ 2 and (CMe₃)₂P? P(SiMe₃)(CMe₃) 4 as well as of the respective PH containing derivatives and Li phosphides thereof. The reaction of 1 with MeOH leads to (Me₃Si)₂P? P(CMe₃) H 6 , while 4 generates (Me₃C)₂P? P(CMe₃) H 7 , and finally 3 gives access to (Me₃C)(Me₃Si)P? P(CMe₃) H 8 . LiBu on the other hand forms the Li phosphides Li(Me₃Si)P? P(SiMe₃)(CMe₃) 10 (through 1 ), Li(Me₃Si)P? P(CMe₃)₂ 11 (through 2 ), Li(Me₃C)P? P(SiMe₃)(CMe₃) 12 (through 3 ), and Li(Me₃C)P? P(CMe₃)₂ 13 (through 4 ), the latter being more easily accessible through the reaction of H(Me₃C)P? P(CMe₃)₂ with LiBu. The introduction of one single CMe₃ substituent into 1 is sufficient to obtain the Li phosphide 10 , which is stable in ethers, as opposed to the corresponding Li Phosphide of the persilylated diphosphane.     

Reaktionen silylierter Cyclotetraphosphane mit Lithiumalkylen

Reactions of Silylated Cyclotetraphosphanes with Lithium Alkyles While the cyclotetraphosphanes P₄(CMe₃)₃SiMe₃ 1 and trans-P₄(CMe₃)₂(SiMe₃)₂ 2 in reaction with LiR (R = Me, n-Bu) in THF yield the cyclic phosphides LiP₄(CMe₃)₃ 3 and trans-LiP₄(CMe₃)₂SiMe₃ 4 , respectively, the compounds P₄(SiMe₃)₄ 5 , P₄(SiMe₃)₃ CMe₃ 6 and cis-P₄(CMe₃)₂(SiMe₃)₂ 7 by cleavage of a P? P bond produce primary n-tetraphosphides, which rearrange (1,3-shift of Li/SiMe₃) in THF even at low temperature to form the corresponding secondary n-tetraphosphides. Warming these solutions to room temperature initiates consecutive reactions including elimination of LiP(SiMe₃)₂, (Me₃Si)₃P, RP(SiMe₃)₂ and producing P-rich compounds. In this way Li₃P₇ is obtained as main-product from compound 5 , and LiP₅(CMe₃)₄, LiP₃(CMe₃)₂, P₄(CMe₃)₄ from compound 7 . However, the reaction of 6 and LiR gives raise only to traces of Li₃P₇ and Li₂P₇CMe₃. The above mentioned primary as well as the secondary n-tetraphosphides generate stable n-tetraphosphane derivatives by reaction with Me₃SiCl, or MeCl, respectively.     

Reaktionen von (tBu)2P?PP(Br)tBu2 mit LiP(SiMe3)2, LiPMe2 und LiMe,LitBu, LinBu

Reactions of (tBu)₂P? P?P(Br)tBu₂ with LiP(SiMe₃)₂, LiPMe₂ and LiMe, LitBu and LinBu The reactions of (tBu)₂P? P?P(Br)tBu₂ 1 with LiP(SiMe₃)₂ 2 yield (Me₃Si)₂P? P(SiMe₃)₂ 4 and P[P(tBu)₂]₂P(SiMe₃)₂ 5 , whereas 1 with LiPMe₂ 2 yields P₂Me₄ 6 and P[(tBu)₂]₂PMe₂ 7 . 1 with LiMe yields the ylid tBu₂P? P?P(Me)tBu₂ (main product) and [tBu₂P]₂PMe 15 . In the reaction of 1 with tBuLi [tBu₂P]₂PH 11 is the main product and also tBuP? P?P(R)tBu₂ 21 is formed. The reaction of 1 with nBuLi leads to [tBu₂P]₂PnBu 17 (main product) and tBu₂P? P?P(nBu)tBu₂ 22 (secondary product).     

Formation and chemical behaviour of silylated phosphanes

Abstract

Our investigations to be presented here have their origin in a number of former results: The formation of [(Me₃Si)₂P]₂SiMe₂ [1] and its rearrangement to P₄(SiMe₂)₆ (a molecule with adamantane structure) and P(SiMe₃)₃, the formation of P₇(SiMe₃)₃ and of some cyclic phosphanes by the thermally induced rearrangement of [(Me₃Si)₂)P]₂SiMe₂ [3], and the formation of P₇(SiMe₃)₃ by reacting P₄ with Na/K-alloy and Me₃SiCl. After finding LiP(SiMe₃)₂ to be such a versatile reagent we turned to elucidate synthesis and chemical behaviour of LiP[P(SiMe₃)₂]₂.     

Bildung siliciumorganischer Verbindungen. 105. Reaktionen des (Cl3Si)2CPMe2Cl mit Silylphosphanen

Formation of Organosilicon Compounds. 105. Reactions of (Cl₃Si)₂C?PMe₂Cl with Silylphosphanes The reaction of (Cl₃Si)₂C?PMe₂Cl 1 with MeP(SiMe₃)₂ proceeds at 130°C (15 hrs.), by cleavage of all Si? P bonds to compounds 2, 3, 4, 5 . The course of this reaction incorporates a number of stages of which the compounds (Cl₃Si)₂C? PMe₂? P(Me)SiMe₃, (Cl₃Si)₂C?PMe₂? PMe? P(Me)SiMe₃ and ClP(Me)SiMe₃ are important and are yet to be isolated. The reaction of (Cl₃Si)₂C?PMe₂Cl with LiP(SiMe₂)₂ produces compound 2 as well as p₂(SiMe₃)₄ and P(SiMe₃)₃. The formation of 2 can be explained by the initial formation of the intermediate (Cl₃Si)₂C?PMe₂? P(SiMe₂)₂ with reacts with 1 to produce 2 and (ClP(SiMe)₃)₂. The formation of P₂(SiMe₃)₄ is also explained by the reaction of ClP(SiMe₃)₂ with LiP(SiMe₃)₄. The reaction of (Cl₃Si)₂C?PMe₂C(H)PMe₂ at 130°C/15–20 hrs. is related to the formation of (Me₃Si)₂C(H)Pme₂ from corresponding Si-methylated phosphorylides with the exception that, at 0°C, this reaction goes to completion within a few minutes.     

Ein Beitrag zur Reaktivität von (η5-C5Me5)(CO)2FeP(SiMe3)2 gegenüber P-Chlormethylenphosphanen

On the Reactivity of (η⁵-C₅Me₅)(CO)₂FeP(SiMe₃)₂ Toward P-Chloromethylene phosphanes The reaction of (η⁵-C₅Me₅)(CO)₂FeP(SiMe₃)₂ ( 2 ) with three equivalents of Cl? P?C(SiMe₃)₂ ( 3a ) afforded the 3-methanediyl-1,3,5,6-tetraphosphabicyclo[3.1.0]hex-2-ene (η⁵-C₅Me₅)(CO)₂Fe? ( 6a ). In contrast, 2 reacts with two equivalents of Cl? P?C(Ph)SiMe₃ ( 3b ) to give the thermolabile (η⁵-C₅Me₅) · (CO)₂Fe? P[P?C(Ph)SiMe₃]₂ ( 4b ) which decomposed during the reaction with further 3b. 4 b was also obtained from (η⁵-C₅Me₅)(CO)₂Fe? P(SiMe₃)? P?C(SiMe₃)₂ ( 1a ) and two equivalents of 3b .     

Übergangsmetallphosphidokomplexe. XVII. Reaktionen von Silylphosphanderivaten mit (R3P)2PtCl2 (R = Et,Ph)

Transition Metal Phosphido Complexes. XVII. Reactions of Silylphosphine Derivatives with (R₃P)₂PtCl₂ (R ? Et, Ph) In reactions of (Et₃P)₂PtCl₂ 1a with LiP(SiMe₃)₂ at low temperatures the substitution products (Et₃P)₂Pt[P(SiMe₃)₂]Cl 2a and (Et₃P)₂Pt[P(SiMe₃)₂]₂ 3a are formed first. At ambient temperature from 3a P(SiMe₃)₃ and PEt₃ are split off yielding a mixture of the diphosphene complex (Et₃P)₂Pt[η²-(PSiMe₃)₂] 4a and the phosphido-bridged platinum(I) complex [Et₃PPtP(SiMe₃)₂]₂(Pt? Pt) 5a . Heating 2a to 80°C in solution gives the P₂-complex [(Et₃P)₂Pt]₂P₂ 6a . 4a and 6a are also obtained reacting 1a with [(Me₃Si)₂P]₂. From 1a and [Me₃Si(Me₃C)P]₂ the diphosphene complex (Et₃P)₂Pt[η²-(PCMe₃)₂] 8a is available. In the reaction of 1a with (Me₃Si)₂P? P(CMe₃)SiMe₃ the formation of the asymmetric diphosphene complex (Et₃P)₂Pt[η²-Me₃SiP?PCMe₃] 9a can be proved n.m.r. spectroscopically. Analogous reactions of (Ph₃P)₂PtCl₂ 1b with LiP(SiMe₃)₂, and with [Me₃Si(Me₃C)P]₂ are much more difficult to survey. The complexes (Ph₃P)₂Pt[η²-(PSiMe₃)₂] 4b , [(Ph₃P)₂Pt]₂P₂ 6b , and (Ph₃P)₂Pt[η²-(PCMe₃)₂] 8b are formed in n.m.r. spectroscopically detectable amounts but could not be isolated as pure compounds. N.m.r. and mass spectral data are reported.     

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.