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.     

Thermolyse sterisch überladener Alanate; Synthese zweier neuer 1-Sila-3-alanata-cyclobutan-Derivate mit AlC2Si-Heterozyklus

Thermolysis of Sterically Stressed Alanates; Synthesis of Two New 1-Sila-3-alanata-cyclobutane Derivatives with Four-membered AlC₂Si-Heterocycles The reaction of high shielded alkyl or aryl alanes with LiCH(SiMe₃)₂ in the presence of the chelating N,N′,N″-trimethyl-triazinane yields the sterically stressed alanates [(Me₃C)₂Al{CH(SiMe₃)₂}₂]^? 12 and [R? Al{CH(SiMe₃)₂}₃]^? (R = Me₃SiCH₂ 13 , Et 14 , Me 15 , C₆H₅ 16 ) each with a Li(triazinane)₂ counter ion. On thermolysis of the sterically most shielded derivatives 12 and 13 at 130 to 150°C one equivalent of bis(trimethylsilyl)methane is liberated, and by deprotonation of methyl groups carbanionic species are formed, which are stabilized by intramolecular coordination to the unsaturated aluminium atoms under formation of AlC₂Si heterocycles ( 19 and 20 ). 20 was characterized by a single crystal structure determination. The remaining alanates give under similar conditions either under dismutation the recently published heterocycle 1 with two intact CH(SiMe₃)₂ groups ( 14 and 15 ) or a methyl alanate by the replacement of a elementorganic substituent ( 16 ).     

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.     

Bildung siliciumorganischer Verbindungen. 108. Thermisch induzierte Reaktionen aminosubstituierter Disilane

Formation of Organosilicon Compounds. 108 [1]. Thermally Induced Reactions of Amino-Substituted Disilanes Thermally induced reactions of amino-substituted disilanes yield Si rich silanes. At 300°C, Me₃Si? SiMe₂? NMeH 1 yields Me₃Si? NMeH 2 and Me₃Si? (SiMe₂)₂-NMeH 3 in a ratio 1 : 2 : 3 = 1,6 : 1 : 1, whereas Me₃Si? SiMe₂? N(iPr)H 4 at 350°C yields Me₃Si? N(iPr)H 5 , Me₃Si? (SiMe₂)₂-N(iPr)H 6 and Me₃Si? (SiMe₂)₃? N(iPr)H 7 in a ratio of 4 : 6 : 7 = 0.8 : 1.0 : 0.6. Me₃Si? SiMe₂? NMe₂ 8 at 300°C (72 h) yields Me₃Si? NMe₂ 9 and Me₃Si-(SiMe₂)₂-NMe₂ 10 in a ratio of 9 : 8 : 10 = 1 : 0.22 : 0.44 The thermal stability of these disilanes is determined by the sterical requirements of the amino substituents NMeH < NMe₂ < N(iPr)H. The introduction of a second NMe₂ group decreases the stability and favours the formation of Si rich silanes. Such, Me₂N? (SiMe₂)₂? NMe₂ 11 already at 250°C (2 h) yields Me₂N? SiMe₂? NMe₂ 12 , Me₂N? (SiMe₂)₂? NMe₂ 13 and Me₂N? (SiMe₂)₄? NMe₂ 14 in a ratio of 11 : 13 : 14 = 0.3 : 0.9 : 1.0. The reactions can be understood as insertions of thermally produced dimethylsilylene into the Si? N bond of the disilanes. This process is strongly favoured as compared to the trapping reactions with Ph? C?C? Ph or Et₃SiH. The mentioned reactions correspond closely to those of the methoxy-disilanes[2]. However (MeN? SiMe₂? SiMe₂)₂ 15 , obtained from HMeN? (SiMe₂)₂? NMeH by condensation [3], at 400°C suffers a ring contraction to octymethyl-1,3-diaza-2,4,5-trisilacyclopentane (69 weight %), and yields also some solid residue, the composition of which corresponds to Si₃C₇NH₂₁.     

N-Silylierung und Si?O-Bindungsspaltung bei der Reaktion lithiierter Siloxy-silylamino-silane mit Chlortrimethylsilan

N-Silylation and Si? O Bond Splitting at the Reaction of Lithiated Siloxy-silylamino-silanes with Chlorotrimethylsilane Lithiated Siloxy-silylamino-silanes were allowed to react in tetrahydrofurane (THF) and in n-octane (favoured) and n-hexane, resp., with chlorotrimethylsilane. The monoamide (Me₃SiO)Me₂Si(NLiSiMe₃) gives in THF and in n-octane the N-substitution product (Me₃SiO)Me₂Si · [N(SiMe₃)₂] 1 , the diamide (Me₃SiO)MeSi(NLiSiMe₃)₂ only in THF the N-substitution products (Me₃SiO)MeSi[N(SiMe₃)₂]₂ 2 (main product) and (Me₃SiO)MeSi[N(SiMe₃)₂](NHSiMe₃) 3 . In n-octane the diamide reacts mainly under Si? O bond splitting. The cyclodisilazane [(Me₃SiNH)MeSi? NSiMe₃]₂ 6 is obtained as the main product. Byproducts are 2, 3 and the tris(trimethylsilylamino) substituted disilazane (Me₃SiO)(Me₃SiNH)MeSi? N · (SiMe₃)? SiMe(NHSiMe₃)₂ 7 . The triamide (Me₃SiO)Si · (NLiSiMe₃)₃ reacts under Si? O and Si? N bond splitting in n-octane as well as in THF. The cyclodisilazanes [(Me₃SiNH)₂ · Si? NSiMe₃]₂ 10 and ( 11 : R = Me₃SiNH, 12 : R = (Me₃Si)₂N) are formed. in THF furthermore the N-substitution products (Me₃SiO)Si[N(SiMe₃)₂] · (NHSiMe₃)₂ 4 and (Me₃SiO)Si[N(SiMe₃)₂]₂(NHSiMe₃) 5 . The Si? O bond splitting occurs in boiling n-octane also in absence of the chlorotrimethylsilane. An amide solution of (Me₃SiO)MeSi(NHSiMe₃)₂ with n-butyllithium in the molar ratio 1 : 1 leads in n-octane and n-hexane to 6 and 7 , in THF to 3 . The amide solutions of (Me₃SiO)Si · (NHSiMe₃)₃ with n-butyllithium the molar ratio 1 : 1 and 1 : 2 give in THF 4 and 5 , respectively.     

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.     

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.     

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).     

An unusual organoyttrium alkyl complex containing a [C5HMe3(η(3)-CH2)-C5H4N-κ]- ligand and an elusive cyclopentadienide-based scandium tuck-over zwitterion obtained by C-H bond activation

The acid–base reaction between Y(CH₂SiMe₃)₃(thf)₂ and the pyridyl‐functionalized cyclopentadienyl (Cp) ligand C₅Me₄H? C₅H₄N (1 equiv) at 0 °C afforded a mixture of two products: (η⁵:κ‐C₅Me₄? C₅H₄N)Y(CH₂SiMe₃)₂(thf) ( 1 a ) and (η⁵:κ‐C₅Me₄? C₅H₄N)₂YCH₂SiMe₃ ( 1 b ), in a 5:2 ratio. Addition of the same ligand (2 equiv) to Y(CH₂SiMe₃)₃(thf)₂, however, generated 1 b together with the novel complex 1 c , the first well defined yttrium mono(alkyl) complex (η⁵:κ‐C₅Me₄? C₅H₄N)[C₅HMe₃(η³‐CH₂)‐C₅H₄N‐κ]Y(CH₂SiMe₃) containing a rare κ/η³‐allylic coordination mode in which the C? H bond activation occurs unexpectedly with the allylic methyl group rather than conventionally on Cp ring. If the central metal was changed to lutetium, the equimolar reaction between Lu(CH₂SiMe₃)₃(thf)₂ and C₅Me₄H? C₅H₄N exclusively afforded the bis(alkyl) product (η⁵:κ‐C₅Me₄? C₅H₄N)Lu(CH₂SiMe₃)₂(thf) ( 2 a ). Similarly, the reaction between the ligand (2 equiv) and Lu(CH₂SiMe₃)₃(thf)₂ gave the mono(alkyl) complex (η⁵:κ‐C₅Me₄? C₅H₄N)₂LuCH₂SiMe₃ ( 2 b ), in which no ligand redistribution was observed. Strikingly, treatment of Sc(CH₂SiMe₃)₃(thf)₂ with C₅Me₄H? C₅H₄N in either 1:1 or 1:2 ratio at 0 °C generated the first cyclopentadienide‐based scandium zwitterionic “tuck‐over” complex 3 , (η⁵:κ‐C₅Me₄? C₅H₄N)Sc(thf)[μ‐η⁵:η¹:κ‐C₅Me₃(CH₂)‐C₅H₄N]Sc(CH₂SiMe₃)₃. In the zwitterion, the dianionic ligand [C₅Me₃(CH₂)‐C₅H₄N]^2? binds both to Sc1³⁺ and to Sc2³⁺, in η⁵ and η¹/κ modes. In addition, the reaction chemistry, the molecular structures, and the mechanism are also discussed in detail.     

Synthese eines funktionalen Aluminiumalkinids,Me3C‐C≡C‐AlBr2, und dessen Reaktionen mit der sperrigen Lithiumverbindung LiCH(SiMe3)2

Synthesis of a Functional Aluminium Alkynide, Me₃C‐C≡C‐AlBr₂, and its Reactions with the Bulky Lithium Compound LiCH(SiMe₃)₂ Treatment of aluminium tribromide with the lithium alkynide (Li)C≡C‐CMe₃ afforded the aluminium alkynide Me₃C‐C≡C‐AlBr₂ ( 1 ) in an almost quantitative yield. 1 crystallizes with trimeric formula units possessing Al₃C₃ heterocycles and the anionic carbon atoms of the alkynido groups in the bridging positions. A dynamic equilibrium was determined in solution which probably comprises trimeric and dimeric formula units. Reaction of 1 with one equivalent of LiCH(SiMe₃)₂ yielded the compound [Me₃C‐C≡C‐Al(Br)‐CH(SiMe₃)₂]₂ ( 2 ), which is a dimer via Al‐C‐Al bridges. Two equivalents of the lithium compound gave a mixture of four main‐products, which could be identified as 2 , Li[Me₃C‐C≡C‐Al{CH(SiMe₃)₂}₃] ( 3 ), Me₃C‐C≡C‐Al[CH(SiMe₃)₂]₂ ( 4 ), and Al[CH(SiMe₃)₂]₃. The lithium atom of 3 is coordinated by the C≡C triple bond and an inner carbon atom of one bis(trimethylsilyl)methyl group. Further interactions were observed to C‐H bonds of methyl groups.     

Synthesis and Insertion Chemistry of Mixed Tether Uranium Metallocene Complexes

The synthesis of mixed tethered alkyl uranium metallocenes has been investigated by examining the reactivity of the bis(tethered alkyl) metallocene [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)₂U] ( 1 ) with substrates that react with only one of the U? C linkages. The effect of these mixed tether coordination environments on the reactivity of the remaining U? C bond has been studied by using CO insertion chemistry. One equivalent of azidoadamantane (AdN₃) reacts with 1 to yield the mixed tethered alkyl triazenido complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)U(η⁵‐C₅Me₄SiMe₂‐CH₂NNN‐Ad‐κ²N^1,3)]. Similarly, a single equivalent of CS₂ reacts with 1 to form the mixed tethered alkyl dithiocarboxylate complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)U(η⁵‐C₅Me₄SiMe₂‐ CH₂C(S)₂‐κ²S,S′)], a reaction that constitutes the first example of CS₂ insertion into a U⁴⁺? C bond. Complex 1 reacts with one equivalent of pyridine N‐oxide by C? H bond activation of the pyridine ring to form a mixed tethered alkyl cyclometalated pyridine N‐oxide complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)(η⁵‐C₅Me₄SiMe₃)U(C₆H₄NO‐κ²C,O)]. The remaining (η⁵‐C₅Me₄SiMe₂CH₂‐κC)^2? ligand in each of these mixed tethered species show reactivity towards CO and tethered enolate ligands form by insertion. Subsequent rearrangement have been identified in [(η⁵‐C₅Me₄SiMe₃)U(C₅H₄NO‐κ²C,O)(η⁵‐C₅Me₄SiMe₂C(?CH₂)O‐κO)] and [(η⁵‐C₅Me₄SiMe₂CH₂NNN‐Ad‐κ²N^1,3)U(η⁵‐C₅Me₄SiMe₂C(?CH₂)O‐κO)].     

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 .     

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.     

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.     

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.     

Über die Umsetzung von Thiazylfluorid mit mehrfunktionellen Stickstoffderivaten

Reaction of Thiazylfluoride with Multifunctional Nitrogen Derivatives From the reaction of NSF 1 with LiN(SiMe₃)R′ (R′ = CMe₃, SiMe₃), linear [e. g. (Me₃C? N?S?N? )₂S ( 11 ), Me₃C? N?S?N? CMe₃ ( 14 ), Me₃Si? N?S?N? SiMe₃ ( 17 ), (Me₃Si)₂N? S? N?S?N? SiMe₃ ( 19 )] and cyclic thiazenes (S₄N₅F ( 22 )) are isolated, (S₃N₄)_n ( 23 ) is obtained in high yield from 1 and 17 (in the ratio 2:1). Possible structures for 23 are discussed; the reaction of 23 with AsF₅ gives S₄N₄ · AsF₅ ( 24 ) in a hitherto unknown modification. Possible reactions of the terminal SN groups are discussed and the structures of 11 and 24 are reported.     

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)°.     

Transient Silenes as Versatile Synthons – The Reaction of Dichloromethyl‐tris(trimethylsilyl)silane with Organolithium Reagents

Treatment of dichloromethyl‐tris(trimethylsilyl)silane (Me₃Si)₃Si–CHCl₂ ( 1 ), prepared by the reaction of tris(trimethylsilyl)silane with chloroform in presence of potassium tertbutoxide, with organolithium reagents (molar ratio 1 : 3) affords the bis(trimethylsilyl)methyl‐disilanes Me₃SiSiR₂–CH(SiMe₃)₂ ( 12 a–d ) ( a : R = Me, b : R = n‐Bu, c : R = Ph, d : R = Mes). The formation of 12 a–d is discussed as proceeding through an exceptional series of isomerization and addition reactions involving intermediate silyl substituted carbenoids and transient silenes. The carbenoid (Me₃Si)₂PhSi–C(SiMe₃)LiCl ( 8 c ) is moderately stable at low temperature and was trapped with water to give (Me₃Si)₂PhSi–CH(SiMe₃)Cl ( 9 c ) and with chlorotrimethylsilane affording (Me₃Si)₂PhSi–CCl(SiMe₃)₂ ( 7 c ). For 12 d an X‐ray crystal structure analysis was performed, which characterizes the compound as a highly congested silane with bond parameters significantly deviating from standard values.     

Nebenreaktionen bei der Umsetzung von Trimethylsilylazid mit Trimethylphosphit und Trisdimethylaminophosphin

Side Reactions upon Interaction of Trimethylsilyl Azide with Trimethylphosphite and Trisdimethylaminophosphine Trisdimethylaminophosphine reacts with trimethylsilyl azide with evolution of nitrogen and formation of N-trimethylsilyl-iminophosphoric acid hexamethyltriamide, (Me₂N)₃ · P ? N? SiMe₃. The diphosphazene (Me₂N)₃P ? N? P(NMe₂)₂ ? N? SiMe₃ is formed in a side reaction with concomitant elimination of dimethylamino trimethylsilane. The reaction of trimethylsilyl azide with trimethylphosphite affords, besides the expected N-trimethylsilyliminophosphorus trimethylester, (MeO)₃P ? N? SiMe₃, the isomeric N-trimethylsilyl-N-methyl-aminophosphoric dimethylester, (MeO₂)P(O)? N(Me)SiMe₃.     

Diamino-di-tert-butylsilane als Bausteine cyclischer (SiN)2−, (SiNBN)2−, (SiN2Sn)- und spirocyclischer (SiN2)2Si-, (SiN2Sn)2S-Verbindungen

Diamino-di-tert-butylsilanes - Building Blocks for Cyclic (SiN)₂, (SiNBN)₂, (SiN₂Sn), and Spirocyclic (SiN₂)₂Si, (SiN₂Sn)₂S Compounds The aminochlorosilanes (Me₃C)₂SiClNHR ( 1 : R?H, 2 : R?Me) are obtained by the ammonolysis ( 1 ) respectively aminolysis ( 2 ) of di-tert-butyldichlorosilane in the n-hexane. The dilithium derivative of diamino-di-tert-butylsilane reacts with FSiMe₂R′ ( 3 : R′?Me, 4 : R′?F) in a molar ratio 1 : 2 to give the 1,3,5-trisilazanes 3 and 4 , (Me₃C)₂SiNHSiMe₂R′, in a molar ratio 1 : 1 with F₃SiN(SiMe₃)₂ to give the 1,3-diaza-2,4-disilacyclobutane 5 , (Me₃C)₂Si(NH)₂SiFN(SiMe₃)₂, and with F₂BN(SiMe₃)₂ to give the 1,3,5,7-tetraaza-2,6-dibora-4,8-disilacyclooctane 6 , [(Me₃C)₂SiNH-BN(SiMe₃)₂-NH]₂. The dilithium derivative of di-tert-butyl-bis(methylamino)silane reacts with SiF₄ with formation of the 1,3,5-trisilazane 7 , (Me₃C)₂Si(NMeSiF₃)₂, and the spirocycic compound 8 , [(Me₃C)₂Si(NMe)₂]₂Si, with SnCl₂ the cyclosilazane 9 , (Me₃C)₂SiNMe₂ is obtained. The dilithium derivative of 3 reacts with SnCl₂ to give the cyclo-1,3-diaza-2-sila-4-stannylen 10 , (Me₃C)₂Si(NSiMe₃)₂Sn. The oxidation of 10 with elemental sulfur leads to the formation of the spirocyclus 11 , [(Me₃C)₂Si(NSiMe₃)₂SnS]₂.