Synthese und Charakterisierung der 1,2-Diphosphanyldisilane [Me4Si2(PH2)2] und [Me4Si2(PHMe)2] sowie deren Reaktionen mitn-Butyllithium

Bicyclic and tricyclic phosphanes with p-block substituents

This review summarises the experimental and structural knowledge on polycyclic phosphanes, with a focus on bicyclic and tricyclic phosphanes, as they have not only been the most studied in the last 25 years, but also show the greatest diversity in terms of constitutional isomerism and structural motifs. Moreover, only polycyclic phosphanes that have p-block substituents at all free valences are discussed.

Synthesis of heteroatomic bridged paracyclophanes

Heteroatomic bridged paracyclophanes were obtained by two independent synthetic approaches. The required precursors consist of para R₂SiCl (R = Me, iPr) substituted aromatic rings (2 and 4). They were subsequently functionalised by using NH₃, [LiPH₂(dme)] or LiAl(PH₂)₄. In the case of the Me-substituted species 2, the reaction with NH₃ directly yielded the Si₂N bridged paracyclophane 5. The Si₂P incorporated derivative 10 was obtained by lithiation of p-C₆H₄(SiiPr₂PH₂)₂ (9) and subsequent salt metathesis with the chlorosilane 4. The second approach involves the use of GaEt₃ in the formation of four membered (GaPn)₂ cycles (Pn = N, P). p-[C₆H₄{SiiPr₂N(H)GaEt₂}₂]₂ (11) and p-[C₆H₄{SiiPr₂P(H)GaEt₂}₂]₂ (12) represent the first examples of stable (GaPn)₂cis isomers as the trans species did not appear in solution. Although 11 and 12 show a similar coordination pattern, they differ in the orientation of the aromatic systems: in the solid structure, 11 adopts a - for paracyclophanes so far unique - T-shape conformation of the phenyl rings, while 12 shows the predominant coplanar orientation. All cyclophanes were characterized by X-ray diffraction, elemental analysis, NMR and IR spectroscopy.

Cyclic NHC-stabilized silylphosphinoalanes and -gallanes

The reaction between prestabilized group 13 metal hydrides and primary silylphosphines lead to the formation of rare, butterfly-like folded, four membered rings including free lone pairs on the phosphorus atoms, wherein the Lewis base can readily be substituted by N-heterocyclic carbenes.

Branched tetrasilane substituted phosphines – synthesis and characterisation of PhSi(SiiPr2)3P and {PhSi(SiMe2)3}2P14

Reactions of branched trichlorotetrasilane with P₇(SiMe₃)₃ and Li₃P are described, yielding the new compounds PhSi(SiiPr₂)₃P and {PhSi(SiMe₂)₃}₂P₁₄.