The reaction of calcium‐bis[bis(trimethylsilyl)amide] with two equivalents triethylgallium yields nearly quantitatively the addition product. In the solid state the calcium atoms are coordinated by two nitrogen atoms and two ethyl groups, whereas in solution all ethyl substituents are magnetically equivalent even at low temperatures. The Ca‐C‐Ga two‐electron three‐center bonds show mean Ca‐N and Ca‐C distances of 243 and 268 pm, respectively.

Die Metallierung von Tri(tert‐butyl)silylphosphan mit Butyllithium und den Bis(trimethylsilyl)amiden von Natrium, Kalium und Rubidium ergibt quantitativ die entsprechenden Alkalimetall‐tri(tert‐butyl)silylphosphanide, die nach Zugabe geeigneter Lewis‐Basen als dimeres (DME)LiP(H)SitBu3 (1), kettenförmiges (DME)NaP(H)SitBu3 (2), monomeres ([18]Krone‐6)KP(H)SitBu3 (3) und dimeres (TMEDA)1.5RbP(H)SitBu3 (4) kristallin isoliert werden. Die Umsetzung von H2PSitBu3 mit Caesium‐bis(trimethylsilyl)amid bei Zimmertemperatur liefert zunächst ein monocyclisches tetrameres Caesium‐tri(tert‐butyl)silylphosphanid (5), an das noch zwei weitere CsN(SiMe3)2‐Moleküle koordinieren. Erst bei 80 °C reagiert dieser Komplex mit weiterem Phosphan zum tetrameren Toluol‐Addukt (η6‐Toluol)CsP(H)SitBu3 (6), dessen zentrales Strukturelement das Cs4P4‐Heterokubanfragment bildet. Die Zusammensetzung dieser Verbindungen konnte durch Einkristallstrukturuntersuchungen belegt werden.

The metathesis reaction of potassium (tris(tert-butyl)silyl)phosphanide with GaCl(3) in a molar ratio of 1:1 leads to the formation of [Cl(2)GaP(H)Si(t)Bu(3)](2) (1) as a mixture of cis and trans isomers with very large (1)J(P,H) and (2)J(P,P) coupling constants. The molecular structure of 1 shows a Ga(2)P(2) cycle with nearly planar coordinated phosphorus atoms under neglection of the hydrogen atoms and Ga-P distances of 239 pm. The reaction of GaCl(3) with 3 equiv of potassium (tris(tert-butyl)silyl)phosphanide as well as the reaction of 1 with 2 equiv of KP(H)Si(t)Bu(3) yields [(t)Bu(3)SiP(H)Ga(mu-PSi(t)Bu(3))](2) (2). The central moiety comprises a four-membered Ga(2)P(2) cycle with one planar P atom and extremely short Ga-P bonds of approximately 226 pm, the other being in a pyramidal environment with an angle sum of 298.4 degrees. The structure of 2 can be described as a GaPGa heteroallyl system which is bonded to a phosphanidyl substituent. This idea and its dependency on the steric demand of the trialkylsilyl groups are investigated by DFT calculations on different isomers of 2.

The metalation of triisopropylsilylphosphane with potassium bis(trimethylsilyl)amide yields quantitatively colorless pyrophoric potassium triisopropylsilylphosphanide (1 ) which is insoluble in hydrocarbons. The reaction of 1 with indium(III)chloride in toluene gives potassium tetrakis(triisopropylsilylphosphanyl)indate (2) in a rather poor yield. In the solid state this compound shows the formation of a one-dimensional polymeric chain with the indium as well as the potassium atoms in a distorted tetrahedral environment. The mean In-P and K-P bond lengths are 257.0 and 330.4 pm, respectively.

The lithiation of potassium triisopropylsilylphosphanide yields the corresponding phosphanediide. The subsequent metathesis reaction with SrI(2) and BaI(2) in the presence of hexamethyldisiloxane gives hexalithium hexapotassium strontium hexakis(triisopropylsilylphosphanediide)bis(trimethylsilanolate) (1) and the corresponding barium derivative (2), respectively. The alkaline earth metal atoms are surrounded octahedrally by the phosphanediide ligands. Six P(3) faces of the octahedron are capped by the K atoms, and the P-P edges of two opposite P(3) faces are bridged by the lithium atoms. The Li cations are also bonded to the Me(3)SiO substituents giving a coordination number of three for the alkali metals.

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Bei der Reaktion von Natrium‐tri(tert‐butyl)silanid mit SbCl3 isoliert man mit mäßiger Ausbeute grün‐braunes ‐2, 2′, 3, 3′, 4, 4′‐Hexakis[tri(tert‐butyl)silyl]‐1, 1′‐di(cyclotetrastiban) (1) mit einem neuartigen Sb8‐Cluster. Verbindung 1 kristallisiert in der triklinen Raumgruppe P1¯. Der große Raumanspruch der Tri(tert‐butyl)silyl‐Gruppen erzwingt sowohl eine Faltung des viergliedrigen Sb4‐Cyclus als auch eine Aufweitung der Sb‐Sb‐Si‐Bindungswinkel auf etwa 105.5°. Die mittlere Sb‐Sb‐Bindungslänge beträgt 285.4 pm und liegt im gleichen Bereich wie bei den Distibanen.

Organic chemistry Z 0200 Influence of the Tri(tert-butyl)silyl Substituents on the Molecular Structures of Phosphanylalanes, -Gallanes and -Indanes-[38 refs.]. -(WEINRICH, S.; KROFTA, M.; SCHULZ, A.; WESTERHAUSEN, M.; Organosilicon Chem. VI: