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N,N',N'-[Tris(trimethylsilyl)]hydrazino-diphenylphosphane, (TMS)2 N-(TMS)N-PPh2 (1), and N,N',N'-[tris(trimethylsilyl)]hydrazino-phenyl(chloro)phosphane, (TMS)2 N-(TMS)N-P(Cl)Ph2 (2), were obtained in the reaction of bis-[lithium-tris(trimethylsilyl)hydrazide] with Ph(n)PCl(3 - n) (n = 1, 2). The structure and bonding of both species are discussed on the basis of experimentally observed (X-ray, Raman, NMR, and MS) and theoretically obtained data (B3LYP/6-31G(d,p), NBO analysis). Oxidation with sulfur and selenium results in the formation of (TMS)2 N-(TMS)N-P(S)Ph2 (4), (TMS)2 N-(TMS)N-P(Se)Ph2 (5), (TMS)2 N-(TMS)N-P(S)Ph(Cl) (6), and (TMS)2 N-(TMS)N-P(Se)Ph(Cl) (7). Moreover, the thermal decomposition of N,N',N'-[tris(trimethylsilyl)]hydrazine-dichlorophosphane, (TMS)2 N-(TMS)N-PCl2 (3) and the reaction with magnesium have been investigated. The formation and molecular structure of the novel MgCl2(THF)2 x 2Mg[(TMS)NP(O)2 N(TMS)2](THF) (8) salt containing the hitherto unknown (TMS)NP(O)2 N(TMS)2(2-) anion are discussed. DFT calculations (B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d,p)) are used to evaluate the bonding, ground-state structures, and energy landscape for the different isomers of 3: the thermodynamics and kinetics of the successive elimination of chlorotrimethylsilane (TMS-Cl) resulting in the formation of covalent azide analogues such as TMS-PNN or TMS-NNP.

Im Gedenken an Erhard KurrasPhosphor-Stickstoff-Verbindungen mit niedrig koordinierten Phosphor(iii)-Atomen sind eine gut untersuchte Substanzklasse. [1][2][3] Jedoch sind kovalente Azid-Analoga wie R-PNN oder R-NNP noch unbekannt (R = organische Gruppe). Im Rahmen unserer Untersuchungen zur Synthese von (TMS)PNN und (TMS)NNP haben wir die Eliminierung von Trimethylsilylchlorid (TMSCl) durch Thermolyse von N,N',N'-[Tris(trimethylsilyl)hydrazino]dichlorphosphan (1) eingehend betrachtet.[4] Diese experimentelle und theoretische Studie offenbarte relativ große Aktivierungsbarrieren (38-45 kcal mol À1 ) für die sukzessive Abspaltung von TMSCl in 1 und deutete darauf hin, dass Lewis-Säuren verwendet werden sollten, um TMSCl bei Raumtemperatur zu eliminieren. Daher haben wir nun die Reaktion von 1 mit der Lewis-Säure Galliumtrichlorid untersucht.[5]Durch 31 P-NMR-Spektroskopie konnte gezeigt werden, dass 1 in Dichlormethan-Lösung mehrere Tage stabil ist (d( 31 P) = 166.6 ppm).[4] Dagegen beobachtet man in den 31 P-NMR-Spektren einer Mischung von 1 (2 ¾quiv.) mit GaCl 3 (1 ¾quiv.) in CH 2 Cl 2 bei Raumtemperatur innerhalb von 2 h die quantitative Bildung einer neuen Phosphorspezies 2 (Schema 1) [6] mit Signalen im Bereich von zweifach koordinierten Phosphor(iii)-Verbindungen (Dubletts bei d( 31 P) = 317.2 (P1) und 292.1 ppm (P2),[7a] 2 J P,P = 22.1 Hz; vgl. ein 1,2,3,5-Diazadiphosphol (RN 2 P 2 C, R = Me): [8] 265.1 ppm, 2 J P,P = 22.7 Hz). Nach Entfernen des Dichlormethans verblieb ein gelbes polykristallines Pulver, das 31 P-MAS-NMR-Experimenten zufolge aus der zuvor in Lösung 31 P-NMR-spektroskopisch beobachteten Substanz bestand. Allerdings findet man im 31 P-MAS-NMR-Spektrum (Abbildung 1) aufgrund des Vorliegens zweier unabhängiger Moleküle in der Elementarzelle vier Resonanzen bei d( 31 P) = 318/312 (P1 oder P3) und 296/285 ppm (P2 oder P4, Abbildung 2). Interessan-

Surprisingly stable is the first example of a binary six π electron aromatic SN cation with an N3 unit, S2N3+ (see picture). It can be isolated on a macroscopic scale when a large counter anion is present. The structure determined by X‐ray investigations is in good agreement with theoretical data. The unequivocal identification was supported by Raman and infrared studies. The structure and bonding are discussed on the basis of MO (molecular orbital) and AIM (atoms‐in‐molecules) analysis.

The Staudinger reactions of SP(N3)3 (1) with 1, 2 and 3 equiv. of triphenylphosphane PPh3 and (TMS)2N–(TMS)N–PPh2 (2) have been investigated (TMS = Me3Si). Reaction with PPh3 yields the single and double Staudinger products SP(N3)2NPPh3 (3) and SP(N3)(NPPh3)2 (4), but not the triple, while the reaction with 2 results only in the formation of the single Staudinger product SP(N3)2NPPh2[N(TMS)N(TMS)]2 (5). Compound 5 is air‐ and moisture‐sensitive but stable under argon over a long period in the solid state and in common organic solvents. Although there are covalently bound azide groups in 3, 4 and 5, these Staudinger products are neither shock‐ nor heat‐sensitive in contrast to 1. Furthermore 3, 4 and 5 are easily prepared in bulk (yield > 95 %), and unlimitedly stable when cooled and stored in the dark. Compound 5 is thermally stable up to over 150 °C while 3 and 4 are stable only up to 96 °C. However, when a solution of 5 is heated, a new surprising eight‐membered ring (6) is formed in an intermolecular TMS–N3 elimination reaction. The structure and bonding is discussed on the basis of experimental X‐ray data and theoretical B3LYP calculations (thermodynamics, energy landscape and charge distribution). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)