On the Staudinger Reaction of SP(N₃)₃ with PPh₃ and(Me₃Si)₂N–(Me₃Si)N–PPh₂

Abstract

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)

A Cationic Cyclic Phosphorus(III) Azide

“…For comparison, the P À NNN distance of 1.706(3) represents a typical single bond. [15] As shown on numerous occasions, [15,16] covalently bound azide groups such as P À NNN display a trans-bent configuration (relative to the P atom); 6 has a N5-N4-N3 bond angle of 174.0(5)8, while the bridging azide group attached to the two GaCl 3 moieties is almost linear (a(N6-N7-N8) = 179.3 (4)8 31 P NMR spectroscopy studies, resulting again in the formation of tetrazaphosphole 3, the only final product. The formation of 3 was unequivocally demonstrated by X-ray crystallography ( Figure 3) and NMR spectroscopy.…”

Tetravalent Group 14 Derivatives of a Bulky Aminocarbazole

“…As expected for 2 the potassium amide without donor solvents present, there are contacts between K and arene‐C atoms between 3.0 and 3.5 Å indicative of π interactions (Figure 1). Within the series of aminocarbazolyl compounds perhaps the most unusual feature is the slightly shortened N−N bond in 3 Si , 3 Ge and 3 Sn (1.400(2), 1.390(5) and 1.397(5) Å), compared to both the other compounds in the series as well as to the sum of covalent radii of 1.42 Å [22] and other main group molecules containing the hydrazine structural motif which display N−N bond lengths in the range of 1.42–1.46 Å, [23–28] even in the instance of the previously reported divalent aminocarbazolyl compounds [16] …”

On New Staudinger Type Reactions of Phosphorus Centered Biradicaloids, [P(μ‐NR)]2 (R = Ter, Hyp), with Ionic and Covalent Azides

“…No further products were observed. In contrast to a Staudinger reaction, [ 63–67 ] where a covalent azide reacts with a phosphine to give an iminophosphorane (R 3 P + R'N 3 → R 3 P=NR' + N 2 ) along with the oxidation of the P III to a P V atom, the formation of a triaza‐diphospha‐pentadiene, R–N=P–N(R')–P=N–R, indicates a new type of Staudinger reaction as no P V ‐species is formed upon N 2 release and the formal two P(II) atoms in the biradicaloid are only oxidized to P III . Moreover, beside the P–N bond making process, due to the Staudinger process, also P–N bond breaking and a structural rearrangement must have occurred (see theory section).…”