β Scribed by Gerald Huber; Alexander Jockisch; Hubert Schmidbaur
No coin nor oath required. For personal study only.
In a continuation of structural investigations of poly(amino)-ble from HSiCl 3 and excess azetidine, but the product was found to contain an unknown impurity. In order to determine silanes, a series of silicon derivatives of aziridine and azetidine have been prepared. Analogies with the isoelectronic the local symmetry and the dynamics of the aziridine rings, 1 H-NMR spectra were recorded at low temperature (Οͺ80Β°C). phosphorus ylide species and the high barrier to inversion at nitrogen in small N heterocycles were suggestive of steeply No splitting of the signals was observed, indicating that the inversion barriers are extremely low, even in the highly pyramidal and rather rigid configurations at the N atoms in the title compounds. Tetrakis(N-aziridino)silane (1) and tetra-strained three-membered heterocycles. Nevertheless, singlecrystal X-ray diffraction studies of the N-triphenylsilyl kis(N-azetidino)silane (2) have been synthesized from SiCl 4 and LiN(CH 2 ) x (x = 2, 3). Compound 1 is also formed when derivatives of aziridine ( 6) and azetidine ( 7) revealed an aziridinyl group with a steeply pyramidal configuration at ni-LiN(CH 2 ) 2 and HSiCl 3 are used as starting materials, but with free aziridine a non-volatile product (1a) is obtained. In nei-trogen in 6 (sum of the angles at N 313.32Β°), and an azetidinyl group with a flat geometry in 7 (sum of the angles at N ther case could any trace of HSi[N(CH 2 ) 2 ] 3 be detected. In contrast, RSiCl 3 (R = Me, Ph) could readily be converted into 350.96Β°). The SiΟͺN bond is significantly shorter in 7 as compared to that in 6. the corresponding tris(N-aziridino)silanes (3, 4) by treatment with excess aziridine. Tris(N-azetidino)silane ( 5) was accessi-
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