Different Reactivity of As4 towards Disilenes and Silylenes

The activation of yellow arsenic is possible with the silylene [ePhC(NtBu)(2)SiN(SiMe3)(2)] (1) and the disilene [(Me3Si)(2)N(eta(1)-Me5C5)Si=Si(eta(1)-Me5C5)N(SiMe3)(2)] (3). The reaction of As-4 with 1 leads to the unprecedented As-10 cage compound [(LSiN(SiMe3)(2))(3)As-10] (2; L - PhC(NtBu)(2)) with an As-7 nortricyclane core stabilized by arsasilene moieties containing silicon(II) bis(trimethylsilyl)amide substituents. In contrast, the compound [Cp*{(SiMe3)(2)N}SiAs](2) (4) containing a butterfly-like diarsadisilabicyclo[1.1.0]butane unit is formed by the reaction of As-4 with the disilene 3. Both compounds were characterized by single-crystal X-ray diffraction analysis, NMR spectroscopy, and mass spectrometry. The reaction outcomes demonstrate the different reaction behavior of yellow arsenic (As-4) compared to white phosphorus (P-4) in the reactions with the corresponding silylenes and disilenes.