Different Reactivity of As 4 towards Disilenes and Silylenes

The activation of yellow arsenic is possible with the silylene [PhC(NtBu) 2 SiN(SiMe 3 ) 2 ] ( 1 ) and the disilene [(Me 3 Si) 2 N(η 1 ‐Me 5 C 5 )Si=Si(η 1 ‐Me 5 C 5 )N(SiMe 3 ) 2 ] ( 3 ). The reaction of As 4 with 1 leads to the unprecedented As 10 cage compound [(LSiN(SiMe 3 ) 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*{(SiMe 3 ) 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.