Beryllium‐Mediated Halide and Aryl Transfer onto Silicon

Abstract

The reactivity of hexamethylcyclotrisiloxane (D3) towards BeCl2, BeBr2, BeI2 and [Be3Ph6]3 was investigated. While BeCl2 only showed unselective reactivity, BeBr2, BeI2 and [Be3Ph6] cleanly react to trinuclear complexes [Be3Br2(OSiMe2Br)4], [Be3I2(OSiMe2I)4] and [Be3Ph2(OSiMe2Ph)4]. This unprecedented bromide, iodide and phenyl transfer reactions from a group II metal onto silicon offer a versatile access to previously unknown diorgano bromo and iodo silanolates.

Synthesis and Derivatives of Beryllium Triflate

“…A similar structural motif is found in the [Be 4 (μ 2 –Cl) 2 (Cl) 4 (μ 2 –Si 2 O 3 (CH 3 ) 4 ) 2 ] 2– anion . The Be–O distances in 1 of 1.556(2)–1.560(2) Å are by tendency shorter than those in [Be 3 I 2 (OSiMe 2 I) 4 ] (1.552(3)–1.6403(18) Å) or [Be 4 (μ 2 –Cl) 2 (Cl) 4 (μ 2 –Si 2 O 3 (CH 3 ) 4 ) 2 ] 2– (1.610(3)–1.616(3) Å) . This would be expected due to the cationic nature of Be 2 (NH 3 ) 6 (μ 2 –Si 2 Me 4 O 3 )] 2+ .…”

“…The origin of the 1,1,3,3-tetramethyldisiloxane-1,3-bis­(olate) moiety was traced back to the triflic acid, which contains significant amounts of silicon grease when obtained through commercial vendors (Supporting Information, Figure S1). Silicon grease and other siloxanes are known to be cleaved by beryllium species. , The formation and isolation of 1 despite the huge excess of NH 3 is also evidence for the high binding preference of beryllium ions to silanolato groups …”