Raman evidence of aromaticity of the thermally stable silylene ((BuNCH)-Bu-t=(CHNBu)-Bu-t)Si

The Raman, IR and UV spectra of the silylene ((BuNCH)-Bu-t=(CHNBu)-Bu-t)Si: (1) as well as the Raman spectra of related compounds with tetravalent sil icon ((BuNCH)-Bu-t=(CHNBu)-Bu-t)(2)Si (2) and ((BuNCH)-Bu-t=(CHNBu)-Bu-t)Si Cl2 (3) and of the heterocycle ((BuNCH)-Bu-t=CHNt- Bu)C=O (4) are reported. Comparison of the spectra obtained for 1-3 reveals a lowered frequency and greatly enhanced intensity of the Raman band corresponding to the C=C stre tching vibration in the spectrum of 1 which is in accord with the aromatic character of the silylene. (C) 2000 Elsevier Science B.V. All rights reserv ed.