Siliciumverbindungen mit starken intramolekularen sterischen Wechselwirkungen
摘要:
Photolysis of hexa-t-butylcyclotrisilane in the presence of several isocyanides bearing electron-withdrawing groups on the nitrogen atoms gives the corresponding 2,4-disitacyclobutane-1,3-diimines (10-12). The X-ray structure analysis of the N-trifluoromethyl derivative 12 shows that the ring atoms as well as the nitrogen atoms and the CF3-carbon atoms lie exactly in one plane. The two trifluoromethyl groups are arranged trans to each other. The colours of these and of related ring compounds are rationalized in terms of steric and electronic requirements of the N-bonded substituents.