Synthesis and Characterization of an Amidinate-Stabilized cis-1,2-Disilylenylethene [cis-LSi{C(Ph)C(H)}SiL] and a Singlet Delocalized Biradicaloid [LSi(μ₂-C₂Ph₂)₂SiL]†

摘要

The synthesis and characterization of novel cis-1,2-disilylenylethene [cis-LSi{C(Ph)C(H)}SiL] (2; L=PhC(NtBu)₂) and a singlet delocalized biradicaloid [LSi(μ₂-C₂Ph₂)₂SiL] (3) are described. Compound 2 was prepared by the reaction of [{PhC(NtBu)₂}Si:]₂ (1) with one equivalent of PhCCH in toluene. Compound 3 was synthesized by the reaction of 1 with two equivalents of PhCCPh in toluene. The results suggest that the reaction proceeds through an [LSi{C(Ph)C(Ph)}SiL] intermediate, which then reacts with another molecule of PhCCPh to form 3. Compounds 2 and 3 have been characterized by X-ray crystallography and NMR spectroscopy. X-ray crystallography and DFT calculations of 3 show that the singlet biradicals are stabilized by the amidinate ligand and the delocalization within the “Si(μ₂-C₂Ph₂)₂Si” six-membered ring.