Comparison of Two Phosphinidenes Binding to Silicon(IV)dichloride as well as to Silylene

The
cyclic alkyl­(amino) carbene (cAAC) anchored silylene with two
phosphinidenes was isolated as (cAAC)­Si­{P­(cAAC)}2 (3) at room temperature, which was synthesized from the reduction
of (Cl2)­Si­{P­(cAAC)}2 (2) using
2 equiv of KC8. Compound 2 resulted from the
reaction of 2 equiv of (cAAC)­PK (1) with 1 equiv of SiCl4. Compounds 2 and 3 are the first
examples where two terminal phosphinidenes are binding each to a silicon
center characterized by single crystal X-ray structural analysis.
Furthermore, the structure and bonding of compounds 2 and 3 have been investigated by theoretical methods
for comparison.