Amidinate-Stabilized Group 9 Metal–Silicon(I) Dimer and −Silylene Complexes

The coordination chemistry of the
amidinate-stabilized silicon­(I) dimer toward group 9 metal complexes
is described. The reaction of [LSi:]2 (1,
L = PhC­(NtBu)2) with [Ir­(cod)­Cl]2 (cod = 1,5-cyclooctadiene) in toluene at ambient temperature afforded
the base-stabilized silicon­(I) dimer-iridium complex [LSi­{Ir­(cod)-μ-Cl-Ir­(cod)}­SiL]­[(cod)­IrCl2] (2). In contrast, the reaction of 1 with [Rh­(cod)­Cl]2 in toluene at ambient temperature afforded
a mixture of the amidinate-stabilized silicon­(I) dimer-rhodium complex
[LSi­{Rh­(cod)-μ-Cl-Rh­(cod)}­SiL] (3) and the dimeric
amidinate-stabilized rhodosilylene [(LSi)­μ-{Rh­(μ-Cl)2Rh­(cod)}]2 (4). Moreover, the latter
reacted with PPh3 to afford a mixture of the Wilkinson’s
catalyst [(PPh3)3RhCl] and the dimeric rhodosilylene
complex [(LSi)­μ-{RhCl­(PPh3)}]2 (5), which underwent a rearrangement to form the rhodosilylene-phosphidorhodium
dimer (LSi)­[μ-{RhCl­(PPh3)}­μ-{RhCl­(LSiPh)}]­(PPh2) (6). Compounds 2–6 were characterized by NMR spectroscopy and X-ray crystallography.
In addition, DFT calculations of compound 4 were performed
to understand its electronic structure.