A 12-Vertex Metallacarborane of Silver(I).

The discovery of ferrocene in 1951 was a significant landmark in the field of organometallic chemistry, and since then, numerous sandwich- or half-sandwich metallic complexes have been reported. However, silver stands as an intriguing exception in this regard, and knowledge of its bonding situation has remained undisclosed. Herein, unprecedented 12-vertex metallacarboranes of Ag(I) ( 2a and 2b ) were synthesized through the reaction of sodium hexamethyldisilazide (NaHMDS) with the mixture of nido -C2 B9 carborane anion-supported N -heterocyclic carbene precursors ( 1a and 1b ) and [Ag(PPh3 )Cl]4 . The X-ray structural analysis of the resulting metallacarboranes revealed a unique "slipped" half-sandwich structure, which is a rarity among cyclopentadienyl analogues. DFT calculations provided insights into the asymmetric π-interactions between the pentagonal C2 B3 face and the silver ion.