The gold(III)-CO bond: a missing piece in the gold carbonyl complex landscape

We investigate the Au(III)-CO bond in the [(C boolean AND N boolean AND C) Au(III) CO](+) complex via charge-displacement (CD) analysis, revealing surprising peculiarities with respect to the Au(I)-CO bond. It shows a large Au(III) <- CO sigma donation and, unexpectedly, an even larger Au(III) -> CO pi backdonation. The overall bonding picture, including a marked anisotropy in the Au(III) -> CO in-plane and out-of-plane pi back-donation components, is consistent with a CO carbon atom highly susceptible to nucleophilic attack.