Observation of d‐Orbital Aromaticity

Abstract

The metal oxide clusters [W3O9]− and [Mo3O9]− were studied by photoelectron spectroscopy and theoretical calculations, which show that [W3O9] and [Mo3O9] both have a D3h structure with a low-lying unoccupied molecular orbital formed from the metal d orbitals. Occupation of this orbital by one or two electrons leads to aromatic anions (see picture) with strong three-center, one-electron and three-center, two-electron metal–metal bonds, respectively. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z502678_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.