Probing the structure and aromaticity in the tungsten trimer W32+ and all-metal compounds W3X+/–, W3Y2+/0, and W3Al3+/+ (X = Li, Na, K and Y = Be, Mg, and Ca)

The electronic structure and chemical bonding in the tungsten trimer W32+ cluster and the single pyramidal W3X+/–, W3Y2+/0, and W3Al3+/+ (X = Li, Na, K and Y = Be, Mg, Ca) all-metal compounds are investigated using density functional theory (DFT) calculations. The ground-state for the W32+ cation is shown to be a singlet 1A1′ (1a1′21a2″21e′42a1′21e″43a1′2) with D3h symmetry. A detailed molecular orbital (MO) analysis reveals that the W32+ (D3h, 1A1′) cation is found to possess the multiple σ- and δ-aromaticity. The multiple d-orbital aromaticity is responsible for a three-center metal–metal bond of the triangular W3 framework. We search the single pyramidal W3X+/–, W3Y2+/0, and W3Al3+/+ (X = Li, Na, K and Y = Be, Mg, Ca) all-metal compounds containing W3 and W32– aromatic ligands to reveal that the W3 (D3h, 3A1′) and W32– (D3h, 1A1′) structural units were preserved perfectly in the single pyramidal all-metal compounds.