Molecular and Electronic Structure of the Cluster [Au8(PPh3)8](NO3)2.

We present a detailed structural discussion of [Au₈(PPh₃)₈](NO₃)₂, crystallized as a CH₂Cl₂ solvate. Its structure is compared with closely related triphenylphosphine-stabilized gold clusters. Characterization by optical extinction spectroscopy, luminescence spectroscopy, voltammetry and DFT calculations was performed to determine the electronic HOMO-LUMO gap. Comparison of its characteristic energies with those of structurally related clusters revealed that the evolution of the HOMO-LUMO gap does not follow a simple scaling law but depends on specific structural features. [ABSTRACT FROM AUTHOR]