Relativistic density‐functional studies of naked and ligated gold clusters

Electronic structure investigations on a broad range of gold compounds, including naked and ligated gold clusters, are reviewed. The calculations have been carried out with a recently introduced relativistic variant of the linear combination of Gaussian‐type orbitals density‐functional (LCGTO–DF) method which affords all‐electron investigations for very large systems. The accuracy of the method will be evaluated for the gold dimer. Then the electronic structure of the naked cluster Au₅₅ is studied, both in I_h and O_h symmetry. Nonrelativistic and relativistic results obtained by the present method are compared to those of the much simpler jellium model. Since triphenylphosphine is among the most common ligands in gold chemistry a series of mononuclear gold phosphine compounds MeAuPR₃ with increasingly complex ligands PR₃ (R = H, CH₃, C₅H₆) is discussed. The calculations reveal the success and the limitations of simpler phosphines often employed as model ligands in theoretical studies. Some aspects of the phosphine gold interaction in these simpler compounds carry over to the main group element centered gold clusters. Thereby one arrives at a rationalization of the particularly high stability of the carbon‐centered octahedral cluster cation [(R₃PAu)₆C]²⁺ as compared to the neighboring isoelectronic boron and nitrogen‐centered clusters. © 1994 John Wiley & Sons, Inc.