Aurophilicity: the effect of the neutral ligand L on [{ClAuL}(2) ] systems.

The effect of the ligand L on the aurophilic Au(I) ⋅⋅⋅Au(I) closed-shell interaction in perpendicular [{ClAuL}(2) ] model systems is investigated. An analogous study of the effect of the halide X (here Cl) exists, and showed a correlation with the softness of the ligand X. In this work, we study the correlation with L=N-heterocyclic carbenes (NHC), cyclic diphosphinocarbenes (PHC), NF(3) , CO, methyl isocyanide CNMe, PF(3) , SH(2) , NH(3) , H(2) O, pyridine, triazene, the carbodiphosphorene model C(PH(3) )(2) , C(3) H(2) , and the related model systems CN(2) or CP(2) . The NHCs yield stronger interactions than PH(3) . The spatial orientation of certain ligands in a "paddle" configuration plays an important role on the strength of the interaction. All are examples on aurophilicity.