Abstract

Ultrasmall ligand-protected clusters are prototypical species for evaluating the variation at the bottom of the nanoscale range. Here we explored the ultrasmall gold-phosphine M-13(dppe)(6) cluster, as a prototypical framework to gain insights into the fundamental similarities and differences between Au, Ag, and Cu, in the 1-3 nm size range, via relativistic DFT calculations. Different charge states involving 8- and 10-cluster electron (ce) species with a 1S(2)1P(6) and 1S(2)1P(6)1D(2) configuration, leading to structural modification in the Au species between Au-13(dppm)(6)(5+) and Au-13(dppm)(6)(3+), respectively. Furthermore, this structural distortion of the M-13 core is found to occur to a lower degree for the calculated Ag and Cu counterparts. Interestingly, optical properties exhibit similar main patterns along with the series, inducing a blue-shift for silver and copper, in comparison to the gold parent cluster. For 10-ce species, the main features of 8-ce are retained with the appearance of several weak transitions in the range. The ligand-core interaction is enhanced for gold counterparts and decreased for lighter counterparts resulting in the Au > Cu > Ag trend for the interaction stabilization. Hence, the Ag and Cu counterparts of the Au-13(dppm)(6) cluster appear as useful alternatives, which can be further explored towards different cluster alternatives for building blocks for nanostructured materials.