We analyze and compare the UV-Visible absorption profiles, computed at the TD-DFT level, of several thiolate, chloride and phosphine ligand protected gold clusters with Au 13 , Au 25 and Au 28 metallic cores. We show by investigating several model clusters and experimentally reported ones that the charge redistribution between the gold core and the ligand shell can be controlled by the electron acceptor or electron donor character of the ligands and their spatial distribution around the metallic core. A correlation between the increase of electronic charge in the gold core and a shift of the optical absorption band toward lower transition energies is highlighted. The identified correlation between the partial charge on the metallic gold core and the position of the lowest electronic transition is robust and remains valid even for small clusters with little structural or electronic similarity.

Because the development of attopulses, charge migration induced by short optical pulses has been extensively investigated. We report a computational purely electronic dynamical study of ultrafast few femtoseconds (fs) charge transfer and charge migration in realistic passivated stoichiometric Au and Au gold nanoclusters functionalized by a bipyridine ligand. We show that a net significant amount of electronic charge (0.1 to 0.4 |e| where |e| is the electron charge) is permanently transferred from the bipyridine chromophore to the gold cluster during the short 5-6 fs UV-vis strong pulse. This electron transfer to the metallic core is induced by the optical excitation of electronic states with a partial charge transfer character involving the chromophore before the onset of nuclei motion. In addition, the photoexcitation by the strong fs pulse builds a nonequilibrium electronic density that beats between the chromophore and the metallic core around the average of the transferred value. Modular systems made of a donor chromophore that can be photoexcited in the UV-vis range coupled to an efficient acceptor that could trap the charge are of interest for applications to nanodevices. Our study provides understanding on the very early, purely electronic dynamics built by the fs optical excitation and the initial charge separation step.

Allan-Herndon-Dudley syndrome (AHDS) is characterized by neuropsychomotor developmental delay/intellectual disability, neurological impairment with a movement disorder, and an abnormal thyroid hormone profile. This disease is an X-linked disorder that mainly affects men. We described a female patient with a de novo variant in the SLC16A2 gene, a milder AHDS phenotype, and a skewed X chromosome inactivation profile. We discuss the mechanisms associated with the expression of the phenotypic characteristics in female patients, including SLC16A2 gene variants and cytogenomic alterations, as well as preferential inactivation of the normal X chromosome.