Photoreactions of coordinated metal nanoclusters may be used to generate novel clusters because they can be easily excited by visible light, but examples of controlled transformation have been so far limited. Herein we report that a core+ exo -type Au 6 cluster ligated by pincer-type 2,6-pyridine bridged diphosphine (2,6-PyDP) spontaneously grows into the corresponding Au 7 cluster upon mild irradiation with visible light. Analysis of the reaction mixture revealed that Au(I) complexes generated from the photo-excited state participate in the transformation, and control experiments demonstrated the critical role of the pincer-type ligand in facilitating the attachment of these Au(I) fragments. We further present the crystal structures and optical properties of the Au 6 and Au 7 clusters to elucidate the effect of the pincer-type 2,6-PyDP ligand. These findings offer a deeper understanding of ligand-controlled photoactivation and photophysical modulation in gold clusters and may serve as a basis for designing photofunctional cluster-based materials. • A pincer-type 2,6-PyDP ligand enables photo-induced growth from Au 6 to Au 7 clusters. • Photo-excited Au 6 cluster releases Au(I) fragments that recombine into the Au 7 cluster. • The 2,6-PyDP pincer ligand directs the attachment of Au(I) fragments to the Au 6 core. • Pincer ligands turn random photoreactions into a rational cluster-design strategy. • Ligand environments modulate the optical properties of core+ exo -type Au clusters.
Iwasaki et al. (Wed,) studied this question.