Molybdate-Templated Luminescent Silver Alkynyl Nanoclusters: Total Structure Determination and Optical Property...

Two novel MoO₄^2--templated luminescent silver alkynyl nanoclusters with 20-nuclearity ([(MoO₄^2-)@Ag₂₀(C≡CBu)₈(Ph₂PO₂)₇(tfa)₂]·(tfa^-) (1)) and 18-nuclearity ([(MoO₄^2-)@Ag₁₈(C≡CBu)₈(Ph₂PO₂)₇]·(OH) (2)) (tfa = trifluoroacetate) were synthesized with the green light maximum emissions at 507 and 516 nm, respectively. The nanoclusters were investigated and characterized by single-crystal X-ray crystallography, electrospray ionization mass spectrum (ESI-MS), X-ray photoelectron spectroscopy, thermogravimetry (TG), photoluminescence (PL), ultraviolet-visible (UV-vis) spectroscopy, and density functional theory calculations (DFT). The two nanoclusters differ in their structure by a supplementary [Ag₂(tfa)₂] organometallic surface motif, which significantly participates in the frontier molecular orbitals of 1, resulting in similar bonding patterns but different optical properties between the two clusters. Indeed, both nanoclusters show strong temperature-dependent photoluminescence properties, which make them potential candidates in the fields of optical devices for further applications.