The fluorescence properties of tiara like structural thiolated palladium clusters.

A series of tiara like structural Pd(SR) (5 ≤n≤ 20) nanoclusters were synthesized by using a modified Brust-Schiffrin route and isolated via thin layer chromatography, and further measured using MALDI-MS. A new crystal structure of tiara like structural Pd(SCHPh) was determined by single-crystal X-ray crystallography. The atomic distance of PdPd increased and the Pd-S bond length decreased with the increase in the n value in the optimized structure of Pd(SR) (5 ≤n≤ 10), which were optimized by density functional theory at the B3LYP level. All these 16 Pd(SR) nanoclusters exhibit weak emission at 620 nm with single band excitation at around 268 nm. The origin of emission of this series of clusters could be illustrated by using a ligand to metal charge transfer model.