Cs⁺ Ions Regulate The Assembly Of Ag₂₉ Clusters

Metal nanocluster is intermediate state between small molecule and metal nanoparticle which act as bridge in them.Due to its precise atomic structure,monodisperse size and excellent performance,it provides a good platform for researchers to study the correlation between structure and properties at the atomic level.Based on such advantages,the study of clusters is particularly important.In recent years,cluster assembly research has attracted more and more attention.Assembling clusters to form higher-dimensional structures has obvious advantages:?1?the molecular characteristics of nanoclusters make their structures reasonable;?2?cluster interactions in supramolecular chemistry can be fully studied on the basis of several nanocluster lattices,cluster-based metal organic skeletons and cluster-assembled supercrystals;?3?assembly clusters play an important role in the study of bridging molecules and supramolecular chemistry;?4?optimizing performance.Although some issues have been made in cluster assembly,it is important to regulate cluster assembly behaviors and obtain cluster based materials with better properties.We assembled the Ag₂₉ nanometer cluster to form a one-dimensional material by regulating the composition of the cluster and the anti-ion and solvent of coordination.The specific contents are as follows:1.In the experiment,we induced the Cs⁺to act as the counterbalance ions of Ag₂₉negatively charged clusters regulating assembly and crystallization of the nanocluster.At the same time,we verified the binding reaction between[Ag₂₉?SSR?₁₂]^3-and Cs⁺by electrospray mass spectrometry and nuclear magnetic resonance.The crystal structure and mechanism information were obtained by X-ray single crystal diffractometer.In addition,the optical properties of the product were characterized by uv-vis absorption spectrum and fluorescence emission spectrum.The results show that:?1?the PPh₃ ligands were stripped from the surface of the cluster to form a 1D Cs⁺-DMF-cluster with changed dimension,and its molecular formula was Cs₃Ag₂₉?SSR?₁₂?DMF?_x;?2?the Cs⁺capture on the surface of the cluster is driven by the interaction between Cs-S and Cs…?;?3?the optical properties?optical absorption and emission?of Cs₃Ag₂₉?SSR?₁₂?DMF?_x in solution are significantly different from those in crystal film.Such discoverys are of great significance to reveal the Cs⁺induced intra-cluster transformation of nanocluster structure and the inter-cluster self-assembly.2.We used Au₂₅ as the research template and doped the template Au₂₅ with hetero-atom and foreign-thiolate.At the same time,the doping process was monitored by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and uv-visible absorption spectrum.In addition,the purity was characterized by HPLC.It is found that ligand exchange and metal exchange are two independent but interrelated processes.The functional complex is more difficult to exchange,the degree of modification is not high,which can only stay in the shallow state,and can not achieve the effect of complete replacement.Such research discusses deeply the specific process of doping occurrence and the corresponding rules,and conducts detailed analysis on the mechanism.That provides experimental and theoretical reference line for the subsequent research.On the other hand,it shows many essential problems and lays a foreshadening for the implementation of functional ligand exchange.