Inter-Cluster Regulation Of Pt₁Ag₂₈ Nanoclusters

Polyoxometalate(POM)is composed of cations and polyanionic clusters with structural diversity.Polyanionic clusters refer to metal-oxygen polyhedrons of some pre-transition metal elements with MO_x(M=Mo,W,V,etc.).It is an inorganic nanocluster formed by the basic unit through co-angular,co-edge oxygen connection,and condensation polymerization.Due to their rich chemical compositions and nanostructure,these inorganic clusters exhibit a variety of physical and chemical properties,what have been used in the fields of nanoscience,light,electricity,magnetic materials,medicine,biological systems,etc.POM has a precise structure,and the particle size is generally between 0.5 nm and 6 nm.Compared with other inorganic nanoparticles,it has the advantages of structure,composition,size,and charge amount.It fits well with another inorganic nanocluster—noble metal nanoclusters.Noble metal nanoclusters are relatively stable micro-microscopic or sub-microscopic aggregates composed of several or even hundreds of metal atoms through physical or chemical bonding.Their physical and chemical properties will change with the number of atoms contained.Thus,it is of great significance to combine POM with noble metal nanoclusters for further research on the atomic level.In the combination of metal nanoclusters and POM,the core-shell structure is mostly studied,which further broadens the diversity of the structure and synthesis methods of POM and metal nanoclusters,but it needs to be added that the arrangement of POM and metal nanoclusters in the crystal lattice and the interaction of the two types of anion and cation after bonding have not been characterized by much research.In this work,we focus on the influence of POM anion on the crystallographic packing mode of[Pt₁Ag₂₈(S-Adm)₁₈(PPh₃)₄]nanoclusters.The specific work is as follows:1.In the experiment,we used pre-synthesized Pt₁Ag₂₈ nanoclusters to react with(NH₄)⁺₁₀[H₂W₁₂O₄₂]^10-,and crystallize the final product.At the same time,we analyzed the crystal with an X-ray single-crystal diffractometer,and obtained the structure and mechanism information of the crystal.Besides,we also used ultraviolet-visible absorption spectroscopy,photoluminescence(PL)spectroscopy,X-ray energy spectroscopy,and electrospray ionization mass spectrometry to characterize the optical properties.The experimental results show that:1.The molecular formula of the reaction product is[Pt₁Ag₂₈(S-Adm)₁₈(PPh₃)₄][W₆O₁₉];2.Due to their different crystal packing modes,Pt₁Ag^-₂₈W₆O₁₉ and Pt₁Ag^-₂₈Cl crystals show unique optical properties and nitrogen adsorption-desorption properties,in which Pt₁Ag^-₂₈Cl shows the largest surface area.2.By adjusting the counterions of[Pt₁Ag₂₈(S-Adm)₁₈(PPh₃)₄]²⁺nanoclusters,such as Cl-anions or POM anions,the control of the accumulation mode of nanocluster crystals has been achieved.The three Pt1Ag₂₈-POMs hybrid materials,Pt1Ag₂₈-Mo₆O₁₉,Pt1Ag₂₈-W₆O₁₉,and Pt₁Ag₂₈-PW₁₂O₄₀ are all controllable and have precise structures.The crystal packing mode and unit cell parameters of cluster crystals are compared.Due to their different crystal packing modes,these Pt₁Ag₂₈ crystals exhibit unique optical properties and nitrogen adsorption-desorption properties.Among them,Pt₁Ag₂₈-Mo₆O₁₉ shows the highest fluorescence intensity in the crystalline state,Pt₁Ag₂₈-Cl shows the largest specific surface area,and Pt₁Ag₂₈-PW₁₂O₄₀ shows the best thermal stability.All in all,through the combination of the inter-cluster binding control of this work and the previously reported intra-cluster control,we have achieved a more comprehensive control of the M₂₉(SR)₁₈(PR₃)₄nanocluster system,which provides more comprehensive insights for metal nanocluster molecules and supramolecular chemistry.