9:30 AM - 11:30 AM
[19a-P2-2] Selective Surface-Modification by Recognizing the Active Facet of Polymer-Metal Complex Nanocrystals
Keywords:polymer-metal complex nanocrystals,Prussian blue,azopyridine derivative
Metal-organic complex crystals exhibit unique optical, electronic and magnetic properties. Especially, polymer-metal complex crystals have coordinatively-unsaturated center metal or ligand molecules exposed on the surface of crystals, where we would perform sophisticated surface modification so as to modulate and/or tune the unique properties. On the other hand, nanocrystals have large specific surface area, compared to bulk crystal. However, it is frequently difficult to nanocrystallize polymer-metal complexes, due to their poor solubility. In addition, since well-control of inorganic/organic interface structure has not still been achieved enough, research on metal-organic complex nanomaterials has been far behind from both viewpoints of foundation and application.
In the present study, we have developed a useful method to prepare a well-defined metal-organic complex nanocrystals. In this method, complex formation would occur on the previously-prepared organic ligand nanocrystals with large surface area. As a result, insoluble main-chain polymer-metal complexes, which show luminescence in solid state, have been nanocrystallized successfully. Especially, bipyridine complex (L = bpy) nanocrysltas were obtained as well-defined pallarerogram plate. From TEM observation and analysis of electron diffraction pattern, it is found that {010} plane of bipyridine complex nanocrystals has grown well, that is, the terminal chain would be located on the {010} plane of nanocrystals as a dangling bond. So, we have tried to modify the surface of nanocrystals by end-capping the terminal chain of polymer complex. Actually, Prussian blue (PB) nanoparticles were selectively adsorbed on the {010} plane of polymer-metal complex nanocrystals. Ligands having N-terminal located on the surface would bind to PB nanoparticles. On the other hand, polymer-metal complex nanocrystals have been also modified with phenylazopyridine (PAZ) showing photochromism. Interestingly, PAZ would also serve as a crystal-growth inhibitor, so that the size of nanocrystals was controlled with the concentration of added PAZ. Moreover, optical properties of nanocrystals were changed by photoisomerization. This fact would open the pathway to novel photoresponsive materials induced by surface effect.
In the present study, we have developed a useful method to prepare a well-defined metal-organic complex nanocrystals. In this method, complex formation would occur on the previously-prepared organic ligand nanocrystals with large surface area. As a result, insoluble main-chain polymer-metal complexes, which show luminescence in solid state, have been nanocrystallized successfully. Especially, bipyridine complex (L = bpy) nanocrysltas were obtained as well-defined pallarerogram plate. From TEM observation and analysis of electron diffraction pattern, it is found that {010} plane of bipyridine complex nanocrystals has grown well, that is, the terminal chain would be located on the {010} plane of nanocrystals as a dangling bond. So, we have tried to modify the surface of nanocrystals by end-capping the terminal chain of polymer complex. Actually, Prussian blue (PB) nanoparticles were selectively adsorbed on the {010} plane of polymer-metal complex nanocrystals. Ligands having N-terminal located on the surface would bind to PB nanoparticles. On the other hand, polymer-metal complex nanocrystals have been also modified with phenylazopyridine (PAZ) showing photochromism. Interestingly, PAZ would also serve as a crystal-growth inhibitor, so that the size of nanocrystals was controlled with the concentration of added PAZ. Moreover, optical properties of nanocrystals were changed by photoisomerization. This fact would open the pathway to novel photoresponsive materials induced by surface effect.