Unlike nucleation and growth in simple precipitation processes, described by the classical theory, metal nanoparticles formed in organic solvents with capping ligands often involve chemical reactions that occur homoge...Unlike nucleation and growth in simple precipitation processes, described by the classical theory, metal nanoparticles formed in organic solvents with capping ligands often involve chemical reactions that occur homogeneously in solution or heterogeneously on the metal surface. These chemical reactions lead to the formation of intermediates that occurs in the process of deposition onto nuclei during the reduction. The understanding of these chemical reactions would enable a better design of functional metal nanocrystals, even those with unconventional hierarchical morphologies. In this study, we report the formation of dish-shaped nanostructures of palladium （Pd） obtained from palladium acetylacetonate （Pd（acac）2） in the presence of oleylamine and oleic acid. The process was correlated with the kinetic-controlled evolution of two-dimensional （2D） Pd nanosheets. The formation of Pd-ligand complexes was revealed using single-crystal X-ray diffraction, ultraviolet-visible spectroscopy, and mass spectrometry. These intermediates affected the formation kinetics of the 2D nanostructures and higher-ordered morphology of the nanodishes.展开更多
基金This work was supported by the US National Science Foundation （Nos. CMMI 0749028 and DMR-0117792）. The authors thank C. Lei and W. Swiech for help with the STEM imaging, C~ M. Bee and D. Zhang for fluorescence microscopic measurements, S. M. Nie for the use of Nuance system and A. M. Smith for insightful discussions. S. H. and I. M. R. acknowledge support from the US Department of Energy （grant No. DE-FC36-05GO15064）. STEM experiments were carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois. X-ray crystallographic data for this study were measured at beamline X12C of the National Synchrotron Light Source, Brookhaven National Laboratory. Financial support comes principally from the Offices of Biological and Environmental Research and of Basic Energy Sciences of the US Department of Energy, and from the National Center for Research Resources （No. P41RR012408） and the National Institute of General Medical Sciences （No. P41GM103473） of the National Institutes of Health.
文摘bio-nano 混血儿材料的设计和合成不能仅仅向新材料提供新奇性质，而且推进我们在 biomolecules 和他们的不能生活的对应物之间的相互作用的基本理解。这里，我们向由在溶解酵素蛋白质的单个晶体以内种 CdS 量点(QD ) 达到如此的一个目标汇报一条新途径。这个 bio-nano 混血儿比它没有水晶的对应物，和如此的荧光性质能是 Ag (I) 或 Hg (II ) 的增加分别地提高或压制的任何一个的射出许多更强壮的红荧光。在溶解酵素晶体以内的 CdS QD 的三维的加入被与电子断层摄影术扫描传播电子显微镜学揭示。更重要地，自从我们的途径没破坏溶解酵素晶体的水晶的性质，金属和蛋白质相互作用能被 X 光检查晶体学学习，因此在 CdS QD 形成提供卓见进 Cd (II ) 的角色。
文摘Unlike nucleation and growth in simple precipitation processes, described by the classical theory, metal nanoparticles formed in organic solvents with capping ligands often involve chemical reactions that occur homogeneously in solution or heterogeneously on the metal surface. These chemical reactions lead to the formation of intermediates that occurs in the process of deposition onto nuclei during the reduction. The understanding of these chemical reactions would enable a better design of functional metal nanocrystals, even those with unconventional hierarchical morphologies. In this study, we report the formation of dish-shaped nanostructures of palladium （Pd） obtained from palladium acetylacetonate （Pd（acac）2） in the presence of oleylamine and oleic acid. The process was correlated with the kinetic-controlled evolution of two-dimensional （2D） Pd nanosheets. The formation of Pd-ligand complexes was revealed using single-crystal X-ray diffraction, ultraviolet-visible spectroscopy, and mass spectrometry. These intermediates affected the formation kinetics of the 2D nanostructures and higher-ordered morphology of the nanodishes.
