Web Release Date: June 18,
Nanoparticulate Metal Complexes Prepared with Compressed Carbon Dioxide: Correlation of Particle Morphology with Precursor Structure
and
Center for Environmentally Beneficial Catalysis, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, Department of Chemical and Petroleum Engineering, and Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
Received March 30, 2005
Abstract:
Nanoparticles of metal complexes are rare because of the limited methods for their preparation. Described in this communication is the use of precipitation with compressed antisolvent (PCA) to process nanoparticles of neutral metal-salen complexes. PCA is a semicontinuous technique utilizing supercritical carbon dioxide (scCO2) as the precipitant. The scCO2 dissolves into a solution of the complex and simultaneously extracts the solvent, resulting in formation of nanoparticles of uniform morphology. Spectroscopic and analytical methods were used to support the assignment that the nanoparticles are composed of metal complexes. Scanning electron microscopy reveals that planar complexes, such as [NiIIsalen], afford rodlike particles with average diameter and length of 85 and 700 nm, respectively. Complexes with nonplanar molecular structures produce nanoparticles with varied structures; for instance, PCA of the six-coordinate [Ru(salen)(NO)(Cl)] complex yields spherical nanoparticles with average diameters of 50 nm. These findings suggest a correlation between the structures of molecular precursors and the morphology of the processed particles, which possibly could be used as a bottom-up approach to the preparation of functional nanoparticles.
Download the full text: PDF | HTML
