Organic carbonates as stabilizing solvents for transition-metal nanoparticles.
Biodegradable, non-toxic, "green" and inexpensive propylene carbonate (PC) solvent is shown to function as a stabilizing medium for the synthesis of weakly-coordinated transition-metal nanoparticles. Kinetically stable nanoparticles (M-NPs) with a small and uniform particle size (typically <5 ± 1 nm) have been reproducibly obtained by easy, rapid (3 min) and energy-saving 50 W microwave irradiation under an argon atmosphere from their metal-carbonyl precursors in PC. The M-NP/PC dispersions are stable for up to three weeks according to repeated TEM studies over this time period. The rhodium nanoparticle/PC dispersion is a highly active catalyst for the biphasic liquid-liquid hydrogenation of cyclohexene to cyclohexane with activities of up to and 1875 (mol product) (mol Rh)(-1) h(-1) and near quantitative conversion at 4 to 10 bar H(2) and 90 °C. From the PC dispersion the M-NPs can be coated with organic capping ligands such as 3-mercaptopropionic acid or trioctylphosphine oxide for further stabilization.
Institut für Anorganische Chemie und Strukturchemie, Heinrich-Heine-Universität Düsseldorf, D-40204 Düsseldorf, Germany.
Christian
C
Vollmer
Ralf
R
Thomann
Christoph
C
Janiak
D055772:Green Chemistry Technology; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011407:Propane / Q000031:analogs & derivatives* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D028561:Transition Elements / Q000737:chemistry*
D012997:Solvents; D028561:Transition Elements; C045990:propylene carbonate; D012238:Rhodium; D011407:Propane