Material Science and Nanoscale Particles
In the past decade, we have witnessed an unprecedented and spectacular growth
of a new field of science. This new field of atoms, clusters, and nanoscale particles
touches on the disciplines of chemistry, physics, electronics, astronomy, mathematics,
A nanoscale particle is 1-10 nm in diameter, is made up of 10-10,000
atoms, and possesses properties different from either atoms or
the bulk material. Neither quantum chemistry nor classical physics
theories apply to this new class of matter. We are involved in
several projects dealing with nanoscale materials: (1) the growth
of superlattices (crystals made up of nanoparticle arrays) ; (2)
colloidal metals in catalysis and thin film growth; (3) new adsorbents
for environmental cleanup; and (4) new magnetic materials for better
Magnetic Properties of Nanoscale Fe Particles
The vaporization of iron metal and condensation of the atoms with hydrocarbons
at very low temperature, followed by warming to room temperature, allow the
growth of small iron clusters about 5 nm in diameter. The magnetic properties
of these ultrafine particles are extremely sensitive to surface coating material.
For example, iron oxide surface contamination causes a large increase in
coercivity (magnetic memory), and a lowering of magnetic field strength.
In order to protect the surface of the iron particles, we are investigating
various ways of synthesizing new core-shell structures, for example, Fe coated
with Li, Mg, MgF2 or SiO2.
Adsorption Properties of Nanoscale Metal Oxide Particles
Ultrafine particles of metal oxides such as MgO, CaO, Al2O3, ZnO or MgO coated
with Fe2O3 exhibit unique surface chemistry, and serve as efficient materials
for adsorption of many toxic gases. We are developing synthesis schemes,
usually utilizing aerogel and hypercritical drying techniques, to prepare
4 nm size metal oxide particles. By studying the adsorption and decomposition
of chlorocarbons and organophosphorus compounds, we have been able to develop
new "destructive adsorbents". Our primary interest is in the surface
chemical transformation that takes place and the structure of the surface
sites that are active.
We also are involved in the synthesis of unusual organometallic reagents that
have potential as homogeneous catalysts. In particular, mu6-arene complexes
of Cr, Fe, Co and Ni are under investigation. The goal is to build in PI-arene
lability. For example, we have prepared (mu6-arene)Cr(CO)2(SiCl3)2, (mu6-arene)Fe(SiCl3)2(H)2,
(mu6-arene)Co(SiCl3)2, and others. X-ray crystal structures, ligand displacement
reactions, arene/arene exchange rates, and homogeneous catalysis (dimerization,
isomerization, and polymerization of alkenes) are under study.
333. Richards, R.; Li,
W.; Decker, S.; Davidson C.; Koper O.; Zaikovski V.; Volodin
A.; Rieker T.; Klabunde K.J.; “Consolidation
of Metal Oxide Nanocrystals. Reactive Pellets with Controllable
Pore Structure That Represent a New Family of Porous, Inorganic
Materials,” J. Amer. Chem. Soc., 122, 4921-4925 (2000).
337. Wagner, G.W.; Koper, O.B.; Lucas, E.; Decker, S.; Klabunde,
K.J.; “Reactions of VX, GD, and HD with Nanosize CaO: Autocatalytic
Dehydrohalogenation of HD,” J. Phys. Chem. B, 104, 5118-5123
343)Lin, X.M.; Jaeger, H.M.; Sorensen, C.M.; Klabunde, K.J.; “Formation
of Long-Range-Ordered Nanocrystal Superlattices on Silicon Nitride
Surfaces,” J. Phys. Chem. B., 105, 3353-3357 (2001).
344. Klabunde, K.J., editor; “Nanoscale Materials in Chemistry,
Wiley Interscience, New York, NY (2001). Also, two chapters
written for this book: Klabunde, K.J.; “Introduction to Nanotechnology,” Chap.
1, pgs 1-13; Klabunde, K.J.; Mulukutla, R.; “Chemical and
Catalytic Aspects of Nanocrystals,” Chap. 7, pgs 223-261.
351. Carnes, C.; Stipp, J., Klabunde, K.J.; “Synthesis,
Characterization, and Adsorption Studies of Nanocrystalline Copper
Oxide and Nickel Oxide,” Langmuir, 18, 1352-1359 (2002).
352. Carnes, C.; Klabunde, K.J.; “Unique Chemical Reactivities
of Nanocrystalline Metal Oxides toward Hydrogen Sulfide,” Chem.
of Materials, 14, 1806-1811 (2002).
353. Diao, Y.; Walawender, W.; Sorensen,
C.; Klabunde, K.J.; Rieker, T.; “Hydrolysis of Magnesium Methoxide. Effects of
Toluene on Gel Structure and Gel Chemistry,” Chem. of Materials,
14, 362-368 (2002).
354. Stoeva, S.; Klabunde, K.J.; Sorensen, C.; Dragieva, I.; “Gram-Scale
Synthesis of Monodisperse Gold Colloids by the Solvated Metal Atom
Dispersion Method and Digestive Ripening and Their Organization
into Two- and Three-Dimensional Structures,” J. of American
Chem. Society, 124, 2305-2311 (2002).
356. Koper, O.; Klabunde, J.; Marchin, G.; Klabunde, K.J.; Stoimenov,
P.; Bohra, L.; “Nanoscale Powders and Formulations with Biocidal
Activity Toward Spores and Vegetative Cells of Bacillus Species,
Viruses, and Toxins,” Current Microbiology, 44, 49-55 (2002).
357. Decker, S.; Klabunde, J.S.; Khaleel, A.; Klabunde, K.J.; “Catalyzed
Destructive Adsorption of Environmental Toxins with Nanocrystalline
Metal Oxides. Fluoro-, Chloro-, Bromocarbons, Sulfur, and
Organophosphorus Compounds,” Environ. Sci. Tech., 36, 762-768