Synthesis of iron oxide nanoparticles with control over shape using imidazolium-based ionic liquids.

Ionic liquid (IL)-coated iron oxide nanoparticles (IONs) were synthesized by the thermal decomposition of Fe(CO)(5) in an IL/DMF solvent system in the absence of stabilizing surfactants at 90 degrees C for 1 h. The IL, [omim][BF(4)], could regulate the shape and allow the preparation of anisotropic IONs, such as barlike and wirelike nanoparticles. The barlike IONs prepared using this method showed good superparamagnetic behavior in a magnetic field and a MR contrast enhancement effect in a MR scanner.