Encapsulated Alkaline-earth Organometallics as Controlled Sources of Calcium, Strontium, and Barium Ions
Abstract
Cyclopentadienyl rings with substituents that interlock with those of a second ring form encapsulated metallocenes ((C5R5)2M) with the alkaline-earth metals (Ca, Sr, Ba). These metallocenes are conveniently manipulated, volatile, hydrocarbon-soluble sources of the metal cations, which make the compounds attractive as precursors to metal oxides and ceramics. The physical properties of the metallocenes are highly sensitive to the degree of encapsulation and to the geometry of the encapsulating ligands; more flexible rings reduce the ability of complexes to pack into lattices, and oils and waxes will be formed. Other main-group metals (Sn, Pb) and lanthanide elements (Sm) can be encapsulated with the same ligands used for the alkaline-earths. Under the proper conditions, ring can be displaced from an encapsulated metallocene, exposing the metal center and activating the complex. Disproportionation of the resulting mono(ring) complexes (C5R5)M(E) into symmetrical (C5R5)2M and M(E)2 species can be blocked. Ligand synergism in mono(ring) complexes can enhance their chemical and thermal stabilities relative to those of the parent symmetrical species. Alkaline-earth, Calcium, Strontium, Barium, Organometallic, Metallocenes, Materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 28, 1994
- Accession Number
- ADA284766
Entities
People
- Timothy P. Hanusa
Organizations
- Vanderbilt University