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Accession Number:
ADA281547
Title:
Encapsulated Alkaline-Earth Organometallics as Controlled Sources of Calcium, Strontium, and Barium Ions
Descriptive Note:
Final rept. 1 Jan 1991-30 Apr 1994
Corporate Author:
VANDERBILT UNIV NASHVILLE TN DEPT OF CHEMISTRY
Report Date:
1994-06-28
Pagination or Media Count:
27.0
Abstract:
Cyclopentadienyl rings with substituents that interlock with those of a second ring form encapsulated metallocenes C5R52M 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, a ring can be displaced from an encapsulated metallocene, exposing the metal center and activating the complex. Disproportionation of the resulting monoring complexes C5R5ME into symmetrical C5R52M and ME2 species can be blocked. Ligand synergism in monoring complexes can enhance their chemical and thermal stabilities relative to those of the parent symmetrical species.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
