Basicity of coordinating ligands in trivalent uranium and cerium metallocene complexes
Although much is known about the affinity of various Lewis bases for transition metal centers, the chemical literature contains only scant information about the relative affinities of Lewis bases for lanthanide and actinide metal centers. In terms of ligand affinities for f-metal centers, traditional HSAB theory characterizes trivalent and tetravalent f-metal cations as ''hard'' acids, preferring to be coordinated to ''hard'' Lewis bases (e.g., nitrogen or oxygen donor ligands) rather than ''soft'' (e.g., phosphorous or sulfur donor ligands) Lewis bases. Recent work by Brennan and Stults, however, has shown that, trimethylphosphine has a much greater affinity than does pyridine for the metal center in (MeC/sub 5/H/sub 4/)/sub 3/U and in (MeC/sub 5/H/sub 4/)/sub 3/Ce. This work established the ligand displacement series PMe/sub 3/, is quantitatively displaced by trimethylphosphine oxide in both the uranium and cerium systems. In the cerium system, trimethylphosphine sulfide and dimethyl sulfoxide were also found to quantitatively displace PMe/sub 3/. Trimethylphosphine oxide was found to be by far the strongest ligand in both systems, quantitatively displacing all ligands studied in both systems, with one exception: in the (me/sub 3/SiC/sub 5/H/sub 4/)/sub 3/U system, t-butyl isocyanide is displaced, but not completely displaced, by OPME/sub 3/. 9 refs.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6727454
- Report Number(s):
- LBL-26010; ON: DE89002491
- Country of Publication:
- United States
- Language:
- English
Similar Records
Tris(cyclopentadienyl)cerium and -uranium: Relative basicity, structure, and reactions
Reactions of a uranium (IV) tertiary alkyl bond. Facile ligand-assisted reduction and insertion of ethylene and carbon monoxide
Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTINIDE COMPLEXES
AFFINITY
CERIUM COMPLEXES
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL PROPERTIES
COMPLEXES
ELECTRONIC STRUCTURE
LIGANDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHINE OXIDES
PHOSPHINES
PHOSPHORUS COMPOUNDS
RARE EARTH COMPLEXES
SULFIDES
SULFOXIDES
SULFUR COMPOUNDS
SYNTHESIS
URANIUM COMPLEXES