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Divalent lanthanide chemistry. Preparation and crystal structures of sodium tris(bis(trimethylsilyl)amido)europate(II) and sodium tris(bis(trimethylsilyl)amido)ytterbate(II), NaM(N(SiMe/sub 3/)/sub 2/)/sub 3/

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00183a013· OSTI ID:6455890

A new synthetic method for high-yield preparations of the divalent silylamides M(N(SiMe/sub 3/)/sub 2/)/sub 2/(MeOCH/sub 2/CH/sub 2/OMe)/sub 2/, where M is Eu or Yb (Me methyl), has been developed that involves reaction of MI/sub 2/ and NaN(SiMe/sub 3/)/sub 2/ in MeOCH/sub 2/CH/sub 2/OMe. Reaction of EuI/sub 2/ and NaN(SiMe/sub 3/)/sub 2/ in Et/sub 2/O (ethyl ether) yields NaEu(N(SiMe/sub 3/)/sub 2/)/sub 3/. Reaction of YbI/sub 2/ with NaN(SiMe/sub 3/)/sub 2/ in Et/sub 2/O yields two products depending upon the crystallization conditions. If Et/sub 2/O is used, Yb(N(SiMe/sub 3/)/sub 2/)/sub 2/(OEt/sub 2/)/sub 2/ is isolated. In contrast, if toluene is used, NaYb(N(SiMe/sub 3/)/sub 2/)/sub 3/ is isolated. The structures were refined to conventional R factors of 0.031 (6757 data, F/sup 2/ > sigma(F/sup 2/)) for the Eu complex and 0.056 (2546 data, F/sup 2/ > 3 sigma(F/sup 2/)) for the Yb complex. In the europium complex there are two crystallographically distinct, but chemically equivalent, molecules. The molecular structures of the Eu and Yb complexes are similar. The lanthanide atom bonds to one of the silylamide ligands exclusively and shares the two others with the sodium atom. The Eu-N and Yb-N (unshared) distances are 2.46 (1) and 2.38 (2) A, respectively; the average Eu-N and Yb-N (shared) distances are 2.55 (2) and 2.46 (2) A, respectively; the average Na-N distance is 2.46 (1) A. Several noteworthy close contacts between the metal ions and methl carbon atoms have been noted, i.e. Na-C = 2.71 A, Eu-C = 2.97 A, and Yb-C = 2.86 A. 16 references, 4 figures, 4 tables.

Research Organization:
Univ. of California, Berkeley
DOE Contract Number:
AC03-76SF00098
OSTI ID:
6455890
Journal Information:
Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 23:15; ISSN INOCA
Country of Publication:
United States
Language:
English