Lanthanide metallocene complexes of the 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinato Ligand, (hpp)1-.
Reaction of the lanthanide metallocene allyl complexes, (C(5)Me(5))(2)Ln(eta(3)-CH(2)CHCH(2))(THF) (Ln = Ce, Sm, Y) with 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, Hhpp, forms a series of metallocene complexes, (C(5)Me(5))(2)Ln(hpp) (Ln = Ce, Sm, Y) in which the (hpp)(1-) anion coordinates as a terminal bidentate ligand. Isomorphous structures were observed by X-ray crystallography regardless of the size of the metal. The acetonitrile adduct, (C(5)Me(5))(2)Sm(hpp)(MeCN), was also crystallographically characterized to provide an unusual pair of eight- and nine-coordinate complexes. The coordination mode of the (hpp)(1-) anion in these complexes is compared with that in other heteroallylic metallocenes like the caprolactamate (C(5)Me(5))(2)Y(ONC(6)H(10)) and the dithiocarbamate (C(5)Me(5))(2)Sm(S(2)CNEt(2)), which was also structurally characterized.
Evans
William J
WJ
Department of Chemistry, University of California, Irvine, California 92697-2025, USA. wevans@uci.edu
Montalvo
Elizabeth
E
Dixon
Dustin J
DJ
Ziller
Joseph W
JW
Dipasquale
Antonio G
AG
Rheingold
Arnold L
AL