title: Observation of internal electron transfer in bulky allyl ytterbium complexes with substituted terpyridine ligands.
abstract: A series of new bulky allyl terpyridyl-ytterbium complexes have been synthesized to determine the effect of allyl ligands on the internal charge-transfer process that exists in these materials. Compared to the pentamethylcyclopentadienyl-ytterbocene compound Cp*2Yb(tpyCN) (nu(C(triple bond)N) = 2172 cm(-1)), the symmetrically substituted allyl complex [1,3-(SiMe3)2C3H3]2Yb(tpyCN) possesses a markedly lowered C(triple bond)N frequency of 2130 cm(-1). Furthermore, the electronic nature of these bulky allyl complexes can be tuned, as demonstrated by the C(triple bond)N frequency of the asymmetric derivatives [1-(SiMe3)C3H4]2Yb(tpyCN) and [1-(SiPh3)-3-(SiMe3)C3H3]2Yb(tpyCN) (2171 and 2164 cm(-1), respectively). The differences in these frequencies can be attributed to differences in the ligands' steric and electronic character. Single-crystal X-ray characterization of [1,3-(SiMe3)2C3H3]2Yb(tpy) reveals that the allyl moiety possesses shorter Yb-C and Yb-N bond distances than the Cp* analogue. The magnetic susceptibility data for [1,3-(SiMe3)2C3H3]2Yb(tpy) departs dramatically from the Curie law, with a room-temperature magnetic moment of 2.95 mu(B).
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
authors.forename: Rosemary E
authors.initials: RE
authors.lastname: White
authors.forename: Christin N
authors.initials: CN
authors.lastname: Carlson
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Veauthier
authors.forename: Cheslan K
authors.initials: CK
authors.lastname: Simpson
authors.forename: J D
authors.initials: JD
authors.lastname: Thompson
authors.forename: Brian L
authors.initials: BL
authors.lastname: Scott
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Hanusa
authors.forename: Kevin D
authors.initials: KD
authors.lastname: John