Synthesis and characterization of (C 5H 9C 9H 6) 2Yb(THF) 2(II) ( 1) and [(C 5H 9C 5H 4) 2Yb(THF)] 2O 2 ( 2), and ring-opening polymerization of lactones with 1

Abstract

Reaction of YbI 2 with two equivalents of cyclopentylindenyl lithium (C 5H 9C 9H 6Li) affords ytterbium(II) substituted indenyl complex (C 5H 9C 9H 6) 2Yb(THF) 2 ( 1) which shows high activity to ring-opening polymerization (ROP) of lactones. The reaction between YbI 2 and cyclopentylcyclopentadienyl sodium (C 5H 9C 5H 4Na) gives complex [(C 5H 9C 5H 4) 2Yb(THF)] 2O 2 ( 2) in the presence of a trace amount of O 2, the molecular structure of which comprises two (C 5H 9C 5H 4) 2Yb(THF) bridged by an asymmetric O 2 unit. The O 2 unit and ytterbium atoms define a plane that contains a C i symmetry center.