A New, Convenient Method for Labeling Cyclopentadienyl Ligands with Deuterium

Abstract

A new, convenient, and cost-effective method for labeling cyclopentadienyl ligands with deuterium has been developed. Heating a solution of Cp2Ca-h10 in DMSO-d6 (99.5% D) for 1 h at 150 °C afforded Cp2Ca-d10 (97% D) cleanly in 95% isolated yield. For the ring-substituted bis(1-cyclopentenyl)calcocene, H/D exchange occurred at the 2,5-positions of the 1-cyclopentenyl substituents as well as at the cyclopentadienyl rings. H/D exchange between rac-Ph2C2H2(C5H4)2Ca and DMSO-d6, by contrast, was extremely inefficient and was accompanied by substantial ansa-calcocene decomposition.