Theoretical Study on the Ring-Opening Polymerization of ε-Caprolactone by [YMeX(THF)5]+ with X = BH4, NMe2

The mechanism of the ring-opening polymerization (ROP) of epsilon-caprolactone by the rare-earth borohydride cations [YMe(BH4)(THF)(5)](+) has been investigated at the DFT level. The reaction with [YMe-(BH4)(THF)(5)](+) is predicted to occur either on the borohydride or on the methyl group. This also indicates the presence of some trans effect that is further demonstrated by replacing the borohydride with a dimethylamido ligand, [YMe(NMe2)(THF)(5)](+).