Supported neodymium catalysts for isoprene and rac-ß-butyrolactone polymerization: modulation of reactivity by controlled grafting.

A series of hybrid materials, bearing neodymium silylamide initiating groups, have been shown to mediate isoprene polymerization when combined with alkyl aluminum activators [methylaluminoxane, AlEt(2)Cl, Al(iBu)(3)]. The surface species nature and relative distribution were correlated with isoprene polymerization activity and selectivity. This approach to stereocontrol modulation has been extended to racemic ß-butyrolactone isoselective ring opening polymerization.

Cationic borohydrido-neodymium complex: synthesis, characterization and its application as an efficient pre-catalyst for isoprene polymerisation.

The cationic borohydrido lanthanide complex [Nd(BH4)2(THF)5][B(C6F5)4]1, prepared from the reaction of Nd(BH4)3(THF)3 with [HNMe2Phl[B(C6F5)4], is highly active towards isoprene polymerisation upon activation with Al(i-Bu)3, whereas the in situ prepared ternary catalytic combination Nd(BH4)3(THF)3/[HNMe2Ph][B(C6F5)4]/Al(i-Bu)3, albeit less active, displays higher cis-selectivity and better control in terms of macromolecular data.