Highly efficient cis-1,4 polymerisation of isoprene using simple homoleptic amido rare earth-based catalysts

Polymerisation of isoprene was performed by means of ternary catalytic systems made of Ln[N(SiMe3)2]3 (Ln = Nd (1), Y (2))/borate/Al(iBu)3 combinations (borate = [HNMe2Ph][B(C6F5)4] (HNB), [CPh3][B(C6F5)4] (TB) or B(C6F5)3 (Barf)). With borate activator B(C6F5)3, highly active (up to 4700 kg mol−1h−1) and selective catalysts are obtained with both neodymium and yttrium metals, leading up to 96% cis-1,4-polyisoprene.