Bis(phenolate)amine-supported lanthanide borohydride complexes for styrene and trans-1,4-isoprene (co-)polymerisations

摘要: New bis(phenolate)amine-supported neodymium borohydride complexes and their previously reported samarium analogues were tested as catalysts for the polymerisation of styrene isoprene. Reaction Na2O2NL (L = py, OMe, NMe2) with Nd(BH4)3(THF)3 afforded Nd(O2NL)(BH4)(THF) py (1-Nd), OMe (2-Nd), NMe2 (3-Nd)). Complex 1-Nd has shown a propensity to form phenolate-O-bridged dimer [Nd(μ-O2Npy)(BH4)]2 (1′-Nd) observed Sm(O2NL)(BH4)(THF) or Pr). X-ray structures 1′-Nd 2-Nd determined are presented. The 3-Nd Sm(O2NL)(BH4)(THF)x (1-Sm), (2-Sm), (3-Sm), Pr (4-Sm)) isoprene in presence n-butylethylmagnesium (Mg(nBu)(Et)). All found be active these conditions, leading polyisoprene up 95.1% trans-1,4 stereoregular. They also atactic polystyrene all cases. Interestingly, samarium-based more than ones toward this latter monomer, sharp contrast what is usually rare earth complexes. structure both trans-polyisoprenes polystyrenes obtained studied detail by MALDI-ToF analysis order better understand mechanisms. coordinative chain transfer (CCTP) monomers was further conducted using Mg(nBu)(Et) agent. Finally, statistical copolymerisation examined catalytic systems, formation poly[(trans-1,4-isoprene)-co-styrene] 39% moieties inserted highly trans-1,4-stereoregular polyisoprene.