Stereospecific Polymerization of Isoprene with Nd(BH4)3(THF)3/MgBu2 as Catalyst

✍ Scribed by Fanny Bonnet; Marc Visseaux; Angela Pereira; Frédéric Bouyer; Denise Barbier-Baudry

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 112 KB
• Volume: 25
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200300289

✦ Synopsis

Abstract

Summary: The neodymium trisborohydride Nd(BH~4~)~3~(THF)~3~ (THF = tetrahydrofuran) has been used as a catalyst precursor for isoprene polymerization for the first time. Associated to an excess of Al(Et)~3~, the resulting catalyst is moderately active, giving a mixture of cis‐ and trans‐ polymer. Addition of a stoichiometric amount of MgBu~2~ to Nd(BH~4~)~3~(THF)~3~ affords a stereospecific catalyst providing trans‐1,4‐polyisoprene, more than 96% regular. That dual component Nd/Mg system also shows a better efficiency and good control of the molecular weights. A molecular structure is tentatively attributed to a bimetallic active species, based on ^1^H NMR experiments.

Possible Nd/Al and Nd/Mg active initiating species.

imagePossible Nd/Al and Nd/Mg active initiating species.