Asymmetric chain-growth synthesis of polyisocyanide with chiral nickel precatalysts

Nickel(II)-aryl complexes [(L-2)Ni(Ar)Br] bearing either chiral phosphine ligands (L-2=RR- orSS-DIPAMP, Ar =ortho-anisyl), or a chiral aryl-group have been prepared, and their structural optical an chiroptical properties have been characterized. Enantiomeric pairs of both catalysts have been used for the asymmetric polymerization of different isocyanides (M1,M2,M3), to give well defined polyisocyanides (P1,P2,P3). Their polymerization behavior has been studied, which confirmed chain-growth polymerization in all cases. The asymmetric induction has been verified by circular dichroism spectroscopy on enantiomeric pairs of all three polymers.