Influence of type and positioning of N-aryl substituents on vinyl polymerization of norbornene by Ni(II) α-diimine complexes

• Published in: The Korean journal of chemical engineering Vol. 25; no. 3; pp. 423 - 425
• Main Authors: Appukuttan, Vinukrishnan, Kim, Jin Hyuk, Ha, Chang Sik, Kim, Il
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.05.2008; 한국화학공학회
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry; Industrial Chemistry/Chemical Engineering; Materials Science; Reaction Engineering; 화학공학; Late Transition Metal; Catalysis; Norbornene; Diimine Ligands; Microstructure; Vinyl Polymerization
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-008-0071-9

Effects of structural variations of the diimine ligand on catalyst activities for vinyl polymerization of norbornene (NB) have been investigated by a series of Ni(II) α -diimine catalysts of the general formula: [{ArN=C(Ac)-C(Ac)=NAr}]NiBr 2 (Ac=acenaphthyl) ( Cat(H) , Ar=C 6 H 5 ; Cat(2,6-Me) , Ar=2,6-C 6 H 3 Me 2 ; Cat(2,6-Et) , Ar=2,6-C 6 H 3 Et 2 ; Cat(2,6- i Pr) , Ar=2,6-C 6 H 3 i -Pr 2 ; Cat(2,3-Me) , Ar=2,3-C 6 H 3 Me 2 ; Cat(2,4-Me) , Ar=2,4-C 6 H 3 Me 2 ; Cat(2,5-Me) , Ar=2,5-C 6 H 3 Me 2 ; Cat(3,5-Me) , Ar=3,5-C 6 H 3 Me 2 ; Cat(2,4,6-Me) , Ar=2,4,6-C 6 H 2 Me 3 ). In situ reactions with methylaluminoxane generated the active catalysts, and they showed good activity towards NB polymerizations. As indicated by relatively higher activities of Cat(H) and Cat(3,5-Me) , it can be generalized that catalysts having 2,6-substituents are less active due to steric interaction between monomer and substituents. In addition, electron donating methyl groups at 2-, 4-or 6-position on the N-aryl have a con effect and that at 3,5-position has a pro effect.