TY - JOUR
T1 - Cationic scandium allyl complexes bearing mono(cyclopentadienyl) ligands
T2 - Synthesis, novel structural variety, and olefin-polymerization catalysis
AU - Yu, Nan
AU - Nishiura, Masayoshi
AU - Li, Xiaofang
AU - Xi, Zhenfeng
AU - Hou, Zhaomin
PY - 2008/9/1
Y1 - 2008/9/1
N2 - The one-pot salt-metathesis reaction of ScCl3, cyclopentadienyl lithium salts, and allylmagnesium chlorides afforded with ease the corresponding base-free half-sandwich scandium di-(η3-allyl) complexes [(C5Me4SiMe3)Sc(C3H 5)2] (1a), [(C5Me5)Sc(C 3H5)2] (1b), and [(C5Me 5)Sc(2-MeC3H4)2] (1c) in high yields. Reaction of 1a with 1 equivalent of [PhNMe2H][B(C 6F5)4] in toluene gave rapidly the N,N-dimethylaniline-coordinated cationic mono-(η3-allyl) complex [(C5Me4SiMe3)Sc(η3-C 3H5)(η6-PhNMe2)][B(C 6F5)4] (2). The similar reaction of 1a with [Ph3C][B(C6F5)4] yielded the analogous toluene-separated ion pair [(C5Me4SiMe 3)Sc(η3-C3H5)(η6- PhMe)][B(C6F5)4] (3). When [PhNMe 2H][BPh4] was treated with 1a, the contact ion pair [(C5Me4SiMe3)Sc(η3-C 3H5)( μ,η6-Ph)BPh3] (4) was obtained. Recrystallization of 2, 3, and 4 in THF yielded the corresponding thf-separated ion pair complexes [(C5Me4SiMe 3)Sc(η3-C3H5)(thf) 2][B(C6F5)4] (5) and [(C 5Me4SiMe3)Sc(η3-C 3H5)(thf)2][BPh4] (6). The N,N-dimethylaniline-coordinated cationic scandium allyl complex 2 and the toluene-coordinated analogue 3 showed high activity (activity: 3>2) toward the polymerization and copolymerization of isoprene and norbornene to afford random copolymers with a broad range of isoprene content (33-86 mol%). The tight ion pair 4 and the thf-coordinated complexes 5 and 6 showed no activity under the same conditions. These results offer unprecedented insight into the structure-activity relationship of a cationic metal polymerization-catalyst system.
AB - The one-pot salt-metathesis reaction of ScCl3, cyclopentadienyl lithium salts, and allylmagnesium chlorides afforded with ease the corresponding base-free half-sandwich scandium di-(η3-allyl) complexes [(C5Me4SiMe3)Sc(C3H 5)2] (1a), [(C5Me5)Sc(C 3H5)2] (1b), and [(C5Me 5)Sc(2-MeC3H4)2] (1c) in high yields. Reaction of 1a with 1 equivalent of [PhNMe2H][B(C 6F5)4] in toluene gave rapidly the N,N-dimethylaniline-coordinated cationic mono-(η3-allyl) complex [(C5Me4SiMe3)Sc(η3-C 3H5)(η6-PhNMe2)][B(C 6F5)4] (2). The similar reaction of 1a with [Ph3C][B(C6F5)4] yielded the analogous toluene-separated ion pair [(C5Me4SiMe 3)Sc(η3-C3H5)(η6- PhMe)][B(C6F5)4] (3). When [PhNMe 2H][BPh4] was treated with 1a, the contact ion pair [(C5Me4SiMe3)Sc(η3-C 3H5)( μ,η6-Ph)BPh3] (4) was obtained. Recrystallization of 2, 3, and 4 in THF yielded the corresponding thf-separated ion pair complexes [(C5Me4SiMe 3)Sc(η3-C3H5)(thf) 2][B(C6F5)4] (5) and [(C 5Me4SiMe3)Sc(η3-C 3H5)(thf)2][BPh4] (6). The N,N-dimethylaniline-coordinated cationic scandium allyl complex 2 and the toluene-coordinated analogue 3 showed high activity (activity: 3>2) toward the polymerization and copolymerization of isoprene and norbornene to afford random copolymers with a broad range of isoprene content (33-86 mol%). The tight ion pair 4 and the thf-coordinated complexes 5 and 6 showed no activity under the same conditions. These results offer unprecedented insight into the structure-activity relationship of a cationic metal polymerization-catalyst system.
KW - Allyl ligands
KW - Cationic complexes
KW - Copolymerization
KW - Lewis bases
KW - Metallocenes
UR - http://www.scopus.com/inward/record.url?scp=54849441660&partnerID=8YFLogxK
U2 - 10.1002/asia.200800145
DO - 10.1002/asia.200800145
M3 - Article
AN - SCOPUS:54849441660
SN - 1861-4728
VL - 3
SP - 1406
EP - 1414
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
IS - 8-9
ER -