DEVELOPMENT OF MIXED-LIGAND-SUPPORTED LANTHANIDE POLYMERIZATION CATALYSTS

(1)反应(C_5Me_5) _2Sm(四氢呋喃)_2 1枚的K (ER)在高收益C_5Me_5 /四氢呋喃给ER-ligated Sm (II)配合物(Sm (C_5Me_5)(四氢呋喃)_m (ER)(μ-C_5Me_5) K(四氢呋喃)_n”]_∞(m = 0或1;n = 1或2;呃= OC_6H_2 ^ tBu_2-2, 6-Me-4 (1) OC_6H_3 ^ iPr_2-2, 6 (1 b) SC_6H_2 ^ iPr_3-2, 4, 6 (1 c) NHC_6H_2 ^ tBu_3-2, 4, 6 (1 d),或者n (SiMe_3) _2 (1 e)),在“(C_5Me_5) K(四氢呋喃)_n”“单位充当中立的协调配体结合Sm (II)中心“C_5Me_5”部分。这些配合物，特别是1a-c，对苯乙烯和乙烯表现出独特的反应活性，在这两种单体存在下，它们不仅可以聚合苯乙烯和乙烯，还可以共聚成嵌段苯乙烯-乙烯共聚物。在ER配体中，硫酸酯配体SC_6H_2^ ipr_2 -2,4,6 （1c）对苯乙烯和乙烯的嵌段共聚具有最高的选择性，而羰基氧化物OC_6H_2^tBu_2-2,6- me -4 （1a）和硅酰胺N(SiMe_3)_2 （1e）对乙烯和苯乙烯的聚合具有最高的活性。(2)在samarocene配合物（C_5Me_5）_2Sm(THF)_2或（C_5Me_5）_2Sm(μ-Me)_2AlMe_2中加入合适的MMAO或AlR_3/[Ph_3C][B(C_6F_5)_4]等助催化剂，形成了立体定向1,4-顺式活性丁二烯聚合和丁二烯与苯乙烯共聚的新催化体系。(3)钐（II）双（芳烷）配合物Sm(OAr)_2(THF)_3 （Ar=OC_6H_2^ tbu_2 -2,6- me -4）对ε-己内酯与δ-戊内酯的开环聚合和ε-己内酯与γ-丁内酯的共聚具有极高的活性。

(1) Reactions of (C_5Me_5)_2Sm(THF)_2 with 1 equiv of K(ER) in THF gave in high yields the C_5Me_5/ER-ligated Sm(II) complexes [(C_5Me_5)Sm(THF)_m(ER)(μ-C_5Me_5)K(THF)_n]_∞ (m=0 or 1 ; n=1 or 2 ; ER=OC_6H_2^tBu_2-2,6-Me-4 (1a), OC_6H_3^iPr_2-2,6 (1b), SC_6H_2^iPr_3-2,4,6 (1c), NHC_6H_2^tBu_3-2,4,6 (1d), or N(SiMe_3)_2 (1e)), in which the "(C_5Me_5)K(THF)_n" unit acts as a neutral coordination ligand bonding to the Sm(II) center with the "C_5Me_5" part. These complexes, particularly 1a-c, showed unique reactivity toward styrene and ethylene, which can not only polymerize styrene and ethylene, but also copolymerize them into block styrene-ethylene copolymers under the presence of both monomers. Among the ER ligands, the thiolate ligand SC_6H_2^iPr_3-2,4,6 (1c) showed the highest selectivity for the block copolymerization of styrene and ethylene, while the aryloxide OC_6H_2^tBu_2-2,6-Me-4 (1a) and the silylamide N(SiMe_3)_2 (1e) gave the highest activity for the polymerization of ethylene and that of styrene, respectively.(2) Addition of an appropriate cocatalyst such as MMAO or AlR_3/[Ph_3C][B(C_6F_5)_4] to the samarocene complex (C_5Me_5)_2Sm(THF)_2 or (C_5Me_5)_2Sm(μ-Me)_2AlMe_2 afforded a novel catalytic system for stereospecific 1,4-cis living polymerization of butadiene and copolymerization of butadiene with styrene.(3) The samarium(II) bis (aryloxide) complex Sm(OAr)_2(THF)_3 (Ar=OC_6H_2^tBu_2-2,6-Me-4) showed an extremely high activity for ring-opening polymerization of ε-caprolactone and δ-valerolactone and copolymerization of ε-caprolactone with γ-butyrolactone.