半夹心稀土二胺基配合物的合成、结构及催化聚合性能
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摘要
本论文采用取代环戊二烯C5Me4R'H (R'= H, Me, SiMe3)等为辅助配体,通过胺基消除反应合成了一系列半夹心型稀土胺基配合物,并对它们进行了结构表征。在此基础上,考察了半夹心钪二胺基配合物作为催化剂前身对苯乙烯的催化聚合性能。
1.用无水ScCl3和LiN(SiRMe2)2 (R= H, Me)按1：2.9的摩尔比反应之后,分离得到三胺基钪配合物Sc[N(SiRMe2)3](THF)n (R= H, n= 1; R= Me, n= 0)。再将三胺基钪配合物与取代环戊二烯C5Me4R'H(R'=H,Me,SiMe3)按1：1的摩尔比在100℃的甲苯中进行胺基消除反应,得到了一系列半夹心结构的钪二胺基配合物(C5Me5)Sc[N(SiHMe2)2]2 (1). (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2)、(C5Me5)Sc[N(SiMe3)2]2 (3)、(C5Me4H)Sc[N(SiMe3)2]2 (4),产率为72-81%。配合物1,2,3,4经过了1H NMR,13C NMR,红外光谱,元素分析等测试；其中,配合物1,2,3还经过了X射线单晶衍射测试。晶体结构表明这些配合物中,中心金属离子配位数是5,呈三角锥型的几何构型。
2.采用Y[N(SiHMe2)3](THF)2和C5Me4SiMe3H以1：1摩尔比反应分离得到了二聚体的钇配合物[Y(C5Me4SiMe3){μ-O(CH2)3CH3}{N(SiHMe2)2}]2 (5),产率为8%。配合物经过了1HNMR,13C NMR,红外光谱,元素分析,X射线单晶衍射等测试。晶体结构表明这是一个Ci对称的双金属分子,每个钇离子配位了一个胺基,一个O(CH2)3CH3基团,和一个环戊二烯基,二两个钇离子通过两个O(CH2)3CH3基团中的氧原子桥联。中心金属构成了扭曲的四面体结构。配合物5的形成推测是Ln-N 6键对THF分子中C-O键的活化所致。
3.配合物(C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), (C5Me4H)Sc[N(SiMe3)2]2 (4)可作为催化剂前身,在三异丁基铝(Al Bu3)和阳离子化试剂([Ph3C][B(C6F5)4]、[PhNMe2H][B(C6F5)4])的作用下催化苯乙烯的间规聚合,得到间规度高达99%的聚苯乙烯。所得到的聚合物进行了1H NMR、13C NMR、DSC、GPC表征。
A series of half-sandwich scandium bis(amide) complexes were synthesized and characterized. These complexes can serve as precatalysts for syndiospecific polymerization of styrene.
1. Treatment of ScCl3 with 2.9 equiv. of LiN(SiRMe2)2 (R= H, Me) afforded the scandium tris(amide) complexes Sc[N(SiRMe2)3](THF)n (R= H, n= 1; R= Me, n= 0). Amine elimination of Sc[N(SiRMe2)3](THF)n with 1 equiv. of cyclopentadienyl derivatives C5Me4R'H (R= H, Me, SiMe3) in toluene at 100℃afforded a series of half-sandwich scandium bis(amide) complexes (C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), (C5Me4H)Sc[N(SiMe3)2]2 (4) in 72-81% isolated yields. These complexes were characterized by elemental analysis, NMR spectroscopy, FT-IR spectroscopy. Single crystal structural determination of 1-3 revealed that the central metal adopts a trigonal geometry.
2. A dimeric yttrium complex [Y(C5Me4SiMe3){μ-O(CH2)3CH3}{N(SiHMe2)2}]2 (5) was isolated as one of the co-products from the reaction of Y{N(SiHMe2)2}3(THF)2 with C5Me4HSiMe3 in 1:1 molar ratio in toluene at 100℃. Complex 5 was characterized by elemental analysis, NMR spectroscopy, FT-IR spectroscopy, and X-ray single crystal structural analysis. X-ray diffraction revealed that complex 5 is a symmetric dimer, and the center metal is eight-coordinated by one nitrogen atom from the amide group, two bridging oxygen atoms from the O(CH2)3CH3 groups, and one cyclopentadienyl ringη5-fashion to adopt a distorted tetrahedron geometry. The formation of complex 5 was postulated to be a result from C-O bond cleavage reaction of THF by (C5Me4SiMe3)Y[N(SiHMe2)2]2.
3. In the presence of Al'Bu3, and activated by one equimolar amount of [Ph3C][B(C6F5)4] or [PhNMe2H][B(C6F5)4], (C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), and (C5Me4H)Sc[N(SiMe3)2]2 (4) showed high activity towards styrene polymerization to give polystyrenes with high syndiotacticity (rrrr> 99%). The polystyrenes were characterized by 1H NMR、13C NMR、DSC and GPC.
1.用无水ScCl3和LiN(SiRMe2)2 (R= H, Me)按1：2.9的摩尔比反应之后,分离得到三胺基钪配合物Sc[N(SiRMe2)3](THF)n (R= H, n= 1; R= Me, n= 0)。再将三胺基钪配合物与取代环戊二烯C5Me4R'H(R'=H,Me,SiMe3)按1：1的摩尔比在100℃的甲苯中进行胺基消除反应,得到了一系列半夹心结构的钪二胺基配合物(C5Me5)Sc[N(SiHMe2)2]2 (1). (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2)、(C5Me5)Sc[N(SiMe3)2]2 (3)、(C5Me4H)Sc[N(SiMe3)2]2 (4),产率为72-81%。配合物1,2,3,4经过了1H NMR,13C NMR,红外光谱,元素分析等测试；其中,配合物1,2,3还经过了X射线单晶衍射测试。晶体结构表明这些配合物中,中心金属离子配位数是5,呈三角锥型的几何构型。
2.采用Y[N(SiHMe2)3](THF)2和C5Me4SiMe3H以1：1摩尔比反应分离得到了二聚体的钇配合物[Y(C5Me4SiMe3){μ-O(CH2)3CH3}{N(SiHMe2)2}]2 (5),产率为8%。配合物经过了1HNMR,13C NMR,红外光谱,元素分析,X射线单晶衍射等测试。晶体结构表明这是一个Ci对称的双金属分子,每个钇离子配位了一个胺基,一个O(CH2)3CH3基团,和一个环戊二烯基,二两个钇离子通过两个O(CH2)3CH3基团中的氧原子桥联。中心金属构成了扭曲的四面体结构。配合物5的形成推测是Ln-N 6键对THF分子中C-O键的活化所致。
3.配合物(C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), (C5Me4H)Sc[N(SiMe3)2]2 (4)可作为催化剂前身,在三异丁基铝(Al Bu3)和阳离子化试剂([Ph3C][B(C6F5)4]、[PhNMe2H][B(C6F5)4])的作用下催化苯乙烯的间规聚合,得到间规度高达99%的聚苯乙烯。所得到的聚合物进行了1H NMR、13C NMR、DSC、GPC表征。
A series of half-sandwich scandium bis(amide) complexes were synthesized and characterized. These complexes can serve as precatalysts for syndiospecific polymerization of styrene.
1. Treatment of ScCl3 with 2.9 equiv. of LiN(SiRMe2)2 (R= H, Me) afforded the scandium tris(amide) complexes Sc[N(SiRMe2)3](THF)n (R= H, n= 1; R= Me, n= 0). Amine elimination of Sc[N(SiRMe2)3](THF)n with 1 equiv. of cyclopentadienyl derivatives C5Me4R'H (R= H, Me, SiMe3) in toluene at 100℃afforded a series of half-sandwich scandium bis(amide) complexes (C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), (C5Me4H)Sc[N(SiMe3)2]2 (4) in 72-81% isolated yields. These complexes were characterized by elemental analysis, NMR spectroscopy, FT-IR spectroscopy. Single crystal structural determination of 1-3 revealed that the central metal adopts a trigonal geometry.
2. A dimeric yttrium complex [Y(C5Me4SiMe3){μ-O(CH2)3CH3}{N(SiHMe2)2}]2 (5) was isolated as one of the co-products from the reaction of Y{N(SiHMe2)2}3(THF)2 with C5Me4HSiMe3 in 1:1 molar ratio in toluene at 100℃. Complex 5 was characterized by elemental analysis, NMR spectroscopy, FT-IR spectroscopy, and X-ray single crystal structural analysis. X-ray diffraction revealed that complex 5 is a symmetric dimer, and the center metal is eight-coordinated by one nitrogen atom from the amide group, two bridging oxygen atoms from the O(CH2)3CH3 groups, and one cyclopentadienyl ringη5-fashion to adopt a distorted tetrahedron geometry. The formation of complex 5 was postulated to be a result from C-O bond cleavage reaction of THF by (C5Me4SiMe3)Y[N(SiHMe2)2]2.
3. In the presence of Al'Bu3, and activated by one equimolar amount of [Ph3C][B(C6F5)4] or [PhNMe2H][B(C6F5)4], (C5Me5)Sc[N(SiHMe2)2]2 (1), (C5Me4SiMe3)Sc[N(SiHMe2)2]2 (2), (C5Me5)Sc[N(SiMe3)2]2 (3), and (C5Me4H)Sc[N(SiMe3)2]2 (4) showed high activity towards styrene polymerization to give polystyrenes with high syndiotacticity (rrrr> 99%). The polystyrenes were characterized by 1H NMR、13C NMR、DSC and GPC.
引文
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