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手性多孔有机聚合物具有较高的稳定性和催化活性,广泛用于多相不对称催化中.目前研究多集中在合成具有微孔结构的聚合物,而少有具有多种孔道结构(包含介孔和微孔)的聚合物的报道.之前我们报道了乙烯基修饰的BINAP配体,(S)-5,5’-divinyl-BINAP,将其与不同单体共聚后得到了一系列具有不同孔结构的有机聚合物.其负载的Rh基催化剂在苯乙烯不对称氢甲酰化反应中,表现出比均相更高的产物对映体选择性.本文采用不同的溴代步骤,合成了(S)-4,4’-divinyl-BINAP配体.将这两种具有乙烯基官能团的手性配体按相同的摩尔比与二乙烯基苯(DVB)共聚,得到两种不同的有机聚合物.负载[RuCl_2(benzene)]_2后,分别得到Ru/4-BINAP@POPs和Ru/5-BINAP@POPs-1.采用一锅法合成了催化剂Ru/5-BINAP@POPs-2;以[RuCl_2(p-cyme)]_2和RuCl_3分别合成了Ru/5-BINAP@POPs-3和Ru/5-BINAP@POPs-4催化剂.N2物理吸附结果显示,Ru/4-BINAP@POPs和Ru/5-BINAP@POPs-1催化剂具有相似的孔道结构;而采用一锅法合成的Ru/5-BINAP@POPs-2催化剂的介孔孔径较大.4-BINAP@POPs和5-BINAP@POPs聚合物的~(13)C核磁显示,其均在145,137和128 ppm处有明显的吸收峰,可归结为萘环和苯环上的碳振动峰;在44.0 ppm处的峰归属为亚甲基上的碳振动峰;31P核磁显示,在聚合物中P基本没有被氧化.将所得到的Ru/POPs催化剂应用于乙酰乙酸甲酯的多相不对称加氢反应中,Ru/5-BINAP@POPs-1催化剂具有与Ru/4-BINAP@POPs更快的反应速率.在相同反应条件下,催化剂活性大小为Ru/5-BINAP@POPs-1>Ru/5-BINAP@POPs-3>Ru/5-BINAP@POPs-4>Ru/5-BINAP@POPs-2.另外Ru/5-BINAP@POPs-1催化剂对β-酮酸酯有着较好的底物适应性,且在釜式反应中可循环使用6次而活性基本不变.分析发现,使用前后的催化剂均没有明显的Ru–Ru键的存在.表明Ru金属高度分散于催化剂上,且具有较高的稳定性,金属不易聚集,这也是其具有高活性和稳定性的原因.
Chiral porous organic polymers have high stability and catalytic activity and are widely used in heterogeneous asymmetric catalysis.Currently, most of the studies focused on the synthesis of polymers with microporous structure, but few have a variety of pore structure Mesoporous and microporous polymer reported previously we reported vinyl modified BINAP ligand, (S) -5,5’-divinyl-BINAP, it was obtained with a variety of monomers copolymerization with a series of The organic polymer with different pore structure showed that the supported Rh-based catalyst exhibited higher enantioselectivity than the homogeneous one in the asymmetric hydroformylation of styrene.In this paper, different bromination steps were used to synthesize (S) -4,4’-divinyl-BINAP Ligand. The two chiral ligands with vinyl functionality were copolymerized with divinylbenzene (DVB) in the same molar ratio to give two different organic (Ru / 5-BINAP @ POPs-1) were synthesized from RuCl_2 (benzene) The Ru / 5-BINAP @ POPs-3 and Ru / 5-BINAP @ POPs-4 catalysts were synthesized by [RuCl_2 (p-cyme)] _2 and RuCl_3 respectively.The results of N2 physical adsorption showed that Ru / 4-BINAP @ P OPs and Ru / 5-BINAP @ POPs-1 catalysts have similar pore structures, whereas the one-pot synthesis of Ru / 5-BINAP @ POPs- The ~ (13) C NMR of BINAP @ POPs showed significant absorption peaks at 145, 137 and 128 ppm, which were attributed to the carbon vibration peaks at the naphthalene and benzene rings. The peak assignments at 44.0 ppm were 31P NMR showed that there was almost no oxidation of P in the polymer.The obtained Ru / POPs catalyst was applied to the heterogeneous asymmetric hydrogenation of methyl acetoacetate, and the Ru / 5 BINAP @ POPs-1 catalyst has a faster reaction rate than Ru / 4-BINAP @ POPs.Under the same reaction conditions, the catalytic activity of Ru / 5-BINAP @ POPs-1> Ru / 5-BINAP @ POPs- 3> Ru / 5-BINAP @ POPs-4> Ru / 5-BINAP @ POPs-2.In addition Ru / 5-BINAP @ POPs-1 catalyst has better substrate adaptability to β-keto acid ester, The results showed that there was no obvious Ru-Ru bond before and after the catalyst was used, which indicated that Ru metal was highly dispersed on the catalyst and had high stability. Metal is not easy to gather, that’s it too Having a high activity and stability reasons.