Synthesis of palladium(ii) complexes containing a new α-d-xylofuranose-modified diphosphine and their application as catalyst precursors in the co- and terpolymerization of CO–ethene and propene
作者:Bianca K. Muñoz-Moreno、Carmen Claver、Aurora Ruiz、Claudio Bianchini、Andrea Meli、Werner Oberhauser
DOI:10.1039/b719748a
日期:——
The diphosphine 3,5-dideoxy-1,2-O-isopropylidene-3,5-bis(di(2-methoxyphenyl)phosphanyl)-α-D-xylofuranose (o-MeO-xylophos), which differs from the known 3,5-dideoxy-1,2-O-isopropylidene-3,5-bis(diphenylphosphanyl)-α-D-xylofuranose (xylophos) by the presence of 2-methoxy substituents on the P-aryl rings, has been synthesized and characterized. These two ligands have been employed to stabilize the PdII complexes [PdCl2(o-MeO-xylophos)] (1a), [PdCl2(xylophos)] (2a), [PdClMe(o-MeO-xylophos)] (1b), [PdClMe(xylophos)] (2b), [Pd(OTs)(H2O)(o-MeO-xylophos)](OTs) (1c) and [Pd(OTs)(H2O)(xylophos)](OTs) (2c). All complexes have been characterized by multinuclear-NMR spectroscopy. The solid-state structure of 1a has been determined by a single crystal X-ray analysis. The Pdâaqua complexes 1c and 2c have been employed to catalyse the COâethene and COâpropene copolymerization as well as the COâetheneâpropene terpolymerization reaction in MeOH. The catalytic activity and the molecular weight of the polyketones have been compared to those of the products obtained with analogous catalysts, [Pd(H2O)2(o-MeO-dppp)](OTs)2 (3c) and [Pd(H2O)(OTs)(dppp)](OTs) (4c), bearing the classical 1,3-bis(diphenylphoshino)propane ligand (dppp). Under comparable catalytic conditions, all catalysts produce structurally similar polymeric materials, with 1c yielding the largest propene incorporation as well as the highest productivity of low-molecular-weight terpolymers.
3,5-二脱氧-1,2-O-异亚丙基-3,5-双(二(2-甲氧基苯基)膦酰基)-δ-D-氧基呋喃糖(邻甲氧基木磷)与已知的3,5-二脱氧-1、2-O-isopropylidene-3,5-bis(diphenylphosphanyl)-α-D-xylofuranose (xylophos)的不同之处在于其 P-芳基环上存在 2-甲氧基取代基。这两种配体被用来稳定 PdII 复合物 [PdCl2(o-MeO-xylophos)] (1a)、[PdCl2(xylophos)] (2a)、[PdClMe(o-MeO-xylophos)] (1b)、[PdClMe(xylophos)] (2b)、[Pd(OTs)(H2O)(o-MeO-xylophos)](OTs) (1c) 和 [Pd(OTs)(H2O)(xylophos)](OTs)(2c)。所有配合物都通过多核核磁共振光谱进行了表征。单晶 X 射线分析确定了 1a 的固态结构。钯水配合物 1c 和 2c 被用于催化一氧化碳与一氧化碳与丙烯的共聚以及一氧化碳与丙烯在 MeOH 中的三元共聚反应。聚酮的催化活性和分子量与使用类似催化剂[Pd(H2O)2(o-MeO-dppp)](OTs)2 (3c)和[Pd(H2O)(OTs)(dppp)](OTs)(4c)得到的产物的分子量进行了比较,这两种催化剂都带有经典的 1,3-双(二苯基樟脑)丙烷配体(dppp)。在相似的催化条件下,所有催化剂都能生成结构相似的聚合物材料,其中 1c 生成的丙烯掺杂量最大,低分子量三元共聚物的生产率也最高。