A novel linkage-isomeric pair of dinuclear Pd(ii) complexes bearing a bis-bidentate tetraphos ligand
作者:Markus Fessler、Georg Czermak、Sylvia Eller、Barbara Trettenbrein、Peter Brüggeller、Lorenzo Bettucci、Claudio Bianchini、Andrea Meli、Andrea Ienco、Werner Oberhauser
DOI:10.1039/b815392b
日期:——
The tetraphosphane all transtetrakis-(di(2-methoxyphenyl)phosphanyl)cyclobutane) (o-MeO-dppcb) has been employed to coordinate metal dichlorides (metal = NiII, PdII and PtII), stereoselectively yielding the dinuclear complexes [Ni2Cl4(μ-(κP1:κP2:κP3:κP4-o-MeO-dppcb))] (3a66) and [Pt2Cl4(μ-(κP1,κP2:κP3,κP4-o-MeO-dppcb))] (2a55), characterized by two six and two five-membered metallacycles, respectively. Conversely, the reaction with PdCl2 led, under comparable synthetic conditions, to the formation of the linkage-isomeric pair [Pd2Cl4(μ-(κP1,κP2:κP3,κP4-o-MeO-dppcb))] (1a55) and [Pd2Cl4(μ-(κP1:κP2:κP3:κP4-o-MeO-dppcb))] (1a66) in a ca. 4 : 1 ratio. The compounds obtained have been characterized in solution by multinuclear NMR spectroscopy and in the solid state by CP-MAS NMR spectroscopy, XRPD and single crystal X-ray diffraction. Compounds 1a55 and 1a66 have been tested as catalyst precursors for the CO–ethene–propene co-and terpolymerization in water–acetic acid mixtures. Their catalytic performance has been compared to that of [PdCl2(o-MeO-dppe)] (1b) (o-MeO-dppe = 1,2-(bis(di(2-methoxyphenyl)phosphanyl))ethane) and of [PdCl2(o-MeO-dppp)] (1c) (o-MeO-dppp = 1,3-bis(di(2-methoxyphenyl)phosphanyl)propane). The most striking result that emerged from the CO–ethene copolymerization study was that 1a55 was three times more productive than 1a66, outperforming, under identical catalytic conditions, even 1b and 1c, that are classified amongst the most active catalysts for the CO–ethene copolymerization reaction.
四膦全反式四-(二(2-甲氧基苯基)膦酰基)环丁烷) (o-MeO-dppcb)已被用来配位金属二氯化物(金属= NiII、PdII 和 PtII),立体选择性地产生双核配合物 [Ni2Cl4(μ- (κP1:κP2:κP3:κP4-o-MeO-dppcb))] (3a66) 和 [Pt2Cl4(μ-(κP1,κP2:κP3,κP4-o-MeO-dppcb))] (2a55),其特征在于两个分别是六个和两个五元金属环。相反,在相当的合成条件下,与 PdCl2 的反应导致形成键联异构体对 [Pd2Cl4(μ-(κP1,κP2:κP3,κP4-o-MeO-dppcb))] (1a55) 和 [Pd2Cl4 (μ-(κP1:κP2:κP3:κP4-o-MeO-dppcb))] (1a66) 在大约。 4:1 比例。所获得的化合物在溶液中通过多核NMR光谱进行表征,在固态中通过CP-MAS NMR光谱、XRPD和单晶X射线衍射进行表征。化合物 1a55 和 1a66 已作为水-乙酸混合物中 CO-乙烯-丙烯共聚合和三元聚合的催化剂前体进行了测试。它们的催化性能与 [PdCl2(o-MeO-dppe)] (1b) (o-MeO-dppe = 1,2-(bis(di(2-methoxy苯基)phosphanyl))乙烷) 和 [ PdCl2(o-MeO-dppp)] (1c) (o-MeO-dppp = 1,3-双(二(2-甲氧基苯基)膦酰基)丙烷)。 CO-乙烯共聚研究中最引人注目的结果是,1a55 的生产率是 1a66 的三倍,在相同的催化条件下,甚至优于 1b 和 1c,它们被列为 CO-乙烯共聚最活跃的催化剂之一反应。