Application of molybdenum bis(imido) complexes in ethylene dimerisation catalysis
作者:William R. H. Wright、Andrei S. Batsanov、Antonis M. Messinis、Judith A. K. Howard、Robert P. Tooze、Martin J. Hanton、Philip W. Dyer
DOI:10.1039/c2dt12061e
日期:——
In combination with EtAlCl2 (Mo : Al = 1 : 15) the imido complexes [MoCl2(NR)(NR′)(dme)] (R = R′ = 2,6-Pri2–C6H3 (1); R = 2,6-Pri2–C6H3, R′ = But (3); R = R′ = But (4); dme = 1,2-dimethoxyethane) and [Mo(NHBut)2(NR)2] (R = 2,6-Pri2–C6H3 (5); R = But (6)) each show moderate TON, activity, and selectivity for the catalytic dimerisation of ethylene, which is influenced by the nature of the imido substituents. In contrast, the productivity of [MoCl2(NPh)2(dme)] (2) is low and polymerisation is favoured over dimerisation. Catalysis initiated by complexes 1–4 in combination with MeAlCl2 (Mo : Al = 1 : 15) exhibits a significantly lower productivity. Reaction of complex 5 with EtAlCl2 (2 equiv.) gives rise to a mixture of products, while addition of MeAlCl2 affords [MoMe2(N–2,6-Pri2–C6H3)2]. Treatment of 6 with RAlCl2 (2 equiv.) (R = Me, Et) yields [Mo(μ-N–But}AlCl2)2] (7) in both cases. Imido derivatives 1 and 3 react with Me3Al and MeAlCl2 to form the bimetallic complexes [MoMe2(NR}AlMe2μ-Cl})(NR′)] (R = R′ = 2,6-Pri2–C6H3 (8); R = 2,6-Pri2–C6H3, R′ = But (10)) and [MoMe2(NR}AlCl2μ-Cl})(NR′)] (R = R′ = 2,6-Pri2–C6H3 (9); R = 2,6-Pri2–C6H3, R′ = But (11)), respectively. Exposure of complex 8 to five equivalents of thf or PMe3 affords the adducts [MoMe2(N–2,6-Pri2–C6H3)2(L)] (L = thf (12); L = PMe3 (13)), while reaction with NEt3 (5 equiv.) yields [MoMe2(N–2,6-Pri2–C6H3)2]. The molecular structures of complexes 5, 9 and 11 have been determined.
结合EtAlCl2(Mo : Al = 1 : 15),酰胺配合物[MoCl2(NR)(NR′)(dme)](R = R′ = 2,6-Pri2–C6H3(1);R = 2,6-Pri2–C6H3,R′ = But(3);R = R′ = But(4);dme = 1,2-二甲氧基乙烷)和[Mo(NHBut)2(NR)2](R = 2,6-Pri2–C6H3(5);R = But(6))各自显示出中等的重氮乙烯催化二聚反应的TON、活性和选择性,这受到酰胺取代基性质的影响。相比之下,[MoCl2(NPh)2(dme)](2)的产率较低,更倾向于聚合而非二聚。结合MeAlCl2(Mo : Al = 1 : 15)的1–4配合物引发的催化反应显示出明显较低的产率。5配合物与EtAlCl2(2 equiv.)反应生成产物混合物,而加入MeAlCl2则得到[MoMe2(N–2,6-Pri2–C6H3)2]。6配合物与RAlCl2(2 equiv.)(R = Me, Et)反应在两种情况下均生成[Mo(μ-N–But}AlCl2)2](7)。酰胺衍生物1和3与Me3Al和MeAlCl2反应形成双金属配合物[MoMe2(NR}AlMe2μ-Cl})(NR′)](R = R′ = 2,6-Pri2–C6H3(8);R = 2,6-Pri2–C6H3,R′ = But(10))和[MoMe2(NR}AlCl2μ-Cl})(NR′)](R = R′ = 2,6-Pri2–C6H3(9);R = 2,6-Pri2–C6H3,R′ = But(11))。将8配合物暴露于五个当量的thf或PMe3,得到加合物[MoMe2(N–2,6-Pri2–C6H3)2(L)](L = thf(12);L = PMe3(13)),而与NEt3(5 equiv.)反应则得到[MoMe2(N–2,6-Pri2–C6H3)2]。5、9和11配合物的分子结构已被确定。