Pd Complex-catalyzed copolymerization of a bicyclic methylenecyclopropane with carbon monoxide to afford a new polyketone
作者:Daisuke Takeuchi、Ayami Yasuda、Kohtaro Osakada
DOI:10.1039/b211032f
日期:——
Alternating copolymerization of 7-methylenebicyclo[4,1,0]heptane with CO in thf is promoted by catalysts prepared from Pd complexes, PdCl(Me)L (L = chelating diimine or diamine), and NaBARF (BARF =
[BC6H3(CF3)2-3,5}4]−), to produce the polyketone containing enone and 1,2-cyclohexane units. The Pd complexes with Schiff-base type diimines, 2,9-disubstituted 1,10-phenanthroline, and tmen are effective as catalysts to afford the polyketone containing mainly the cis-1,2-disubstituted cyclohexane ring. Polymerization in thf using Schiff-base diimine as the ligand for Pd produces product with a narrow molecular weight distribution (Mw/Mn
= 1.10–1.19). The increase in molecular weight during polymerization and polymer growth caused by addition of new monomer indicates living polymerization. The reaction catalyzed by cationic Pd complexes with 2,2′-bipy and phen, prepared from NaBARF and PdCl(Me)L (L = 2,2′-bipy, phen) in CH3CN, produces polymer that contains both trans- and cis-disubstituted cyclohexane rings in almost equal amounts. Heating of the polymer with cis-disubstituted cyclohexane in the presence of sodium o-chlorophenolate induces epimerization of the polymer into thermodynamically more stable polyketones with trans-disubstituted cyclohexane.
在四氢呋喃中,使用由钯复合物、PdCl(Me)L(L = 螯合双亚胺或双胺)和NaBARF(BARF = [BC6H3(CF3)2-3,5}4]−)制备的催化剂,促进7-亚甲基双环[4,1,0]庚烷与CO的交替共聚反应,生成含有烯酮和1,2-环己烷单元的聚酮。带有席夫碱型双亚胺、2,9-二取代的1,10-菲咯啉和tmen的钯复合物作为催化剂有效,主要生成含有顺式-1,2-二取代环己烷环的聚酮。在四氢呋喃中使用席夫碱双亚胺作为钯的配体进行聚合反应,产生分子量分布窄的产物(Mw/Mn = 1.10–1.19)。聚合反应中分子量的增加和新单体的加入导致的聚合物增长表明了活性聚合。由NaBARF和PdCl(Me)L(L = 2,2′-联吡啶,苯)在CH3CN中制备的阳离子钯复合物催化的反应,生成含有几乎等量的反式和顺式-二取代环己烷环的聚合物。在邻氯苯酚钠存在下加热含有顺式-二取代环己烷的聚合物,诱导聚合物的差向异构化,转变为热力学上更稳定的含有反式-二取代环己烷的聚酮。