A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- t...A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide （CO） and styrene. The available bipyridine and its derivatives were coordinated with palladium （ II ） acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry （DSC） and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2＇-bipyridine ligand（l 356 gSTCO/（gPd · h））, when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.展开更多
基金Supported by Tianjin Natural Science Foundation(No.07JCYBJC00600)
文摘A series of 4,4＇-disubstituted-[2,2＇]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been syn- thesized and employed in the copolymerization of carbon monoxide （CO） and styrene. The available bipyridine and its derivatives were coordinated with palladium （ II ） acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of t3C NMR, FTIR, differential scanning calo- rimetry （DSC） and element analysis techniques concerning its structure and thermal performance. The effect of dif- ferent electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of co- polymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composi- tion, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2＇-bipyridine ligand（l 356 gSTCO/（gPd · h））, when the molecular weight and polydispersity index of the polyketone are Mn = 8 502, Mw = 1 3440 and Mw/Mn = 1.581, respectively.
