通过钴催化的1,3-丁二烯聚合反应控制外部二苯基环己基膦进料以实现顺式-1,4- syn -1,2序列控制的聚丁二烯
摘要:
微观结构和单元顺序是决定聚丁二烯材料性能的关键参数。在此贡献中,我们报道了合成,6-(二-叔丁基膦)的表征胺稠2-R-吡啶化合物(R = 1' ħ恶唑(L1); 4',4'-二甲基恶唑啉(L2); 4'-异丙基恶唑啉(L3)负载的二氯化钴配合物及其在丁二烯的区域选择性,序列和分子量控制的聚合反应中的性能。与MMAO组合,钴介导的聚合反应显示了许多活的特性与顺-1,4聚合系统在0–80°C的宽温度范围内。我们表明,可以在152–164 kg / mol的范围内调整数均分子量,而MWD值在1.04–1.34的范围内。催化剂上的空间体积对聚合速率有不利影响(k obs(Co1,无 取代基)为0.037 L / mol·min。> K obs(Co3,异丙基)为0.030 L / mol·min。> K obs (Co 2,二甲基)至0.024L / mol·min。以二苯基环己基膦(Ph 2 C
Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions
摘要:
Well-defined (PNN)-N-N-N-C pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their (PNP)-P-3 analogs. These reactions proceed under mild and base-free conditions via protonation-deprotonation of the 'NH' group in the aromatization-dearomatization process. (c) 2012 Elsevier Ltd. All rights reserved.