RCOO-取代的镍(Ⅱ)配合物单组分高效催化乙烯均聚和共聚反应

合成并表征了含RCOO-基团的单核(Ni¹~Ni²)及双核(Ni³)镍配合物[(2,6-R₂-C₆H₃)—N=C(H)—(3-Ph-5-PhCOO-2-O-C₆H₂)-κ²-N,O]Ni(CH₃)(pyridine)](R=iPr;3,5-tBu₂C₆H₃),并用于催化乙烯均聚和共聚反应。 作为单组分催化剂,这些配合物可以有效地催化乙烯聚合得到中等相对分子质量的支化聚乙烯(PE)。 供电性的PhCOO—基团促进了催化剂Ni¹的引发,从而在低温下比Ni⁰活性更高。 引入大位阻的2,6-(3,5-二叔丁基苯基)苯胺基团,催化剂Ni²在5×10⁵ Pa下的活性高达1.8×10⁶ g PE mol^-1·Ni^-1·h^-1,是活性最高的水杨醛亚胺中性镍催化剂之一。 与相应的单核催化剂相比,双核催化剂Ni³对三苯基膦具有更好的耐受性。 这些催化剂可催化乙烯与1,5-己二烯、1,7-辛二烯、6-溴-1-己烯或10-十一烯酸甲酯的共聚合,制备功能化聚乙烯。

Nickel(Ⅱ) Complexes Containing RCOO-Substituent as Highly Active Single-Component Catalysts for Ethylene (Co)Polymerization

Mononuclear nickel complexes [(2,6-R₂-C₆H₃)—N=C(H)—(3-Ph-5-PhCOO-2-O-C₆H₂)-κ²-N,O]Ni(CH₃)(pyridine)](R=iPr; 3,5-tBu₂C₆H₃)(Ni¹~Ni²) and binuclear nickel complex(Ni³) were synthesized, characterized and applied in ethylene (co)polymerization. As single-component catalysts, all these complexes are capable of converting ethylene to branched polyethylenes(PE) with moderate relative molecular mass. The electron-donating group PhCOO— facilitates the initiation of catalyst Ni¹, leading to better catalytic activity at low temperature compared to nickel methyl pyridine comples(Ni⁰). Introducing bulky 2,6-(3,5-(t-Bu)₂C₆H₃)₂C₆H₃N— moiety, the activities of Ni² up to 1.8×10⁶ g of PE mol^-1·Ni^-1·h^-1(at 5×10⁵ Pa ethylene) were among the highest values using phenoxyiminato neutral nickel catalysts. Binuclear catalyst Ni³ showes better tolerance toward PPh₃ donor additive than its mononuclear counterpart. In the presence of comonomers 1,5-hexadiene, 1,7-octadiene, 6-bromo-1-hexene, or methyl 10-undecenoate, these catalysts effectively enchain these comonomers into the polymer chain to give functionalized polyethylenes.