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https://www.selleckchem.com/products/h3b-6527.html In transition-metal catalyst structures, both the ligand structure and the initiating group are crucial components for olefin polymerization. Compared to numerous studies on tuning the electronic and steric effects of ligands, there is no report on the comprehensive investigation of initiating groups. In this contribution, five different initiating groups including "NiMe", "NiPh", "Ni(allyl)", "Ni(COD)", and "Ni(acac)/AlEt2Cl" were designed and installed into sterically bulky phosphino-phenolate nickel complexes Ni1-Ni5, respectively, which were further tested for ethylene (co)polymerization. In ethylene polymerization, the order of activity was Ni1-PPh3 (NiMe) > Ni2 (NiPh) ≫ Ni3 (Ni(allyl)) = Ni4 (Ni(COD)) = Ni5 (Ni(acac)) at low temperature conditions (30 °C) with Ni1 being the most active group (850 kg mol-1 h-1). By comparison, at high temperatures (50 °C-90 °C), the activity followed the trend of Ni2 > Ni1-PPh3 > Ni4 ≫ Ni5 > Ni3 with Ni2 exhibiting the highest activity of 6290 kg mol-1 h-1. These results indicated that the choice of initiating groups was important in the polymerization reaction. In addition, Ni1-pyr and Ni2 enabled the copolymerization of ethylene with polar comonomers such as vinyl trimethoxysilane, 6-chloro-1-hexene, and nbutyl allyl ether to give polar functionalized polyethylenes with incorporation of up to 1.28 mol% and high molecular weights (up to 66 kDa).Research in the development of new molecular catalysts for the selective transformation of CO2 to reduced forms of carbon is attracting enormous interest from chemists. Molecular catalyst design hinges on the elaboration of ligand scaffolds to manipulate the electronic and structural properties for the fine tuning of the reactivity pattern. A cornucopia of ligand sets have been designed along this line and more and more are being reported. In this quest, the porphyrin molecular platform has been under intensive focus due to the unmatche

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