Recent Advances in Transition Metal‐Based Catalysts for Ethylene Copolymerization with Polar Comonomer

Abstract

The synthesis of polar functionalized polyolefin (PFP) offers improvement in mixing properties, polymer surface, and rheological properties with the potential of upgraded polyolefins for modern and ingenious applications. The synthesis of PFP from metal-based catalyzed olefin (non-polar in nature) copolymerization with polar comonomers embodies energy-efficient, atomefficient, and apparently an upfront methodology. Despite their outstanding success during conventional polymerization of olefin, 3 rd and 4 th group (early transition metal)-based catalysts, owing to their electrophilic nature, face challenges mainly due to Lewis basic sites of the polar monomers. On the contrary, late transition metal-based catalysts have also made progress, in recent years, for PFP synthesis. The recent past has also witnessed several advancements in the development of dominating palladium-based catalysts while their lower resistance towards ligand functional groups has limited the practical application of abundant and cheaper nickel-based catalysts. However, the relentless efforts of the scientific community, during the past half-decade, have indicated rigorous progress in the development of nickel-based catalysts for PFP synthesis. In this review, we have abridged the recent research trends in both early as well as late transition metal-based catalyst development. Furthermore, we have highlighted the role of transition metalbased catalysts in influencing the polymer properties.

Unveiling the Detailed Mechanism and Origins of Chemo-, Regio-, and Stereoselectivity of Rare-Earth Catalyzed Alternating Copolymerization of Polar and Nonpolar Olefins

“…In the past few decades, enormous effects have been made by using various transition metal catalysts. However, the traditional group IV metal complexes (e.g., Ti and Zr) often suffer from the poisoning effects caused by the strong acid–base interaction between the Lewis basic polar functional groups and the Lewis acidic metal centers (Figure a-I) . In contrast, the late-transition metal catalysts, such as Ni and Pd complexes, are less oxophilic and thus generally more tolerant of polar groups (Figure a-II).…”

Mechanistic Insights into Rare-Earth-Catalyzed Alternating Copolymerization through C–H Polyaddition of Functionalized Organic Compounds to Unconjugated Dienes

“…Consequently, the development of high-efficiency and sequence-controlled methods for incorporating chemical functionalities or polar groups into polyolefin chains has been of great interest and significance in both academia and industry over the past decades. Notably, among various approaches, the coordination copolymerization of polar and nonpolar olefins has been extensively investigated by using various transition metal catalysts since it is a straightforward and atom-efficient strategy for synthesis of functional polyolefin materials . In this content, it is noteworthy that rare-earth alkyl catalysts have emerged as a new class of highly efficient catalysts for the copolymerization of a wide range of polar and nonpolar olefins in the past decade. − As we know, precise control of monomer sequence in the primary structure of functional polyolefins is crucial, as it will dictate subsequent secondary and tertiary structures, as well as final properties .…”

Origins of Ligand-Controlled Stereoselective Polymerization of ortho-Methoxystyrene by Rare-Earth Catalysts: A Theoretical Perspective

“…Among the approaches, in principle, the coordination polymerization of polar olefins is a straightforward and atom-efficient strategy for the synthesis of polar functionalized polyolefins . Nonetheless, in traditional group 4 or late-transition metal catalysts, the presence of polar groups on the monomer often poisons the metal catalysts and triggers rearrangement reactions during chain growth, resulting in low activity and the difficulty of controlling stereoselectivity. , Over the past two decades, cationic rare-earth catalysts have been extensively employed in catalyzing the polymerization of various types of nonpolar olefins, exhibiting outstanding activity, regioselectivity, and stereoselectivity . Regarding the polar olefin polymerization, in 2015, Cui and co-workers reported the first example of stereoselective coordination polymerization of the polar o MOS by using the cationic β-diketiminato rare-earth catalysts through the novel “self-assisted mechanism” .…”