Synthesis and Characterization of Heteroscorpionate Rare‐Earth Metal Dialkyl Complexes and Catalysis on MMA Polymerization

Abstract

A series of rare-earth metal alkyl complexes supported by a heteroscorpionate ligand were prepared and structurally characterized. X-ray diffraction analysis revealed that the heteroscorpionate ligand is face-capping on the rare-earth metal in k 3 mode, making the configuration of the afforded dialkyl metal complexes similar to that of half-metallocenes.

Heteroscorpionate Rare‐Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring‐Opening Polymerization of rac‐Lactide

“…[24] The in situ generated lithium salt reacted with diphenylphosphine chloride to give the targeted [bis(3,5-dimethylpyrazolyl)methyl]-diphenylphosphine compound (1) as white solids. When exposed to oxygen atmosphere or treated with organoazide compound, 1 transferred cleanly to the corresponding oxophosphine or iminophosphine derivatives 2 and 3 (Scheme 2).…”

Synthesis and structural characterisation of tetrahedral zinc(II) and trigonal bipyramidal cadmium(II) complexes containing N′-cyclohexyl substituted N,N-bispyrazolyl ligand

“…Thus, MMA polymerisation through coordination complexes is used to achieve PMMA with high syndiotacticity, which resulted in T g up to 140°C [66,67,35]. The syndiotacticity of resultant PMMA was around 69%, which was similar to both Zn(II) and Cd(II) complexes.…”

“…Among the various metals, titanium [14,15], zirconium [16], hafnium [17], cobalt [18][19][20], chromium [21,22], nickel [23][24][25], ruthenium [26][27][28], palladium [29][30][31], and lanthanide [32]-based complexes with various ligand architectures have mainly been employed for MMA polymerisation with moderate-to-high activities and tacticities. Moreover, despite numerous reports on metal complexes with N-donor ligands [33,34], little is known regarding pyrazolyl-based late transition metal complexes as catalysts for methyl methacrylate polymerisation [35][36][37] compared with early transition metal complexes [38][39][40][41] because late transition metal complexes are generally more tolerant towards polar functional monomers (including MMA) due to their less-oxophilic nature. In contrast, the steric and electronic properties of pyrazolyl-based ligands can be fine-tuned by an appropriate choice of substitutions on the 2-N, 3-C, 4-C, and 5-C atoms of the pyrazole moiety [42][43][44][45], and have been employed in diverse potential applications [46][47][48][49][50].…”

Cd(II) and Zn(II) Complexes Containing N,N'-Bidentate N-(Pyridin-2-ylmethylene)cyclopentanamine: Synthesis, Characterisation and Methyl Methacrylate Polymerisation

“…Thus, studies on nonradical-mediated MMA polymerisation, which able to produce a higher T g up to 140 o C, have been performed, and some transition metal complexes have successfully been applied to this process. [45][46][47][48][49][50][51][52][53] Recently, we explored the development of transition metal complexes as catalysts for homogeneous polymerisation of MMA to produce syndiotactic PMMA. Although the ligand impy has been applied to rhenium, copper, palladium and platinum complexes, rhenium and copper complexes did not utilized as catalyst for MMA polymerisation.…”