N-tripodal ligands to generate copper catalysts for the syndiotactic polymerization of methyl-methacrylate: Crystal structures of copper complexes

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

“…Similarly Cu(II) complexes with N-(2-furanylmethyl)-N-(1-3,5-dimethyl-1H-pyrazolylmethyl)-N-(phenylmethyl)-amine [36] yielded syndiotactic PMMA with rr value up to 0.78 with only 30% conversion. However, all the Zn(II) and Cd(II) complexes in the current study have shown 100% conversion.…”

“…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.…”

Synthesis, characterization, and MMA polymerization activity of tetrahedral Co (II) complex bearing N, N-bis(1-pyrazolyl)methyl ligand based on aniline moiety

“…Moreover, despite many reports on nitrogen-based metal complexes [19,20], little is known about pyrazole-based ligand late transition metal complexes as catalysts for olefin polymerization [21][22][23][24] and methyl methacrylate polymerization, [25][26][27] in comparison with early transition metal complexes [20,[28][29][30][31]. In particular, pyrazoles, which are among the fundamental heterocycles, have been extensively used as N-donor ligands to metals since the first review of pyrazole-derived ligands in 1972 [32][33][34].…”

“…Specifically, the highly active 2,6-bis (imino)pyridines initially discovered independently by the groups of Brookhart and Gibson [7][8][9][10][11] are well known cobalt and iron systems [12][13][14][15][16]. A further modification involves appending a donor side arm to construct tridentate chelating ligands, such as [N,O], [N,N,N], and [N,N,O] ligands [17,18].Moreover, despite many reports on nitrogen-based metal complexes [19,20], little is known about pyrazole-based ligand late transition metal complexes as catalysts for olefin polymerization [21][22][23][24] and methyl methacrylate polymerization, [25][26][27] in comparison with early transition metal complexes [20,[28][29][30][31]. In particular, pyrazoles, which are among the fundamental heterocycles, have been extensively used as N-donor ligands to metals since the first review of pyrazole-derived ligands in 1972 [32][33][34].…”