Early Metal Di(pyridyl) Pyrrolide Complexes with Second Coordination Sphere Arene−π Interactions: Ligand Binding and Ethylene Polymerization

Abstract

Early metal complexes supported by hemilabile, monoanionic di(pyridyl) pyrrolide ligands substituted with mesityl and anthracenyl groups were synthesized to probe the possibility of second coordination sphere arene−π interactions with ligands with potential for allosteric control in coordination chemistry, substrate activation, and olefin polymerization. Yttrium alkyl, indolide, and amide complexes were prepared and structurally characterized; close contacts between the anthracenyl substituents and Y-bound ligands are observed in the solid state. Titanium, zirconium, and hafnium tris(dimethylamido) complexes were synthesized, and their ethylene polymerization activity was tested. In the solid state structure of one of the Ti tris(dimethylamido) complexes, coordination of Ti to only one of the pyridine donors is observed pointing to the hemilabile character of the di(pyridyl) pyrrolide ligands.

Copper complexes from 3,5-disubstituted N-hydroxyethylpyrazole ligands: Cleavage of C N bond as well as formation of second coordination sphere complexes

“…Reactions and manipulation were carried out in air at room temperature (r.t.). The 2-(3,5-diphenyl-1Hpyrazol-1-yl) ethanol (HL1) and 2-(3,5-(2-dipyridyl)-1H-pyrazol-1-yl)ethanol (HL2) were synthesised as described in the literature [27,28]. Elemental analyses (EA) (C, H, N) were carried out on a Thermo Scientific Flash 2000 CHNS Analyses.…”

“…Moreover, recent reports stress the importance of similar ligands in the field of catalysis, as the use of dipyridyl substituents linked by fivemembered ring spacers (such as pyrazole), greatly increase the catalytic ability of those substituents to interact with incoming substrates [27]. was observed, resulting in the presence of the corresponding N-unsubstituted pyrazole ligand in their structures.…”

Effect of Substituents of Cerium Pyrazolates and Pyrrolates on Carbon Dioxide Activation

“…Metal silylamides, however, were shown to engage in a cascade of reactions with CO 2 , ultimately affording metal siloxides [ 41 , 42 , 43 ]. Whereas pyrrole-derived pincer-type ligands are quite popular in rare-earth–metal coordination chemistry [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ], examples of pure pyrrolyl ligands have remained scarce [ 52 , 53 , 54 , 55 ]. Likewise, rare-earth–metal complexes bearing a carbazolyl ligand have been reported [ 56 , 57 , 58 , 59 , 60 , 61 , 62 ].…”