β-Diiminato Complexes of VIII and TiIII – Formation and Structure of Stable Paramagnetic Dialkylmetal Compounds

Oligomerisation of Ethylene by Bis(imino)pyridyliron and -cobalt Complexes

“…In olefin polymerisation catalysis, monodentate, bidentate and tridentate ligands containing bulky aryl substituents have been used across the transition series, resulting in the formation of high molecular weight polyolefins. Examples of this kind can be found for dianionic bidentate [58±64] and tridentate [65±69] diamide ligands in Group 4 metal catalysts, monoanionic bidentate ligands for Groups 4 and 6, [70,71] and neutral bidentate ligands for Group 10 metal catalysts. [31, 72±77] In some cases, the molecular weight of the resulting polymer product was found to be related to the steric bulk of the aryl substituents, whereby increased size results in higher molecular weight polyolefins.…”

Syntheses, structure and ethylene polymerization behavior of β-diiminato titanium complexes

“…b-Diiminato ligands have been known for many years and were initially applied in spectroscopic studies of coordination compounds [30][31][32]. In the last few years b-diiminato has been used as neutral or monoanionic ligands in wide range of transition metal [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], main group element [48][49][50][51][52] and lanthanide [53] complexes, some of which display activity for olefin polymerization.…”

“…Jin and Novak tried to synthesize (b-diiminato)TiCl 3 using TiCl 4 AE 2THF, but did not come true [40]. Budzelaar [36] and Theopold [37] reported, respectively, Ti(III) complexes which display only low activities towards olefin polymerization. Collins and co-workers [34,39] and Jin and Novak [40] prepared, independently, the zirconium (IV) complexes with b-diiminato ligand, and all the complexes show low to moderate catalytic activities towards olefin polymerization.…”

Group 1 and 13 complexes of aryl-substituted bis(phosphinimino)methyls

“…A review of the recent literature revealed a widespread use of chelating, anionic ligands derived by deprotonation of bulky aryl-substituted b-aminoimines such as I and related ligands bearing other flanking Nsubstituents, which have the potential for precise steric and electronic ÔtuningÕ of a reactive metal site. Ligands of this type have been used to support a variety of lowcoordinate transition metal [3][4][5][6][7][8][9][10][11][12][13], main group element [14][15][16][17][18][19][20] and f-element complexes [21,22]. Furthermore, many of these systems have shown great utility in, for example, ring opening polymerisation catalysis [23][24][25][26] or as synthetic mimics for low-coordinate metal environments encountered in biological systems [27][28][29][30].…”