Salicylaldiminato ligands

Salicylaldiminato ligands have also been studied and the bis(chelate) complex (101) has been reported to produce high molecular weight PE with an activity of 96gmmol 1 h 1bar 1267... 

Compounds of MnIV with the various multidentate ligands with different donor atoms have been postulated, especially as products of the oxygenation of the Mn" salicylaldiminato ligands (Section 41.3.9.3). But there is no unequivocal proof of this oxidation state in these compounds. It would be surprising if Mniv species do not form, even if they turn out to be oxidatively unstable. But we currently know nothing of consequence about the detail. 

Finally there are many types of uninegative A.A chelate ligands,138 examples being (9-XXIXa) and (9-XXIXb) the former is similar to acetylacetonates while the latter is analogous to salicylaldiminato ligands. 

Catalysts based on salicylaldiminato ligands (commonly referred to as phenoxy-imine ligands) were introduced for ethylene polymerization in 1998.1126 This remarkable class of highly active catalysts can lead to an unique variety of linear PEs.1121,1127-1144 Several reviews have been dedicated to these systems.1140 1145-1149 The performances of some of these bis(phenoxy-imine) systems are reported in Table 18. The most typical and most widely investigated systems in this class are complexes 135-138. 

Fig. 2.3 Weakly coordinated pyridine (C) provides access to higher molecular weight products (Klabunde, Ittel et al.). (D) Neutral Ni(ll) complexes with a chelating NnO-ligand (Carvell et al.). (E) Grubbs catalyst based on a salicylaldiminato ligand.

The planar Ni complex containing the iSW -ethylenebis(salicylaldiminato) ligand, [Niii(saen)], reacts with GaXa (X = Cl or Br) to form a 1 1 adduct represented as GaX2[Ni(saen)]2)+(GaX4). 1 1 Adducts in which the planarity of the transition metal is maintained are formed with I11X3 (X Cl or Br), however. ... 

Deubel and Ziegler showed by theoretical investigation that the coordination behavior of AN has a dependence on the formal charge of the metal center of the catalyst. That means in cationic a-diimine complexes the AN favors o-coordination, whereas in neutral salicylaldiminato ligand-based Pd(II) or Ni(II) complexes the probability of o- and n-coordination is... 

The dynamics of the square-planar - octahedral isomerization of a nickel(II) complex with N-(2-piperidinoethyl)salicylaldiminato ligands has been studied by ultrasonic relaxation methods- O This rearrangement can be represented as follows. Scheme 11.8 ... 

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