Salicylaldiminato complexes

Most nickel(II) complexes with the various Schiff bases derived from salicylaldehyde and different amines have usually been easily prepared by three general methods (i) the reaction of a nickel(II) salt, usually hydrated nickel(II) acetate, with the preformed Schiff base using water, EtOH, MeOH or their mixtures as reaction medium (ii) the condensation reaction of bis(salicylaldehydato)nickel(II) with the appropriate amine in refluxing EtOH or H20/EtOH mixture (iii) the template reaction of the aldehyde with the appropriate amine in the presence of a nickel salt. In Table 97 the formulas, synthetic methods and some physicochemical properties for a number of nickel(II) salicylaldiminato complexes are reported. Examples of dinuclear complexes formed with Schiff bases are specifically reported in Section 50.5.8.5. 

With miniemulsions of salicylaldiminato complexes (Structure 6 b) stable latexes of high molecular weight, semicrystalline polyethylene (Mn 10s gmol-1, MJMn 2 to 4) could be obtained [25]. 

The most important and thoroughly examined examples of square-tetrahedral equilibria are provided by the JV-(.yec-aIkyl)salicylaldiminato complexes and the aminotropone iminato complexes (25-G-X).11 In the tetra-... 

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... 

Recently, bis(imino)pyridyl Fe(II)-based catalysts have been reported to afford isospecific chain-end controlled propene polymerization occurring through secondary monomer insertion.138 139 Even more recently, catalytic systems based on the octahedral bis(salicylaldiminato)Ti complex have been reported to afford syndiospecific chain-end controlled propene polymerization,140 which possibly occurs through secondary monomer insertion.141... 

A possible support to the latter model comes from its geometrical similarity with the octahedral bis(salicylaldiminato)Ti complex (Figures 122c,d)... 

Most recently, Grubbs group demonstrated that some neutral salicylaldiminato nickel(II) complexes, whose skeleton structure appears as lb in Figure 1, show catalytic activities rivaling those of the bisimine complexes [9], This potentially opens the door to a new class of catalysts as the active sites derived from these nickel complexes are neutral, thus reducing the ion-pairing problems encountered in the current catalysts. 

Hoxine = 8-hydroxyquinoline) involves the ions [Cr(oxine) ] (n = 0—3). The diastereoisomers of the complexes tris[A -( of 5 )-a-benzylethyl-5-nitro-salicylaldiminato]chromium(iii) (62), involving optically active ligands, have... 

Shen and co-workers reported a method for preparing lanthanide-NHC halides through protonolysis.75 Reaction of the imidazolium bromide salt with anionic LiLn(N Pr)4 affords salicylaldiminato-functionalized NHC-lanthanide bromides (Scheme 33). The complexes were all characterised by single crystal X-ray diffraction and exhibit capped octahedral geometries. The NHC-Ln MIC bond angles decrease Nd>Sm>Er> which is consistent with decreasing ionic radii, and the Ln-NHC bond lengths also... 

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