Salicylaldimine

I have carried out widespread studies on the application of a sensitive and selective preconcentration method for the determination of trace a mounts of nickel by atomic absorption spectrometry. The method is based on soi ption of Cu(II) ions on natural Analcime Zeolit column modified with a new Schiff base 5-((4-hexaoxyphenylazo)-N-(n-hexyl-aminophenyl)) Salicylaldimine and then eluted with O.IM EDTA and determination by EAAS. Various parameters such as the effect of pH, flow rate, type and minimum amount of stripping and the effects of various cationic interferences on the recovery of ions were studied in the present work. 

Ligand abbreviations salen = IV, JV -ethylenebis(salicylaldimine) dianion salbn = JV,Af -butyl-enebis(salicylaldimine) dianion salphen = lV,iV -o-phenylenebis(salicylaldimine) dianion 2-MeImd = 2-methylimidazole H4fsa2en = JV,iV -ethylenebis(3-carboxysalicylaldimine) eq = equatorial ax = axial... 

Ligand substitution in salicylaldiminate [NiA2] complexes has been studied in detail.1161 Substitution in chiral [NiA2] species by chiral salen-type tetradentate H2B ligands in acetone proceeds according to Equation (7) ... 

The asymmetric synthesis of dihydrochrysanthemolactone 217 by intramolecular cyclopropanation of diazoacetate 216 in the presence of chiral salicylaldimine/... 

In 1966, Nozaki et al. reported that the decomposition of o-diazo-esters by a copper chiral Schiff base complex in the presence of olefins gave optically active cyclopropanes (Scheme 58).220 221 Following this seminal discovery, Aratani et al. commenced an extensive study of the chiral salicylaldimine ligand and developed highly enantioselective and industrially useful cyclopropanation.222-224 Since then, various complexes have been prepared and applied to asymmetric cyclo-propanation. In this section, however, only selected examples of cyclopropanations using diazo compounds are discussed. For a more detailed discussion of asymmetric cyclopropanation and related reactions, see reviews and books.17-21,225... 

Salicylaldimine ligands often give stable Fe(III) complexes, so it is uncommon to meet Fe(II) complexes with such ligands. The dark blue-green complex [Fe 17] (17) shows an unusual thermally-induced, two-step spin-state conversion where two sharp transitions are separated by a plateau extending over 35 K in which 50% high-spin and 50% low-spin molecules coexist [41]. 

Brunner and Berghofer (48) investigated ligands composed of a combination of salicylaldimines and oxazolines. Intriguing effects of the electronic character of the phenol were noted. The electron poor p-nitrophenol 74b provided the trans cyclopropane in 53% ee, compared to 6% ee using the parent phenol ligand 74a. 

A quite similar structural Mn402 assembly is present in the salicylaldiminate dication [Mn402 N(CH2CH2=NCHC6H40)3 2]2 +, Figure 48.67... 

Using this approach, a dynamic combinatorial library (DCL) of rapidly equilibrating metal complexes was formed by incubating a series of salicylaldimines with the transition metal salt ZnCl in aqueous solution (Fig. 3.3). Divalent zinc was chosen as the transition metal for its known tetravalent coordination geometry with salicylaldimines [7] and its compatibility with DNA. (In retrospect, this was a somewhat naive view of both... 

Figure 3.3 Dynamic bis-salicylaldimine Ztf + complexafion identifies an oligo d(A T) DNA ligand. Right The selected A-methyl 2-aminoethyl pyrrolidine based bis-salicylaldimine complex 1 (hypothetical), which binds to oligo d(A T) DNA.

Figure 3.4 Multistage imine formation and metal complexation produces a diverse library of amine-, salicylaldehyde- and salicylaldimine-zinc complexes.

---