Salicylaldimine, complexes

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.

Salicylaldimine complexes of iron(III) catalyze epoxidation of stilbene by hypochlorite. ... 

Structural motifs related to Schiff-base ligands have been explored. Three tridentate ligands have been coordinated to the VO (quin) fragment (quin = 8-quinolinato). The octahedral azobenzene complex VO (quin) (2-hydroxy-2 -carboxy-5-methylazobenzene) shown in Fig.22 has a reversible reduction (by CV and controlled potential electrolysis) at ca —0.31 V versus Cp2Fe/CH2Cl2. This potential is 0.58 V more positive than the potential found in the analogous Schiff-base VO (quin) (V-(l-hydroxyethyl)salicylaldimine) complex. The latter complex reduction is also... 

In fact, several reports have appeared on the spectroscopic features of complexes of zinc and cadmium with Schiff bases. The electronic absorption spectra of various salicylaldimine complexes of zinc have been determined335 to clarify assignments made previously for similar copper(II) complexes. A band at ca. 41000 cm-1 has been reassigned as an n-n transition of the oxygen lone pair, rather than the o-3d transition proposed earlier. 

Structural surprises are not confined to 2,6-DAP derivatives though zinc and cadmium complexes have been obtained with the quadridentate thioiminato Schiff base N,N -ethylenebis(monothioacetonimine) 347 uv and visible spectra indicate planar geometry, rather than the tetrahedral geometry observed for the salicylaldimine complexes. 

A crystal structure determination for this compound showed that while the square planar coordination of palladium is retained, strain within the molecule is relieved by a folding of the ligand239 similar to that described above for salicylaldimine complexes. The fl position of these ligands may be substituted by electrophilic reagents before or after complexation.282... 

While the precise role of metal coordination in the formation of cyclic ethers is open to some doubt, such is not the case where there is good supporting coordination from nitrogen donor atoms. This is illustrated by the macrocyclization on a salicylaldimine complex (equation 39).161... 

Several reports have appeared on complexes of zinc and cadmium with Schiff bases. The electronic absorption spectra of various salicylaldimine complexes of zinc have been determined54 to clarify assignments made previously for similar copper(n)... 

Fig. 3 A self-assembling ionophore. Formation of a Ni(II)-salicylaldimine complex preorganizes a crown ether-like cation binding site...

Holm, R. H. Spectral and magnetic studies of substituted Ni(II) salicylaldimine complexes, in Advances in the Chemistry of the Coordination Compounds, Kirschner, S. (ed.). Macmillan New York, 1961. 

Polymerizations with nickel salicylaldimine complexes 87-101 were performed in a 1 L steel autoclave at 40 bar and 30 °C. The nickel complexes (0.09 mmol) were activated with equimolar amounts of Ni(COD)2 in toluene solutions for 30 min after which the autoclave was pressurized with ethene. The reaction was terminated after 1.5 h by venting the ethene and the formed polymer powder was isolated. Details are summarized in Tab. 3.9. For comparison, complex 134, a nickel salicylaldimine complex with a 2,6-(diisopropyl)phenyl imine substituent, was screened under the same conditions. 

In 1966 Nozaki et al. [14] reported the first examples of enantioselective metal-catalyzed cyclopropanation reactions of diazo compounds. Although the enantiomeric excesses induced by chiral copper-salicylaldimine complexes were low (Scheme 2), this work proved to be seminal as it demonstrated the principle... 

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