Schiff bases heptadentate

Partial hydrolysis of a potentially heptadentate Schiff-base tripodal ligand derived from tris-(2-aminoethyl)amine and 2-hydroxyacetophenone, induced by copper(II) salts, was reported and the final copper(II) complex (377) was characterized.333 Using salicylaldehyde as a co-ligand, with a copper(II) complex (378), catalytic epoxidation was demonstrated 334... 

The potentially heptadentate Schiff base, obtained from tris(2-aminoethyl)amine and three moles of SAL and shown in Figure 21a, reacts with trivalent metal ions to form neutral 1 1 compounds, and in so doing acts as a hexadentate ligand. An X-ray structural analysis of an Fem complex has shown that the tertiary nitrogen atom of the amine is not bonded to Fe.144... 

Figure 21 Some potentially heptadentate Schiff Bases...

As previously observed with hexadentate Schiff bases, potentially heptadentate ligands easily form dinuclear metal complexes. This is the case with trisalicylidenetriethylenetetramine, shown in Figure 21b, which gives methoxo145 and hydroxo146 dinuclear Fe111 complexes. 

Many complexes have been prepared using Schiff-base-type ligands, which can be heptadentate and octadentate and give mononuclear or dinuclear complexes. ... 

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