Explanation

(d)
Hexadentate ligand donates six pair of electrons to central atom.
(a) 2, 2-dipyridyl-bidentate ligand
[image:9_image156.emf]
(b) DMG-bidentate ligand
$CH_{3} - C\text{=}N - O \rightarrow$
$|$
$CH_{3} - C = N \rightarrow$
$|$
$OH$
(c) Ethylenediamine-pentadentate ligand
$\therefore$ None of the given ligand is hexadentate ligand.