Question

Which of the following ligand does not act as bidentate ligand

• A. dipy
• B. dien
• C. gly$^{-}$
• D. dmg$^{-}$

Answer 1

Answer: (B)

dien

Answer 2

A bidentate ligand has two donor atoms that can coordinate to a central metal atom.

1. dipy (2,2'-bipyridine): It has two nitrogen atoms and acts as a bidentate ligand.
2. dien (diethylenetriamine, NH$_2$CH$_2$CH$_2$NHCH$_2$CH$_2$NH$_2$): It has three nitrogen atoms and acts as a tridentate ligand.
3. gly$^{-}$ (glycinate ion, $^{-}$OOC-CH$_2$-NH$_2$): It has a nitrogen and an oxygen atom and acts as a bidentate ligand.
4. dmg$^{-}$ (dimethylglyoximate ion, CH$_3$-C(=N-O$^{-}$)-C(=N-OH)-CH$_3$): It has two nitrogen atoms and acts as a bidentate ligand.

Therefore, dien does not act as a bidentate ligand.