Question 10

The complex is $[M(NCS)(NO_2)(gly)]^-$.

1. Linkage Isomerism: Both $NCS^-$ and $NO_2^-$ are ambidentate ligands. Possible combinations of coordination sites:

• $(N-CS, N-O_2)$
• $(S-CN, N-O_2)$
• $(N-CS, O-NO)$
• $(S-CN, O-NO)$ There are 4 such linkage combinations.

2. Geometrical Isomerism: For each linkage combination, the complex is of the type $[M(A)(B)(C-D)]$, where $C-D$ is the unsymmetrical bidentate glycinate ligand ($NH_2-CH_2-COO^-$). In a square planar geometry, the bidentate ligand occupies cis positions. The two monodentate ligands $A$ and $B$ can be arranged in 2 ways:

• $A$ trans to $N$ (of gly), $B$ trans to $O$ (of gly)
• $B$ trans to $N$ (of gly), $A$ trans to $O$ (of gly)

Total isomers = (4 linkage combinations) $\times$ (2 geometrical isomers) = 8.