Question

Draw all geometrical and linkage isomers of square planar \(\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2}(\mathrm{SCN})_{2}\)

Short answer

There are four isomers for the square planar complex \(\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2}(\mathrm{SCN})_{2}\): 1. Cis isomer with both thiocyanate ligands S-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{S}\mathrm{CN})_{2}\) 2. Cis isomer with both thiocyanate ligands N-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{N}\mathrm{CS})_{2}\) 3. Trans isomer with both thiocyanate ligands S-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{S}\mathrm{CN})_{2}\) 4. Trans isomer with both thiocyanate ligands N-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{N}\mathrm{CS})_{2}\)

Step-by-step solution

Identify the central atom and ligands

In this square planar complex, the central atom is Platinum (Pt), and there are two types of ligands: ammine (NH3) and thiocyanate (SCN).

Draw the square planar complex

The initial complex consists of Platinum (Pt) surrounded by the ligands in a square planar arrangement. There are two ammine ligands and two thiocyanate ligands.

Determine the possible geometrical isomers

Geometrical isomers are formed when the ligands are arranged differently around the central atom. In this case, there are two possibilities: 1. The ammine ligands are adjacent to each other (cis isomer). 2. The ammine ligands are opposite each other (trans isomer).

Draw the geometrical isomers

For the square planar complex with the given formula, we have two geometrical isomers: 1. Cis isomer: The ammine ligands are adjacent to each other and the thiocyanate ligands are opposite each other in the square plane.  2. Trans isomer: The ammine ligands are opposite to each other and the thiocyanate ligands are also opposite each other in the square plane. 

Determine the possible linkage isomers

Linkage isomers arise from different sites of attachment of ligands. In thiocyanate (SCN), there are two possible sites of attachment: sulfur (S) or nitrogen (N). Thus, the thiocyanate ligand can create two linkage isomers: S-bound or N-bound.

Draw the linkage isomers for cis and trans isomers

Here are the possible linkage isomers for the cis and trans geometrical isomers: - Cis isomer: 1. Cis - Both thiocyanate ligands are S-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{S}\mathrm{CN})_{2}\) 2. Cis - Both thiocyanate ligands are N-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{N}\mathrm{CS})_{2}\) - Trans isomer: 1. Trans - Both thiocyanate ligands are S-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{S}\mathrm{CN})_{2}\) 2. Trans - Both thiocyanate ligands are N-bound: \(\mathrm{Pt}(\mathrm{NH}_{3})_{2}(\mathrm{N}\mathrm{CS})_{2}\) So, there are a total of four isomers for the given square planar complex: two geometrical isomers with each having two linkage isomers.