Question

Write the IUPAC name of $\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{3}}}\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right){\text{C}}{{\text{l}}_{\text{2}}}} \right]$.

Answer 1

Hint:We can write the name of the complex by using IUPAC rules. According to that, name all the ligands are written in alphabetical order. Then write the name of the metal. The oxidation state of the metal is also shown in the name.

Complete answer:
To write the IUPAC name of coordination compounds some rules are used which are as follows:
1. Write the name of the cation part then the name of the anion part.
2. Write the name of the ligand in alphabetical order.
3. For neutral ligand, the name of the compound is used as such but for water use ‘aqua’ for ammonia use ‘ammine’
4. For anionic ligands replace the,
a. Ide with o.
b. Ate with ato.
c. Ite with ito.
5. Use Greek prefix to denote the number of the ligand. If the name of the ligand has a Greek prefix then use bis for two, tris for three.
6. Write the name of the metal.
7. For the cationic complex, write the metal name as such.
8. For anionic complexes, use the suffix ‘ate’.

The coordination entity $\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{3}}}\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right){\text{C}}{{\text{l}}_{\text{2}}}} \right]$ of platinum metal has one chloride, three ammonia and one water as ligands.

Determine the charge of platinum metal as follows:
Suppose the charge of the platinum metal is x. Charge of chloride is $ - 1$ and the charge of ammonia and water ligands is zero.
\[x + \left( {0 \times 3} \right) + \left( {0 \times 1} \right)\left( { - 1 \times - 2} \right) = 0\]
$x = + 2$
So, the charge on the platinum metal is $ + 2$.
The name of the $\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{3}}}\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right){\text{C}}{{\text{l}}_{\text{2}}}} \right]$ complex is as follows:
The name of the neutral ligand will be written as such, the ammine is ammine and water is named as aqua. Chlorine is named as chloro.
Ammine will come first then aqua followed by chloro and then platinum metal with oxidation state as Diamminedichloroplatinum(II).

Therefore, the IUPAC name of $\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{3}}}\left( {{{\text{H}}_{\text{2}}}{\text{O}}} \right){\text{C}}{{\text{l}}_{\text{2}}}} \right]$ is Triammineaquadichloroplatinum(II).

Note:
The molecules that bind with the central atom are known as ligands. The ligands which donate electron density through negative charge are known as an anionic ligand. The ligands that have lone pairs are known as neutral ligands and the ligands that have positive charge are known as cationic ligands. Amine and aqua both start from the alphabet ‘A’ so, which will come first is decided on the basis of the second letter of the name, not on the basis of the prefix.