Question

The IUPAC name of the following complex is
\[ [Co(NH_2CH_2CH_2NH_2)_2Br_2]Br \]

• A. Bis(ethane-1,2-diamine) dibromido cobalt (III) bromide
• B. Di(ethane-1,2-diamine) dibromido cobalt (III) bromide
• C. Tribromido bis(ethane-1,2-diamine) cobalt (III)
• D. Dibromido bis(ethylene diamine) cobalt (III) bromide

Hint:

In coordination compounds, ligands inside the coordination sphere are named first, followed by the metal with oxidation state in Roman numerals, and then the counter ion. For repeated complex ligands like ethylene diamine, use prefixes such as \(bis\), \(tris\), etc.

Answer 1

The Correct Option is D

Step 1: Identify ligands and metal.
The complex [Co(en)\(_2\)Br\(_2\)]Br has Co as metal, two en (ethylenediamine = ethane-1,2-diamine) ligands and two Br\(^-\) as ligands, with one outer Br\(^-\) as counter ion. Co oxidation state: charge = +1 (complex cation) + 2(Br\(^-\) ligands with -1 each), so Co = +3.

Step 2: Apply IUPAC naming rules.
Ligands named alphabetically: bromido (Br\(^-\)) before diamine; use prefix bis for polydentate en. Name inside bracket: dibromido bis(ethylene diamine) cobalt(III). Counter ion: bromide. The correct IUPAC name uses the old accepted name ethylenediamine (option 4). \[ oxed{ ext{Dibromido bis(ethylene diamine) cobalt (III) bromide}} \]