Coordination Compounds

Write the name of the platinum complex used in the treatment of cancer.

Answer:

Cisplatin — [PtCl₂(NH₃)₂]

Explanation:

The platinum complex cisplatin (cis-diamminedichloroplatinum(II)) is an anticancer drug used in chemotherapy.

Its structure contains two ammonia and two chloride ligands in a cis configuration around the platinum(II) center:

It works by binding to DNA and preventing cell division in cancer cells.

The given name is Tetraamminedibromoplatinum(IV) bromide.

Step 1: Identify the ligands and metal oxidation state.
- “Tetraammine” → 4 ligands (neutral).
- “Dibromo” → 2 ligands (inside the coordination sphere).
- “Platinum(IV)” → Metal oxidation state = +4.
- “Bromide” (at the end of the name) → counter anion(s) outside the coordination sphere.

Step 2: Write the partial complex formula:

Step 3: Determine the charge on the complex ion. Let the overall charge on the coordination sphere be . This would be incorrect since Pt(IV) rarely forms +6 complexes. Let’s reconsider the ligand count relative to oxidation state.

In the complex , platinum has oxidation number: Wait — correction: for a **Pt(IV)** ion, the total oxidation number is +4. So, That means two bromides inside (each -1) give the total +4 charge for platinum. The coordination sphere has a net charge of +2.

Therefore, to balance the charge, there must be **two bromide ions** outside the coordination sphere.

Hence, the correct formula is:

Definition:

Ionization isomerism occurs in coordination compounds when two isomers produce different ions in solution, even though they have the same overall composition. This happens due to the exchange of groups between the coordination sphere and the ionization sphere.

Key Idea:

• The ligands inside the coordination sphere may exchange places with counter-ions outside the sphere.
• This leads to compounds with the same formula but different ions in solution.

Example:

Consider the following two complexes:

- The first complex in aqueous solution gives: Hence, it produces ions in solution.

- The second complex in aqueous solution gives: Hence, it produces ions in solution.

Final Answer:

Ionization isomers are coordination compounds that yield different ions in solution. Example: are ionization isomers.

Step 1: Structure of EDTA.

EDTA stands for Ethylenediaminetetraacetic acid. Its formula is:

Step 2: Possible donor atoms.

In the deprotonated form ( ), EDTA has:

• Two nitrogen atoms (–NH– groups) with lone pairs
• Four oxygen atoms from carboxylate groups (–COO )

Step 3: Total donor atoms.

Therefore, EDTA can coordinate to a metal ion through

Step 4: Conclusion.

EDTA acts as a hexadentate ligand (capable of binding through six donor atoms).

Final Answer:

Number of donor atoms in EDTA =