Q.The square planar complex $[\text{Pt}(\text{NH}_3)_2\text{Cl}_2]$ exists as cis and trans geometrical isomers. Describe the arrangement of ligands in each isomer, state which one has a net dipole moment, and name the well-known anticancer drug that corresponds to the cis isomer.

[!TLDR] Cis: NH$_3$/Cl adjacent (90 degrees), net dipole; trans: opposite (180 degrees), zero net dipole. [!ANSWER] Cis-[Pt(NH3)2Cl2] = cisplatin (anticanc …

$[\text{Pt}(\text{NH}_3)_2\text{Cl}_2]$ is a square planar, $\text{MA}_2\text{B}_2$-type complex, and two geometrical isomers are possible. In the cis isomer, the two $\text{NH}_3$ ligands occupy adjacent corners of the square (bond angle $90^{\circ}$ between them), and the two $\text{Cl}^-$ ligands likewise occupy the other two adjacent corners. This asymmetric arrangement means the bond dipoles do not cancel, giving the cis isomer a net molecular dipole moment. In the trans isomer, the two $\text{NH}_3$ ligands occupy diametrically opposite corners ($180^{\circ}$ apart), and the two $\text{Cl}^-$ ligands occupy the other opposite pair; here the higher symmetry means the two Pt-N bond dipoles cancel exactly against each other, and separately the two Pt-Cl bond dipoles cancel exactly against each other, giving the trans isomer zero net dipole moment. This particular cis isomer, cis-$[\text{Pt}(\text{NH}_3)_2\text{Cl}_2]$, is the well-known anticancer drug cisplatin, which binds to and cross-links DNA within rapidly dividing tumour cells, disrupting their replication; i …

For a square planar $\text{MA}_2\text{B}_2$ complex, place identical ligands either adjacent (cis, 90°) or opposite (trans, 180°); assess symmetry to determine whethe …

Assuming cis and trans platinum complexes are pharmacologically interchangeable since they share the identical molecular formula — geometrical isomers can have dramatically d …