Question $3$

$[$Answer All Parts$]$

Part $($a$)$

$[35$ Marks$]$

Using the structures of the clinical diagnostic ${?}^{99m}Tc$ agents Cardiolite and Ceretec shown below:

i$.$ Identify the oxidation sate of both metal ions.

ii$.$ Explain the role of complex charge toward their bio$-$distribution properties.

iii. Contrast their ligand coordination environments with respect to complex stability in vivo.

iv$.$ Using the structure of Ceretec only, predict the possible pharmacokinetic effects of substituting the peripheral methyl group $($shown in red$)$ with the following $R$ groups; acetic $(-C{H}_2\frac{C}{O}OH),$ isopropyl $(-CH(C{H}_3{)}_2),$ and benzyl $(-C{H}_2{C}_6{H}_5).$