Complete Table 4.1 by suggesting formulae for $X$ and $Y$.
Draw three-dimensional diagrams of the two stereoisomers of $[\text{Ru(bipy)}_3]^{3+}$. In your structures, use N-N to represent the bipy ligand.
Suggest how pyrazine can bond to two different ruthenium ions.
Pyrazine is an aromatic compound, and its bonding and structure resemble those of benzene. Describe and explain the shape of pyrazine. In your answer, include the hybridisation of the carbon and nitrogen atoms and how orbital overlap forms $\pi$ bonds between the atoms in the ring.
Predict how many peaks appear in the carbon-$13$ NMR spectrum of pyrazine. Explain your answer.
The overall charge of the ruthenium complex in Fig. 4.1 is $5+$. Deduce the likely oxidation states of the two ruthenium ions in the complex.
OsO$_4$ reacts with alkenes in much the same way as cold dilute acidified MnO$_4^-$. Fig. 4.2 shows a proposed synthesis of a condensation polymer $G$. Suggest a reagent for step $1$.
Draw the structure of one repeat unit of the condensation polymer $G$ only. Show the ester linkage in full.