Write an equation for reaction 1, using $[\text{H}]$ to indicate the reducing agent.
Suggest a reagent that would be suitable for reaction 1.
State the mechanism for reaction 2.
Valine and glycine, $\text{H}_2\text{NCH}_2\text{COOH}$, make the tripeptide Gly-Val-Gly. Draw the structure of this tripeptide. Show the peptide bonds fully displayed.
Valine exists as two stereoisomers. Draw three-dimensional diagrams to show the two stereoisomers of valine. In your diagrams, the $-\text{CH}(\text{CH}_3)_2$ group can be represented by -R. State the type of stereoisomerism shown.
Valine is an amino acid. Draw valine in zwitterion form.
Valinate, $\text{Val}^-$, is the anion of valine. It participates in a ligand substitution reaction with hexaaquanickel(II) ions, and complex $Z$ is produced. $\left[\text{Ni}(\text{H}_2\text{O})_6\right]^{2+}(aq) + 2\text{Val}^-(aq) \rightleftharpoons \left[\text{Ni}(\text{H}_2\text{O})_2(\text{Val})_2\right](aq) + 4\text{H}_2\text{O}(l)$. Write an expression for $K_{\text{stab}}$ for this equilibrium.
At room temperature, the numerical value of $K_{\text{stab}}$ is $2.34 \times 10^5$. Explain what this value shows about the equilibrium and the stability of complex $Z$.
$Z$ is an octahedral complex with formula $\left[\text{Ni}(\text{H}_2\text{O})_2(\text{Val})_2\right]$. Use this information to state the type of ligand that the valinate ion is acting as in this complex.
Valinate, $\text{Val}^-$, is the anion of valine and it undergoes ligand substitution with hexaaquanickel(II) ions to form complex $Z$. $$[\text{Ni}(\text{H}_2\text{O})_6]^{2+}(aq) + 2\text{Val}^-(aq) \rightleftharpoons [\text{Ni}(\text{H}_2\text{O})_2(\text{Val})_2](aq) + 4\text{H}_2\text{O}(l)$$ Write an expression for $K_{\text{stab}}$ for this equilibrium.
At room temperature, the numerical value of $K_{\text{stab}}$ is $2.34 \times 10^5$. Explain what this value shows about the equilibrium and the stability of complex $Z$.
$Z$ is an octahedral complex with formula $[\text{Ni}(\text{H}_2\text{O})_2(\text{Val})_2]$. Use this information to state the type of ligand that the valinate ion is acting as in this complex.