Question #44578

Pure $\beta$-D-glucopyranose ($[\alpha]_D = +18.7^\circ$) is dissolved in an aqueous buffer at 298 K containing a large excess of a transition metal ion, $M^{2+}$. The ion $M^{2+}$ forms a kinetically inert and thermodynamically highly stable chelate complex ($C$, $[\alpha]_D = +120^\circ$) exclusively with the \textit{cis}-1,2-diol system present in $\alpha$-D-glucopyranose ($[\alpha]_D = +112^\circ$). The $\beta$-anomer does not coordinate with $M^{2+}$. Assuming the chelate $C$ remains completely intact, what is the final specific rotation of the carbohydrate species in solution at equilibrium, and what is the observation when this final solution is treated with $Br_2/H_2O$?