\b[Nitrogen-bound $\mathrm{Eu{-}NCS}$] is favoured. Eu(III) is a small, highly charged <hard Lewis acid>, whereas the <nitrogen> end of <thiocyanate> is harder than its more polarizable sulfur end. The <hard and soft acids and bases> argument therefore predicts N coordination, together with coordination through both <nitrogen> atoms of each <bipyridine>.

Solution

Past exam of the chemistry course of the year 3 of the natural sciences course of the University of Cambridge / 2021 / Paper 1 / 10 / c / i / Solution

 Solution (source code)