On the usability of salt metathesis reactions for the synthesis of sterically crowded tris-formamidinate Ln(iii) complexes: success and limits. Spontaneous reduction of Eu(iii) to Eu(ii)

New homoleptic complexes of Eu 3+ and Nd 3+ bearing three bulky N , N ′-bis(diisopropylphenyl)formamidinates were prepared using salt metathesis in a toluene medium. In the presence of THF, the sterically-induced reduction of Eu 3+ to Eu 2+ was observed.