Evidence for increased exchange interactions with 5d compared to 4d metal ions. Experimental and theoretical insights into the ferromagnetic interactions of a series of trinuclear [{M(CN)8}3-/NiII] compounds (M = MoV or WV).

Two main questions are addressed in this study: (i) What increase of exchange interaction can be expected when replacing a paramagnetic metal ion with a heavier congener located farther down the periodic table (i.e., 3d-4d-5d), and (ii) for a molecular unit with higher coordination numbers, eight in the present case, how is the magnetic information transferred from the metal ion to its ligand set? Qualitative and quantitative investigations on a series of trimetallic cyano-bridged {MoV(CN)8-NiII} and {WV(CN)8-NiII} compounds revealed ferromagnetic interactions but with a strength modulated by the spin organization and their nature.