Sources of Naked Divalent First-Row Metal Ions: Synthesis and Characterization of [MII(NCMe)6]2+ (M=V, Cr, Mn, Fe, Co, Ni) Salts of Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate

Chemically facile loss of MeCN ligands in [MII(NCMe)6][TFPB]2 {M=V, Cr, Mn, Fe, Co, Ni; [TFPB]−=tetrakis[3,5-bis(trifluoromethyl)phenyl]borate} leads to an excellent source of “naked” divalent first-row metal ions. These salts are thermally stable up to 130 °C (figure). Loss of the first MeCN leads to an η2 nitrile. From an analysis of the ligand field parameters MeCN is a stronger field ligand than H2O, but slightly weaker than NH3.