Polynuclear Metal Complexes Obtained from the Task-Specific Ionic Liquid Betainium Bistriflimide

The task-specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf 2 N], was used to dissolve metal oxides and hydroxides. The crystal structures of the resulting metal betaine bistriflimide complexes exhibit a rich structural variety. A trimeric structure was found for the cobalt(II) compound, [Co 3 (bet) 8 (Hbet) 2 (H 2 O) 2 ][Tf 2 N] 9 [Hbet], a tetrameric structure for the manganese(II) and zinc(II) compound, [Mn 4 (bet) 10 (H 2 O) 4 ][Tf 2 N] 8 and [Zn 4 (bet) 10 (H 2 O) 2 ][Tf 2 N] 8, respectively, a pentameric structure for the nickel(II) compound, [Ni 5 (bet) 12 (H 2 O) 6 ][Tf 2 N] 10, an oxo-hydroxo-cluster formation for the lead(II) compound, [(Pb 4 O)Pb(OH)(bet) 8 (Tf 2 N) 3 ][Tf 2 N] 4 ·MeOH, and a polymeric structure for the silver(I) compound, [Ag 2 (bet) 2 (Tf 2 N)Ag 2 (bet) 2 ][Tf 2 N] 3 . The zwitterionic nature of the betaine ligand and the weakly coordinating ability of the bis(trifluoromethylsulfonyl)imide [Tf 2 N] − anion facilitates the incorporation of metal ions into oligonuclear and polynuclear metal complexes.