LAUSR

Reaction of NdIII and ErIII nitrate salts with a 1,3,5-tris(dipicolylamine)-triazine (dpat) ligand yielded two unprecedented examples of [Ln(NO3)6/5]3-/2- (Ln = Nd, Er) moieties completely encapsulated by the ligands. They are found in the two new complexes, [(H3dpat)2][(Nd(NO3)6)2]·2CH3CN (1), and the related [(H3dpat)2][(Er(NO3)5)3]·3CH3CN·2H2O (2). The structures of the complexes are similar and they crystallize in the triclinic P-1 space group with a = 12.1630(3), b = 12.2694(3), c = 17.6357(5) Å, V = 2611.10(12) Å3, and a = 14.3372(4), b = 17.1271(4), c = 25.2207(7) Å, V = 5934.7(3) Å3, respectively. Anion-π interactions, which are reported here for the first time for LnIII ion complexes, hydrogen bonding interactions and π-π stacking support the formation of the encapsulated species. Evidence of the protonated dpat ligand in 1 and 2 was found through isolation of (H2dpat)(NO3)2. Finally, the pH-dependent ability of the ligand to extract LaIII and nitrate ions from aqueous into toluene solution is demonstrated.