Stepwise formation of cyclodimer and cage via decomposition of hexafluorophosphate anion. Structures and related properties of (2,2′-bipyridine)palladium(II) complexes of 1,3,5-tris(nicotinoyloxyethyl)cyanurate

Reaction of (bpy)Pd(PF6)2 (bpy = 2,2′-bipyridine) with new tridentate ligand 1,3,5-tris(nicotinoyloxyethyl)cyanurate (L) followed by slow evaporation of solvents allows to form amorphous microspheres consisting of [(bpy)Pd(L)]2(PF6)4 without any template or additive. Recrystallization of amorphous microspheres yields, after three weeks, single crystals consisting of [(bpy)3Pd3(μ3-HPO4)(L)](PF3(OH)3)·3F. Formation of the crystalline product can be induced from the decomposition of the PF6− anions. Alternatively, direct reactions of (bpy)Pd(PF6)2 with L in the presence of Na2HPO4 or Na2HAsO4 under reflux conditions produce the same single crystals in the form of cage molecules, [(bpy)3Pd3(μ3-HPO4)(L)](PF3(OH)3)·3F and [(bpy)3Pd3(μ3-HAsO4)(L)](PF3(OH)3)·3F, respectively.