Crystallogeny and photobehavior of supramolecular aggregates based on Nd(III)-binicotinate sheets: Toward the effect of 4,4′-bipyridine

By the hydrothermal reactions of Nd2O3 with 2,2′-binicotinic acid (H2Bn) in the absence and presence of 4,4′-bipyridine(4,4′-bpy), two complexes, [Nd2(Bn)3(H2O)2]·4.5H2O (1) and [Nd2(Bn)3(H2O)2]·2H2O(4,4′-bpy) (2) were synthesized, of which the 4,4′-bpy-free 1 shows only the emissions based on Bn2 − within 300–500 nm, but the 4,4′-bpy-containing 2 shows also a band centered at 640 nm attributable to the exciplex [(4,4′-bpy)·Bn2 −]* coupled through π–π interaction.