Self-assembly of 2D zinc metal–organic frameworks based on mixed organic ligands

Abstract Self-assembly of Zn(NO 3 ) 2 ·6H 2 O, 5-amino-2,4,6-triiodoisophthalic acid (H 2 atiip) and 4,4′-bipyridine (bpy) or 1,3-di(4-pyridyl)propane (dpp) gave rise to three unusual zinc metal–organic frameworks, Zn 2 (bpy) 2 (atiip) 2 ·3H 2 O·2dmf ( 1 ), Zn 8 (dpp) 8 (atiip) 8 ·4H 2 O ( 2 ), Zn(dpp)(atiip)·(dmf)·(H 2 O) ( 3 ). All complexes possess 2D layer frameworks constructed from 1D Zn-carboxylate tubular unit for 1 , 1D Zn-carboxylate helical chain for 2 and 3 . In 1 and 2 , the bpy or dpp act as both bridging and blocking ligands and the blocking ligands play an important role in the formation of the 2D layer frameworks. Both 2 and 3 contain two different large metallomacrocycles. Photoluminescence measurements of 1 – 3 in the solid state at room temperature show that all complexes exhibit luminescence, which can be assigned to an intraligand π → π ∗ transition or ligand-to-metal charge transfer (LMCT).