Synthesis, structure and property of lanthanide–organic frameworks with pyridyl- and carboxylate-containing ligand

Three new lanthanide–organic frameworks {[La(IP-py)(HIP-py)(H2O)2]·H2O}n (1), {[Sm2(IP-py)2(IP-pyH)2(H2O)2]·12H2O}n (2) and {[Tb3(IP-py)4(IP-pyH)(H2O)5]·9H2O}n (3) have been prepared by reactions of the corresponding lanthanide salt with 5-(isonicotinamido)isophthalic acid (H2IP-py). The complexes have been fully characterized by means of IR, elemental analyses and single-crystal X-ray diffraction. In compounds 1–3, the lanthanide centers are eight- and nine-coordinated with different coordination geometries and the carboxylate groups of the ligand show different coordination modes leading to the formation of different 2D network structures which are well-defined by the bulky and inert functional groups. Interestingly an unprecedented 2D network of water molecules was observed in complex 2. The luminescent properties of complexes 2 and 3 were investigated.