Construction of three new metal-organic frameworks with distinct SBUs: trinuclear {Cd3(COO)6} clusters, inorganic -Cd-O-Cd- chains, and heterometallic trinuclear {Cd2Ba(COO)4} clusters

Abstract

Three metal-organic frameworks (MOFs), [Cd3(OABDC)2(e-urea)4]n (1), [Cd3(OABDC)2(H2O)5)]n (2) and [Cd2Ba(OABDC)2(H2O)7]n (3) (H3OABDC = 5-oxyacetate isophthalic acid, e-urea = 2-imidazolidinone), were prepared using H3OABDC and metal salts. Single-crystal X-ray diffraction analyses reveal that 1 features a 2-D layered structure constructed from trinuclear {Cd3(COO)6} SBUs and represents a (3,6)-connected kgd topology. Compounds 2 and 3 are 3-D inorganic–organic hybrid frameworks; 2 employs infinite inorganic –Cd–O–Cd– chains as SBUs, whereas (3,6)-connected ant-type 3 employs heterometallic trinuclear {Cd2Ba(COO)4} clusters as SBUs. The structures of these three compounds indicate that the SBUs play an important role in the construction of MOFs. Moreover, the thermal stabilities and solid-state photoluminescent properties of these three compounds have also been investigated.