A hexanuclear cluster based metal-organic framework for Fe 3+ sensing

Through assembly of two metal ions (Li + and Zn 2+ ) and a quadridentate carboxylate ligand H 4 L1 (5-(bis(4-carboxybenzyl)amino)isophthalic acid), a new metal-organic framework ( HNU-22, HNU is the abbreviation of Hainan University) was successfully constructed with the formula of ZnLi 2 (L1)(DMF)(H 2 O) (DMF = N, N ′-dimethylformamide). It should be noted that Li + and Zn 2+ are both involved in coordination, four Li + and two Zn 2+, are connected together through the O atoms of the carboxylate ligand, forming the heteronuclear Li 4 Zn 2 cluster, which has never been reported in the literature. It is a rod-shaped metal cluster, and the linkage mode is Li-Zn-Li 2 -Zn-Li. When the metal clusters and organic ligands are simplified, HNU-22 can be regarded as a 4,8-connected topology with the flu symbol. Furthermore, HNU-22 shows luminescence sensing property toward Fe 3+.