A hexanuclear cluster based metal-organic framework for Fe3+ sensing

Through assembly of two metal ions (Li+ and Zn2+) 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 ZnLi2(L1)(DMF)(H2O) (DMF = N,N'-dimethylformamide). It should be noted that Li+ and Zn2+ are both involved in coordination, four Li+ and two Zn2+, are connected together through the O atoms of the carboxylate ligand, forming the heteronuclear Li4Zn2 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 Fe3+. (C) 2018 Elsevier B.V. All rights reserved.