Redox-Active Metal-Organic Frameworks with Three-Dimensional Lattice Containing the -Tetrathiafulvalene-Tetrabenzoate.

Metal-organic frameworks (MOFs) constructed by tetrathiafulvalene-tetrabenzoate (HTTFTB) have been widely studied in porous materials, while the studies of other TTFTB derivatives are rare. Herein, the meta derivative of the frequently used -HTTFTB ligand, -HTTFTB, and lanthanide (Ln) metal ions (Tb, Er, and Gd) were assembled into three novel MOFs. Compared with the reported porous Ln-TTFTB, the resulted three-dimensional frameworks, Ln--TTFTB ([Ln(-TTFTB)(-HTTFTB)(HCOO)(DMF)]·2DMF·3HO), possess a more dense stacking which leads to scarce porosity. The solid-state cyclic voltammetry studies revealed that these MOFs show similar redox activity with two reversible one-electron processes at 0.21 and 0.48 V (vs. Fc/Fc). The results of magnetic properties suggested Dy--TTFTB and Er--TTFTB exhibit slow relaxation of the magnetization. Porosity was not found in these materials, which is probably due to the meta-configuration of the -TTFTB ligand that seems to hinder the formation of pores. However, the -TTFTB ligand has shown to be promising to construct redox-active or electrically conductive MOFs in future work.