A Metal–Organic Framework Based on a Nickel Bis(dithiolene) Connector: Synthesis, Crystal Structure, and Application as an Electrochemical Glucose Sensor

Functionalizing
the redox-active tetrathia­fulvalene (TTF)
core with groups capable of coordination to metals provides new perspectives
on the modulation of architectures and electronic properties of organic–inorganic
hybrid materials. With a view to extending this concept, we have now
synthesized nickel bis­(dithiolene-dibenzoic acid), [Ni­(C2S2­(C6H4COOH)2)2], which can be considered as the inorganic analogue of the
organic tetrathiafulvalene-tetrabenzoic acid (H4TTFTB).
Likewise, [Ni­(C2S2­(C6H4COOH)2)2] is a redox-active linker for
new functional metal–organic frameworks, as demonstrated here
with the synthesis of [Mn2{Ni­(C2S2­(C6H4COO)2)2}­(H2O)2]·​2DMF, (1, DMF = N,N-dimethylformamide). 1 is isomorphic to
the reported [Mn2(TTFTB)­(H2O)2] (2) but is a better electrochemical glucose sensor due to the
multiple oxidation–reduction states of the [NiS4] core, which allow glucose to be oxidized to glucolactone by the
high oxidation state [NiS4] center. As a non-enzymatic
glucose sensor, 1 on Cu foam (CF), 1-CF, was synthesized by a one-step hydrothermal method and
exhibited an excellent electrochemical performance. The fabricated 1-CF electrode offers a high sensitivity of 27.9 A M–1 cm–2, with a wide linear detection range from
2.0 × 10–6 to 2.0 × 10–3 M, a low detection limit of 1.0 × 10–7 M
(signal/noise = 3), and satisfactory stability and reproducibility.