Two Compounds Constructed from Bimolybdenum-Capped Sandwich-Type Tetra-Ni-molybdogermanate and N‑Donor Multidentate Ligand

Two
organic–inorganic hybrid bimolybdenum-capped tetra-NiII sandwich-type molybdogermanates, namely, (H2L)4[Ni4(H2O)2­{B-α-GeMo9O34 (MoO2)}2]·6H2O (1), [Ni2(HL)4(H2O)2]­[Ni4(H2O)2­{B-α-GeMo9O34(MoO2)}2]·12H2O (2), L = 2,4,5-tri­(4-pyridyl)­imidazole,
were prepared with hydrothermal synthesis method and characterized
by elemental analysis, IR spectroscopy, powder X-ray diffraction,
thermogravimetric analysis, and single-crystal X-ray diffraction.
Their magnetic properties and electrochemical properties were investigated.
The results show that compounds 1 and 2 contain
a new bimolybdenum-capped sandwich-type heteropolymolybdate anion,
[Ni4(H2O)2­{B-α-GeMo9O34(MoO2)}2]8–. The compound 1 is a zero-dimensional supramolecular
compound, and the supramolecular architecture of compound 2 is constructed from covalent layers through hydrogen bonds and π–π
interaction. The two compounds both present electrocatalytic activities
for the reduction of nitrite.