Tetra-μ-oxido-tetrakis{dioxido[3-(2-pyridyl)-1H-pyrazole]molybdenum(VI)}

In the title compound, [Mo4O12(C8H7N3)4], the MoVI ion has a distorted octahedral coordination completed by two terminal O atoms, two μ-oxide atoms and two N atoms from one 3-(2-pyridyl)-1H-pyrazole ligand. It is noteworthy that in the tetranuclear unit ( symmetry), any three MoVI atoms define a plane, and the fourth lies 1.8 (1) Å out of that plane. The degree of linearity of the oxide bridges between two Mo atoms is 175.38 (13)°. Moreover, the N—H group forms an intramolecular hydrogen bond (four per molecule).

In the title compound, [Mo 4 O 12 (C 8 H 7 N 3 ) 4 ], the Mo VI ion has a distorted octahedral coordination completed by two terminal O atoms, two -oxide atoms and two N atoms from one 3-(2pyridyl)-1H-pyrazole ligand. It is noteworthy that in the tetranuclear unit (4 symmetry), any three Mo VI atoms define a plane, and the fourth lies 1.8 (1) Å out of that plane. The degree of linearity of the oxide bridges between two Mo atoms is 175.38 (13) . Moreover, the N-H group forms an intramolecular hydrogen bond (four per molecule).
Financial support from the Natural Science Foundation of China (grant No. 20171028, 20325105), the National Ministry of Science and Technology of China (grant No. 2001CB6105-07) and the Ministry of Education of China, Shandong University, is gratefully acknowledged.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: ZQ2001).

S3. Refinement
All hydrogen atoms bound to carbon were refined using a riding model with C-H = 0.93 Å and U iso = 1.2U eq (C) for aromatic atoms. The H atom on nitrogen was located from difference density maps and was refined with a distance restraint of N-H = 0.97 (1) Å.   The packing diagram of the title compound with the hydrogen bonds of N2-H1A···O2. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq