Crystal structure of a new polyoxometalate (POM) compound with a high level of crystallographic disorder

Abstract

The crystal structure, Hirshfeld surface analysis and spectroscopic analysis of a new polyoxometalate (POM) compound, namely, nonakis(2-methoxyaniline) bis(diphosphopentamolybdate) trihydrate, (C 7 H 9 NO) 9 [P 2 Mo 5 O 23 ] 2 Á3H 2 O, is reported. The title compound was synthesized using the solution method and was structurally characterized by single-crystal X-ray diffraction, which revealed P1 symmetry. A study of the intermolecular interactions using Hirshfeld surface analysis confirmed that the hydrogen-bonding interactions play the dominant role in the stability of the crystal structure. The refinement was complicated by extensive disorder affecting 11 of the 16 ions and molecules in the asymmetric unit. IR and UV-Vis spectroscopic techniques were used to identify the vibrational modes and to classify this compound as an insulator.

Supramolecular architecture of a novel non-centrosymmetric heteromolybdate hybrid for nonlinear optical applications: structure, characterization, stability study and DFT calculations

“…The observation of the spectrum records a maximum at 206 nm (ε = 0.041 10 6 mol − 1 .L.cm − 1 ) and a shoulder centred at 230 nm (ε = 0.022 10 6 mol − 1 .L.cm − 1 ). They are assigned respectively to a process of type (LMCT) of (O t →Mo) and (O µ →Mo), where the electrons are promoted from the low-energy electronic states, which are mainly of oxygen 2p orbitals, to the high-energy states, which are mainly of metal d orbitals [50][51][52]. From the graph in Fig.…”

Recent Advances in Confining Polyoxometalates and the Applications

“…[ 8–10 ] The metal ions on the POM framework have empty orbitals, so they can also serve as Lewis acid sites. [ 11–14 ] In short, the unique structure and properties of POMs make them attractive in catalysis, [ 15,16 ] biomedicine, [ 17–19 ] nanotechnology, [ 20,21 ] crystallography, [ 22–24 ] and material science. [ 25,26 ] Nevertheless, the practical application of POMs is greatly limited by their instability and easy‐agglomeration characteristics.…”

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In short, the unique structure and properties of POMs make them attractive in catalysis, [15,16] biomedicine, [17][18][19] nanotechnology, [20,21] crystallography, [22][23][24] and material science. [25,26] Nevertheless, the practical application of POMs is greatly limited by their instability and easy-agglomeration characteristics.Specifically, the structure of POM is labile in aqueous/organic solvents because the polyhedral subunits of POM anion may detach from the skeletons and multiple POM species may form when the solution is in equilibrium.

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