Synthesis, Structure and Hirshfeld Surface Analysis of A New Decavanadate Compound: Na ₂[H ₄V ₁₀O ₂₈]·14H ₂O

Abstract

Objective:

The synthesis and structural study of a new acid decavanadate compound with a monovalent inorganic cation. This compound makes a contribution to inorganic decavanadate family.

Methods:

The synthesis of the compound was carried out by evaporation at room temperature. Good quality crystals were chosen for single crystal x-ray diffraction using a polarizing microscope. Hirshfeld surface analysis, in particular dnorm surface and fingerprint plots, is used to decode intermolecular interactions in the structure of the studied decavanadate compound.

Results:

A new acid decavanadate compound, Na₂[H₄V₁₀O₂₈]·14H₂O, was synthesized and characterized by single crystal X-ray diffraction. The decavanadate compound crystallizes in the triclinic system and the cell parameters are: a=11.282(5) Å, b=10.424(3) Å, c=8.502(1) Å, α=112.81(2)°, β=87.25(2)°, γ=111.49(5)°, V=852.4(5) Å3 and Z=2. The formula unit of Na₂[H₄V₁₀O₂₈]·14H₂O compound is formed by an acidic decavanadate group [H₄V₁₀O₂₈]^2-, a Na₂(H₂O)10²⁺ dimer and four molecules of water. The decavanadate group is formed by ten distorted VO₆ octahedra interconnected by edge sharing. Decavanadate groups [H₄V₁₀O₂₈]^2-, the Na₂(H₂O)10²⁺ dimers and the water molecules stack in layers parallel to the (010) plane. The cohesion of the structure is ensured by hydrogen bonds and van der Waals interactions. The study of the Hirshfeld surface shows that O…H/H…O and H…H interactions dominate the structure.

Conclusion:

A novel synthesized decavanadate compound decorated by inorganic cations is reported and studied by X-ray diffraction. The cohesion is assured by: O-H…O hydrogen bonds and van der Waals interactions. The Hirshfeld surface analysis confirms the presence of O…H/H…O and H…H contacts in the structure.

Main article text

1 INTRODUCTION

Polyoxometalates (POM) are oxo clusters of transition metal ions, such as Mo, W, V, Nb, and Ta, forming a variety of structures. POMs have different sizes and shapes which may allow for the inclusion of other anions. In the structure of POMs, one or more of the metal oxoanions can be substituted^[1–3].

Polyoxometalates (POM) have potential applications in various fields of science and technology, catalytic, magnetic, and electrochemical, in light of their properties such as thermal stability, redox activity, solubility in polar and non-polar solvents^[4,5]. POMs have dominated medicinal chemistry for their intriguing antiviral and anti-tumor activities. Among the POMs, polyoxovanadate compounds (POVs) are known for their extensive applications in several fields such as chemical, physical and biological sciences. Vanadium plays an important role in biological systems and biochemistry^[6,7]. Although POVs generally contain vanadium in the +5 oxidation state, recent reports have described POVs with two oxidation states, V(IV) and V(V). Several decavanadate compounds are stable under physiological conditions. The stability of POV under the given experimental conditions requires due consideration in the research on the effects of POV^[1,8].

Decavanadate compounds are formed in the pH range 6-8 and show a potential interest in several fields such as catalysis, nanotechnology, electrochemistry, materials science, anticancer, antibacterial and antiviral activity^[1,8–10]. In the present work, we will focus on the synthesis, structure and Hirshfeld surface analysis of a new decavanadate compound: Na₂[H₄V₁₀O₂₈]·14H₂O.

2 EXPERIMENTAL

2.1 Materials and Measurements

All solvents and reagents were obtained from commercial sources and used without further purification.

2.2 Synthesis of Na₂[H₄V₁₀O₂₈]·14H₂O Compound

The compound Na₂[H₄V₁₀O₂₈]·14H₂O was obtained from a mixture of 0.6 g of V₂O₅ (99.99%, FLUKA) and 0.5 g of NaVO₃ (Prolabo, 98%) in 100 mL of pure water. The mixture obtained was placed under magnetic stirring and heating for approximately 2 hours. After five days of slow evaporation at room temperature, orange good quality crystals were obtained.

2.3 Hirshfeld Surface Study

Hirshfeld surfaces (HS) were constructed to represent the asymmetric unit of the compound and the analysis was performed using the Crystal-Explorer program^[11].

2.4 X-ray Crystallography

An Enraf-Nonius CAD4^[12] 4-circle diffractometer was used to collect the diffracted intensities (λ = 0.71067 Å). The resolution of the structure was performed by the direct method using the SHELXS-97^[13] program and the refinement was performed by the least-squares method using SHELXL-2014^[14]. Hydrogen atoms were attached using the HFIX instruction. The absorption correction was performed by psi-scan^[15]. All the figures of the structure have been represented by the DIAMOND software^[16].

Crystal data, data collection, and structural refinement details are summarized in Table 1.

Table 1.

Crystallographic Characteristics, X-ray Data Collection, and Structure-Refinement Parameters of Na₂[H₄V₁₀O₂₈]·14H₂O Compound

Crystal Data
Chemical formula	Na2[H4V10O28]·14H2O
Formula weight (g;mol−1)	1263.67
Crystal system, space group	Triclinic, P-1
T (K)	298(2)
a b c (Å)	11.282(5), 10.424(3), 8.502(1)
α, β, γ (°)	112.81(2), 87.25(2), 111.49(5)
V(Å3)	852.4(5)
Z	2
Radiation λ (Å)	MoKα 0.71073
Crystal size (mm3)	0.68×0.54×0.39
μ (mm−1)	2.771
F(000)	682
Data Collection
Diffractometer	Enraf-Nonius CAD4
Absorption correction	Ψ-scan
Tmin,Tmax	0.181,0.339
Range for data collection (°)	2.3≤θ≤ 27
h, k, l ranges	-14≤ h ≤14, -12≤ k ≤13, -10≤ l ≤1
Scan mode	ω/2θ
No. of measured, independent, and observed	4205, 3713, 3304
[I >2σ(I)] reflections
Rint	0.016
Refinement
R1 [F2 > 2 σ (F2)]	0.033
wR2(F2)	0.1
S	1.09
No. of parameters	301
Maximum residual electron density Δρmax (e.Å−3)	0.642
Minimum residual electron density Δρmin (e.Å−3)	-0.705

3 RESULTS AND DISCUSSION

3.1 Crystal Structure

The formula unit of Na₂[H₄V₁₀O₂₈]·14H₂O compound was formed by an acidic decavanadate group [H₄V₁₀O₂₈]^2-, a Na₂(H₂O)₁₀ ²⁺ dimer, and four molecules of water. The structure of the decavanadate group [V₁₀O₂₈]^6- is formed by ten VO₆ octahedra interconnected by sharing of edges^[17,18](Figure 1).

Figure 1.

Formula unit of Na₂[H₄V₁₀O₂₈]·14H₂O compound.

The projection, according to c, of the structure of the compound Na₂[H₄V₁₀O₂₈]·14H₂O shows that the decavanadate groups [H₄V₁₀O₂₈]^2-, the Na₂(H₂O)₁₀ ²⁺ dimers, and the water molecules stack in layers parallel to the (010) plane (Figure 2).

Figure 2.

(A) Projection of the structure of Na₂[H₄V₁₀O₂₈]·14H₂O compound according to the caxis, (B) Decavanadate group, (C) Na₂(H₂O)₁₀ ²⁺dimer.

The cohesion of the structure is ensured by O-H…O hydrogen bonds and van der Waals interactions (Figure 3). These bonds are weak according to Brown’s criterion^[19] (Table 2). The comparison of the studied structure with the two structures (NH₄)₄Li₂[V₁₀O₂₈]·10H₂O and Na_5.22Li_0.78[V₁₀O₂₈]·20H₂O: studied by KSIKSI et al.^[18,20], shows that sodium and lithium form dimers in the structure studied and the compound (NH₄)₄Li₂[V₁₀O₂₈]·10H₂O. The cohesion in these two structures is ensured only by hydrogen bonds and van der Waals interactions. In the structure of Na_5.22Li_0.78[V₁₀O₂₈]·20H₂O, sodium forms infinite chains. The cohesion of the decavanadate structure Na_5.22Li_0.78[V₁₀O₂₈]·20H₂O is ensured by the pooling of oxygen vertices, ridges and vertices, and by van der Waals interactions. Sodium forms chains, interconnected by the pooling of vertices, edges and faces. These strong bonds can provide better stability to decavanadates compounds, which encourages the synthesis of decavanadates compounds containing sodium.

Figure 3.

Cohesion of the structure by O-H…Ohydrogen bonds.

Table 2.

Hydrogen Bonds of Na₂[H₄V₁₀O₂₈]·14H₂O Compound

D—H…A	d(D—H)	d(H…A)	d(D…A)	<D—H…A>
O20-H5…O13	0.901	1.902	2.800	173.97
O15-H15A…O1	0.776	2.114	2.719	135.00
O15-H15A…O6i	0.776	2.168	2.665	122.37
O15-H15A…O8i	0.776	2.268	2.682	114.28
O15-H15A…O11	0.776	2.299	2.668	110.16
O16-H16A…O8ii	0.873	2.203	3.040	160.52
O16-H16B…O15iii	0.811	2.048	2.853	172.50
O17-H17A…O2	0.813	2.058	2.866	172.12
O17-H17B…O11	0.848	1.987	2.829	172.09
O18-H18A…O1iii	0.769	2.252	2.954	152.11
O18-H18A…O10iv	0.769	2.539	3.110	132.27
O18-H18B…O9	0.869	2.039	2.869	159.32
O19-H19A…O3	0.888	1.914	2.799	174.07
O19-H19B…O8iv	0.871	2.306	2.979	134.05
O19-H19B…O10iv	0.871	2.310	3.054	143.32
O20-H20A…O12v	0.860	2.248	2.982	143.22
O21-H21A…O14vi	1.063	2.187	3.222	164.03
O21-H21B…O11	0.909	2.490	3.079	122.83
O21-H21B…O13I	0.909	2.336	3.093	140.60
O21-H21B…O15i	0.909	2.341	3.161	150.04
O22-H22A…O2	0.855	2.485	3.031	122.49
O22-H22A…O7vii	0.855	2.126	2.863	144.07
O22-H22B…O3	0.884	2.440	3.038	125.43
O22-H22B…O10iv	0.884	2.255	2.924	132.32

Symmetry codes : i: -x+1, -y+1, -z+1, ii: x+1, y+1, z+1, iii: x, y+1, z+1, iv: -x+1, -y+2, -z+1, v: -x+2, -y+2, -z+2, vi: x-1, y-1, z, vii: -x+1, -y+1, -z.

3.2 Hirshfeld Surface Analysis of Na₂[H₄V₁₀O₂₈]·14H₂O

The Hirshfeld surface of the decavanadate compound studied in normal mode d_norm is shown in Figure 4A. This figure shows that the main interactions are between the surfaces H…H and O…H/H…O^[21,22]. The structure of the compound Na₂[H₄V₁₀O₂₈]·14H₂O is dominated by the interactions O…H/H…O (59.5 ℅), H…H (14.9 ℅), and V…O/O…V contacts (11.8 ℅) (Figures 4 A, B and C). The O…O contacts represent 9.3 ℅.

Figure 4.

Hirshfeld surface and fingerprint plot of Na₂[H₄V₁₀O₂₈]·14H₂O compound

4 CONCLUSION

A new compound decavanadate, Na₂[H₄V₁₀O₂₈]·14H₂O, was synthesized by slow evaporation at room temperature. The structure is formed by the decavanadate groups, Na₂(H₂O)₁₀ ²⁺ dimers, and water molecules. The cohesion of the structure is ensured by hydrogen bonds and van der Waals interactions. The study of the HS surface shows that the structure is dominated by O…H/H…O, H…H and V…O/O…V contacts.

Acknowledgments

Financial support from the Ministry of Higher Education and Scientific Research of Tunisia is gratefully acknowledged. This work is done as part of a federated research project under the code PRF2019-D3P2.

Conflicts of Interest

There is no conflict of interest between the authors of this article.

Author Contribution

Ksiksi R wrote the manuscript; Ksiksi R and Nasri R performed the data curation; Graia M reviewed the article, and Zid MF supervised the project.

Abbreviation List

T, Temperature

A, b, c, α, β, γ, Cells

V, Volume

Μ, Absorption coefficient

T, Absorption transmission factor

R, Reliability factors

F(000), Structure factor

Dnorm, Normalized contact distance

References

1. Aureliano M, Gumerovac NI, Sciortino G, et al.. Polyoxovanadates with emerging biomedical activities. Coordin Chem Rev. 2021. Vol. 447:214143. [Cross Ref]

2. Pope MT, Müller A. Polyoxometalate Chemistry: An Old Field with New Dimensions in Several Disciplines. Angew Chem Int Edit. 1991. Vol. 30:34–48. [Cross Ref]

3. Hayashi Y. Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects. Coordin Chem Rev. 2011. Vol. 255:2270–2280. [Cross Ref]

4. Čolović MB, Lacković M, Lalatović J, et al.. Polyoxometalates in Biomedicine: Update and Overview. Curr Med Chem. 2020. Vol. 27:362–379. [Cross Ref]

5. Chermann JC, Raynaud M, Jasmin C, et al.. Powerful new inhibitor of murine leukaemia and sarcoma viruses. Nature. 1970. Vol. 227:173–174. [Cross Ref]

6. Ksiksi R, Abdelkafi-Koubaa Z, Mlayah-Bellalouna S, et al.. Synthesis, structural characterization and antitumoral activity of (NH₄)4Li₂V₁₀O₂₈·10H₂O compound. J Mol Struct. 2021. Vol. 1229:129492. [Cross Ref]

7. Casan-Pastor N, Gomez-Romero P. Polyoxometalates: from Inorganic Chemistry to Materials Science. Front Mol Biosci. 2004. Vol. 9:1759–1770. [Cross Ref]

8. Louati M, Ksiksi R, Elbini-Dhouib I, et al.. Synthesis, structure and characterization of a novel decavanadate, Mg(H₂O)6(C₄N₂H₇)4V₁₀O₂₈·4H₂O, with a potential antitumor activity. J Mol Struct. 2021. Vol. 1242:130711. [Cross Ref]

9. Ksiksi R, Jendoubi I, Chebbi H, et al.. Synthesis, characterization, and crystal structure of a novel decavanadate Mg(H₂O)6(C₆H₁₄N₂)2V₁₀O₂₈·8H₂O. J Struct Chem+. 2021. Vol. 62:1243–1250. [Cross Ref]

10. Wolff SK, Grimwood DJ, McKinnon JJ, et al.. Crystal Explorer, Université de Western Australia. 2012

11. Wolff SK, Greenwood DJ, McKinnon JJ, et al.. Crystal Explorer 3.1. University of Western Australia. 2012

12. , CAD4 software. Version 5.0. Enraf-Nonius. Delft. The Netherlands: 1989

13. Sheldrick GM. A short history of SHELX. Acta Crystallogr A. 2008. Vol. 64:112–122. [Cross Ref]

14. Sheldrick GM. Crystal structure refinement with SHELXL. Acta Crystallogr C. 2015. Vol. 71:3–8. [Cross Ref]

15. North ACT, Phillips DC, Mathews FS. A semi-empirical method of absorption correction. Acta Crystallogr A. 1968. Vol. 24:351–359. [Cross Ref]

16. Brandenburg K. DIAMOND. Crystal Impact GbR. Germany: 2006

17. Sánchez-Lara E, Treviño S, Sánchez-Gaytán BL, et al.. Decavanadate salts of cytosine and metformin: a combined experimental-theoretical study of potential metallodrugs against diabetes and cancer. Front Chem. 2018. Vol. 6:1–18. [Cross Ref]

18. Ksiksi R, Graia M, Driss A, et al.. Décavanadate sel double de dilithium et tétraammonium décahydrate, (NH₄)4Li₂ [V₁₀O₂₈]·10H₂O. Acta Crystallogr E. 2004. Vol. 60:i105–i107. [Cross Ref]

19. Brown ID. On the geometry of O—H…O hydrogen bonds. Acta Crystallogr A. 1976. Vol. 32:24–31. [Cross Ref]

20. Ksiksi R, Graia M, Jouini T. Sel mixte de lithium et de sodium eicosahydrate, Na_5.22Li₀·78[V₁₀O₂₈]·20H₂O. Acta Crystallogr E. 2005. Vol. 61:i177–i179. [Cross Ref]

21. Aissa T, Ksiksi R, Elbini-Dhouib I, et al.. Synthesis of a new vanadium complex (V), hexa [4-methylimidazolium] decavanadate trihydrate (C₄H₇N₂) ₆V₁₀O₂₈·3H₂O: Physico-chemical and biological characterizations. J Mol Struct. 2021. Vol. 1236:130331. [Cross Ref]

22. Moussa OB, Chebbi H, Zid MF. Synthesis, crystal structure, vibrational study, optical properties and Hirshfeld surface analysis of bis (2, 6-diaminopyridinium) tetrachloridocobaltate (II) monohydrate. J Mol Struct. 2019. Vol. 1180:72–80. [Cross Ref]