Tetrakis(2,6-di­methyl­pyridinium) di­hydrogen deca­vanadate dihydrate

Erik Rakovský; Lukáš Krivosudský

doi:10.1107/S1600536814011118

. 2014 May 21;70(Pt 6):m225–m226. doi: 10.1107/S1600536814011118

Tetrakis(2,6-dimethylpyridinium) dihydrogen decavanadate dihydrate

Erik Rakovský ^a,^*, Lukáš Krivosudský ^a

PMCID: PMC4051003 PMID: 24940209

Abstract

The structure of the title compound, (C₇H₁₀N)₄[H₂V₁₀O₂₈]·2H₂O, was solved from a non-merohedrally twinned crystal (ratio of twin components ∼0.6:0.4). The asymmetric unit consists of one-half decavanadate anion (the other half completed by inversion symmetry), two 2,6-dimethylpyridinium cations and one water molecule of crystallization. In the crystal, the components are connected by strong N—H⋯O and O—H⋯O hydrogen bonds, forming a supramolecular chain along the b-axis direction. There are weak C—H⋯O interactions between the chains.

Related literature

For our previously published research on polyoxidovanadates, see: Rakovský & Gyepes (2006 ▶); Pacigová et al. (2007 ▶); Klištincová et al. (2008 ▶, 2010 ▶); Bartošová et al. (2012 ▶). For more general background to their applications, see: Crans (1998 ▶); Hagrman et al. (2001 ▶). Other decavanadates with pyridinium derivatives as the cations have been reported by Asgedom et al. (1996 ▶); Arrieta et al. (1988 ▶); Santiago et al. (1988 ▶). For IR spectra interpretation, see: Ban-Oganowska et al. (2002 ▶); Elassal et al. (2011 ▶); Medhi & Mukherjee (1965 ▶). For hydrogen-bond criteria, see: Jeffrey (1997 ▶). graphic file with name e-70-0m225-scheme1.jpg

Experimental

Crystal data

(C₇H₁₀N)₄[H₂V₁₀O₂₈]·2H₂O
M _r = 1428.09
Monoclinic,
a = 24.7777 (5) Å
b = 8.35654 (16) Å
c = 25.0089 (6) Å
β = 113.878 (3)°
V = 4735.0 (2) Å³
Z = 4
Mo Kα radiation
μ = 1.98 mm⁻¹
T = 293 K
0.41 × 0.22 × 0.08 mm

Data collection

Oxford Diffraction Gemini R diffractometer
Absorption correction: gaussian (CrysAlis PRO; Agilent, 2014 ▶) T _min = 0.575, T _max = 0.873
59285 measured reflections
5867 independent reflections
5086 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.084
S = 1.08
5867 reflections
344 parameters
6 restraints
H atoms treated by a mixture of constrained and restrained refinement
Δρ_max = 0.77 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2014 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL2014/1 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2010 ▶); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009 ▶) and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, Ie. DOI: 10.1107/S1600536814011118/gk2606sup1.cif

e-70-0m225-sup1.cif^{(30.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814011118/gk2606Isup2.hkl

e-70-0m225-Isup2.hkl^{(321.7KB, hkl)}

CCDC reference: 1003037

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O13—H13⋯O1ⁱ	0.80 (2)	2.00 (2)	2.789 (2)	172 (3)
N1—H1⋯O9	0.82 (2)	1.81 (2)	2.625 (2)	178 (3)
C15—H15⋯O2ⁱⁱ	0.93	2.54	3.396 (3)	152
N2—H2⋯O1W	0.83 (2)	1.89 (2)	2.689 (3)	163 (3)
C21—H21A⋯O4ⁱⁱⁱ	0.96	2.62	3.270 (3)	125
C21—H21B⋯O5^iv	0.96	2.50	3.454 (3)	171
C24—H24⋯O12^v	0.93	2.49	3.297 (3)	145
C25—H25⋯O7^v	0.93	2.53	3.237 (3)	134
C25—H25⋯O10^v	0.93	2.51	3.264 (3)	138
C27—H27B⋯O1ⁱ	0.96	2.46	3.347 (4)	153
O1W—H1W⋯O11ⁱ	0.83 (2)	2.02 (2)	2.833 (2)	168 (3)
O1W—H2W⋯O8	0.83 (2)	1.90 (2)	2.718 (2)	171 (3)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

This work was supported by the Slovak Grant Agency VEGA (project No. 1/0336/13).

supplementary crystallographic information

1. Comment

The reaction system V₂O₅ – 2,6-dimethylpyridine – H₂O – HClO₄ was studied as a part of our study of the formation of transition metal complexes with substituted pyridinium ligands in the presence of polyoxovanadate anions. We wish to obtain a better understanding of the role of the counter-ion in the formation of H_nV₁₀O₂₈^(6–ⁿ^)– species and the influence of the cation and the decavanadate anion protonation mode on the IR spectra and information about possible side products of the syntheses. This article is a continuation of our previous work on salts of polyoxovanadates with organic cations (Rakovský & Gyepes, 2006; Pacigová et al., 2007). The oxovanadates(V) and peroxovanadium compounds are also of great interest in biochemistry and medicine because of their diverse biological activities (Crans, 1998). Heterobimetallic compounds containing, beside polyoxovanadate core, entities composed of other transition metals bound to organic ligands have been extensively studied due to their potential applications in the field of catalysis and material science (Hagrman et al., 2001; Klištincová et al., 2008; Klištincová et al., 2010; Bartošová et al., 2012). Several decavanadates with pyridine and its derivatives are already known. Asgedom et al. (1996) reported the structure of (C₅H₆N)₆V₁₀O₂₈.2H₂O. Pyridinium cations are bonded directly to the decavanadate anions via hydrogen bonds as it is in (C₇H₁₀N)₃H₃V₁₀O₂₈.H₂O (Arrieta et al., 1988) and (C₆H₈N)₃H₃V₁₀O₂₈.H₂O (Santiago et al., 1988).

The system mentioned above was studied in the pH range 2.5–7 and the crystalline product was only obtained at pH 2.5, which is typical pH value for the dihydrogendecavanadate formation. The asymmetric unit of the title compound, (I), consists of one-half decavanadate anion of C_i symmetry, lying on a special position on the centre of symmetry, which is protonated on the µ-OV₃ bridging atom O13, two 2,6-dimethylpyridinium cations and one water molecule of crystallization (Fig. 1). The terminal vanadium-oxygen bond lengths are in the range 1.5916 (17)–1.6153 (16) Å, with an average value of 1.601 (10) Å. The bond lengths of the bridging O atoms with coordination numbers two are in the range 1.6768 (14)–2.0752 (15) Å with the mean value of 1.84 (12) Å . There are 2 types of µ-OV₃ bridging oxygen groups present: unprotonated (O12) with bond lengths in the range 1.8757 (15)–1.9931 (14) Å with the mean value of 1.95 (6) Å, and protonated (O13) with bond lengths in the range 2.0678 (15)–2.1170 (14) Å with the mean value of 2.10 (3) Å. Bond lengths of the six-coordinated µ-OV₆ oxygen atom (O14) are in the range 2.0592 (13)–2.3588 (14) Å with an average value of 2.24 (13) Å.

The supramolecular structure is formed by D–H···O hydrogen bonds [D = N, O or C, with H···O ≤ 2.72 Å and D–H···O > 120° (Jeffrey, 1997)] between cations and anions, cations and water molecules, between two anions and between water molecules and anions (Table 1). Adjacent [H₂V₁₀O₂₈]^4– anions are mutually linked together by the system of strong hydrogen bonds: directly by two anion-anion hydrogen bonds O13–H1V···O1 and via two bridging water molecules, where water acts as a H-bond donor for both anions, forming O1W–H1W···O11 and O1W–H2W···O8 hydrogen bonds. N–H group of the first cation is donating H-bond to the anion, thus forming N1–H10···O9 hydrogen bond, N–H group of the second cation acts as a H-bond donor for the water molecule, forming N2–H20···O1W hydrogen bond. This system of hydrogen bonds is forming supramolecular chain running in the b axis direction (Fig. 2).

The C–H···O weak hydrogen bonds present in the structure are involved in the interaction between neighbouring supramolecular chains, with exception of C21–H21B···O5 and C27–H27B···O1 bonds, which are reinforcing mutual bonding between one of the anions, cation and the water molecule hydrogen-bonded to the cation.

2. Experimental

All reactants with the exception of purified vanadium pentoxide were obtained commercially and used without further purification.

Purified vanadium pentoxide was prepared as follows: to 1.5 l of water, NH₄VO₃ (50 g) and NH₃ (60 ml, w = 25%) were added. The mixture was stirred and heated in a water bath until the temperature reached 343 K and left cool down for about 1 h. After cooling the mixture was filtered. White NH₄VO₃ was precipited by adding of crystalline NH₄NO₃ (70 g) to the filtrate, filtered out and washed with distilled water (20 ml) and ethanol (20 ml). The product was dried on air. Purified NH₄VO₃ was heated in a porcelain dish at 773 K for at least 2 h.

2 NH₄VO₃→ V₂O₅ + 2 NH₃ + H₂O

Test for purity of prepared V₂O₅: small amout of the product added to cold 1 M solution of KOH in a test tube completely dissolves.

Synthesis of the (C₇H₁₀N)₄H₂V₁₀O₂₈.2H₂O (I): V₂O₅ (0.9 g, 0.005 mol) was dissolved after stirring overnight in 100 ml of 0.1 M solution of 2,6-dimethylpyridine. Yellow solution obtained was filtered and adjusted to pH 2.5 with 4 M HClO₄. Orange plate crystals were isolated after standing 5 days at 277 K.

Vanadium was determined gravimetrically as V₂O₅. C, H and N were estimated on a CHN analyser (Carlo Erba). Analysis calculated for C₂₈H₄₆N₄O₃₀V₁₀ (found): C 23.55 (23.59), H 3.25 (3.21), N 3.92 (3.89), V 35.67 (35.58).

The FT—IR spectra were performed with a Nonius 6700 FTIR spectrophotometer in nujol mulls. The IR spectrum of prepared compound exhibits characteristic bands of the decavanadate anion [965 (s), 944 (s), 926 (m), 829 (s) and 589 (m) cm^-1] (Klištincová et al., 2010) as well as characteristic bands for protonated 2,6-dimethylpyridine (2534 (sh) – ν(NH⁺); 1629 (s), 1641 (s) – δ(NH⁺)) and other bands for the base (716 (s), 794 (s) – δ(CH); 971 (s) – ν(C–CH₃₎; 1175 (m), 1280 (m) – δ(CH comb.), 1415 (m) – ν(C–C) or ν(C–N)) (Ban-Oganowska et al., 2002; Elassal et al., 2011; Medhi et al., 1965).