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Acta Cryst. (2007). E63, m2086    [ doi:10.1107/S1600536807028346 ]

Bis(DL-valinium) pentafluoridooxidoniobate(V)

M. A. Pushilin, A. V. Gerasimenko and R. L. Davidovich

Abstract top

The asymmetric unit of the title compound [systematic name: (R)-1-carboxy-2-methylpropan-1-aminium (S)-1-carboxy-2-methylpropan-1-aminium pentafluoridooxidoniobate(V)], (C5H12NO2)2[NbOF5], consists of a discrete [NbOF5]2- complex anion and two protonated valinium cations. The Nb atom has a distorted octahedral geometry and the Nb-F bond trans to the Nb=O bond is significantly longer than the other four Nb-F bonds in the polyhedron. The valinium cations are linked to the pentafluoridooxidoniobate(V) anions via O-H...F, N-H...F and N-H...O hydrogen bonds.

Comment top

Recently, a significant number of organic-inorganic hybrid materials have been prepared and studied because of their important structure-dependent properties, such as non-linear optical activity, piezoelectricity and ferroelectricity. The early transition metal fluorine complexes with out-of-centre distortions in metal oxide fluoride anions are of a special interest. We report here the crystal structure of a new organic-inorganic hybrid compound bis(DL-valinium) pentafluorooxoniobate(V), (C5H12NO2)2[NbOF5] with an isolated ordered [NbOF5]2- complex anion, (I).

The asymmetric unit of the crystal structure (I) consists of a discrete anionic complex [NbOF5]2−, and two protonated valinium cations (Fig. 1). The Nb atom in [NbOF5]2− is coordinated by five F atoms and one O atom forming a distorted octahedron. The Nb—F bond trans to the Nb–O bond is significantly longer than other four Nb–F bonds in the polyhedron (Table 1).

The Nb atom is displaced from the equatorial plane of the octahedron in the direction to the axial O atom by 0.283 Å. The bond lengths and angles in the Nb-octahedron are comparable with corresponding values observed for discrete and ordered [NbOF5]2- anions (Sarin et al., 1977; Zhu et al., 2005; Zhu & Tang, 2005).

In the valinium cation the amine group is protonated and carries a positive charge. Four valinium cations are linked by N—H···O intermolecular hydrogen bonds to form a tetrameric associate (Fig. 2) which is linked with [NbOF5]2− anions by N—H···F, N—H···O and O—H···F hydrogen bonds forming layers parallel to the ac plane. Note that there are two very strong O—H···F hydrogen bonds between hydroxyl groups of the valinium cations and the axial fluorine atom F1 of the [NbOF5]2− anions (Table 2), and a weak interaction C1···F5iii [2.840 (1) Å] which is little less than the sum of van der Waals radii C and F atoms (3.17 Å) (Bondi, 1964). The layers are connected via van der Vaals interactions.

Related literature top

For related literature, see: Bondi (1964); Sarin et al. (1977); Zhu et al. (2005); Zhu & Tang (2005).

Experimental top

The title compound was synthesized by the reaction of Nb2O5 (1.33 g, 5 mmol) in a solution of hydrofluoric acid (48%, 40 ml) with DL-valine (2.34 g, 20 mmol), in molar stoichiometric ratio DL-valine: Nb2O5 = 4:1. The obtained solution was allowed to evaporate slowly by normal temperature. After few days, colorless crystals suitable for X-ray diffraction were obtained. Then they were separated from solution, washed with small amount of acetone and dried in air.

Refinement top

After checking their presence in the difference map, all H atoms were placed in geometrically idealized positions and refined in the riding-model approximation, with C—H = 0.96 or 0.98 Å, N—H = 0.89 Å and O—H = 0.82 Å, and Uiso(H) = 1.2 or 1.5 times Ueq(C,N,O).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of the asymmetric unit of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The tetrameric associate of valinium cations. Hydrogen bonds are shown as dashed lines.
[Figure 3] Fig. 3. Part of the polymeric layer of (I), viewed parallel to the ac plane. Hydrogen bonds are shown as dashed lines.
(R)-1-carboxy-2-methylpropan-1-aminium (S)-1-carboxy-2-methylpropan-1-aminium pentafluoridooxidoniobate(V) top
Crystal data top
(C5H12NO2)2[NbOF5]F(000) = 896
Mr = 440.22Dx = 1.679 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5444 reflections
a = 9.8018 (4) Åθ = 3.1–31.4°
b = 19.4213 (8) ŵ = 0.76 mm−1
c = 10.1979 (4) ÅT = 296 K
β = 116.190 (1)°Prism, colourless
V = 1742.01 (12) Å30.32 × 0.31 × 0.30 mm
Z = 4
Data collection top
Bruker SMART 1000 CCD area-detector
diffractometer		5717 independent reflections
Radiation source: fine-focus sealed tube, Siemens K FN Mo 2k 904829 reflections with I > 2σ(I)
graphiteRint = 0.037
Detector resolution: 8.33 pixels mm-1θmax = 31.5°, θmin = 3.1°
ω scansh = −14→14
Absorption correction: gaussian
(SADABS and XPREP in SAINT; Bruker, 2003)		k = −28→24
Tmin = 0.861, Tmax = 0.907l = −14→14
20336 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.078H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0347P)2 + 0.5786P]
where P = (Fo2 + 2Fc2)/3
5717 reflections(Δ/σ)max = 0.003
214 parametersΔρmax = 0.51 e Å−3
0 restraintsΔρmin = −0.53 e Å−3
Crystal data top
(C5H12NO2)2[NbOF5]V = 1742.01 (12) Å3
Mr = 440.22Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.8018 (4) ŵ = 0.76 mm−1
b = 19.4213 (8) ÅT = 296 K
c = 10.1979 (4) Å0.32 × 0.31 × 0.30 mm
β = 116.190 (1)°
Data collection top
Bruker SMART 1000 CCD area-detector
diffractometer		5717 independent reflections
Absorption correction: gaussian
(SADABS and XPREP in SAINT; Bruker, 2003)		4829 reflections with I > 2σ(I)
Tmin = 0.861, Tmax = 0.907Rint = 0.037
20336 measured reflectionsθmax = 31.5°
Refinement top
R[F2 > 2σ(F2)] = 0.030H-atom parameters constrained
wR(F2) = 0.078Δρmax = 0.51 e Å−3
S = 1.08Δρmin = −0.53 e Å−3
5717 reflectionsAbsolute structure: ?
214 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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 (Å2) top
xyzUiso*/Ueq
Nb0.235617 (10)0.589755 (5)0.515321 (10)0.02581 (2)
F10.45989 (8)0.58700 (4)0.71168 (8)0.03843 (19)
F20.18570 (9)0.53106 (5)0.64105 (9)0.0547 (2)
F30.19702 (10)0.66821 (5)0.60355 (10)0.0596 (3)
F40.35143 (9)0.64148 (5)0.43684 (9)0.0515 (2)
F50.32661 (10)0.50686 (5)0.47622 (9)0.0497 (2)
O10.06771 (12)0.58416 (5)0.35884 (11)0.0463 (3)
O20.71168 (9)0.61373 (5)0.71263 (9)0.0353 (2)
H20.63280.60290.71670.053*
O30.80342 (9)0.52104 (5)0.85526 (9)0.03338 (19)
O40.42829 (11)0.38945 (7)1.01660 (10)0.0536 (3)
H40.47790.39681.10430.080*
O50.62023 (9)0.44382 (6)1.00016 (10)0.0413 (2)
N11.06725 (10)0.52398 (5)0.83578 (10)0.0287 (2)
H1A1.08460.51490.92740.043*
H1B1.15510.53200.83260.043*
H1C1.02130.48810.77910.043*
N20.51056 (12)0.42889 (6)0.71323 (11)0.0347 (2)
H2A0.58300.45570.77720.052*
H2B0.45130.45360.63530.052*
H2C0.55310.39480.68590.052*
C10.81841 (11)0.56954 (6)0.78715 (11)0.0255 (2)
C20.96776 (11)0.58594 (6)0.78260 (12)0.0261 (2)
H2D0.94700.59430.68070.031*
C31.04893 (13)0.64997 (7)0.87360 (14)0.0345 (3)
H31.15490.64760.88930.041*
C41.05203 (18)0.65008 (8)1.02461 (15)0.0487 (4)
H4A1.10800.68941.07880.073*
H4B1.10010.60881.07580.073*
H4C0.94990.65221.01420.073*
C50.98365 (18)0.71604 (8)0.79079 (18)0.0501 (4)
H5A0.87740.71880.76670.075*
H5B0.99630.71650.70260.075*
H5C1.03590.75470.85050.075*
C60.50189 (13)0.41305 (6)0.94618 (13)0.0324 (3)
C70.41666 (13)0.39942 (7)0.78283 (13)0.0328 (3)
H70.31970.42420.74480.039*
C80.38306 (15)0.32244 (7)0.74971 (13)0.0407 (3)
H80.32180.30760.79890.049*
C90.5257 (2)0.27905 (9)0.8098 (2)0.0689 (6)
H9A0.49850.23120.79580.103*
H9B0.58340.28820.91230.103*
H9C0.58570.29020.75960.103*
C100.2884 (3)0.31069 (12)0.58804 (18)0.0818 (6)
H10A0.19640.33710.55480.123*
H10B0.26370.26270.57050.123*
H10C0.34490.32480.53610.123*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Nb0.02638 (4)0.02999 (5)0.02207 (4)−0.00066 (3)0.01161 (3)−0.00177 (3)
F10.0257 (3)0.0612 (5)0.0272 (3)−0.0028 (3)0.0105 (2)−0.0045 (3)
F20.0510 (4)0.0752 (6)0.0440 (4)−0.0150 (4)0.0265 (3)0.0105 (4)
F30.0600 (4)0.0565 (5)0.0594 (5)0.0131 (4)0.0237 (4)−0.0211 (4)
F40.0620 (4)0.0553 (5)0.0488 (4)−0.0135 (4)0.0351 (3)0.0027 (3)
F50.0647 (4)0.0452 (4)0.0345 (3)0.0173 (4)0.0175 (3)−0.0055 (3)
O10.0400 (5)0.0512 (6)0.0327 (5)−0.0015 (4)0.0023 (4)−0.0012 (4)
O20.0263 (3)0.0379 (4)0.0435 (4)0.0028 (3)0.0169 (3)0.0086 (4)
O30.0301 (3)0.0401 (5)0.0309 (3)−0.0010 (3)0.0143 (3)0.0079 (3)
O40.0571 (4)0.0776 (7)0.0329 (4)−0.0320 (5)0.0260 (3)−0.0153 (4)
O50.0319 (3)0.0568 (6)0.0338 (4)−0.0099 (4)0.0132 (3)−0.0030 (4)
N10.0251 (3)0.0345 (5)0.0286 (4)0.0003 (3)0.0137 (3)−0.0015 (3)
N20.0446 (4)0.0319 (5)0.0296 (4)−0.0027 (4)0.0183 (3)0.0046 (4)
C10.0239 (4)0.0307 (5)0.0220 (4)−0.0017 (4)0.0102 (3)−0.0015 (4)
C20.0240 (4)0.0300 (5)0.0253 (4)−0.0019 (4)0.0117 (3)−0.0007 (4)
C30.0298 (4)0.0339 (6)0.0387 (5)−0.0045 (4)0.0140 (4)−0.0042 (5)
C40.0579 (7)0.0480 (8)0.0354 (6)−0.0046 (6)0.0163 (5)−0.0123 (6)
C50.0543 (7)0.0331 (7)0.0589 (8)−0.0042 (6)0.0213 (6)0.0017 (6)
C60.0347 (4)0.0356 (6)0.0284 (5)−0.0025 (4)0.0153 (4)−0.0026 (4)
C70.0312 (4)0.0395 (6)0.0270 (5)−0.0003 (4)0.0121 (4)0.0034 (4)
C80.0515 (6)0.0426 (7)0.0284 (5)−0.0182 (5)0.0182 (4)−0.0031 (5)
C90.0978 (12)0.0320 (8)0.0783 (11)0.0037 (8)0.0402 (9)0.0043 (7)
C100.1092 (13)0.0918 (13)0.0339 (7)−0.0555 (11)0.0221 (8)−0.0165 (8)
Geometric parameters (Å, °) top
Nb—O11.7172 (9)C2—H2D0.98
Nb—F31.8906 (9)C3—C51.5140 (19)
Nb—F21.9331 (9)C3—C41.527 (2)
Nb—F41.9339 (9)C3—H30.98
Nb—F51.9648 (9)C4—H4A0.96
Nb—F12.2270 (7)C4—H4B0.96
O2—C11.3065 (13)C4—H4C0.96
O2—H20.82C5—H5A0.96
O3—C11.2170 (15)C5—H5B0.96
O4—C61.3053 (17)C5—H5C0.96
O4—H40.82C6—C71.5214 (16)
O5—C61.2008 (15)C7—C81.5361 (19)
N1—C21.4920 (14)C7—H70.98
N1—H1A0.89C8—C101.510 (2)
N1—H1B0.89C8—C91.511 (2)
N1—H1C0.89C8—H80.98
N2—C71.5018 (17)C9—H9A0.96
N2—H2A0.89C9—H9B0.96
N2—H2B0.89C9—H9C0.96
N2—H2C0.89C10—H10A0.96
C1—C21.5188 (15)C10—H10B0.96
C2—C31.5456 (16)C10—H10C0.96
O1—Nb—F1174.23 (4)C4—C3—H3106.7
O1—Nb—F299.19 (5)C2—C3—H3106.7
O1—Nb—F3100.50 (5)C3—C4—H4A109.5
O1—Nb—F498.35 (5)C3—C4—H4B109.5
O1—Nb—F595.41 (4)H4A—C4—H4B109.5
F2—Nb—F180.08 (3)C3—C4—H4C109.5
F2—Nb—F4161.34 (3)H4A—C4—H4C109.5
F2—Nb—F585.52 (4)H4B—C4—H4C109.5
F3—Nb—F185.23 (3)C3—C5—H5A109.5
F3—Nb—F289.84 (5)C3—C5—H5B109.5
F3—Nb—F493.19 (5)H5A—C5—H5B109.5
F3—Nb—F5163.95 (4)C3—C5—H5C109.5
F4—Nb—F181.83 (3)H5A—C5—H5C109.5
F4—Nb—F586.54 (4)H5B—C5—H5C109.5
F5—Nb—F178.84 (3)O5—C6—O4125.39 (12)
C1—O2—H2109.5O5—C6—C7122.76 (12)
C6—O4—H4109.5O4—C6—C7111.81 (10)
C2—N1—H1A109.5N2—C7—C6107.23 (9)
C2—N1—H1B109.5N2—C7—C8112.56 (11)
H1A—N1—H1B109.5C6—C7—C8111.78 (10)
C2—N1—H1C109.5N2—C7—H7108.4
H1A—N1—H1C109.5C6—C7—H7108.4
H1B—N1—H1C109.5C8—C7—H7108.4
C7—N2—H2A109.5C10—C8—C9111.80 (16)
C7—N2—H2B109.5C10—C8—C7110.84 (12)
H2A—N2—H2B109.5C9—C8—C7112.54 (11)
C7—N2—H2C109.5C10—C8—H8107.1
H2A—N2—H2C109.5C9—C8—H8107.1
H2B—N2—H2C109.5C7—C8—H8107.1
O3—C1—O2124.96 (10)C8—C9—H9A109.5
O3—C1—C2122.72 (9)C8—C9—H9B109.5
O2—C1—C2112.31 (10)H9A—C9—H9B109.5
N1—C2—C1107.69 (9)C8—C9—H9C109.5
N1—C2—C3110.49 (8)H9A—C9—H9C109.5
C1—C2—C3113.45 (10)H9B—C9—H9C109.5
N1—C2—H2D108.4C8—C10—H10A109.5
C1—C2—H2D108.4C8—C10—H10B109.5
C3—C2—H2D108.4H10A—C10—H10B109.5
C5—C3—C4112.13 (13)C8—C10—H10C109.5
C5—C3—C2111.61 (10)H10A—C10—H10C109.5
C4—C3—C2112.49 (11)H10B—C10—H10C109.5
C5—C3—H3106.7
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···F10.821.702.5179 (11)174
N1—H1A···O3i0.892.112.9619 (12)160
N1—H1B···O5i0.892.162.8372 (12)133
N1—H1B···F2ii0.892.102.7103 (14)125
N1—H1C···O1iii0.891.902.7898 (14)173
O4—H4···F1iv0.821.732.5314 (12)166
N2—H2A···O30.892.323.1418 (13)153
N2—H2B···F50.891.862.7457 (13)178
N2—H2C···F4iii0.891.992.8048 (16)151
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x+1, y, z; (iii) −x+1, −y+1, −z+1; (iv) −x+1, −y+1, −z+2.
Table 1
Selected geometric parameters (Å, °) top
Nb—O11.7172 (9)Nb—F41.9339 (9)
Nb—F31.8906 (9)Nb—F51.9648 (9)
Nb—F21.9331 (9)Nb—F12.2270 (7)
O1—Nb—F1174.23 (4)F3—Nb—F185.23 (3)
O1—Nb—F299.19 (5)F3—Nb—F289.84 (5)
O1—Nb—F3100.50 (5)F3—Nb—F493.19 (5)
O1—Nb—F498.35 (5)F3—Nb—F5163.95 (4)
O1—Nb—F595.41 (4)F4—Nb—F181.83 (3)
F2—Nb—F180.08 (3)F4—Nb—F586.54 (4)
F2—Nb—F4161.34 (3)F5—Nb—F178.84 (3)
F2—Nb—F585.52 (4)
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···F10.821.702.5179 (11)174
N1—H1A···O3i0.892.112.9619 (12)160
N1—H1B···O5i0.892.162.8372 (12)133
N1—H1B···F2ii0.892.102.7103 (14)125
N1—H1C···O1iii0.891.902.7898 (14)173
O4—H4···F1iv0.821.732.5314 (12)166
N2—H2A···O30.892.323.1418 (13)153
N2—H2B···F50.891.862.7457 (13)178
N2—H2C···F4iii0.891.992.8048 (16)151
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x+1, y, z; (iii) −x+1, −y+1, −z+1; (iv) −x+1, −y+1, −z+2.
Acknowledgements top

The authors thank G. A. Fedorishcheva for assistance in synthesis of the compound. This study was supported by the Russian Foundation for Basic Research (project No. 05–03–33298).

references
References top

Bondi, A. (1964). J. Phys. Chem. 68, 441–451.

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Bruker (2003). SAINT (Version 6.45) and SADABS (Version 2.10). Bruker AXS Inc., Madison, Wisconsin, USA.

Sarin, V. A., Dudarev, V. Ya., Fykin, L. E., Gorbunova, Yu. E., Il'in, E. G. & Buslaev, Yu. A. (1977). Dokl. Akad. Nauk SSSR, 236, 393–396. (In Russian.)

Zhu, G., Liu, Y.-Y., Wang, G. & Tang, Z.-X. (2005). Acta Cryst. E61, m1566–m1567.

Zhu, G. & Tang, Z. (2005). Acta Cryst. E61, m2118–m2120.