Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028346/ci2394sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028346/ci2394Isup2.hkl |
CCDC reference: 657545
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.
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).
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.
For related literature, see: Bondi (1964); Sarin et al. (1977); Zhu et al. (2005); Zhu & Tang (2005).
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.
(C5H12NO2)2[NbOF5] | F(000) = 896 |
Mr = 440.22 | Dx = 1.679 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 5444 reflections |
a = 9.8018 (4) Å | θ = 3.1–31.4° |
b = 19.4213 (8) Å | µ = 0.76 mm−1 |
c = 10.1979 (4) Å | T = 296 K |
β = 116.190 (1)° | Prism, colourless |
V = 1742.01 (12) Å3 | 0.32 × 0.31 × 0.30 mm |
Z = 4 |
Bruker SMART 1000 CCD area-detector diffractometer | 5717 independent reflections |
Radiation source: fine-focus sealed tube, Siemens K FN Mo 2k 90 | 4829 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
Detector resolution: 8.33 pixels mm-1 | θmax = 31.5°, θmin = 3.1° |
ω scans | h = −14→14 |
Absorption correction: gaussian (SADABS and XPREP in SAINT; Bruker, 2003) | k = −28→24 |
Tmin = 0.861, Tmax = 0.907 | l = −14→14 |
20336 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.030 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.078 | H-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 parameters | Δρmax = 0.51 e Å−3 |
0 restraints | Δρmin = −0.53 e Å−3 |
(C5H12NO2)2[NbOF5] | V = 1742.01 (12) Å3 |
Mr = 440.22 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.8018 (4) Å | µ = 0.76 mm−1 |
b = 19.4213 (8) Å | T = 296 K |
c = 10.1979 (4) Å | 0.32 × 0.31 × 0.30 mm |
β = 116.190 (1)° |
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 = 0.907 | Rint = 0.037 |
20336 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 0 restraints |
wR(F2) = 0.078 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.51 e Å−3 |
5717 reflections | Δρmin = −0.53 e Å−3 |
214 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Nb | 0.235617 (10) | 0.589755 (5) | 0.515321 (10) | 0.02581 (2) | |
F1 | 0.45989 (8) | 0.58700 (4) | 0.71168 (8) | 0.03843 (19) | |
F2 | 0.18570 (9) | 0.53106 (5) | 0.64105 (9) | 0.0547 (2) | |
F3 | 0.19702 (10) | 0.66821 (5) | 0.60355 (10) | 0.0596 (3) | |
F4 | 0.35143 (9) | 0.64148 (5) | 0.43684 (9) | 0.0515 (2) | |
F5 | 0.32661 (10) | 0.50686 (5) | 0.47622 (9) | 0.0497 (2) | |
O1 | 0.06771 (12) | 0.58416 (5) | 0.35884 (11) | 0.0463 (3) | |
O2 | 0.71168 (9) | 0.61373 (5) | 0.71263 (9) | 0.0353 (2) | |
H2 | 0.6328 | 0.6029 | 0.7167 | 0.053* | |
O3 | 0.80342 (9) | 0.52104 (5) | 0.85526 (9) | 0.03338 (19) | |
O4 | 0.42829 (11) | 0.38945 (7) | 1.01660 (10) | 0.0536 (3) | |
H4 | 0.4779 | 0.3968 | 1.1043 | 0.080* | |
O5 | 0.62023 (9) | 0.44382 (6) | 1.00016 (10) | 0.0413 (2) | |
N1 | 1.06725 (10) | 0.52398 (5) | 0.83578 (10) | 0.0287 (2) | |
H1A | 1.0846 | 0.5149 | 0.9274 | 0.043* | |
H1B | 1.1551 | 0.5320 | 0.8326 | 0.043* | |
H1C | 1.0213 | 0.4881 | 0.7791 | 0.043* | |
N2 | 0.51056 (12) | 0.42889 (6) | 0.71323 (11) | 0.0347 (2) | |
H2A | 0.5830 | 0.4557 | 0.7772 | 0.052* | |
H2B | 0.4513 | 0.4536 | 0.6353 | 0.052* | |
H2C | 0.5531 | 0.3948 | 0.6859 | 0.052* | |
C1 | 0.81841 (11) | 0.56954 (6) | 0.78715 (11) | 0.0255 (2) | |
C2 | 0.96776 (11) | 0.58594 (6) | 0.78260 (12) | 0.0261 (2) | |
H2D | 0.9470 | 0.5943 | 0.6807 | 0.031* | |
C3 | 1.04893 (13) | 0.64997 (7) | 0.87360 (14) | 0.0345 (3) | |
H3 | 1.1549 | 0.6476 | 0.8893 | 0.041* | |
C4 | 1.05203 (18) | 0.65008 (8) | 1.02461 (15) | 0.0487 (4) | |
H4A | 1.1080 | 0.6894 | 1.0788 | 0.073* | |
H4B | 1.1001 | 0.6088 | 1.0758 | 0.073* | |
H4C | 0.9499 | 0.6522 | 1.0142 | 0.073* | |
C5 | 0.98365 (18) | 0.71604 (8) | 0.79079 (18) | 0.0501 (4) | |
H5A | 0.8774 | 0.7188 | 0.7667 | 0.075* | |
H5B | 0.9963 | 0.7165 | 0.7026 | 0.075* | |
H5C | 1.0359 | 0.7547 | 0.8505 | 0.075* | |
C6 | 0.50189 (13) | 0.41305 (6) | 0.94618 (13) | 0.0324 (3) | |
C7 | 0.41666 (13) | 0.39942 (7) | 0.78283 (13) | 0.0328 (3) | |
H7 | 0.3197 | 0.4242 | 0.7448 | 0.039* | |
C8 | 0.38306 (15) | 0.32244 (7) | 0.74971 (13) | 0.0407 (3) | |
H8 | 0.3218 | 0.3076 | 0.7989 | 0.049* | |
C9 | 0.5257 (2) | 0.27905 (9) | 0.8098 (2) | 0.0689 (6) | |
H9A | 0.4985 | 0.2312 | 0.7958 | 0.103* | |
H9B | 0.5834 | 0.2882 | 0.9123 | 0.103* | |
H9C | 0.5857 | 0.2902 | 0.7596 | 0.103* | |
C10 | 0.2884 (3) | 0.31069 (12) | 0.58804 (18) | 0.0818 (6) | |
H10A | 0.1964 | 0.3371 | 0.5548 | 0.123* | |
H10B | 0.2637 | 0.2627 | 0.5705 | 0.123* | |
H10C | 0.3449 | 0.3248 | 0.5361 | 0.123* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Nb | 0.02638 (4) | 0.02999 (5) | 0.02207 (4) | −0.00066 (3) | 0.01161 (3) | −0.00177 (3) |
F1 | 0.0257 (3) | 0.0612 (5) | 0.0272 (3) | −0.0028 (3) | 0.0105 (2) | −0.0045 (3) |
F2 | 0.0510 (4) | 0.0752 (6) | 0.0440 (4) | −0.0150 (4) | 0.0265 (3) | 0.0105 (4) |
F3 | 0.0600 (4) | 0.0565 (5) | 0.0594 (5) | 0.0131 (4) | 0.0237 (4) | −0.0211 (4) |
F4 | 0.0620 (4) | 0.0553 (5) | 0.0488 (4) | −0.0135 (4) | 0.0351 (3) | 0.0027 (3) |
F5 | 0.0647 (4) | 0.0452 (4) | 0.0345 (3) | 0.0173 (4) | 0.0175 (3) | −0.0055 (3) |
O1 | 0.0400 (5) | 0.0512 (6) | 0.0327 (5) | −0.0015 (4) | 0.0023 (4) | −0.0012 (4) |
O2 | 0.0263 (3) | 0.0379 (4) | 0.0435 (4) | 0.0028 (3) | 0.0169 (3) | 0.0086 (4) |
O3 | 0.0301 (3) | 0.0401 (5) | 0.0309 (3) | −0.0010 (3) | 0.0143 (3) | 0.0079 (3) |
O4 | 0.0571 (4) | 0.0776 (7) | 0.0329 (4) | −0.0320 (5) | 0.0260 (3) | −0.0153 (4) |
O5 | 0.0319 (3) | 0.0568 (6) | 0.0338 (4) | −0.0099 (4) | 0.0132 (3) | −0.0030 (4) |
N1 | 0.0251 (3) | 0.0345 (5) | 0.0286 (4) | 0.0003 (3) | 0.0137 (3) | −0.0015 (3) |
N2 | 0.0446 (4) | 0.0319 (5) | 0.0296 (4) | −0.0027 (4) | 0.0183 (3) | 0.0046 (4) |
C1 | 0.0239 (4) | 0.0307 (5) | 0.0220 (4) | −0.0017 (4) | 0.0102 (3) | −0.0015 (4) |
C2 | 0.0240 (4) | 0.0300 (5) | 0.0253 (4) | −0.0019 (4) | 0.0117 (3) | −0.0007 (4) |
C3 | 0.0298 (4) | 0.0339 (6) | 0.0387 (5) | −0.0045 (4) | 0.0140 (4) | −0.0042 (5) |
C4 | 0.0579 (7) | 0.0480 (8) | 0.0354 (6) | −0.0046 (6) | 0.0163 (5) | −0.0123 (6) |
C5 | 0.0543 (7) | 0.0331 (7) | 0.0589 (8) | −0.0042 (6) | 0.0213 (6) | 0.0017 (6) |
C6 | 0.0347 (4) | 0.0356 (6) | 0.0284 (5) | −0.0025 (4) | 0.0153 (4) | −0.0026 (4) |
C7 | 0.0312 (4) | 0.0395 (6) | 0.0270 (5) | −0.0003 (4) | 0.0121 (4) | 0.0034 (4) |
C8 | 0.0515 (6) | 0.0426 (7) | 0.0284 (5) | −0.0182 (5) | 0.0182 (4) | −0.0031 (5) |
C9 | 0.0978 (12) | 0.0320 (8) | 0.0783 (11) | 0.0037 (8) | 0.0402 (9) | 0.0043 (7) |
C10 | 0.1092 (13) | 0.0918 (13) | 0.0339 (7) | −0.0555 (11) | 0.0221 (8) | −0.0165 (8) |
Nb—O1 | 1.7172 (9) | C2—H2D | 0.98 |
Nb—F3 | 1.8906 (9) | C3—C5 | 1.5140 (19) |
Nb—F2 | 1.9331 (9) | C3—C4 | 1.527 (2) |
Nb—F4 | 1.9339 (9) | C3—H3 | 0.98 |
Nb—F5 | 1.9648 (9) | C4—H4A | 0.96 |
Nb—F1 | 2.2270 (7) | C4—H4B | 0.96 |
O2—C1 | 1.3065 (13) | C4—H4C | 0.96 |
O2—H2 | 0.82 | C5—H5A | 0.96 |
O3—C1 | 1.2170 (15) | C5—H5B | 0.96 |
O4—C6 | 1.3053 (17) | C5—H5C | 0.96 |
O4—H4 | 0.82 | C6—C7 | 1.5214 (16) |
O5—C6 | 1.2008 (15) | C7—C8 | 1.5361 (19) |
N1—C2 | 1.4920 (14) | C7—H7 | 0.98 |
N1—H1A | 0.89 | C8—C10 | 1.510 (2) |
N1—H1B | 0.89 | C8—C9 | 1.511 (2) |
N1—H1C | 0.89 | C8—H8 | 0.98 |
N2—C7 | 1.5018 (17) | C9—H9A | 0.96 |
N2—H2A | 0.89 | C9—H9B | 0.96 |
N2—H2B | 0.89 | C9—H9C | 0.96 |
N2—H2C | 0.89 | C10—H10A | 0.96 |
C1—C2 | 1.5188 (15) | C10—H10B | 0.96 |
C2—C3 | 1.5456 (16) | C10—H10C | 0.96 |
O1—Nb—F1 | 174.23 (4) | C4—C3—H3 | 106.7 |
O1—Nb—F2 | 99.19 (5) | C2—C3—H3 | 106.7 |
O1—Nb—F3 | 100.50 (5) | C3—C4—H4A | 109.5 |
O1—Nb—F4 | 98.35 (5) | C3—C4—H4B | 109.5 |
O1—Nb—F5 | 95.41 (4) | H4A—C4—H4B | 109.5 |
F2—Nb—F1 | 80.08 (3) | C3—C4—H4C | 109.5 |
F2—Nb—F4 | 161.34 (3) | H4A—C4—H4C | 109.5 |
F2—Nb—F5 | 85.52 (4) | H4B—C4—H4C | 109.5 |
F3—Nb—F1 | 85.23 (3) | C3—C5—H5A | 109.5 |
F3—Nb—F2 | 89.84 (5) | C3—C5—H5B | 109.5 |
F3—Nb—F4 | 93.19 (5) | H5A—C5—H5B | 109.5 |
F3—Nb—F5 | 163.95 (4) | C3—C5—H5C | 109.5 |
F4—Nb—F1 | 81.83 (3) | H5A—C5—H5C | 109.5 |
F4—Nb—F5 | 86.54 (4) | H5B—C5—H5C | 109.5 |
F5—Nb—F1 | 78.84 (3) | O5—C6—O4 | 125.39 (12) |
C1—O2—H2 | 109.5 | O5—C6—C7 | 122.76 (12) |
C6—O4—H4 | 109.5 | O4—C6—C7 | 111.81 (10) |
C2—N1—H1A | 109.5 | N2—C7—C6 | 107.23 (9) |
C2—N1—H1B | 109.5 | N2—C7—C8 | 112.56 (11) |
H1A—N1—H1B | 109.5 | C6—C7—C8 | 111.78 (10) |
C2—N1—H1C | 109.5 | N2—C7—H7 | 108.4 |
H1A—N1—H1C | 109.5 | C6—C7—H7 | 108.4 |
H1B—N1—H1C | 109.5 | C8—C7—H7 | 108.4 |
C7—N2—H2A | 109.5 | C10—C8—C9 | 111.80 (16) |
C7—N2—H2B | 109.5 | C10—C8—C7 | 110.84 (12) |
H2A—N2—H2B | 109.5 | C9—C8—C7 | 112.54 (11) |
C7—N2—H2C | 109.5 | C10—C8—H8 | 107.1 |
H2A—N2—H2C | 109.5 | C9—C8—H8 | 107.1 |
H2B—N2—H2C | 109.5 | C7—C8—H8 | 107.1 |
O3—C1—O2 | 124.96 (10) | C8—C9—H9A | 109.5 |
O3—C1—C2 | 122.72 (9) | C8—C9—H9B | 109.5 |
O2—C1—C2 | 112.31 (10) | H9A—C9—H9B | 109.5 |
N1—C2—C1 | 107.69 (9) | C8—C9—H9C | 109.5 |
N1—C2—C3 | 110.49 (8) | H9A—C9—H9C | 109.5 |
C1—C2—C3 | 113.45 (10) | H9B—C9—H9C | 109.5 |
N1—C2—H2D | 108.4 | C8—C10—H10A | 109.5 |
C1—C2—H2D | 108.4 | C8—C10—H10B | 109.5 |
C3—C2—H2D | 108.4 | H10A—C10—H10B | 109.5 |
C5—C3—C4 | 112.13 (13) | C8—C10—H10C | 109.5 |
C5—C3—C2 | 111.61 (10) | H10A—C10—H10C | 109.5 |
C4—C3—C2 | 112.49 (11) | H10B—C10—H10C | 109.5 |
C5—C3—H3 | 106.7 |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···F1 | 0.82 | 1.70 | 2.5179 (11) | 174 |
N1—H1A···O3i | 0.89 | 2.11 | 2.9619 (12) | 160 |
N1—H1B···O5i | 0.89 | 2.16 | 2.8372 (12) | 133 |
N1—H1B···F2ii | 0.89 | 2.10 | 2.7103 (14) | 125 |
N1—H1C···O1iii | 0.89 | 1.90 | 2.7898 (14) | 173 |
O4—H4···F1iv | 0.82 | 1.73 | 2.5314 (12) | 166 |
N2—H2A···O3 | 0.89 | 2.32 | 3.1418 (13) | 153 |
N2—H2B···F5 | 0.89 | 1.86 | 2.7457 (13) | 178 |
N2—H2C···F4iii | 0.89 | 1.99 | 2.8048 (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. |
Experimental details
Crystal data | |
Chemical formula | (C5H12NO2)2[NbOF5] |
Mr | 440.22 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 296 |
a, b, c (Å) | 9.8018 (4), 19.4213 (8), 10.1979 (4) |
β (°) | 116.190 (1) |
V (Å3) | 1742.01 (12) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.76 |
Crystal size (mm) | 0.32 × 0.31 × 0.30 |
Data collection | |
Diffractometer | Bruker SMART 1000 CCD area-detector |
Absorption correction | Gaussian (SADABS and XPREP in SAINT; Bruker, 2003) |
Tmin, Tmax | 0.861, 0.907 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 20336, 5717, 4829 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.736 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.078, 1.08 |
No. of reflections | 5717 |
No. of parameters | 214 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.51, −0.53 |
Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 2003), SAINT, SHELXTL (Bruker, 1998), SHELXTL.
Nb—O1 | 1.7172 (9) | Nb—F4 | 1.9339 (9) |
Nb—F3 | 1.8906 (9) | Nb—F5 | 1.9648 (9) |
Nb—F2 | 1.9331 (9) | Nb—F1 | 2.2270 (7) |
O1—Nb—F1 | 174.23 (4) | F3—Nb—F1 | 85.23 (3) |
O1—Nb—F2 | 99.19 (5) | F3—Nb—F2 | 89.84 (5) |
O1—Nb—F3 | 100.50 (5) | F3—Nb—F4 | 93.19 (5) |
O1—Nb—F4 | 98.35 (5) | F3—Nb—F5 | 163.95 (4) |
O1—Nb—F5 | 95.41 (4) | F4—Nb—F1 | 81.83 (3) |
F2—Nb—F1 | 80.08 (3) | F4—Nb—F5 | 86.54 (4) |
F2—Nb—F4 | 161.34 (3) | F5—Nb—F1 | 78.84 (3) |
F2—Nb—F5 | 85.52 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···F1 | 0.82 | 1.70 | 2.5179 (11) | 174 |
N1—H1A···O3i | 0.89 | 2.11 | 2.9619 (12) | 160 |
N1—H1B···O5i | 0.89 | 2.16 | 2.8372 (12) | 133 |
N1—H1B···F2ii | 0.89 | 2.10 | 2.7103 (14) | 125 |
N1—H1C···O1iii | 0.89 | 1.90 | 2.7898 (14) | 173 |
O4—H4···F1iv | 0.82 | 1.73 | 2.5314 (12) | 166 |
N2—H2A···O3 | 0.89 | 2.32 | 3.1418 (13) | 153 |
N2—H2B···F5 | 0.89 | 1.86 | 2.7457 (13) | 178 |
N2—H2C···F4iii | 0.89 | 1.99 | 2.8048 (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. |
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.