Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014805/ob6071sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014805/ob6071Isup2.hkl |
CCDC reference: 175330
The title complex was prepared by mixing solutions of UO2(NO3)2·6H2O and 4-picoline N-oxide in ethanol in a 1:2 molar ratio. Crystals of (I) were obtained by recrystalization from ethanol.
The data collection nominally covered over a hemisphere of reciprocal space, by a combination of three sets of exposures; each set had a different ϕ angle for the crystal and each exposure covered 0.3° in ω. Crystal decay was monitored by repeating the initial frames at the end of data collection and analyzing the duplicate reflections. H atoms were placed geometrically and refined with a riding model (including free rotation about the methyl C—C bonds), and with Uiso constrained to be 1.2 (1.5 for the methyl group) times Ueq of the carrier atom.
Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1994); software used to prepare material for publication: SHELXL97.
Fig. 1. The structure of (I) showing 50% probability displacement ellipsoids. H atoms have been omitted. |
[UO2(NO3)2(C6H7NO)2] | F(000) = 572 |
Mr = 612.30 | Dx = 2.283 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 7.9772 (2) Å | Cell parameters from 6110 reflections |
b = 13.5738 (2) Å | θ = 2–26° |
c = 8.2288 (2) Å | µ = 9.17 mm−1 |
β = 91.583 (2)° | T = 203 K |
V = 890.68 (3) Å3 | Prism, yellow |
Z = 2 | 0.32 × 0.26 × 0.22 mm |
Siemens SMART diffractometer | 1998 independent reflections |
Radiation source: fine-focus sealed tube | 1750 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
Area–detector ω scans | θmax = 27.5°, θmin = 2.6° |
Absorption correction: multi-scan (Blessing, 1995) | h = −10→10 |
Tmin = 0.088, Tmax = 0.133 | k = 0→17 |
8841 measured reflections | l = 0→10 |
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)] = 0.022 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.052 | H-atom parameters constrained |
S = 1.24 | w = 1/[σ2(Fo2) + (0.0153P)2 + 1.8153P] where P = (Fo2 + 2Fc2)/3 |
1998 reflections | (Δ/σ)max = 0.058 |
125 parameters | Δρmax = 0.35 e Å−3 |
0 restraints | Δρmin = −0.65 e Å−3 |
[UO2(NO3)2(C6H7NO)2] | V = 890.68 (3) Å3 |
Mr = 612.30 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.9772 (2) Å | µ = 9.17 mm−1 |
b = 13.5738 (2) Å | T = 203 K |
c = 8.2288 (2) Å | 0.32 × 0.26 × 0.22 mm |
β = 91.583 (2)° |
Siemens SMART diffractometer | 1998 independent reflections |
Absorption correction: multi-scan (Blessing, 1995) | 1750 reflections with I > 2σ(I) |
Tmin = 0.088, Tmax = 0.133 | Rint = 0.020 |
8841 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 0 restraints |
wR(F2) = 0.052 | H-atom parameters constrained |
S = 1.24 | Δρmax = 0.35 e Å−3 |
1998 reflections | Δρmin = −0.65 e Å−3 |
125 parameters |
x | y | z | Uiso*/Ueq | ||
U | 0.5000 | 0.0000 | 0.0000 | 0.03137 (7) | |
O1 | 0.4182 (3) | 0.1119 (2) | 0.0744 (4) | 0.0411 (7) | |
O2 | 0.4078 (4) | −0.0894 (2) | 0.2504 (4) | 0.0466 (8) | |
O3 | 0.6626 (4) | −0.0385 (3) | 0.2626 (4) | 0.0496 (8) | |
O4 | 0.5620 (5) | −0.1196 (4) | 0.4666 (5) | 0.0841 (15) | |
O5 | 0.7773 (3) | 0.0636 (2) | 0.0205 (4) | 0.0402 (7) | |
N1 | 0.5452 (5) | −0.0839 (3) | 0.3319 (5) | 0.0477 (9) | |
N2 | 0.8448 (4) | 0.1495 (2) | −0.0266 (4) | 0.0305 (7) | |
C1 | 1.0004 (5) | 0.1475 (3) | −0.0851 (6) | 0.0379 (9) | |
H1A | 1.0573 | 0.0873 | −0.0950 | 0.045* | |
C2 | 1.0760 (5) | 0.2338 (3) | −0.1304 (6) | 0.0406 (10) | |
H2A | 1.1852 | 0.2319 | −0.1704 | 0.049* | |
C3 | 0.9946 (5) | 0.3236 (3) | −0.1182 (5) | 0.0334 (8) | |
C4 | 0.8339 (5) | 0.3213 (3) | −0.0584 (6) | 0.0414 (10) | |
H4A | 0.7735 | 0.3804 | −0.0493 | 0.050* | |
C5 | 0.7614 (5) | 0.2347 (3) | −0.0123 (6) | 0.0409 (10) | |
H5A | 0.6529 | 0.2349 | 0.0294 | 0.049* | |
C6 | 1.0758 (6) | 0.4187 (3) | −0.1663 (6) | 0.0464 (11) | |
H6A | 1.1452 | 0.4075 | −0.2595 | 0.070* | |
H6B | 1.1449 | 0.4431 | −0.0762 | 0.070* | |
H6C | 0.9899 | 0.4668 | −0.1942 | 0.070* |
U11 | U22 | U33 | U12 | U13 | U23 | |
U | 0.02075 (10) | 0.02665 (11) | 0.04704 (13) | −0.00248 (8) | 0.00718 (7) | 0.00057 (9) |
O1 | 0.0318 (14) | 0.0309 (14) | 0.0609 (19) | 0.0016 (11) | 0.0108 (13) | −0.0049 (13) |
O2 | 0.0317 (15) | 0.061 (2) | 0.0475 (18) | −0.0150 (14) | 0.0002 (13) | 0.0063 (15) |
O3 | 0.0351 (15) | 0.0585 (19) | 0.055 (2) | −0.0167 (15) | 0.0014 (14) | 0.0097 (16) |
O4 | 0.063 (2) | 0.123 (4) | 0.066 (3) | −0.036 (3) | −0.012 (2) | 0.037 (3) |
O5 | 0.0261 (13) | 0.0305 (14) | 0.064 (2) | −0.0059 (11) | 0.0027 (12) | 0.0084 (13) |
N1 | 0.040 (2) | 0.053 (2) | 0.049 (2) | −0.0126 (17) | −0.0001 (17) | 0.0080 (19) |
N2 | 0.0222 (14) | 0.0269 (16) | 0.0423 (18) | −0.0040 (12) | 0.0019 (12) | 0.0018 (13) |
C1 | 0.0263 (18) | 0.032 (2) | 0.055 (3) | 0.0016 (15) | 0.0082 (16) | −0.0020 (19) |
C2 | 0.0269 (18) | 0.038 (2) | 0.058 (3) | −0.0020 (16) | 0.0120 (18) | 0.0030 (19) |
C3 | 0.0305 (18) | 0.034 (2) | 0.035 (2) | −0.0053 (16) | −0.0005 (15) | 0.0010 (16) |
C4 | 0.034 (2) | 0.028 (2) | 0.063 (3) | 0.0020 (16) | 0.0099 (19) | −0.0016 (19) |
C5 | 0.0255 (18) | 0.033 (2) | 0.065 (3) | 0.0004 (16) | 0.0125 (18) | 0.000 (2) |
C6 | 0.044 (2) | 0.037 (2) | 0.058 (3) | −0.0086 (19) | 0.006 (2) | 0.007 (2) |
U—O1 | 1.769 (3) | N2—C1 | 1.344 (5) |
U—O1i | 1.769 (3) | C1—C2 | 1.373 (6) |
U—O5i | 2.376 (3) | C1—H1A | 0.9400 |
U—O5 | 2.376 (3) | C2—C3 | 1.387 (6) |
U—O2i | 2.518 (3) | C2—H2A | 0.9400 |
U—O2 | 2.518 (3) | C3—C4 | 1.386 (5) |
U—O3i | 2.544 (3) | C3—C6 | 1.502 (5) |
U—O3 | 2.544 (3) | C4—C5 | 1.368 (6) |
O2—N1 | 1.272 (5) | C4—H4A | 0.9400 |
O3—N1 | 1.269 (5) | C5—H5A | 0.9400 |
O4—N1 | 1.214 (5) | C6—H6A | 0.9700 |
O5—N2 | 1.345 (4) | C6—H6B | 0.9700 |
N2—C5 | 1.341 (5) | C6—H6C | 0.9700 |
O1—U—O1i | 180.0 (3) | N1—O3—U | 96.7 (2) |
O1—U—O5i | 89.13 (11) | N2—O5—U | 132.4 (2) |
O1i—U—O5i | 90.87 (11) | O4—N1—O2 | 122.0 (4) |
O1—U—O5 | 90.87 (11) | O4—N1—O3 | 122.7 (4) |
O1i—U—O5 | 89.13 (11) | O2—N1—O3 | 115.3 (4) |
O5i—U—O5 | 180.00 (13) | C5—N2—O5 | 121.2 (3) |
O1—U—O2i | 89.32 (13) | C5—N2—C1 | 120.9 (3) |
O1i—U—O2i | 90.68 (13) | O5—N2—C1 | 117.8 (3) |
O5i—U—O2i | 114.18 (10) | N2—C1—C2 | 119.8 (4) |
O5—U—O2i | 65.82 (10) | N2—C1—H1A | 120.1 |
O1—U—O2 | 90.68 (13) | C2—C1—H1A | 120.1 |
O1i—U—O2 | 89.32 (13) | C1—C2—C3 | 121.3 (4) |
O5i—U—O2 | 65.82 (10) | C1—C2—H2A | 119.3 |
O5—U—O2 | 114.18 (10) | C3—C2—H2A | 119.3 |
O2i—U—O2 | 180.00 (17) | C4—C3—C2 | 116.4 (4) |
O1—U—O3i | 86.18 (14) | C4—C3—C6 | 121.5 (4) |
O1i—U—O3i | 93.82 (14) | C2—C3—C6 | 122.0 (4) |
O5i—U—O3i | 64.07 (10) | C5—C4—C3 | 121.3 (4) |
O5—U—O3i | 115.93 (10) | C5—C4—H4A | 119.3 |
O2i—U—O3i | 50.18 (9) | C3—C4—H4A | 119.3 |
O2—U—O3i | 129.82 (9) | N2—C5—C4 | 120.1 (3) |
O1—U—O3 | 93.82 (14) | N2—C5—H5A | 119.9 |
O1i—U—O3 | 86.18 (14) | C4—C5—H5A | 119.9 |
O5i—U—O3 | 115.93 (10) | C3—C6—H6A | 109.5 |
O5—U—O3 | 64.07 (10) | C3—C6—H6B | 109.5 |
O2i—U—O3 | 129.82 (9) | H6A—C6—H6B | 109.5 |
O2—U—O3 | 50.18 (9) | C3—C6—H6C | 109.5 |
O3i—U—O3 | 180.00 (17) | H6A—C6—H6C | 109.5 |
N1—O2—U | 97.8 (2) | H6B—C6—H6C | 109.5 |
Symmetry code: (i) −x+1, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | [UO2(NO3)2(C6H7NO)2] |
Mr | 612.30 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 203 |
a, b, c (Å) | 7.9772 (2), 13.5738 (2), 8.2288 (2) |
β (°) | 91.583 (2) |
V (Å3) | 890.68 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 9.17 |
Crystal size (mm) | 0.32 × 0.26 × 0.22 |
Data collection | |
Diffractometer | Siemens SMART diffractometer |
Absorption correction | Multi-scan (Blessing, 1995) |
Tmin, Tmax | 0.088, 0.133 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8841, 1998, 1750 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.052, 1.24 |
No. of reflections | 1998 |
No. of parameters | 125 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.35, −0.65 |
Computer programs: SMART (Siemens, 1995), SMART, SAINT (Siemens, 1995), SHELXS (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Siemens, 1994), SHELXL97.
U—O1 | 1.769 (3) | O2—N1 | 1.272 (5) |
U—O5 | 2.376 (3) | O3—N1 | 1.269 (5) |
U—O2 | 2.518 (3) | O4—N1 | 1.214 (5) |
U—O3 | 2.544 (3) |
Although aromatic N-oxide complexes of uranium(VI) have been known for some time (Ahuja & Singh, 1973, and references therein), few have been structurally characterized. Those that have been structurally characterized invariably have a second donor group attached to the aromatic ring giving bidentate ligands. One such example is (2,2'-bipyridine N,N'-dioxide)dinitratodioxouranium(VI) (Alcock & Roberts, 1987) in which the uranium is eight-coordinate via two bidentate nitrate groups, two N-oxide O atoms and the two oxo ligands.
The title compound, (I), is eight-coordinate, with a hexagonal bipyramidal geometry. The U atom lies on a centre of symmetry, dictating a trans arrangement of the N-oxide ligands unlike the 2,2'-bipyridine N,N'-dioxide complex where a cis arrangement is dictated by ligand constraints. The NO3 groups are bound slightly asymmetrically, with U—O bonds of 2.518 (3) and 2.544 (3) Å. These are significantly longer than the U—O (N-oxide) bonds of 2.376 (3) Å. These values are comparable to those found in the 2,2'-bipyridine N,N'-dioxide complex of 2.513 (18) and 2.378 (14) Å (Alcock & Roberts, 1987). The U═O distance is 1.769 (3) Å, which is typical of values found in uranyl complexes. There are no significant intermolecular interactions.