Download citation
Download citation
link to html
The title compound, [UO2(NO3)2(C6H7NO)2], has a centre of symmetry. This is the first uranyl complex of a simple monodentate N-oxide ligand to be structurally characterized.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014805/ob6071sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014805/ob6071Isup2.hkl
Contains datablock I

CCDC reference: 175330

Key indicators

  • Single-crystal X-ray study
  • T = 203 K
  • Mean [sigma](C-C) = 0.006 Å
  • R factor = 0.022
  • wR factor = 0.052
  • Data-to-parameter ratio = 16.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
ABSTM_02 Alert C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10 Tmin and Tmax reported: 0.088 0.133 Tmin and Tmax expected: 0.070 0.133 RR = 1.255 Please check that your absorption correction is appropriate. SHFSU_01 Alert C The absolute value of parameter shift to su ratio > 0.05 Absolute value of the parameter shift to su ratio given 0.058 Additional refinement cycles may be required.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

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 UO distance is 1.769 (3) Å, which is typical of values found in uranyl complexes. There are no significant intermolecular interactions.

Experimental top

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.

Refinement top

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.

Computing details top

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.

Figures top
[Figure 1] Fig. 1. The structure of (I) showing 50% probability displacement ellipsoids. H atoms have been omitted.
Dinitratodioxobis(4-picoline N-oxide)uranium(VI) top
Crystal data top
[UO2(NO3)2(C6H7NO)2]F(000) = 572
Mr = 612.30Dx = 2.283 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 7.9772 (2) ÅCell parameters from 6110 reflections
b = 13.5738 (2) Åθ = 2–26°
c = 8.2288 (2) ŵ = 9.17 mm1
β = 91.583 (2)°T = 203 K
V = 890.68 (3) Å3Prism, yellow
Z = 20.32 × 0.26 × 0.22 mm
Data collection top
Siemens SMART
diffractometer
1998 independent reflections
Radiation source: fine-focus sealed tube1750 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.020
Area–detector ω scansθmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan
(Blessing, 1995)
h = 1010
Tmin = 0.088, Tmax = 0.133k = 017
8841 measured reflectionsl = 010
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)] = 0.022Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.052H-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 parametersΔρmax = 0.35 e Å3
0 restraintsΔρmin = 0.65 e Å3
Crystal data top
[UO2(NO3)2(C6H7NO)2]V = 890.68 (3) Å3
Mr = 612.30Z = 2
Monoclinic, P21/cMo Kα radiation
a = 7.9772 (2) ŵ = 9.17 mm1
b = 13.5738 (2) ÅT = 203 K
c = 8.2288 (2) Å0.32 × 0.26 × 0.22 mm
β = 91.583 (2)°
Data collection top
Siemens SMART
diffractometer
1998 independent reflections
Absorption correction: multi-scan
(Blessing, 1995)
1750 reflections with I > 2σ(I)
Tmin = 0.088, Tmax = 0.133Rint = 0.020
8841 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0220 restraints
wR(F2) = 0.052H-atom parameters constrained
S = 1.24Δρmax = 0.35 e Å3
1998 reflectionsΔρmin = 0.65 e Å3
125 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
U0.50000.00000.00000.03137 (7)
O10.4182 (3)0.1119 (2)0.0744 (4)0.0411 (7)
O20.4078 (4)0.0894 (2)0.2504 (4)0.0466 (8)
O30.6626 (4)0.0385 (3)0.2626 (4)0.0496 (8)
O40.5620 (5)0.1196 (4)0.4666 (5)0.0841 (15)
O50.7773 (3)0.0636 (2)0.0205 (4)0.0402 (7)
N10.5452 (5)0.0839 (3)0.3319 (5)0.0477 (9)
N20.8448 (4)0.1495 (2)0.0266 (4)0.0305 (7)
C11.0004 (5)0.1475 (3)0.0851 (6)0.0379 (9)
H1A1.05730.08730.09500.045*
C21.0760 (5)0.2338 (3)0.1304 (6)0.0406 (10)
H2A1.18520.23190.17040.049*
C30.9946 (5)0.3236 (3)0.1182 (5)0.0334 (8)
C40.8339 (5)0.3213 (3)0.0584 (6)0.0414 (10)
H4A0.77350.38040.04930.050*
C50.7614 (5)0.2347 (3)0.0123 (6)0.0409 (10)
H5A0.65290.23490.02940.049*
C61.0758 (6)0.4187 (3)0.1663 (6)0.0464 (11)
H6A1.14520.40750.25950.070*
H6B1.14490.44310.07620.070*
H6C0.98990.46680.19420.070*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
U0.02075 (10)0.02665 (11)0.04704 (13)0.00248 (8)0.00718 (7)0.00057 (9)
O10.0318 (14)0.0309 (14)0.0609 (19)0.0016 (11)0.0108 (13)0.0049 (13)
O20.0317 (15)0.061 (2)0.0475 (18)0.0150 (14)0.0002 (13)0.0063 (15)
O30.0351 (15)0.0585 (19)0.055 (2)0.0167 (15)0.0014 (14)0.0097 (16)
O40.063 (2)0.123 (4)0.066 (3)0.036 (3)0.012 (2)0.037 (3)
O50.0261 (13)0.0305 (14)0.064 (2)0.0059 (11)0.0027 (12)0.0084 (13)
N10.040 (2)0.053 (2)0.049 (2)0.0126 (17)0.0001 (17)0.0080 (19)
N20.0222 (14)0.0269 (16)0.0423 (18)0.0040 (12)0.0019 (12)0.0018 (13)
C10.0263 (18)0.032 (2)0.055 (3)0.0016 (15)0.0082 (16)0.0020 (19)
C20.0269 (18)0.038 (2)0.058 (3)0.0020 (16)0.0120 (18)0.0030 (19)
C30.0305 (18)0.034 (2)0.035 (2)0.0053 (16)0.0005 (15)0.0010 (16)
C40.034 (2)0.028 (2)0.063 (3)0.0020 (16)0.0099 (19)0.0016 (19)
C50.0255 (18)0.033 (2)0.065 (3)0.0004 (16)0.0125 (18)0.000 (2)
C60.044 (2)0.037 (2)0.058 (3)0.0086 (19)0.006 (2)0.007 (2)
Geometric parameters (Å, º) top
U—O11.769 (3)N2—C11.344 (5)
U—O1i1.769 (3)C1—C21.373 (6)
U—O5i2.376 (3)C1—H1A0.9400
U—O52.376 (3)C2—C31.387 (6)
U—O2i2.518 (3)C2—H2A0.9400
U—O22.518 (3)C3—C41.386 (5)
U—O3i2.544 (3)C3—C61.502 (5)
U—O32.544 (3)C4—C51.368 (6)
O2—N11.272 (5)C4—H4A0.9400
O3—N11.269 (5)C5—H5A0.9400
O4—N11.214 (5)C6—H6A0.9700
O5—N21.345 (4)C6—H6B0.9700
N2—C51.341 (5)C6—H6C0.9700
O1—U—O1i180.0 (3)N1—O3—U96.7 (2)
O1—U—O5i89.13 (11)N2—O5—U132.4 (2)
O1i—U—O5i90.87 (11)O4—N1—O2122.0 (4)
O1—U—O590.87 (11)O4—N1—O3122.7 (4)
O1i—U—O589.13 (11)O2—N1—O3115.3 (4)
O5i—U—O5180.00 (13)C5—N2—O5121.2 (3)
O1—U—O2i89.32 (13)C5—N2—C1120.9 (3)
O1i—U—O2i90.68 (13)O5—N2—C1117.8 (3)
O5i—U—O2i114.18 (10)N2—C1—C2119.8 (4)
O5—U—O2i65.82 (10)N2—C1—H1A120.1
O1—U—O290.68 (13)C2—C1—H1A120.1
O1i—U—O289.32 (13)C1—C2—C3121.3 (4)
O5i—U—O265.82 (10)C1—C2—H2A119.3
O5—U—O2114.18 (10)C3—C2—H2A119.3
O2i—U—O2180.00 (17)C4—C3—C2116.4 (4)
O1—U—O3i86.18 (14)C4—C3—C6121.5 (4)
O1i—U—O3i93.82 (14)C2—C3—C6122.0 (4)
O5i—U—O3i64.07 (10)C5—C4—C3121.3 (4)
O5—U—O3i115.93 (10)C5—C4—H4A119.3
O2i—U—O3i50.18 (9)C3—C4—H4A119.3
O2—U—O3i129.82 (9)N2—C5—C4120.1 (3)
O1—U—O393.82 (14)N2—C5—H5A119.9
O1i—U—O386.18 (14)C4—C5—H5A119.9
O5i—U—O3115.93 (10)C3—C6—H6A109.5
O5—U—O364.07 (10)C3—C6—H6B109.5
O2i—U—O3129.82 (9)H6A—C6—H6B109.5
O2—U—O350.18 (9)C3—C6—H6C109.5
O3i—U—O3180.00 (17)H6A—C6—H6C109.5
N1—O2—U97.8 (2)H6B—C6—H6C109.5
Symmetry code: (i) x+1, y, z.

Experimental details

Crystal data
Chemical formula[UO2(NO3)2(C6H7NO)2]
Mr612.30
Crystal system, space groupMonoclinic, P21/c
Temperature (K)203
a, b, c (Å)7.9772 (2), 13.5738 (2), 8.2288 (2)
β (°) 91.583 (2)
V3)890.68 (3)
Z2
Radiation typeMo Kα
µ (mm1)9.17
Crystal size (mm)0.32 × 0.26 × 0.22
Data collection
DiffractometerSiemens SMART
diffractometer
Absorption correctionMulti-scan
(Blessing, 1995)
Tmin, Tmax0.088, 0.133
No. of measured, independent and
observed [I > 2σ(I)] reflections
8841, 1998, 1750
Rint0.020
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.022, 0.052, 1.24
No. of reflections1998
No. of parameters125
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.35, 0.65

Computer programs: SMART (Siemens, 1995), SMART, SAINT (Siemens, 1995), SHELXS (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Siemens, 1994), SHELXL97.

Selected bond lengths (Å) top
U—O11.769 (3)O2—N11.272 (5)
U—O52.376 (3)O3—N11.269 (5)
U—O22.518 (3)O4—N11.214 (5)
U—O32.544 (3)
 

Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds