Diacetatodiaqua­dioxouranium(VI) acetic acid disolvate

The coordination polyhedron of the U atom in the title compound, [U(C₂H₃O₂)₂O₂(H₂O)₂]·2CH₃COOH, is a distorted hexa­gonal bipyramid, with the equatorial positions occupied by four O atoms of two bidentate-chelating acetate anions and two O atoms of coordinated water mol­ecules. The complex lies on an inversion centre. A two-dimensional network of hydrogen bonds is present in the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.022
• wR factor = 0.051
• Data-to-parameter ratio = 20.9

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.168     0.289
            Tmin and Tmax expected:      0.121     0.289
            RR =      1.391
            Please check that your absorption correction is appropriate.
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.36
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature .        293 K
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.26
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              C2 H4 O2

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

Carboxylate compounds of the actinides play a significant role in laboratory practice and radiochemical industry. Several uranyl compounds are known, in which both acetate anions and acetic acid molecules are present (Ramos Silva et al., 1999; Grigor'ev et al., 2004). Here, we present a further example of a uranyl acetate compound, (I), containing acetic acid as solvate.

The U atom in compound (I) lies on an inversion centre. Itscoordination polyhedron is a distorted hexagonal bipyramid, with the equatorial positions occupied by four O atoms of two bidentate-chelating acetate anions and two O atoms of coordination water molecules (Fig. 1). Crystallographically independent bond lengths in the U-atom environment are given in Table 1.

The coordination water and solvate acetic acid molecules act as H donors in several types of hydrogen bonds (Table 2). The acceptors in these bonds are O atoms of acetate anions and acetic acid. The hydrogen bonding results in the formation of infinite chains in the [100] direction (Fig. 2) and these chains are combined into layers parallel to the (011) plane (Fig. 3).

S2. Experimental

Crystals of (I) were obtained as an admixture in an attempt to recrystallize anhydrous uranyl acetate in glacial acetic acid at 413 K.

S3. Refinement

All H atoms were initially located in a difference Fourier map. The methyl H atoms were then constrained to an ideal geometry, with C—H distances of 0.96 Å and U_iso(H) = 1.5U_eq(C), but each group was allowed to rotate freely about its C—C bond. The positions of H atoms bonded to O atoms were refined freely along with isotropic displacement parameters.

Computing details

Data collection: P3/PC (Siemens, 1989); cell refinement: P3/PC; data reduction: P3/PC; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1998); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. A view of (I), showing the atom-labelling scheme for the asymmetric unit. Displacement ellipsoids are drawn at the 50% probability level and H atoms are represented by circles of arbitrary size. Dashed lines indicate the hydrogen-bonding interactions.
	Fig. 2. Part of an infinite chain in the crystal structure of (I).
	Fig. 3. A layer in the crystal structure of (I), viewed along the direction of the chains.

Bis(acetato)diaquadioxouranium(VI) acetic acid disolvate

Crystal data

[UO2(C2H3O2)2(H2O)2]·2C2H4O2	Z = 1
Mr = 544.25	F(000) = 254
Triclinic, P1	Dx = 2.291 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.914 (2) Å	Cell parameters from 24 reflections
b = 7.822 (2) Å	θ = 13.1–14.0°
c = 8.211 (2) Å	µ = 10.34 mm^−1
α = 95.00 (2)°	T = 293 K
β = 113.74 (2)°	Irregular, yellow
γ = 99.79 (2)°	0.24 × 0.18 × 0.12 mm
V = 394.6 (2) Å^3

Data collection

Siemens P3/PC diffractometer	2316 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.021
Graphite monochromator	θmax = 30.1°, θmin = 2.7°
ω/2θ scans	h = 0→9
Absorption correction: ψ scan (North et al., 1968)	k = −11→10
Tmin = 0.168, Tmax = 0.289	l = −11→10
2494 measured reflections	2 standard reflections every 98 reflections
2316 independent reflections	intensity decay: 0.0%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.022	Hydrogen site location: difference Fourier map
wR(F^2) = 0.051	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0313P)^2] where P = (Fo^2 + 2Fc^2)/3
2316 reflections	(Δ/σ)max < 0.001
111 parameters	Δρmax = 1.36 e Å^−3
0 restraints	Δρmin = −1.55 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
U	0.5000	0.5000	0.5000	0.02319 (6)
O1	0.8816 (4)	0.6529 (4)	0.6462 (4)	0.0421 (7)
H1A	0.936 (10)	0.717 (8)	0.754 (9)	0.052 (15)*
H1B	0.964 (14)	0.638 (11)	0.613 (12)	0.09 (3)*
O2	0.5474 (5)	0.4010 (4)	0.6929 (4)	0.0388 (6)
O3	0.4226 (4)	0.2003 (3)	0.3289 (4)	0.0388 (6)
O4	0.7500 (4)	0.3501 (3)	0.4119 (4)	0.0347 (5)
C1	0.6119 (6)	0.2055 (4)	0.3420 (5)	0.0284 (6)
C2	0.6669 (7)	0.0461 (5)	0.2752 (7)	0.0422 (9)
H2A	0.5488	−0.0538	0.2437	0.063*
H2B	0.7952	0.0252	0.3681	0.063*
H2C	0.6923	0.0639	0.1706	0.063*
O5	0.0829 (6)	−0.1835 (5)	−0.0019 (4)	0.0480 (7)
O6	0.1202 (5)	−0.0887 (4)	0.2740 (4)	0.0405 (6)
H6	0.217 (10)	−0.006 (8)	0.272 (8)	0.049 (15)*
C3	0.0257 (6)	−0.1988 (5)	0.1181 (5)	0.0332 (7)
C4	−0.1547 (9)	−0.3402 (6)	0.1096 (7)	0.0507 (11)
H4A	−0.1605	−0.4471	0.0391	0.076*
H4B	−0.2897	−0.3048	0.0545	0.076*
H4C	−0.1300	−0.3594	0.2295	0.076*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
U	0.01944 (8)	0.02120 (8)	0.02777 (9)	0.00096 (5)	0.01174 (6)	−0.00310 (5)
O1	0.0222 (12)	0.0482 (16)	0.0470 (16)	−0.0042 (11)	0.0164 (11)	−0.0211 (13)
O2	0.0422 (15)	0.0369 (13)	0.0379 (14)	0.0070 (11)	0.0185 (12)	0.0062 (11)
O3	0.0248 (12)	0.0300 (12)	0.0569 (17)	0.0010 (9)	0.0184 (12)	−0.0119 (11)
O4	0.0266 (11)	0.0294 (11)	0.0466 (15)	0.0003 (9)	0.0195 (11)	−0.0085 (10)
C1	0.0284 (15)	0.0292 (14)	0.0294 (15)	0.0051 (12)	0.0159 (13)	−0.0014 (12)
C2	0.044 (2)	0.0322 (17)	0.057 (2)	0.0092 (15)	0.0303 (19)	−0.0053 (16)
O5	0.0474 (17)	0.0554 (18)	0.0382 (15)	0.0018 (14)	0.0213 (13)	−0.0047 (13)
O6	0.0463 (16)	0.0355 (13)	0.0344 (14)	−0.0029 (12)	0.0186 (12)	−0.0038 (11)
C3	0.0358 (17)	0.0293 (15)	0.0328 (17)	0.0087 (13)	0.0130 (14)	0.0015 (13)
C4	0.054 (3)	0.040 (2)	0.050 (2)	−0.0085 (19)	0.023 (2)	−0.0008 (18)

Geometric parameters (Å, º)

U—O2^i	1.760 (3)	C1—C2	1.487 (5)
U—O2	1.760 (3)	C2—H2A	0.9600
U—O1	2.441 (3)	C2—H2B	0.9600
U—O1^i	2.441 (3)	C2—H2C	0.9600
U—O3^i	2.480 (3)	O5—C3	1.208 (5)
U—O3	2.480 (3)	O6—C3	1.323 (4)
U—O4	2.536 (3)	O6—H6	0.86 (6)
U—O4^i	2.536 (3)	C3—C4	1.493 (6)
O1—H1A	0.88 (7)	C4—H4A	0.9600
O1—H1B	0.75 (9)	C4—H4B	0.9600
O3—C1	1.262 (4)	C4—H4C	0.9600
O4—C1	1.265 (4)
O2^i—U—O2	180.000 (1)	O3—U—O4^i	128.94 (8)
O2^i—U—O1	92.61 (14)	O4—U—O4^i	180.000 (1)
O2—U—O1	87.39 (14)	U—O1—H1A	121 (4)
O2^i—U—O1^i	87.39 (13)	U—O1—H1B	124 (7)
O2—U—O1^i	92.61 (14)	H1A—O1—H1B	114 (7)
O1—U—O1^i	180.0	C1—O3—U	96.8 (2)
O2^i—U—O3^i	86.98 (13)	C1—O4—U	94.0 (2)
O2—U—O3^i	93.02 (13)	O3—C1—O4	117.7 (3)
O1—U—O3^i	64.58 (10)	O3—C1—C2	120.4 (3)
O1^i—U—O3^i	115.42 (10)	O4—C1—C2	121.9 (3)
O2^i—U—O3	93.02 (13)	C1—C2—H2A	109.5
O2—U—O3	86.98 (13)	C1—C2—H2B	109.5
O1—U—O3	115.42 (10)	H2A—C2—H2B	109.5
O1^i—U—O3	64.58 (10)	C1—C2—H2C	109.5
O3^i—U—O3	180.0	H2A—C2—H2C	109.5
O2^i—U—O4	86.50 (12)	H2B—C2—H2C	109.5
O2—U—O4	93.50 (12)	C3—O6—H6	110 (4)
O1—U—O4	65.22 (9)	O5—C3—O6	122.3 (4)
O1^i—U—O4	114.78 (9)	O5—C3—C4	125.0 (4)
O3^i—U—O4	128.94 (8)	O6—C3—C4	112.7 (4)
O3—U—O4	51.06 (8)	C3—C4—H4A	109.5
O2^i—U—O4^i	93.50 (12)	C3—C4—H4B	109.5
O2—U—O4^i	86.50 (12)	H4A—C4—H4B	109.5
O1—U—O4^i	114.78 (9)	C3—C4—H4C	109.5
O1^i—U—O4^i	65.22 (9)	H4A—C4—H4C	109.5
O3^i—U—O4^i	51.06 (8)	H4B—C4—H4C	109.5

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H6···O3	0.86 (6)	1.84 (6)	2.672 (4)	163 (6)
O1—H1A···O5^ii	0.88 (7)	1.86 (7)	2.727 (4)	168 (6)
O1—H1B···O4^iii	0.75 (9)	2.05 (9)	2.778 (4)	163 (9)

Symmetry codes: (ii) x+1, y+1, z+1; (iii) −x+2, −y+1, −z+1.