Chloroheptakis(dimethyl sulfoxide)­uranium(IV) trichloride

In the title complex, [UCl(C₂H₆OS)₇]Cl₃, the uranium metal center is coordinated in a distorted bicapped trigonal prism geometry by seven O atoms from di­methyl sulfoxide ligands and by a terminal chloride ligand. Charge balance is maintained by three outer-sphere chloride ions per uranium(IV) metal center. Principle bond lengths include U-O 2.391 (2)-2.315 (2) Å, U-Cl 2.7207 (9) Å, and average S-O 1.540 (5) Å.

S1. Comment

Uranium tetrachloride readily dissolves in anhydrous dimethylsulfoxide (DMSO) to give deep green solutions from which well formed emerald green crystals can be isolated. Pristine crystals are reported to correctly analyze for UCl₄^.7DMSO, but may be converted to UCl₄^.5DMSO or UCl₄^.3DMSO upon washing with carbon tetrachloride or prolonged exposure to vacuum (Bagnall et al., 1968). Available evidence demonstrates that UCl₄^.3DMSO adopts an auto-ionized structure, [UCl₂(dmso)₆][UCl₆], in both solution and the solid state, composed of discrete eight-coordinate uranium cations and six-coordinate uranium anions (Bombieri & Bagnall, 1975; Sakurai et al., 1980). The central member of the series, UCl₄^.5DMSO, probably adopts the ionic [UCl₃(dmso)₅]Cl structure supported by spectroscopic evidence and by analogy to unpublished structural data cited for the thorium analog (Alvey et al., 1973). Based on its relative thermal stability, the solid state structure of the title complex has been suggested to consist of [UCl₃(dmso)₅]Cl with two additional DMSO molecules weakly held in the crystal lattice (Bagnall et al., 1968; Davies & Miller, 1983). However, we now find that UCl₄^.7DMSO crystallizes as [UCl(dmso)₇]Cl₃.

Complex (I) crystallizes in space group P2₁/n with no unusual intermolecular contacts. The geometry around the eight coordinate uranium (IV) metal center is best described as a distorted bicapped trigonal prism when evaluated by the shape parameters δ' and ϕ, where δ' is the angle of intersection between pairs of faces along the type b edges and ϕ is the torsion angle of the BAAB trapezoidal atoms (δ' (°) = 12.4, 19.7, 45.0, 47.3; and ϕ(°) = 15.4, 17.3. (Porai-Koshits & Aslanov, 1972; Muetterties & Guggenberger, 1974). The vertices of the trigonal prism are defined by five oxygen atoms of the DMSO ligands and by a terminal chloride ligand O1, O2, O3, Cl1, O4 and O7. The two face capping vertices are defined by oxygen atoms O5 and O6. Charge balance is maintained by three outer-sphere chloride ligands per uranium (IV) metal center.

The δ' and ϕ analyses require that dodecahedral A and B site labels be imposed on the eight-coordinate structure. Using this formalism the chloride ligand of the title complex occupies one of the less sterically encumbered B sites, as is generally observed for the related dodecohedral complexes. The U—Cl bond length of 2.7207 (9) Å is within the range of values reported in other seven and eight-coordinate uranium (IV) structures e.g. 2.813 (4) Å [UCl(OPMe₃)₆]⁺³ (Bombieri et al., 1976); 2.62 (2) and 2.72 (4) Å [UCl₃(EtCONEt₂)₄]⁺ (Bagnall et al., 1982); av. 2.597 (3) Å UCl₄(thf)₃ (Van Der Sluys et al., 1993); 2.665 (5) Å [UCl(dmf)₇]⁺³ (Kepert et al., 1983); 2.70 (2) Å [UCl₂(dmso)₆]⁺² (Bombieri & Bagnall, 1975); 2.624 (4) Å [UCl₄(NCMe)₄] (Cotton et al., 1984); 2.609 (9) Å [UCl₄(Me₂NCH2CH2NMe₂)₂] (Zalkin et al., 1986); 2.869 (3) and 2.638 (4) Å UCl₄ (Taylor & Wilson, 1973).

The U—O bond lengths of the title complex range from 2.391 (2) to 2.315 (2) Å, with an average value of 2.36 (3) Å. The two most closely related uranium(IV) complexes show a similar range of U—O bond lengths e.g. 2.36 (4) to 2.27 (4) Å [UCl₂(dmso)₆]⁺² (Bombieri & Bagnall, 1975) and 2.40 (1) to 2.30 (1) Å [UCl(dmf)₇]⁺³ (Kepert et al., 1983). The S—O bond lengths of the coordinated DMSO ligands are lengthened to an average value of 1.540 (5) Å compared to free DMSO at 1.492 (1) Å (Calligaris & Carugo, 1996).

S2. Experimental

UCl₄ (100 mg, 0.263 mmol) was dissolved in dimethylsulfoxide (10 ml35) to give a homogeneous forest green solution, which was carefully layered with diethylether (10 ml) and allowed to stand for two days. A few well formed deep green crystals were separated and coated with mineral oil. In the absence of mineral oil, isolated crystals rapidly became opaque due to desolvation, as evidenced by elemental analysis, which correctly analyzed for UCl₄^.DMSO. Analysis calculated for C₁₀H₃₀Cl₄O₅S₅U: C 15.67, H 3.94%; found: C 15.56, H 4.16%.

S3. Refinement

Hydrogen atom positions were idealized, and allowed to ride on the attached atoms. All hydrogen atom isotropic temperature factors were set to 0.08 Ų.

Computing details

Data collection: SMART 4.210 (Siemens, 1996); cell refinement: SAINT 4.05 (Siemens, 1996); data reduction: SAINT 4.05 (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL 5.10 (Bruker, 1997); software used to prepare material for publication: SHELXTL 5.10 (Bruker, 1997).

Figures

Fig. 1. Displacement ellipsoid plot (50% probability) showing the molecular structure of [U(C2H6OS)7Cl]Cl3 and giving the atom numbering scheme used in Table 1.

(I)

Crystal data

C14H42Cl4O7S7U	F(000) = 1816
Mr = 926.73	Dx = 1.865 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.6350 (5) Å	Cell parameters from 8192 reflections
b = 22.0785 (11) Å	θ = 1.6–26.4°
c = 15.5217 (8) Å	µ = 5.72 mm^−1
β = 91.818 (1)°	T = 203 K
V = 3300.2 (3) Å^3	Irregular, emerald green
Z = 4	0.12 × 0.10 × 0.04 mm

Data collection

Bruker P4/CCD diffractometer	6416 independent reflections
Radiation source: fine-focus sealed tube	5686 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω and ϕ scans	θmax = 26.4°, θmin = 1.6°
Absorption correction: empirical (using intensity measurements) SADABS (Sheldrick, 1996)	h = −11→11
Tmin = 0.59, Tmax = 0.69	k = −27→25
14577 measured reflections	l = −19→17

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)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.056	H-atom parameters not refined
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0325P)^2] where P = (Fo^2 + 2Fc^2)/3
6416 reflections	(Δ/σ)max = 0.002
298 parameters	Δρmax = 1.05 e Å^−3
0 restraints	Δρmin = −0.91 e Å^−3

Special details

Experimental. Crystal decay determined by comparing equivalent reflections collected throughout the data collection

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
U1	0.251474 (11)	0.094426 (5)	0.306477 (7)	0.01380 (5)
Cl1	−0.02784 (9)	0.08572 (4)	0.32422 (6)	0.0294 (2)
Cl2	0.74604 (9)	−0.13717 (4)	0.20007 (6)	0.0302 (2)
Cl3	0.74530 (11)	0.11411 (6)	0.03553 (8)	0.0513 (3)
Cl4	0.27258 (10)	0.30736 (4)	0.10469 (6)	0.0296 (2)
S1	0.10841 (11)	0.14202 (5)	0.50174 (6)	0.0324 (2)
S2	0.33331 (9)	−0.05097 (4)	0.39659 (5)	0.01960 (17)
S3	0.04666 (8)	−0.03228 (4)	0.21876 (5)	0.01841 (17)
S4	0.22887 (9)	0.11681 (4)	0.07626 (5)	0.02119 (18)
S5	0.04602 (9)	0.23303 (4)	0.32579 (5)	0.02053 (17)
S6	0.50715 (8)	0.00256 (4)	0.21322 (5)	0.01800 (17)
S7	0.50628 (9)	0.21278 (4)	0.34974 (6)	0.02238 (18)
O1	0.2185 (3)	0.10328 (11)	0.45801 (15)	0.0272 (6)
O2	0.3741 (2)	0.01616 (10)	0.38328 (14)	0.0195 (5)
O3	0.1800 (2)	0.00509 (10)	0.23549 (15)	0.0223 (5)
O4	0.2096 (2)	0.13536 (10)	0.17084 (14)	0.0224 (5)
O5	0.1823 (2)	0.19681 (10)	0.32540 (15)	0.0211 (5)
O6	0.4283 (2)	0.06314 (11)	0.21238 (15)	0.0226 (5)
O7	0.4506 (2)	0.14771 (11)	0.35074 (16)	0.0258 (6)
C1	0.0702 (5)	0.0995 (2)	0.5952 (3)	0.0457 (12)
H1A	0.0170	0.0643	0.5788	0.069*
H1B	0.0178	0.1240	0.6335	0.069*
H1C	0.1553	0.0870	0.6238	0.069*
C2	0.2028 (6)	0.2024 (2)	0.5511 (3)	0.0559 (14)
H2A	0.2320	0.2301	0.5076	0.084*
H2B	0.2828	0.1865	0.5818	0.084*
H2C	0.1447	0.2232	0.5906	0.084*
C3	0.4959 (4)	−0.08977 (16)	0.4094 (3)	0.0311 (9)
H3A	0.5388	−0.0927	0.3545	0.047*
H3B	0.4805	−0.1297	0.4316	0.047*
H3C	0.5558	−0.0677	0.4488	0.047*
C4	0.2823 (5)	−0.05308 (18)	0.5062 (2)	0.0369 (10)
H4A	0.1939	−0.0335	0.5109	0.055*
H4B	0.3504	−0.0324	0.5418	0.055*
H4C	0.2753	−0.0944	0.5246	0.055*
C5	−0.0156 (4)	−0.00878 (17)	0.1154 (2)	0.0288 (8)
H5A	−0.0559	0.0308	0.1194	0.043*
H5B	−0.0846	−0.0369	0.0941	0.043*
H5C	0.0601	−0.0076	0.0766	0.043*
C6	0.1122 (4)	−0.10442 (14)	0.1908 (2)	0.0260 (8)
H6A	0.1511	−0.1238	0.2414	0.039*
H6B	0.1828	−0.0997	0.1491	0.039*
H6C	0.0381	−0.1288	0.1668	0.039*
C7	0.1021 (4)	0.16077 (17)	0.0189 (2)	0.0293 (8)
H7A	0.0112	0.1454	0.0299	0.044*
H7B	0.1182	0.1585	−0.0418	0.044*
H7C	0.1084	0.2022	0.0375	0.044*
C8	0.3793 (4)	0.15535 (17)	0.0433 (2)	0.0256 (8)
H8A	0.4602	0.1367	0.0695	0.038*
H8B	0.3747	0.1970	0.0608	0.038*
H8C	0.3845	0.1532	−0.0183	0.038*
C9	−0.0231 (4)	0.23357 (17)	0.2178 (2)	0.0275 (8)
H9A	−0.0615	0.1945	0.2040	0.041*
H9B	0.0496	0.2427	0.1789	0.041*
H9C	−0.0946	0.2638	0.2123	0.041*
C10	0.1053 (4)	0.30907 (16)	0.3299 (3)	0.0327 (9)
H10A	0.1470	0.3172	0.3857	0.049*
H10B	0.0283	0.3360	0.3196	0.049*
H10C	0.1728	0.3152	0.2865	0.049*
C11	0.6796 (4)	0.02402 (18)	0.2417 (2)	0.0300 (9)
H11A	0.6853	0.0352	0.3015	0.045*
H11B	0.7062	0.0579	0.2071	0.045*
H11C	0.7410	−0.0094	0.2319	0.045*
C12	0.5275 (4)	−0.01520 (18)	0.1030 (2)	0.0326 (9)
H12A	0.4399	−0.0278	0.0779	0.049*
H12B	0.5938	−0.0474	0.0982	0.049*
H12C	0.5599	0.0199	0.0732	0.049*
C13	0.6853 (3)	0.20532 (17)	0.3774 (2)	0.0272 (8)
H13A	0.6963	0.1953	0.4374	0.041*
H13B	0.7318	0.2429	0.3665	0.041*
H13C	0.7248	0.1738	0.3433	0.041*
C14	0.5210 (5)	0.23090 (19)	0.2391 (2)	0.0403 (11)
H14A	0.4300	0.2366	0.2134	0.060*
H14B	0.5669	0.1984	0.2104	0.060*
H14C	0.5739	0.2675	0.2337	0.060*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
U1	0.01258 (7)	0.01499 (7)	0.01387 (7)	−0.00035 (4)	0.00107 (5)	0.00115 (5)
Cl1	0.0159 (4)	0.0289 (5)	0.0438 (5)	−0.0047 (3)	0.0069 (4)	−0.0134 (4)
Cl2	0.0290 (5)	0.0259 (4)	0.0356 (5)	−0.0007 (4)	0.0000 (4)	−0.0006 (4)
Cl3	0.0252 (5)	0.0670 (8)	0.0618 (7)	−0.0013 (5)	0.0023 (5)	0.0328 (6)
Cl4	0.0391 (5)	0.0212 (4)	0.0283 (4)	0.0026 (4)	−0.0042 (4)	0.0011 (4)
S1	0.0380 (6)	0.0441 (6)	0.0151 (4)	0.0209 (5)	0.0010 (4)	−0.0022 (4)
S2	0.0228 (4)	0.0159 (4)	0.0199 (4)	0.0004 (3)	−0.0028 (3)	0.0021 (3)
S3	0.0183 (4)	0.0176 (4)	0.0193 (4)	−0.0003 (3)	−0.0005 (3)	−0.0022 (3)
S4	0.0271 (5)	0.0185 (4)	0.0181 (4)	0.0000 (3)	0.0029 (3)	0.0017 (3)
S5	0.0183 (4)	0.0181 (4)	0.0253 (4)	0.0014 (3)	0.0028 (3)	0.0002 (3)
S6	0.0171 (4)	0.0201 (4)	0.0169 (4)	0.0016 (3)	0.0024 (3)	0.0002 (3)
S7	0.0191 (4)	0.0184 (4)	0.0295 (4)	−0.0007 (3)	−0.0022 (4)	−0.0028 (3)
O1	0.0307 (15)	0.0348 (15)	0.0163 (12)	0.0111 (11)	0.0050 (11)	−0.0011 (10)
O2	0.0240 (13)	0.0139 (11)	0.0206 (11)	−0.0024 (9)	0.0001 (10)	0.0043 (9)
O3	0.0156 (12)	0.0228 (12)	0.0281 (13)	−0.0027 (10)	−0.0022 (10)	−0.0073 (10)
O4	0.0246 (13)	0.0256 (13)	0.0173 (11)	0.0071 (10)	0.0030 (10)	0.0038 (10)
O5	0.0185 (12)	0.0180 (12)	0.0266 (12)	0.0026 (9)	−0.0010 (10)	−0.0017 (10)
O6	0.0167 (12)	0.0237 (13)	0.0280 (13)	0.0044 (10)	0.0083 (10)	0.0054 (10)
O7	0.0169 (13)	0.0222 (13)	0.0381 (14)	−0.0055 (10)	−0.0014 (11)	0.0014 (11)
C1	0.040 (3)	0.069 (3)	0.029 (2)	0.015 (2)	0.0163 (19)	0.009 (2)
C2	0.083 (4)	0.045 (3)	0.040 (3)	0.014 (3)	0.002 (3)	−0.016 (2)
C3	0.028 (2)	0.0223 (19)	0.043 (2)	0.0042 (15)	−0.0004 (18)	0.0078 (17)
C4	0.054 (3)	0.029 (2)	0.029 (2)	−0.0047 (19)	0.0175 (19)	0.0035 (16)
C5	0.027 (2)	0.032 (2)	0.0260 (18)	−0.0014 (16)	−0.0100 (16)	0.0048 (16)
C6	0.030 (2)	0.0165 (17)	0.031 (2)	0.0029 (14)	−0.0023 (16)	−0.0033 (14)
C7	0.031 (2)	0.033 (2)	0.0239 (18)	−0.0033 (16)	−0.0045 (16)	0.0030 (16)
C8	0.0234 (19)	0.032 (2)	0.0215 (17)	0.0003 (15)	0.0069 (15)	0.0004 (15)
C9	0.0247 (19)	0.029 (2)	0.0284 (19)	0.0091 (15)	−0.0023 (16)	0.0026 (15)
C10	0.033 (2)	0.0167 (18)	0.049 (2)	0.0018 (15)	0.0007 (19)	−0.0056 (17)
C11	0.0175 (18)	0.040 (2)	0.033 (2)	0.0015 (16)	−0.0023 (16)	0.0002 (17)
C12	0.042 (2)	0.035 (2)	0.0207 (18)	0.0015 (18)	0.0006 (17)	−0.0079 (16)
C13	0.0180 (18)	0.031 (2)	0.0321 (19)	−0.0044 (15)	−0.0075 (15)	0.0053 (16)
C14	0.050 (3)	0.038 (2)	0.031 (2)	−0.014 (2)	−0.017 (2)	0.0144 (18)

Geometric parameters (Å, º)

U1—O4	2.315 (2)	S3—C5	1.773 (3)
U1—O7	2.336 (2)	S3—C6	1.772 (3)
U1—O3	2.352 (2)	S4—O4	1.541 (2)
U1—O5	2.378 (2)	S4—C8	1.770 (4)
U1—O6	2.381 (2)	S4—C7	1.777 (4)
U1—O2	2.390 (2)	S5—O5	1.538 (2)
U1—O1	2.391 (2)	S5—C10	1.774 (4)
U1—Cl1	2.7207 (9)	S5—C9	1.784 (3)
S1—O1	1.537 (3)	S6—O6	1.538 (2)
S1—C1	1.777 (4)	S6—C12	1.772 (3)
S1—C2	1.773 (5)	S6—C11	1.771 (3)
S2—O2	1.549 (2)	S7—O7	1.533 (2)
S2—C3	1.791 (4)	S7—C13	1.772 (3)
S2—C4	1.786 (4)	S7—C14	1.773 (4)
S3—O3	1.542 (2)
O4—U1—O7	100.89 (8)	O1—S1—C1	103.28 (18)
O4—U1—O3	82.03 (8)	O1—S1—C2	104.9 (2)
O7—U1—O3	141.80 (8)	C1—S1—C2	99.3 (2)
O4—U1—O5	72.52 (8)	O2—S2—C3	104.33 (15)
O7—U1—O5	73.48 (8)	O2—S2—C4	103.33 (16)
O3—U1—O5	140.93 (8)	C3—S2—C4	98.5 (2)
O4—U1—O6	70.30 (8)	O3—S3—C5	104.59 (16)
O7—U1—O6	74.31 (8)	O3—S3—C6	102.75 (15)
O3—U1—O6	70.96 (8)	C5—S3—C6	98.88 (18)
O5—U1—O6	124.08 (8)	O4—S4—C8	105.80 (15)
O4—U1—O2	143.62 (8)	O4—S4—C7	103.33 (16)
O7—U1—O2	80.15 (8)	C8—S4—C7	98.54 (17)
O3—U1—O2	76.12 (8)	O5—S5—C10	102.59 (16)
O5—U1—O2	139.62 (7)	O5—S5—C9	107.05 (15)
O6—U1—O2	75.18 (8)	C10—S5—C9	97.91 (18)
O4—U1—O1	146.91 (8)	O6—S6—C12	104.71 (16)
O7—U1—O1	78.64 (9)	O6—S6—C11	103.24 (16)
O3—U1—O1	118.90 (9)	C12—S6—C11	99.68 (19)
O5—U1—O1	75.77 (8)	O7—S7—C13	104.38 (15)
O6—U1—O1	138.33 (8)	O7—S7—C14	105.06 (17)
O2—U1—O1	69.37 (8)	C13—S7—C14	98.55 (19)
O4—U1—Cl1	88.57 (6)	S1—O1—U1	126.50 (13)
O7—U1—Cl1	144.29 (6)	S2—O2—U1	129.40 (12)
O3—U1—Cl1	73.28 (6)	S3—O3—U1	139.25 (14)
O5—U1—Cl1	76.86 (6)	S4—O4—U1	137.71 (13)
O6—U1—Cl1	140.42 (6)	S5—O5—U1	137.53 (13)
O2—U1—Cl1	111.92 (6)	S6—O6—U1	127.58 (13)
O1—U1—Cl1	75.13 (7)	S7—O7—U1	138.86 (14)