A 35-year-old mystery solved: a facile synthetic route and structural confirmation of tetra­chloro­bis­(diethyl ether)tungsten(IV)

The true identity of the diethyl ether adduct of tungsten(IV) chloride, WCl₄(Et₂O)_x, has been in doubt since 1985. Initially postulated as the bis-adduct, WCl₄(Et₂O)₂, questions arose when elemental analyses were more in line with a mono-ether adduct, viz. WCl₄(Et₂O). It was proposed that this was due to the thermal instability of the bis-adduct. Here, we report the room-tem­per­ature X-ray crystal structure and Hirshfeld surface characteristics of trans-tetra­chlor­ido­bis­(diethyl ether)tungsten(IV), trans-WCl₄(Et₂O)₂ or trans-[WCl₄(C₄H₁₀O)₂]. The com­pound crystallizes, with half of the mol­ecule in the asymmetric unit, in the centrosymmetric space group P2₁/n. The W—O distance is 2.070 (2) Å, while the W—Cl distances are 2.3586 (10) and 2.3554 (10) Å.

Computing details

Data collection: CrysAlis PRO (Rigaku OD, 2019); cell refinement: CrysAlis PRO (Rigaku OD, 2019); data reduction: CrysAlis PRO (Rigaku OD, 2019); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

trans-Tetrachloridobis(diethyl ether-κO)tungsten(IV)

Crystal data

[WCl4(C4H10O)2]	F(000) = 452
Mr = 473.89	Dx = 2.083 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 7.5962 (3) Å	Cell parameters from 2974 reflections
b = 11.4871 (4) Å	θ = 2.9–29.6°
c = 9.0245 (4) Å	µ = 8.33 mm^−1
β = 106.339 (4)°	T = 297 K
V = 755.66 (5) Å^3	Block, clear dark yellow
Z = 2	0.26 × 0.15 × 0.08 mm

Data collection

XtaLAB Mini II diffractometer	2198 independent reflections
Radiation source: fine-focus sealed X-ray tube, Rigaku (Mo) X-ray Source	1587 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
Detector resolution: 10.0000 pixels mm^-1	θmax = 30.7°, θmin = 3.0°
ω scans	h = −10→10
Absorption correction: analytical (CrysAlis PRO; Rigaku OD, 2019)	k = −16→15
Tmin = 0.514, Tmax = 0.771	l = −12→12
5730 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.026	w = 1/[σ^2(Fo^2) + (0.0201P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.058	(Δ/σ)max < 0.001
S = 1.01	Δρmax = 0.97 e Å^−3
2198 reflections	Δρmin = −0.84 e Å^−3
73 parameters	Extinction correction: SHELXL2018 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0042 (3)
Primary atom site location: dual

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
W1	0.500000	0.500000	0.500000	0.02813 (8)
Cl1	0.50132 (15)	0.62664 (9)	0.29459 (12)	0.0478 (3)
Cl2	0.18755 (13)	0.46261 (10)	0.37950 (14)	0.0499 (3)
O1	0.5713 (3)	0.36274 (19)	0.3799 (3)	0.0351 (6)
C3	0.4782 (5)	0.2489 (3)	0.3603 (4)	0.0432 (9)
H3A	0.431735	0.231808	0.250967	0.052*
H3B	0.374195	0.252988	0.402553	0.052*
C1	0.7191 (5)	0.3719 (3)	0.3027 (4)	0.0416 (9)
H1A	0.809652	0.311634	0.342222	0.050*
H1B	0.779554	0.446707	0.327048	0.050*
C2	0.6467 (5)	0.3597 (4)	0.1311 (5)	0.0625 (13)
H2A	0.741798	0.378525	0.084061	0.094*
H2B	0.545042	0.411744	0.093420	0.094*
H2C	0.606815	0.281033	0.105847	0.094*
C4	0.6026 (5)	0.1521 (3)	0.4381 (5)	0.0640 (13)
H4A	0.699018	0.142437	0.389573	0.096*
H4B	0.533600	0.081207	0.429453	0.096*
H4C	0.654820	0.170806	0.545233	0.096*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
W1	0.02576 (11)	0.03029 (12)	0.02982 (12)	−0.00172 (8)	0.01026 (8)	0.00141 (10)
Cl1	0.0638 (7)	0.0434 (6)	0.0416 (6)	0.0016 (5)	0.0236 (5)	0.0107 (5)
Cl2	0.0297 (4)	0.0603 (6)	0.0569 (7)	−0.0043 (4)	0.0074 (5)	−0.0078 (6)
O1	0.0341 (13)	0.0310 (13)	0.0466 (16)	−0.0052 (10)	0.0218 (12)	−0.0061 (12)
C3	0.045 (2)	0.035 (2)	0.052 (3)	−0.0119 (17)	0.016 (2)	−0.008 (2)
C1	0.036 (2)	0.044 (2)	0.053 (3)	0.0007 (16)	0.0257 (19)	−0.002 (2)
C2	0.069 (3)	0.073 (3)	0.053 (3)	0.006 (2)	0.029 (3)	−0.003 (3)
C4	0.082 (3)	0.035 (2)	0.075 (3)	0.001 (2)	0.021 (3)	0.004 (2)

Geometric parameters (Å, º)

W1—Cl1^i	2.3586 (10)	C3—C4	1.500 (5)
W1—Cl1	2.3586 (10)	C1—H1A	0.9700
W1—Cl2^i	2.3554 (10)	C1—H1B	0.9700
W1—Cl2	2.3554 (10)	C1—C2	1.497 (4)
W1—O1^i	2.070 (2)	C2—H2A	0.9600
W1—O1	2.070 (2)	C2—H2B	0.9600
O1—C1	1.482 (3)	C2—H2C	0.9600
O1—C3	1.473 (4)	C4—H4A	0.9600
C3—H3A	0.9700	C4—H4B	0.9600
C3—H3B	0.9700	C4—H4C	0.9600
Cl1—W1—Cl1^i	180.0	H3A—C3—H3B	107.8
Cl2—W1—Cl1^i	91.37 (4)	C4—C3—H3A	109.1
Cl2^i—W1—Cl1	91.37 (4)	C4—C3—H3B	109.1
Cl2^i—W1—Cl1^i	88.63 (4)	O1—C1—H1A	109.2
Cl2—W1—Cl1	88.63 (4)	O1—C1—H1B	109.2
Cl2^i—W1—Cl2	180.0	O1—C1—C2	111.9 (3)
O1^i—W1—Cl1^i	89.92 (7)	H1A—C1—H1B	107.9
O1—W1—Cl1	89.92 (7)	C2—C1—H1A	109.2
O1^i—W1—Cl1	90.08 (7)	C2—C1—H1B	109.2
O1—W1—Cl1^i	90.08 (7)	C1—C2—H2A	109.5
O1—W1—Cl2^i	90.16 (7)	C1—C2—H2B	109.5
O1^i—W1—Cl2	90.16 (7)	C1—C2—H2C	109.5
O1—W1—Cl2	89.84 (7)	H2A—C2—H2B	109.5
O1^i—W1—Cl2^i	89.84 (7)	H2A—C2—H2C	109.5
O1—W1—O1^i	180.0	H2B—C2—H2C	109.5
C3—O1—W1	123.46 (18)	C3—C4—H4A	109.5
C3—O1—C1	114.1 (2)	C3—C4—H4B	109.5
C1—O1—W1	122.43 (19)	C3—C4—H4C	109.5
O1—C3—H3A	109.1	H4A—C4—H4B	109.5
O1—C3—H3B	109.1	H4A—C4—H4C	109.5
O1—C3—C4	112.6 (3)	H4B—C4—H4C	109.5
W1—O1—C3—C4	−115.4 (3)	C3—O1—C1—C2	63.1 (4)
W1—O1—C1—C2	−115.7 (3)	C1—O1—C3—C4	65.8 (4)

Symmetry code: (i) −x+1, −y+1, −z+1.