Crystal structure of di-μ-iodido-bis-[(dimethyl sulfoxide-κO)(tri-phenyl-phosphane-κP)copper(I)].

The centrosymmetric dinuclear title compound, [Cu2I2(C2H6OS)2(C18H15P)2], represents the first example of a CuI complex ligated by an O-bound dimethyl sulfoxide ligand. In the crystal, the two tetrahedrally coordinated Cu(I) atoms are bridged by two μ2-iodido ligands in an almost symmetrical rhomboid geometry. The loose Cu⋯Cu contact of 2.9874 (8) Å is longer than the sum of the van der Waals radii of two Cu atoms (2.8 Å), excluding a significant cupriophilic inter-action in the actual dimer. C-H⋯O and C-H⋯I hydrogen bonding interactions as well as C-H⋯π(aryl) interactions stabilize the three-dimensional supramolecular network.

Chemical context

There exists a large family of dinuclear CuI⋯CuI-halide-bridged complexes of the type [PPh3(L′)Cu(μ2-I)2Cu(L′)PPh3], with the ligands L commonly bearing the coordinating N and S atoms, in which cupriophilic inter­actions may play a crucial role in determining their photophysical properties (Lobana et al., 2012 ▶ and references therein; Engelhardt et al., 1989 ▶). The title compound, [PPh3(DMSO)Cu(μ2-I)2Cu(DMSO)PPh3] (1), belongs to this family of compounds for which an association of L = PPh3 and L′ = DMSO has never been mentioned before.

Database survey

The polar aprotic solvent (CH3)2S=O (DMSO) is frequently used in organic chemistry for reactions involving salts such nucleophilic substitutions reactions, but it has also found widespread use as a ligating solvent in the coordination chemistry of transition metals, where it may act both as an S-donor and an O-donor ligand towards a metal centre (Selbin et al., 1961 ▶). A survey of the Cambridge Structural Database (CSD; Groom & Allen, 2014 ▶) reveals a large number of structurally characterized CuII halide complexes ligated by O-bound DMSO ligands. However, we found just one entry concerning a CuI halide complex, namely the tetra­metallic chain complex [Cu4Br(μ-Br)3(μ-dpmppm)2(DMSO)2] (dpmppm = bis­[(di­phenyl­phosphinometh­yl)phenyl­phos­phino]methane) reported by Takemura et al. (2009 ▶). Note that in the case of a soft CuI ion (compared with a harder CuII ion according the HSAB principle), DMSO could be a priori coordinating either via the sulfur or via the oxygen atom. Surprisingly, we found no CuII complex ligated by DMSO in the CSD.

Structural commentary

CuI is known to afford with DMSO in the presence of P2S5 the 2D coordination polymer [(Me2S)3{Cu4(μ-I)4}], the production of SMe2 being explained by the de­oxy­genation of Me2SO by P2S5 (Zhou et al., 2006 ▶). In the context of our research on the coordination of thio­ethers R–S–R on CuX salts (Knorr et al., 2010 ▶; Lapprand et al., 2013 ▶), we reacted a CuI solution in hot DMSO with a stoichiometric amount of PPh3 and succeeded in isolating in moderate yield X-ray-suitable crystals of (1). Structural analysis revealed that a centrosymmetric dinuclear complex is formed (Fig. 1 ▶), in which the two tetra­hedrally coordinated CuI atoms are bridged by two μ2-iodido ligands in a slightly asymmetric rhomboid manner. Despite the soft character of CuI, the DMSO ligands are O-bound. The Cu—O bond length of 2.140 (2) Å is considerably longer than those of polymeric CuII compounds [(DMSO)2CuBr2] [1.962 (9) Å; Willett et al., 1977 ▶] and [(DMSO)2CuCl2] [1.955 (4) Å; Willett & Chang, 1970 ▶], but is in the same range as found for [Cu4Br(μ-Br)3(μ-dpmppm)2(DMSO)2] [2.200 (7) Å]. The Cu⋯Cu contact of 2.9874 (8) Å is longer than the sum of the van der Waals radii of two Cu atoms (2.8 Å), excluding any cupriophilic inter­action. This separation is in the same range as reported for [PPh3(pyridine)Cu(μ2-I)2Cu(pyridine)PPh3] (2.97 Å) (Bow­maker et al., 1994 ▶), and the P—Cu bond lengths are also quite similar in the two compounds [2.2295 (10) vs 2.24 Å].

Figure 1

The mol­ecular structure of title compound built over a symmetry centre, with atom labels and 50% probability displacement ellipsoids for non-H atoms. Symmetry code for unlabelled atoms is (1 − x, −y, −z).

Supra­molecular features

The assembly of the crystal structure seems to be first governed by C—H⋯O-type hydrogen bonds (inter­molecular ligand-to-ligand DMSO inter­actions), leading to a 1D chain structure extending in the [110] direction (Fig. 2 ▶). Further, the very weak C—H⋯I inter­actions (for a 2D structure), followed by those of the C—H⋯π(ar­yl) type are probably responsible for the 3D assembly (Table 1 ▶).

Figure 2

One-dimensional chain along [110] built via C—H⋯O inter­molecular inter­actions between the DMSO ligands.

Table 1

Hydrogen-bond geometry (, )

DHA	DH	HA	D A	DHA
C2H2AOi	0.98	2.46	3.434(5)	173
C1H1BIii	0.98	3.12	3.931(4)	142
C2H2BIii	0.98	3.15	3.978(4)	143
C26H26C16iii	0.95	2.85	3.781(5)	168

Symmetry codes: (i) ; (ii) ; (iii) .

Synthesis and crystallization

Tri­phenyl­phosphane (262 mg, 1.0 mmol) was added to a solution of CuI (192 mg, 1.0 mmol) in 10 ml of DMSO. The reaction mixture was first stirred at room temperature for 30 min and then heated for further 30 min to 368 K. After allowing the mixture to reach ambient temperature, yellowish crystals were formed (36% yield). Characterization data: 1H NMR (CDCl3): 2.62 (s, 6H, Me), 7.30–7.57 (m, 15H, Ph).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▶. All H atoms were placed in calculated positions and treated in a riding-model approximation. C—H distances were set to 0.95 (aromatic) and 0.98 Å (meth­yl) with U(H) = xU(C), where x = 1.5 for methyl and 1.2 for aromatic H atoms.

Table 2

Experimental details

Crystal data
Chemical formula	[Cu2I2(C2H6OS)2(C18H15P)2]
M r	1061.67
Crystal system, space group	Triclinic, P
Temperature (K)	115
a, b, c ()	8.6099(2), 9.3435(2), 14.5279(4)
, , ()	91.016(1), 104.049(1), 116.004(1)
V (3)	1008.60(4)
Z	1
Radiation type	Mo K
(mm1)	2.80
Crystal size (mm)	0.17 0.05 0.05
Data collection
Diffractometer	Nonius KappaCCD
No. of measured, independent and observed [I > 2(I)] reflections	8368, 4586, 3541
R int	0.036
(sin /)max (1)	0.649
Refinement
R[F 2 > 2(F 2)], wR(F 2), S	0.035, 0.077, 0.99
No. of reflections	4586
No. of parameters	228
H-atom treatment	H-atom parameters constrained
max, min (e 3)	0.78, 0.98

Computer programs: DENZO and SCALEPACK (Otwinowski Minor, 1997 ▶), SIR97 (Altomare et al., 1999 ▶), SHELXL2012 (Sheldrick, 2008 ▶), ORTEP-3 for Windows and WinGX (Farrugia, 2012 ▶).

Crystal structure: contains datablock(s) I, 08br35. DOI: 10.1107/S1600536814025203/gk2619sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814025203/gk2619Isup2.hkl

CCDC reference: 1034622

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Cu2I2(C2H6OS)2(C18H15P)2]	Z = 1
Mr = 1061.67	F(000) = 524
Triclinic, P1	Dx = 1.748 Mg m−3
a = 8.6099 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.3435 (2) Å	Cell parameters from 8449 reflections
c = 14.5279 (4) Å	θ = 1.0–27.5°
α = 91.016 (1)°	µ = 2.80 mm−1
β = 104.049 (1)°	T = 115 K
γ = 116.004 (1)°	Prism, clear light colourless
V = 1008.60 (4) Å3	0.17 × 0.05 × 0.05 mm

Nonius KappaCCD diffractometer	3541 reflections with I > 2σ(I)
Radiation source: X-ray tube, Enraf–Nonius FR590	Rint = 0.036
Horizonally mounted graphite crystal monochromator	θmax = 27.5°, θmin = 2.9°
Detector resolution: 9 pixels mm-1	h = −11→11
CCD rotation images, thick slices scans	k = −12→12
8368 measured reflections	l = −18→18
4586 independent reflections

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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.077	H-atom parameters constrained
S = 0.99	w = 1/[σ2(Fo2) + (0.0332P)2] where P = (Fo2 + 2Fc2)/3
4586 reflections	(Δ/σ)max = 0.001
228 parameters	Δρmax = 0.78 e Å−3
0 restraints	Δρmin = −0.98 e Å−3

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.

	x	y	z	Uiso*/Ueq
C1	1.1097 (5)	0.1762 (5)	0.1426 (3)	0.0287 (9)
H1A	1.2180	0.1767	0.1319	0.043*
H1B	1.0227	0.0656	0.1443	0.043*
H1C	1.1417	0.2424	0.2038	0.043*
C2	1.2026 (5)	0.4468 (4)	0.0613 (3)	0.0289 (10)
H2A	1.2436	0.4995	0.1276	0.043*
H2B	1.1687	0.5138	0.0179	0.043*
H2C	1.2999	0.4324	0.0458	0.043*
C11	0.4456 (4)	−0.0357 (4)	0.2784 (3)	0.0164 (8)
C12	0.2884 (5)	−0.1295 (4)	0.2069 (3)	0.0261 (9)
H12	0.2763	−0.1044	0.1432	0.031*
C13	0.1487 (5)	−0.2598 (4)	0.2276 (3)	0.0309 (10)
H13	0.0407	−0.3222	0.1784	0.037*
C14	0.1662 (5)	−0.2989 (4)	0.3195 (3)	0.0270 (9)
H14	0.0711	−0.3890	0.3335	0.032*
C15	0.3233 (5)	−0.2061 (4)	0.3913 (3)	0.0228 (8)
H15	0.3355	−0.2321	0.4548	0.027*
C16	0.4625 (5)	−0.0756 (4)	0.3707 (3)	0.0178 (8)
H16	0.5703	−0.0130	0.4199	0.021*
C17	0.8273 (4)	0.1580 (4)	0.3337 (3)	0.0154 (7)
C18	0.8942 (5)	0.0488 (4)	0.3218 (3)	0.0193 (8)
H18	0.8316	−0.0358	0.2693	0.023*
C19	1.0498 (5)	0.0623 (4)	0.3852 (3)	0.0235 (9)
H19	1.0937	−0.0127	0.3763	0.028*
C20	1.1422 (5)	0.1862 (4)	0.4623 (3)	0.0244 (9)
H20	1.2490	0.1959	0.5063	0.029*
C21	1.0783 (5)	0.2938 (4)	0.4742 (3)	0.0240 (9)
H21	1.1414	0.3784	0.5267	0.029*
C22	0.9227 (4)	0.2810 (4)	0.4107 (3)	0.0187 (8)
H22	0.8807	0.3573	0.4198	0.022*
C23	0.5978 (4)	0.3083 (4)	0.2747 (2)	0.0145 (7)
C24	0.6736 (5)	0.4388 (4)	0.2269 (3)	0.0201 (8)
H24	0.7384	0.4338	0.1835	0.024*
C25	0.6536 (5)	0.5769 (4)	0.2431 (3)	0.0236 (9)
H25	0.7075	0.6670	0.2119	0.028*
C26	0.5561 (5)	0.5829 (4)	0.3040 (3)	0.0229 (9)
H26	0.5403	0.6760	0.3131	0.028*
C27	0.4813 (5)	0.4551 (4)	0.3520 (3)	0.0219 (8)
H27	0.4160	0.4612	0.3948	0.026*
C28	0.5013 (4)	0.3171 (4)	0.3378 (3)	0.0180 (8)
H28	0.4496	0.2290	0.3708	0.022*
O	0.8790 (3)	0.2915 (3)	0.0820 (2)	0.0270 (6)
P	0.62437 (12)	0.13151 (10)	0.24350 (7)	0.0145 (2)
S	1.01292 (12)	0.25565 (10)	0.04801 (7)	0.0206 (2)
Cu	0.62834 (6)	0.10410 (5)	0.09145 (3)	0.01942 (12)
I	0.60513 (3)	−0.17153 (2)	0.03064 (2)	0.02049 (9)

	U11	U22	U33	U12	U13	U23
C1	0.023 (2)	0.038 (2)	0.028 (2)	0.0175 (19)	0.0055 (18)	0.0123 (18)
C2	0.0155 (19)	0.023 (2)	0.045 (3)	0.0060 (16)	0.0084 (18)	0.0055 (18)
C11	0.0143 (18)	0.0132 (17)	0.022 (2)	0.0066 (14)	0.0051 (15)	0.0019 (14)
C12	0.024 (2)	0.027 (2)	0.018 (2)	0.0044 (17)	0.0029 (17)	0.0028 (16)
C13	0.016 (2)	0.029 (2)	0.031 (3)	−0.0013 (17)	0.0020 (18)	−0.0011 (18)
C14	0.022 (2)	0.0182 (19)	0.035 (3)	0.0016 (16)	0.0126 (18)	0.0056 (17)
C15	0.026 (2)	0.024 (2)	0.025 (2)	0.0136 (17)	0.0135 (18)	0.0091 (16)
C16	0.0168 (18)	0.0154 (18)	0.021 (2)	0.0070 (15)	0.0063 (15)	0.0023 (15)
C17	0.0111 (17)	0.0169 (18)	0.018 (2)	0.0052 (14)	0.0061 (15)	0.0048 (14)
C18	0.0224 (19)	0.0148 (17)	0.022 (2)	0.0087 (15)	0.0071 (16)	0.0064 (15)
C19	0.024 (2)	0.027 (2)	0.030 (2)	0.0174 (17)	0.0132 (18)	0.0116 (17)
C20	0.0179 (19)	0.032 (2)	0.024 (2)	0.0124 (17)	0.0052 (17)	0.0087 (17)
C21	0.0163 (19)	0.0224 (19)	0.025 (2)	0.0049 (16)	−0.0009 (16)	−0.0038 (16)
C22	0.0152 (18)	0.0184 (18)	0.022 (2)	0.0087 (15)	0.0026 (16)	0.0017 (15)
C23	0.0095 (16)	0.0136 (17)	0.0149 (19)	0.0030 (14)	−0.0016 (14)	−0.0017 (14)
C24	0.0180 (19)	0.0182 (18)	0.023 (2)	0.0073 (15)	0.0049 (16)	0.0033 (15)
C25	0.029 (2)	0.0147 (18)	0.022 (2)	0.0084 (16)	0.0022 (17)	0.0042 (15)
C26	0.024 (2)	0.0166 (19)	0.026 (2)	0.0151 (16)	−0.0068 (17)	−0.0038 (16)
C27	0.0200 (19)	0.024 (2)	0.025 (2)	0.0128 (16)	0.0060 (17)	−0.0005 (16)
C28	0.0162 (18)	0.0177 (18)	0.019 (2)	0.0076 (15)	0.0031 (15)	0.0024 (15)
O	0.0147 (13)	0.0222 (13)	0.0462 (19)	0.0076 (11)	0.0138 (12)	0.0082 (12)
P	0.0139 (4)	0.0123 (4)	0.0175 (5)	0.0062 (4)	0.0042 (4)	0.0020 (4)
S	0.0147 (5)	0.0205 (5)	0.0232 (5)	0.0059 (4)	0.0036 (4)	0.0038 (4)
Cu	0.0195 (2)	0.0204 (2)	0.0200 (3)	0.0100 (2)	0.0066 (2)	0.00351 (19)
I	0.02019 (14)	0.01809 (13)	0.02255 (15)	0.01034 (10)	0.00187 (10)	0.00121 (10)

C1—H1A	0.9800	C19—C20	1.393 (5)
C1—H1B	0.9800	C20—H20	0.9500
C1—H1C	0.9800	C20—C21	1.367 (5)
C1—S	1.777 (4)	C21—H21	0.9500
C2—H2A	0.9800	C21—C22	1.384 (5)
C2—H2B	0.9800	C22—H22	0.9500
C2—H2C	0.9800	C23—C24	1.396 (5)
C2—S	1.781 (3)	C23—C28	1.401 (5)
C11—C12	1.387 (5)	C23—P	1.828 (3)
C11—C16	1.388 (5)	C24—H24	0.9500
C11—P	1.834 (3)	C24—C25	1.398 (4)
C12—H12	0.9500	C25—H25	0.9500
C12—C13	1.386 (5)	C25—C26	1.374 (5)
C13—H13	0.9500	C26—H26	0.9500
C13—C14	1.382 (5)	C26—C27	1.379 (5)
C14—H14	0.9500	C27—H27	0.9500
C14—C15	1.387 (5)	C27—C28	1.392 (4)
C15—H15	0.9500	C28—H28	0.9500
C15—C16	1.386 (5)	O—S	1.514 (2)
C16—H16	0.9500	O—Cu	2.140 (2)
C17—C18	1.399 (4)	P—Cu	2.2295 (10)
C17—C22	1.388 (5)	Cu—Cui	2.9874 (8)
C17—P	1.825 (3)	Cu—I	2.6144 (4)
C18—H18	0.9500	Cu—Ii	2.6463 (5)
C18—C19	1.381 (5)	I—Cui	2.6463 (5)
C19—H19	0.9500
H1A—C1—H1B	109.5	C22—C21—H21	119.6
H1A—C1—H1C	109.5	C17—C22—H22	119.6
H1B—C1—H1C	109.5	C21—C22—C17	120.8 (3)
S—C1—H1A	109.5	C21—C22—H22	119.6
S—C1—H1B	109.5	C24—C23—C28	119.5 (3)
S—C1—H1C	109.5	C24—C23—P	115.5 (3)
H2A—C2—H2B	109.5	C28—C23—P	124.9 (3)
H2A—C2—H2C	109.5	C23—C24—H24	120.2
H2B—C2—H2C	109.5	C23—C24—C25	119.6 (3)
S—C2—H2A	109.5	C25—C24—H24	120.2
S—C2—H2B	109.5	C24—C25—H25	119.9
S—C2—H2C	109.5	C26—C25—C24	120.3 (3)
C12—C11—C16	119.1 (3)	C26—C25—H25	119.9
C12—C11—P	117.3 (3)	C25—C26—H26	119.7
C16—C11—P	123.6 (3)	C25—C26—C27	120.6 (3)
C11—C12—H12	119.8	C27—C26—H26	119.7
C13—C12—C11	120.5 (4)	C26—C27—H27	120.0
C13—C12—H12	119.8	C26—C27—C28	120.0 (3)
C12—C13—H13	119.9	C28—C27—H27	120.0
C14—C13—C12	120.2 (4)	C23—C28—H28	120.0
C14—C13—H13	119.9	C27—C28—C23	119.9 (3)
C13—C14—H14	120.1	C27—C28—H28	120.0
C13—C14—C15	119.7 (4)	S—O—Cu	121.91 (13)
C15—C14—H14	120.1	C11—P—Cu	116.27 (11)
C14—C15—H15	120.0	C17—P—C11	102.77 (16)
C16—C15—C14	120.1 (4)	C17—P—C23	103.83 (14)
C16—C15—H15	120.0	C17—P—Cu	115.71 (12)
C11—C16—H16	119.8	C23—P—C11	104.58 (15)
C15—C16—C11	120.4 (3)	C23—P—Cu	112.25 (12)
C15—C16—H16	119.8	C1—S—C2	98.10 (19)
C18—C17—P	117.0 (3)	O—S—C1	106.07 (17)
C22—C17—C18	118.1 (3)	O—S—C2	104.70 (16)
C22—C17—P	124.9 (3)	O—Cu—P	106.70 (8)
C17—C18—H18	119.5	O—Cu—Cui	116.74 (8)
C19—C18—C17	121.0 (3)	O—Cu—I	108.23 (6)
C19—C18—H18	119.5	O—Cu—Ii	101.47 (7)
C18—C19—H19	120.1	P—Cu—Cui	136.38 (3)
C18—C19—C20	119.8 (3)	P—Cu—Ii	114.07 (3)
C20—C19—H19	120.1	P—Cu—I	114.48 (3)
C19—C20—H20	120.2	I—Cu—Cui	55.904 (14)
C21—C20—C19	119.6 (3)	Ii—Cu—Cui	54.897 (14)
C21—C20—H20	120.2	I—Cu—Ii	110.801 (16)
C20—C21—H21	119.6	Cu—I—Cui	69.201 (16)
C20—C21—C22	120.8 (3)
C11—C12—C13—C14	−1.1 (6)	C22—C17—P—C23	4.7 (4)
C12—C11—C16—C15	−0.9 (5)	C22—C17—P—Cu	128.1 (3)
C12—C11—P—C17	−154.0 (3)	C23—C24—C25—C26	−1.6 (5)
C12—C11—P—C23	97.8 (3)	C24—C23—C28—C27	0.2 (5)
C12—C11—P—Cu	−26.6 (3)	C24—C23—P—C11	−158.7 (3)
C12—C13—C14—C15	0.8 (6)	C24—C23—P—C17	93.8 (3)
C13—C14—C15—C16	−0.5 (5)	C24—C23—P—Cu	−31.8 (3)
C14—C15—C16—C11	0.6 (5)	C24—C25—C26—C27	1.9 (5)
C16—C11—C12—C13	1.2 (5)	C25—C26—C27—C28	−1.1 (5)
C16—C11—P—C17	23.6 (3)	C26—C27—C28—C23	0.1 (5)
C16—C11—P—C23	−84.6 (3)	C28—C23—C24—C25	0.5 (5)
C16—C11—P—Cu	151.0 (2)	C28—C23—P—C11	17.9 (3)
C17—C18—C19—C20	0.0 (5)	C28—C23—P—C17	−89.5 (3)
C18—C17—C22—C21	−0.7 (5)	C28—C23—P—Cu	144.8 (3)
C18—C17—P—C11	78.3 (3)	P—C11—C12—C13	178.8 (3)
C18—C17—P—C23	−172.9 (3)	P—C11—C16—C15	−178.4 (2)
C18—C17—P—Cu	−49.5 (3)	P—C17—C18—C19	178.3 (3)
C18—C19—C20—C21	−0.3 (6)	P—C17—C22—C21	−178.3 (3)
C19—C20—C21—C22	0.1 (6)	P—C23—C24—C25	177.4 (3)
C20—C21—C22—C17	0.4 (6)	P—C23—C28—C27	−176.3 (2)
C22—C17—C18—C19	0.5 (5)	Cu—O—S—C1	−72.7 (2)
C22—C17—P—C11	−104.1 (3)	Cu—O—S—C2	−175.87 (19)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···Oii	0.98	2.46	3.434 (5)	173
C1—H1B···Iiii	0.98	3.12	3.931 (4)	142
C2—H2B···Iiii	0.98	3.15	3.978 (4)	143
C26—H26···C16iv	0.95	2.85	3.781 (5)	168