A twofold parallel inter­penetration network from the assembly of a flexible spacer and CuI: poly[μ-iodido-μ-4,4′-(methyl­enedithio)dipyridine-κ²N:N′-copper(I)]

The title compound, [CuI(C₁₁H₁₀N₂S₂)]_n, is built around centrosymmetric dinuclear Cu₂I₂ cores, each of which is linked to four neighboring Cu₂I₂ units via flexible dithio­ether ligands, viz. 4,4′-(methylenedithio)dipyridine, to form a two-dimensional grid containing rhombus-shaped cavities with diagonal distances of ca 15 and 22 Å. Two of these networks inter­penetrate in a woven fashion, and the resulting structure does not possess any open channels or cavities. Each Cu atom is in a distorted tetra­hedral coordination environment.

S1. Comment

Recently, there has been much interest in the use of flexible bridging ligands in the construction of supramolecular architectures (Blake et al., 1995; Bu et al., 2002; Jaya Prakash & Radhakrishnan, 2006; Li et al., 2003; Tong et al., 1999; Wu et al., 2006; Zhang et al., 2006), because such ligands encode more variable chemical information, such as conformational freedom. These studies have shown that the nature of the anions, the terminal groups and the spacer length of potentially bridging ligands play fundamental roles in determining the structural types of the final assemblies.

Heterocyclic flexible thioethers containing N– and S-atom donors are well established ligands in coordination and metallosupramolecular chemistry. N and S atoms in such ligands have different donor properties which influence their abilities to coordinate to metal centers (Sharma et al., 1998; Su et al., 1999; Yang et al., 1997). These properties, together with the relative numbers and orientations of the donor atoms, may give rise to interesting coordination architectures.

Previously, 2-pyridyl and 2-pyrimidinyl dithioether ligands with flexible spacers (alkane or arene) have been used successfully to construct metal complexes that exhibit various structures, including discrete molecules, and one- and two-dimensional coordination polymers (Bu et al., 2003; Hong et al., 2000; Peng et al., 2006; Song et al., 2003; Wang et al., 2001; Xie & Bu, 2003; Xie, Du et al., 2004; Xie, Zhang et al., 2004; Xie et al., 2005; Zheng et al., 2003, 2005). However, complexes involving the bis(4-pyridylthio)methane ligand are still comparatively rare (Amoedo-Portela et al., 2005). We report here the crystal structure of the novel two-dimensional title Cu^I complex, (I).

Each Cu^I center in the title complex is four-coordinated by two N atoms from two different dithioether ligands and two iodide ligands. The iodide ligand bridges, slightly asymmetrically, two Cu^I centers to give a doubly-bridged dinuclear centrosymmetric Cu₂I₂ unit. Each Cu₂I₂ core is connected by four ditopic bis(4-pyridylthio)methane ligands to four neighbouring Cu₂I₂ units, which generates a rhombus-shaped two-dimensional grid containing 52-membered metallocycles composed of four dithioether ligands, six Cu^I centers and two iodide ligands (Fig. 1). The grid lies parallel to the (100) plane. The metallocyclic cavities are so large that a second layer weaves through the first to form a two-dimensional parallel interpenetration network (Fig. 2). Weak intermolecular C—H···I interactions (Table 2) exist between the two interpenetrating networks. The extent of interpenetration in this complex fills all the available voids, so no small molecules or solvent molecules are encapsulated.

The structures of the dichloro and dibromo Cu^I complexes with the same organic ligand as (I) have been reported by Amoedo-Portela et al. (2005). Those complexes are isostructural with one another, but not with (I), even though all three crystallize in the same space group and their unit-cell dimensions are similar. All three structures exhibit the same style of two-dimensional interpenetration networks, but the Cu₂I₂ cores present in (I) are replaced by mononuclear CuX₂ cores with terminal halide (X) ligands in the dichloro and dibromo complexes.

The topology of the two-dimensional network in (I) is also similar to the previously reported coordination polymer of [Cu₂Br₂(bpe)₂]_n [bpe is 1,2-bis(4-pyridyl)ethane; Hu et al., 2006], which contains 48-membered metallocycles. However, there is a significant difference in the way the networks interweave. In [Cu₂Br₂(bpe)₂]_n, two independent sets of two-dimensional square grids running in almost perpendicular directions interpenetrate to form three-dimensional network. In (I), parallel networks interweave and these layers then stack upon one another. The ligand 1,3-bis(4-pyridyl)propane (bpp) is an analogue of bis(4-pyridylthio)methane, but in the complex [Cu₂Br₂(bpp)₂]_n, the Cu₂Br₂ cores are linked by bpp ligands in two different conformations (trans–trans and trans–gauche) to form a one-dimensional double-stranded tubular chain. Such results reveal that flexible bridging ligands play fundamental roles in determining the structural topologies of their metal-organic architectures.

The dithioether ligand in (I) adopts a trans–gauche conformation, where the dihedral angle between the two pyridyl rings is 69.67 (11)°; this is comparable to that in the related [CuX₂(C₁₁H₁₀N₂S₂)₂]_n (X = Cl and Br) analogues (Amoedo-Portela et al., 2005). The torsion angles C3—S1—C6—S2 and C11—S2—C6—S1 are 70.2 (2) and 80.8 (2)°, respectively, which are about 10° larger than the corresponding torsion angles in the [CuX₂(C₁₁H₁₀N₂S₂)₂]_n complexes.

Related literature

For related literature, see: Amoedo-Portela, Carballo, Casas, Garcia-Martinez, Lago-Blanco, Sanchez-Gonzalez, Sordo & Vazquez-Lopez (2005); Blake et al. (1995); Bu et al. (2002, 2003); Hong et al. (2000); Hu et al. (2006); Jaya Prakash & Radhakrishnan (2006); Li et al. (2003); Peng et al. (2006); Sharma et al. (1998); Song et al. (2003); Su et al. (1999); Tong et al. (1999); Wang et al. (2001); Wu et al. (2006); Xie & Bu (2003); Xie et al. (2005); Xie, Du, Li & Bu (2004); Xie, Zhang & Bu (2004); Xu et al. (1997); Yang et al. (1997); Zhang et al. (2006); Zheng et al. (2003, 2005).

S2. Experimental

The ligand bis(4-pyridylthio)methane was synthesized according to the reported procedure (Xu et al., 1997). Equimolar quantities (0.025 mmol) of CuI (5.0 mg), bis(4-pyridylthio)methane (6.1 mg) and acetonitrile (10 ml) in a 23 ml Teflon reactor was heated to 428 K for 3 d and then cooled to room temperature at a rate of 0.1 K min^-1. The precipitate was filtered off and the filtrate was allowed to stand at room temperature for one week, after which well shaped yellow crystals were obtained (m.p. 482 K; yield 2.1 mg, 20%).

S3. Refinement

H atoms were placed at calculated positions with C—H distances of 0.93 Å (aromatic) or 0.97 Å (methylene) and refined as riding [U_iso(H) = 1.2U_eq(C)].

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL7 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXTL (Bruker, 2002).

Figures

	Fig. 1. Figure 1. A section of the two-dimensional planar sheet structure of the title complex, with displacement ellipsoids drawn at the 30% probability level and H atoms omitted for clarity. [Symmetry codes: (A) -x + 2, -y + 1, -z + 1; (B) -x + 2, y + 1, -z + 1/2.]
	Fig. 2. Figure 2. The packing of the twofold parallel interpenetrating sheets in the title complex.

poly[µ-4,4'-(methylenedithio)dipyridine-κ²N:N'- µ-iodido-copper(I)]

Crystal data

[CuI(C11H10N2S2)]	F(000) = 1632
Mr = 424.77	Dx = 2.079 Mg m^−3
Monoclinic, C2/c	Melting point: 482 K
Hall symbol: -C2yc	Mo Kα radiation, λ = 0.71073 Å
a = 13.6695 (9) Å	Cell parameters from 4353 reflections
b = 11.5996 (8) Å	θ = 2.6–27.5°
c = 17.1524 (12) Å	µ = 4.17 mm^−1
β = 93.673 (1)°	T = 295 K
V = 2714.1 (3) Å^3	Block, yellow
Z = 8	0.34 × 0.24 × 0.20 mm

Data collection

Bruker APEX area-detector diffractometer	2594 independent reflections
Radiation source: fine-focus sealed tube	2362 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ϕ and ω scans	θmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→16
Tmin = 0.331, Tmax = 0.489	k = −12→14
7375 measured reflections	l = −20→16

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 constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0289P)^2 + 2.4421P] where P = (Fo^2 + 2Fc^2)/3
2594 reflections	(Δ/σ)max = 0.002
154 parameters	Δρmax = 0.38 e Å^−3
0 restraints	Δρmin = −0.35 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
I1	1.148788 (12)	0.444480 (16)	0.447736 (11)	0.04126 (8)
Cu1	0.96090 (3)	0.53429 (3)	0.42665 (3)	0.04816 (11)
S1	0.78569 (6)	0.06493 (7)	0.25605 (5)	0.0484 (2)
S2	0.93412 (6)	0.07621 (7)	0.12943 (6)	0.0531 (2)
C1	0.89439 (18)	0.3846 (2)	0.29536 (18)	0.0377 (6)
H1	0.9160	0.4464	0.2665	0.045*
C2	0.86239 (19)	0.2875 (2)	0.25519 (17)	0.0379 (6)
H2	0.8626	0.2845	0.2010	0.045*
C3	0.82977 (17)	0.1943 (2)	0.29706 (17)	0.0341 (6)
C4	0.83090 (19)	0.2054 (2)	0.37750 (17)	0.0381 (6)
H4	0.8091	0.1452	0.4077	0.046*
C5	0.8642 (2)	0.3052 (2)	0.41235 (18)	0.0399 (6)
H5	0.8646	0.3107	0.4665	0.048*
C6	0.8086 (2)	0.0805 (3)	0.15416 (19)	0.0459 (7)
H6A	0.7734	0.0198	0.1253	0.055*
H6B	0.7808	0.1533	0.1360	0.055*
C7	0.9626 (2)	−0.0709 (2)	0.12739 (19)	0.0422 (7)
C8	1.0475 (2)	−0.1013 (3)	0.0923 (2)	0.0517 (8)
H8	1.0879	−0.0444	0.0736	0.062*
C9	1.0720 (2)	−0.2148 (3)	0.0852 (2)	0.0511 (8)
H9	1.1296	−0.2325	0.0618	0.061*
C10	0.9377 (2)	−0.2721 (3)	0.1465 (2)	0.0501 (8)
H10	0.8998	−0.3305	0.1663	0.060*
C11	0.9081 (2)	−0.1599 (3)	0.1567 (2)	0.0500 (8)
H11	0.8522	−0.1440	0.1829	0.060*
N1	0.89648 (15)	0.39579 (19)	0.37225 (14)	0.0360 (5)
N2	1.01744 (16)	−0.3027 (2)	0.11012 (15)	0.0434 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.03957 (11)	0.04239 (13)	0.04286 (14)	−0.00011 (7)	0.01071 (8)	−0.00298 (8)
Cu1	0.0491 (2)	0.0368 (2)	0.0592 (3)	−0.01039 (15)	0.00835 (18)	−0.00788 (17)
S1	0.0522 (4)	0.0413 (4)	0.0532 (5)	−0.0126 (3)	0.0148 (4)	−0.0158 (3)
S2	0.0518 (4)	0.0364 (4)	0.0737 (6)	−0.0043 (3)	0.0240 (4)	−0.0107 (4)
C1	0.0347 (13)	0.0323 (14)	0.0469 (19)	0.0014 (11)	0.0094 (12)	0.0027 (12)
C2	0.0433 (14)	0.0374 (15)	0.0335 (16)	0.0018 (12)	0.0069 (12)	−0.0019 (12)
C3	0.0286 (12)	0.0306 (14)	0.0436 (17)	0.0027 (10)	0.0061 (11)	−0.0058 (11)
C4	0.0409 (14)	0.0333 (14)	0.0411 (17)	−0.0027 (11)	0.0098 (12)	0.0027 (12)
C5	0.0448 (14)	0.0400 (16)	0.0348 (16)	−0.0032 (12)	0.0028 (12)	−0.0021 (12)
C6	0.0409 (15)	0.0486 (17)	0.0480 (19)	0.0017 (13)	0.0000 (13)	−0.0174 (14)
C7	0.0416 (15)	0.0378 (15)	0.0484 (19)	−0.0040 (12)	0.0120 (13)	−0.0106 (13)
C8	0.0476 (16)	0.0417 (17)	0.069 (2)	−0.0104 (13)	0.0260 (16)	−0.0115 (15)
C9	0.0395 (15)	0.0447 (18)	0.071 (2)	−0.0051 (13)	0.0205 (15)	−0.0103 (16)
C10	0.0538 (17)	0.0436 (17)	0.055 (2)	−0.0106 (14)	0.0212 (15)	−0.0034 (15)
C11	0.0471 (16)	0.0440 (18)	0.061 (2)	−0.0053 (13)	0.0238 (15)	−0.0135 (15)
N1	0.0317 (11)	0.0320 (12)	0.0443 (15)	−0.0020 (9)	0.0029 (10)	−0.0038 (10)
N2	0.0432 (13)	0.0391 (13)	0.0487 (16)	0.0010 (10)	0.0088 (11)	−0.0048 (11)

Geometric parameters (Å, º)

Cu1—N1	2.030 (2)	C4—H4	0.9300
Cu1—N2^i	2.021 (2)	C5—N1	1.346 (4)
Cu1—I1	2.7737 (5)	C5—H5	0.9300
Cu1—I1^ii	2.7138 (5)	C6—H6A	0.9700
Cu1—Cu1^ii	2.7860 (9)	C6—H6B	0.9700
S1—C3	1.748 (3)	C7—C11	1.386 (4)
S1—C6	1.804 (3)	C7—C8	1.388 (4)
S2—C7	1.751 (3)	C8—C9	1.366 (4)
S2—C6	1.794 (3)	C8—H8	0.9300
C1—N1	1.324 (4)	C9—N2	1.349 (4)
C1—C2	1.376 (4)	C9—H9	0.9300
C1—H1	0.9300	C10—N2	1.338 (4)
C2—C3	1.388 (4)	C10—C11	1.378 (4)
C2—H2	0.9300	C10—H10	0.9300
C3—C4	1.385 (4)	C11—H11	0.9300
C4—C5	1.368 (4)
I1—Cu1—I1^ii	118.990 (17)	S2—C6—H6A	108.0
N1—Cu1—I1	97.67 (6)	S1—C6—H6A	108.0
N1—Cu1—I1^ii	101.03 (7)	S2—C6—H6B	108.0
N1—Cu1—N2^i	131.66 (10)	S1—C6—H6B	108.0
N2^i—Cu1—I1	103.84 (7)	H6A—C6—H6B	107.3
N2^i—Cu1—I1^ii	105.21 (7)	C11—C7—C8	116.8 (3)
I1—Cu1—Cu1^ii	58.433 (14)	C11—C7—S2	126.4 (2)
N1—Cu1—Cu1^ii	108.61 (7)	C8—C7—S2	116.7 (2)
Cu1—I1—Cu1^ii	61.010 (17)	C9—C8—C7	120.0 (3)
C3—S1—C6	103.13 (14)	C9—C8—H8	120.0
C7—S2—C6	104.41 (14)	C7—C8—H8	120.0
N1—C1—C2	124.4 (3)	N2—C9—C8	123.9 (3)
N1—C1—H1	117.8	N2—C9—H9	118.1
C2—C1—H1	117.8	C8—C9—H9	118.1
C1—C2—C3	118.7 (3)	N2—C10—C11	124.3 (3)
C1—C2—H2	120.6	N2—C10—H10	117.8
C3—C2—H2	120.6	C11—C10—H10	117.8
C4—C3—C2	117.4 (2)	C10—C11—C7	119.3 (3)
C4—C3—S1	117.5 (2)	C10—C11—H11	120.3
C2—C3—S1	125.1 (2)	C7—C11—H11	120.3
C5—C4—C3	119.8 (3)	C1—N1—C5	116.4 (2)
C5—C4—H4	120.1	C1—N1—Cu1	121.13 (18)
C3—C4—H4	120.1	C5—N1—Cu1	122.0 (2)
N1—C5—C4	123.3 (3)	C10—N2—C9	115.5 (3)
N1—C5—H5	118.4	C10—N2—Cu1^iii	122.2 (2)
C4—C5—H5	118.4	C9—N2—Cu1^iii	120.9 (2)
S2—C6—S1	117.02 (17)
N2^i—Cu1—I1—Cu1^ii	116.44 (8)	C8—C7—C11—C10	−3.0 (5)
N1—Cu1—I1—Cu1^ii	−107.17 (7)	S2—C7—C11—C10	176.3 (3)
I1^ii—Cu1—I1—Cu1^ii	0.0	C2—C1—N1—C5	−0.4 (4)
N1—C1—C2—C3	0.0 (4)	C2—C1—N1—Cu1	172.2 (2)
C1—C2—C3—C4	0.4 (4)	C4—C5—N1—C1	0.2 (4)
C1—C2—C3—S1	179.42 (19)	C4—C5—N1—Cu1	−172.3 (2)
C6—S1—C3—C4	−174.3 (2)	N2^i—Cu1—N1—C1	27.3 (2)
C6—S1—C3—C2	6.8 (3)	I1^ii—Cu1—N1—C1	149.40 (19)
C2—C3—C4—C5	−0.6 (4)	I1—Cu1—N1—C1	−88.96 (19)
S1—C3—C4—C5	−179.6 (2)	Cu1^ii—Cu1—N1—C1	−148.16 (18)
C3—C4—C5—N1	0.3 (4)	N2^i—Cu1—N1—C5	−160.53 (19)
C7—S2—C6—S1	80.8 (2)	I1^ii—Cu1—N1—C5	−38.4 (2)
C3—S1—C6—S2	70.2 (2)	I1—Cu1—N1—C5	83.2 (2)
C6—S2—C7—C11	−13.9 (3)	Cu1^ii—Cu1—N1—C5	24.0 (2)
C6—S2—C7—C8	165.5 (3)	C11—C10—N2—C9	2.4 (5)
C11—C7—C8—C9	2.6 (5)	C11—C10—N2—Cu1^iii	−164.4 (3)
S2—C7—C8—C9	−176.9 (3)	C8—C9—N2—C10	−2.9 (5)
C7—C8—C9—N2	0.5 (6)	C8—C9—N2—Cu1^iii	164.1 (3)
N2—C10—C11—C7	0.5 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···I1^iv	0.93	3.15	3.922 (3)	142

Symmetry code: (iv) −x+2, y, −z+1/2.