Poly­[disilver(I)-μ₈-1,5-naphthalene­disulfonato]

The title complex, poly­[disilver(I)-μ₈-1,5-naphthalene­di­sulfon­ato-3,4-η:7,8-η:κ⁶O:O′:O′′:O′′′:O′′′′:O′′′′′], [Ag₂(C₁₀H₆O₆S₂)]_n, exists as a three-dimensional framework of Ag^I atoms connected by η¹⁰,μ₈-1,5-naphthalene­di­sulfonate ligands through both Ag–sulfonate and Ag–η²-arene interactions. Each Ag^I atom exhibits a distorted tetrahedral geometry defined by three O atoms of independent sulfonate groups and one C=C bond of the naphthalene group.

S1. Comment

The study of the solid-state coordination and structural chemistry of organosulfonates has received growing attention over the past few years. Organosulfonate ions have proved able to generate not only highly robust and fascinating architectures but also `softer' networks with sponge-like properties by connecting main group metals (Cai, 2001) and some transition metal ions, such as barium(II) or silver(I), as reviewed by Côté & Shimizu (2003). Cai (2004, and references therein) has recently has reviewed the coordinating preferences of some aromatic mono- and disulfonates with main group metals and some transition metals, and also the structural and functional properties of cadmium sulfonates. Organodisulfonates exhibit a greater potential to form a higher-dimensional and more stable structure than do monosulfonates. However, there is little structural information about arenedisulfonate complexes involving the silver(I) ion, which often adopts distorted coordination geometries owing to the inherent lack of ligand field stabilization effects. Along with their soft Lewis acidic properties, Ag⁺ ions may be a particularly good match for the flexible coordinative tendencies of sulfonate anions, leading to networks that may be readily capable of rearrangement.

We have obtained a novel complex, [Ag₂(1,5-nds²⁻)]_n, (I), (1,5-nds is 1,5-naphthalenedisulfonate acid) by the reaction of AgNO₃ with 1,5-naphthalenedisulfonate acid in ethanol. A search of the Cambridge Structural Database reveals one other silver complex with the same ligand, namely [Ag(1,5-nds²⁻)(MeCN)₂]n.n(H₃O⁺).2n(H₂O), in which the silver(I) ion adopts a tetrahedral geometry and the 1,5-nds²⁻ ligand displays a η²,µ-² coordination mode (each sulfonate group is monodentate), bridging the silver(I) ions to form a chain structure (Shimizu et al., 1999).

In (I), however, the 1,5-nds²⁻ ligand adopts a η¹⁰,µ⁸ coordination mode, leading to a three-dimensional framework through both Ag–sulfonate and Ag–η²-arene interactions. To the best of our knowledge, (I) is the first metal complex involving the η¹⁰,µ⁸-1,5-nds²⁻ ligand.

The local coordination around the Ag^I atom, together with the atom-numbering scheme of (I), is shown in Fig. 1. The asymmetric unit contains one Ag^I atom and one-half of a 1,5-naphthalenedisulfonate anion (1,5-nds²⁻), the coordination being completed by inversion symmetry. The Ag^I atom is coordinated by three O atoms of independent sulfonate groups, with Ag—O bond lengths ranging from 2.377 (3) to 2.396 (3) [mean 2.385 (3) Å]; these are shorter than the Ag—O bond lengths [2.380 (2)–2.439 (2) Å] in the one-dimensional silver complex with 1,5-nds²⁻ (see above), suggesting a stronger Ag—O_sulfonate interaction. In addition, the Ag^I atom in (I) also interacts with a naphthalene group through a C═C π bond, with Ag—C distances of 2.478 (4) and 2.645 (4) Å, within the range reported for silver(I)–aromatic complexes (2.36–2.77 Å; Munakata et al., 1997, 1998, 1999). The next closest contact between silver and carbon atoms is 3.148 (3) Å. Therefore, the Ag^I atom exhibits a distorted tetrahedral geometry (regarding the C═C group as one donor). The silver(I) ion interacts with the shortest naphthalene C—C bond, as reported in other related silver(I) complexes (Munakata et al., 1997, 1998, 1999; Iuliucci et al., 1996; Ciolowski et al., 1996; Pietsch & Rappé 1996; Hoffmann et al., 1993; Lewandos et al., 1982). However, the naphthalene ring has a standard pattern of bond lengths, whereby the shortest are always those labelled in the current structure as C1—C2 and C4—C5 (Allen et al., 1997). Thus coordination by the silver ion does not seem to have changed this pattern significantly. The silver ion may coordinate preferentially to this bond because it is shorter and more electron rich.

The dihedral angle between the naphthalene ring and the plane defined by the three O atoms of the SO₃⁻ group is 83.6 (3)°. As shown in Fig. 2, the six O atoms of two SO₃⁻ groups are coordinated to the Ag(I) ions and the two SO₃⁻ groups function as a µ⁶– bridge and construct a layer structure parallel to (011), with alternating organic–inorganic components. The inorganic portion consists of eight-membered rings [represented as (Ag—O—S—O)₂], which exhibit `chair-like' profiles. The eight-membered rings propagate parallel to the a axis by sharing one edge (Ag—O—S) with neighboring rings, forming Ag1···Ag1A, Ag1···Ag1B, Ag1A···Ag1B and Ag1B···Ag1F distances of 5.208 (3), 4.507 (3), 4.406 (3) and 13.310 (3) Å, respectively [symmetry codes: (A) x + 1, y, z; (B) 1 − x, −y, 1 − z; (F) x, 1 + y, 1 − z]. The naphthalene ring moiety of the 1,5-nds²⁻ group shows a η⁴,µ² coordination mode, bridging two Ag^I ions, with a Ag1C···Ag1D separation of 6.883 (3) Å [symmetry code: (C) x, y, z − 1; (D) 1 − x, 1 − y, −z], and forming a three-dimensional network. The dihedral angle between the plane of the naphthalene ring and the Ag1/C4/C5 plane is 77.3 (3) °. In consequence, 1,5-nds²⁻ ions act as η¹⁰,µ⁸ bridges and link the silver ions into a three-dimensional framework through both Ag–sulfonate and Ag–arene interactions (Fig. 3).

S2. Experimental

The title complex, (I), was synthesized by the addition of AgNO₃ (2 mmol) to an ethanol solution of 1,5-naphthalenedisulfonic acid (6 mmol). The mixed solution was protected from light and allowed to evaporate slowly at room temperature; colorless prismatic crystals of (I) were isolated after about six days. Analysis calculated for C₁₀H₆Ag₂O₆S₂: C 23.93, H 1.02%; found: C 23.79, H 10.6%.

S3. Refinement

H atoms were placed in calculated positions [C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C)] and refined using the riding-model approximation. Any influence of the Ag atom on the H-atom geometry at the coordinated double bond was neglected.

Computing details

Data collection: RAPID-AUTO (Rigaku Corporation, 1998); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC and Rigaku Corporation, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976).

Figures

	Fig. 1. The local coordination around the sulfonate ligand (center) and the Ag^I atom (left) in (I). Ag···C═C interactions are denoted by dashed lines, and displacement ellipsoids are shown at the 30% probability level. The atom-numbering scheme of the asymmetric unit is shown, together with symmetry-equivalent atoms [symmetry codes: (A) x + 1, y, z; (B) 1 − x, −y, 1 − z; (C) x, y, z − 1; (D) 1 − x, 1 − y, −z; (E) −x, 1 − y, −z; (F) x, y + 1, z − 1; (G) 1 − x, 1 − y, 1 − z].
	Fig. 2. A perspective view of the organic–inorganic layer of (I). The C—Ag interactions and the H atoms have been omitted, and the naphthalene rings are represented by only the central four C atoms. (Symmetry codes as in Fig. 1.)
	Fig. 3. The packing of (I), showing the three-dimensional framework; H atoms have been omitted.

poly[disilver(I)-µ₈-1,5-naphthalenedisulfonato- 3,4-η:7,8-η:κ⁶O:O':O'':O''':O'''':O''''']

Crystal data

[Ag2(C10H6O6S2)]	Z = 1
Mr = 502.01	F(000) = 240
Triclinic, P1	Dx = 2.936 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.2082 (10) Å	Cell parameters from 2193 reflections
b = 7.3705 (15) Å	θ = 3.7–27.4°
c = 7.8068 (16) Å	µ = 3.84 mm^−1
α = 96.35 (3)°	T = 293 K
β = 106.91 (3)°	Prism, colorless
γ = 92.79 (3)°	0.37 × 0.25 × 0.18 mm
V = 283.93 (11) Å^3

Data collection

Rigaku R-AXIS RAPID diffractometer	1264 independent reflections
Radiation source: fine-focus sealed tube	1243 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
Detector resolution: 10 pixels mm^-1	θmax = 27.5°, θmin = 3.7°
ω scan	h = −6→6
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −9→9
Tmin = 0.329, Tmax = 0.501	l = −10→10
2425 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H-atom parameters constrained
wR(F^2) = 0.092	w = 1/[σ^2(Fo^2) + (0.0557P)^2 + 0.7228P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1264 reflections	Δρmax = 0.69 e Å^−3
92 parameters	Δρmin = −0.93 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.032 (4)

Special details

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
Ag1	0.29373 (6)	0.24243 (5)	0.58092 (4)	0.03645 (19)
S1	0.65683 (18)	0.19537 (13)	0.31105 (12)	0.0229 (2)
O1	0.6470 (6)	0.3288 (4)	0.4626 (4)	0.0324 (6)
O2	0.9326 (6)	0.1749 (4)	0.3077 (4)	0.0306 (6)
O3	0.5058 (6)	0.0213 (4)	0.3022 (4)	0.0330 (6)
C1	0.2500 (8)	0.1976 (5)	0.0041 (5)	0.0261 (7)
C2	0.4846 (7)	0.2903 (5)	0.1133 (4)	0.0210 (7)
C3	0.5809 (7)	0.4616 (5)	0.0760 (4)	0.0209 (7)
C4	0.8318 (7)	0.5592 (5)	0.1837 (5)	0.0229 (7)
C5	0.9105 (7)	0.7258 (5)	0.1452 (5)	0.0249 (7)
H1	0.1957	0.0835	0.0282	0.031*
H4	0.9414	0.5087	0.2802	0.027*
H5	1.0708	0.7892	0.2177	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.0307 (2)	0.0492 (3)	0.0294 (2)	0.00896 (15)	0.00738 (15)	0.00697 (15)
S1	0.0206 (4)	0.0292 (5)	0.0178 (4)	0.0034 (3)	0.0027 (3)	0.0067 (3)
O1	0.0342 (15)	0.0433 (17)	0.0191 (12)	0.0046 (12)	0.0076 (11)	0.0015 (11)
O2	0.0214 (13)	0.0416 (16)	0.0286 (14)	0.0088 (11)	0.0046 (11)	0.0085 (12)
O3	0.0302 (15)	0.0348 (15)	0.0333 (15)	0.0001 (12)	0.0042 (12)	0.0169 (12)
C1	0.0225 (17)	0.0268 (18)	0.0251 (18)	−0.0027 (14)	0.0011 (14)	0.0054 (14)
C2	0.0184 (15)	0.0277 (17)	0.0152 (14)	0.0014 (13)	0.0015 (12)	0.0053 (12)
C3	0.0177 (15)	0.0247 (16)	0.0172 (15)	0.0013 (13)	0.0008 (13)	0.0016 (13)
C4	0.0170 (16)	0.0301 (17)	0.0178 (15)	0.0021 (13)	−0.0006 (12)	0.0029 (13)
C5	0.0176 (16)	0.0309 (18)	0.0215 (16)	−0.0048 (13)	0.0004 (13)	0.0016 (14)

Geometric parameters (Å, º)

Ag1—O1	2.377 (3)	S1—O3	1.456 (3)
Ag1—O2^i	2.382 (3)	S1—O2	1.459 (3)
Ag1—O3^ii	2.396 (3)	S1—O1	1.467 (3)
Ag1—C4^iii	2.478 (4)	S1—C2	1.781 (4)
Ag1—C5^iii	2.645 (4)	O2—Ag1^v	2.382 (3)
C1—C2	1.367 (5)	O3—Ag1^ii	2.396 (3)
C1—C5^iv	1.415 (5)	C1—H1	0.9300
C2—C3	1.427 (5)	C4—Ag1^iii	2.478 (4)
C3—C3^iv	1.432 (7)	C4—H4	0.9300
C3—C4	1.438 (5)	C5—Ag1^iii	2.645 (4)
C4—C5	1.368 (6)	C5—H5	0.9300
C5—C1^iv	1.415 (5)
O1—Ag1—O2^i	99.85 (10)	C2—C1—C5^iv	120.4 (3)
O1—Ag1—O3^ii	94.92 (11)	C2—C1—H1	119.8
O1—Ag1—C4^iii	123.14 (12)	C5^iv—C1—H1	119.8
O1—Ag1—C5^iii	147.95 (11)	C1—C2—C3	121.4 (3)
O2^i—Ag1—C5^iii	108.49 (11)	C1—C2—S1	117.5 (3)
O2^i—Ag1—C4^iii	112.45 (11)	C3—C2—S1	121.0 (3)
O2^i—Ag1—O3^ii	114.39 (11)	C2—C3—C3^iv	118.1 (4)
O3^ii—Ag1—C4^iii	110.94 (12)	C2—C3—C4	122.9 (3)
O3^ii—Ag1—C5^iii	86.91 (12)	C3^iv—C3—C4	119.0 (4)
C4^iii—Ag1—C5^iii	30.75 (13)	C5—C4—C3	120.5 (3)
O3—S1—O2	113.08 (19)	C5—C4—Ag1^iii	81.4 (2)
O3—S1—O1	112.68 (19)	C3—C4—Ag1^iii	103.8 (2)
O2—S1—O1	111.78 (18)	C5—C4—H4	119.8
S1—O1—Ag1	111.48 (18)	C3—C4—H4	119.8
S1—O2—Ag1^v	119.46 (17)	C4—C5—C1^iv	120.5 (3)
S1—O3—Ag1^ii	123.88 (17)	C4—C5—Ag1^iii	67.9 (2)
O3—S1—C2	105.64 (17)	C1^iv—C5—Ag1^iii	111.6 (3)
O2—S1—C2	107.81 (17)	C4—C5—H5	119.7
O1—S1—C2	105.22 (17)	C1^iv—C5—H5	119.7
O3—S1—O1—Ag1	−16.4 (2)	O2—S1—C2—C1	125.5 (3)
O2—S1—O1—Ag1	−145.02 (16)	O1—S1—C2—C1	−115.1 (3)
C2—S1—O1—Ag1	98.23 (18)	O3—S1—C2—C3	−179.0 (3)
O2^i—Ag1—O1—S1	−48.23 (19)	O2—S1—C2—C3	−57.8 (3)
O3^ii—Ag1—O1—S1	67.60 (18)	O1—S1—C2—C3	61.6 (3)
C4^iii—Ag1—O1—S1	−173.42 (15)	C1—C2—C3—C3^iv	2.4 (6)
C5^iii—Ag1—O1—S1	159.63 (18)	S1—C2—C3—C3^iv	−174.1 (3)
O3—S1—O2—Ag1^v	−103.1 (2)	C1—C2—C3—C4	−177.5 (4)
O1—S1—O2—Ag1^v	25.4 (2)	S1—C2—C3—C4	6.0 (5)
C2—S1—O2—Ag1^v	140.54 (17)	C2—C3—C4—C5	−177.9 (4)
O2—S1—O3—Ag1^ii	29.9 (3)	C3^iv—C3—C4—C5	2.1 (6)
O1—S1—O3—Ag1^ii	−98.0 (2)	C2—C3—C4—Ag1^iii	−89.9 (3)
C2—S1—O3—Ag1^ii	147.6 (2)	C3^iv—C3—C4—Ag1^iii	90.2 (4)
C5^iv—C1—C2—C3	−2.9 (6)	C3—C4—C5—C1^iv	−1.7 (6)
C5^iv—C1—C2—S1	173.8 (3)	C3—C4—C5—Ag1^iii	101.0 (3)
O3—S1—C2—C1	4.3 (4)	Ag1^iii—C4—C5—C1^iv	−102.8 (4)

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