Polymeric ([mu]₂-nitrato-[kappa]²O:O')([mu]₂-nitrato-[kappa]²O:O)([mu]₄-pyridinium-4-thiol­ato-[kappa]⁴S:S:S:S)­disilver(I)

The title compound, [Ag₂(NO₃)₂(C₅H₅NS)]_n, was obtained from the reaction of silver nitrate with bis(4-pyridyl) disufide (4-PDS) in a mixture of ethanol and water, which suggests that the di­sulfide bond of 4-PDS can be cleaved under mild conditions. The structure of the title compound is a two-dimensional infinite array in which the asymmetric unit contains two Ag atoms, a pyridinium-4-thiol­ate mol­ecule and two nitrate groups. Each pyridinium-4-thiol­ate mol­ecule acts as a [mu]₄ bridge, linking four Ag atoms, with Ag-S bond distances of 2.4870 (19), 2.5791 (19), 2.5992 (19) and 2.848 (2) Å. The Ag...Ag distances lie in the range 2.889 (2)-3.049 (1) Å.

S1. Comment

Design of inorganic–organic hybrid framework assemblies has become an active research area (Shimizu et al., 1999; Shi et al., 2000; Zhao et al., 2001) because of their potential application as functional solid materials (Carlucci et al., 1995; Wang et al., 1995; Yaghi et al., 1996; Matsumoto et al., 1999; Triki et al., 1999). Many studies have focused on inorganic–organic hybrid materials containing N-donor ligands, and the coordination chemistry of organosulfur compounds has also been studied intensively. We chose 4-PDS (4,4'-dipyridyldisufide) as a ligand with both N and S donors. We found that under mild conditions the disulfide bond of 4-PDS could be cleaved and the title compound was obtained. A number of one-, two- and three-dimensional coordination polymers containing the pyridine-2-thiol ligand have been developed (Hong et al., 1999; Kato et al., 2002; Liaw et al., 2002; Lobana et al., 1999; Su et al., 1999; Su et al., 2002; Yih et al., 2003). However, only a few crystal structures of discrete and one-dimensional complexes containing the pyridine-4-thiol ligand have been reported (Brand et al., 2000; Paw et al., 1998). We report here the synthesis and crystal structure of a two-dimensional lamellar polymer, (I), containing pyridine-4-thiol as a bridging ligand. As far as we know, this is the first example of a two-dimensional polymer constructed by pyridine-4-thiol acting as a µ₄-bridging ligand. The structure of (I) is a two-dimensional infinite array in which the asymmetric unit contains two silver(I) ions, an SC₅H₄NH molecule and two NO₃⁻ anions. The pyridine-4-thiol ligand exists in a tautomeric form, with the H⁺ ion transferred from the S atom to the more basic N atom (Maresca et al., 2000). The Ag atoms are bridged by both SC₅H₄NH and NO₃ groups, and all Ag atoms are coordinated by two S atoms from two different ligands and two O atoms from two different NO₃ groups in a distorted tetrahedral coordination (Fig. 1). Each pyridine-4-thiol ligand acts as a µ₄-bridge, linking four Ag atoms with Ag—S bond distances of 2.487 (2), 2.579 (2), 2.599 (2) and 2.848 (2) Å, respectively. Interestingly, the µ-NO₃ groups have two different bridging patterns, which is unusual (Hashimoto et al., 2000). In one pattern, two O atoms of one NO₃ group bond to two different Ag atoms, with Ag—O bond distances of 2.494 (6) and 2.412 (6) Å. In the other pattern, one O atom of an NO₃ group bonds to two different Ag^I atoms, with Ag—O bonds distances of 2.538 (6) and 2.355 (5) Å. As expected, the average Ag—O bond distance [2.450 (6) Å] is shorter than that of Ag—S [2.628 (2) Å]. The Ag···Ag separations range from 2.889 (2) to 3.049 (1) Å; all are best considered as non-bonding, although some ofthe values are very similar to those in metallic silver (2.88 Å; Blower et al., 1987; Raper et al., 1985). Together, the Ag—S and Ag—O bonds and Ag···Ag interactions link the repeat units into a two-dimensional lamellar structure (Fig. 2). Fig. 3 shows that (I) is a good example of a layered inorganic–organic solid, where the inorganic layer contains sulfido/oxygen-bridged silver(I) centers and the organic layer contains the pyridyl groups. The interlayer distance is 9.86 Å. The pyridyl groups stack in an ABAB··· pattern, the dihedral angle between the planes of A and B pyridyl rings being 10.91 °.

S2. Experimental

A mixture of AgNO₃ (0.39 g, 2.3 mmol), 4-PDS (0.18 g, 0.82 mmol), ethanol (20 ml) and water (20 ml) was stirred at 323 K for 1 h. The solution was then filtered and the filtrate was kept in a container covered with filter paper. After 90 d, colorless block crystals were isolated (yield 0.069 g, 13%) from the remaining solution (about 5 ml). Analysis calculated for C₅H₅Ag₂N₃O₆S: C 13.32, H 1.12, N 9.32, S 7.11%; found: C 13.36, H 1.18, N 9.26, S 7.13%. IR (KBr, cm⁻¹): 1763 (w), 1745 (w), 1614 (s), 1583 (s), 1531 (w), 1470 (s), 1381 (s), 1281 (m), 1223 (m), 1198 (m), 1103 (s), 1030 (m), 1012 (m), 999 (m), 922 (w), 823 (w), 800 (s), 715 (s), 640 (w), 492 (s), 422 (s). The emission spectrum of (I) in the solid state showed a broad band at 538 nm when irradiated at 238 nm, which is almost the same as that of the free pyridine-4-thiol ligand.

S3. Refinement

H atoms were placed in idealized postions and treated as riding on their parent atoms?

Computing details

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

Figures

	Fig. 1. A section of the crystal structure of (I). H atoms have been omitted for clarity. [Symmetry codes: (I) −0.5 − x, −0.5 + y, −0.5 − z; (II) −0.5 − x, 0.5 + y, −0.5 − z; (III) −x, 2 − y, −z.]
	Fig. 2. A view of a single lamella of the structure of (I). Pyridyl groups have been removed for clarity.
	Fig. 3. The structure of (I), showing the overall lamellar structure, with pyridyl groups protruding into the interlayer region. The view is along the b axis.

Polymeric (µ₂-nitrato-κ²O:O')(µ₂-nitrato-κ²O:O)(µ₄-pyridinium-4- thiolato-κ⁴S:S:S:S)disilver(I)(Ag—Ag)

Crystal data

[Ag2(NO3)2(C5H5NS)]	F(000) = 856
Mr = 450.92	Dx = 2.992 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 11.1738 (9) Å	Cell parameters from 1859 reflections
b = 8.2212 (7) Å	θ = 2.1–25.0°
c = 12.1466 (10) Å	µ = 4.14 mm^−1
β = 116.224 (2)°	T = 293 K
V = 1000.96 (14) Å^3	Block, colorless
Z = 4	0.30 × 0.16 × 0.16 mm

Data collection

Bruker SMART CCD area-detector diffractometer	1735 independent reflections
Radiation source: fine-focus sealed tube	1446 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
ϕ and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −12→13
Tmin = 0.377, Tmax = 0.618	k = −9→9
3067 measured reflections	l = −14→6

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)] = 0.043	H-atom parameters constrained
wR(F^2) = 0.108	w = 1/[σ^2(Fo^2) + (0.0467P)^2 + 9.1855P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1735 reflections	Δρmax = 1.29 e Å^−3
155 parameters	Δρmin = −1.46 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: 0.0052 (5)

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
Ag1	−0.31321 (6)	0.87153 (7)	−0.25664 (6)	0.0330 (2)
Ag2	−0.06264 (7)	0.84271 (9)	−0.01379 (7)	0.0446 (3)
S1	−0.12295 (18)	1.0801 (2)	−0.20167 (16)	0.0232 (4)
C5	−0.0113 (8)	0.8638 (9)	−0.3011 (7)	0.0269 (16)
H5A	−0.0611	0.7850	−0.2849	0.032*
O3	−0.2605 (6)	0.8403 (7)	0.0188 (6)	0.0439 (16)
N1	0.1432 (6)	0.9345 (8)	−0.3746 (6)	0.0297 (15)
H1A	0.1983	0.9056	−0.4029	0.036*
N2	−0.3270 (6)	0.9722 (8)	−0.0064 (6)	0.0292 (15)
C2	0.0493 (8)	1.1433 (9)	−0.3057 (7)	0.0280 (17)
H2A	0.0416	1.2533	−0.2920	0.034*
O2	−0.3484 (7)	1.0406 (8)	0.0732 (6)	0.0495 (17)
C3	0.1310 (8)	1.0937 (11)	−0.3561 (7)	0.0334 (18)
H3A	0.1782	1.1702	−0.3776	0.040*
C1	−0.0227 (7)	1.0278 (9)	−0.2748 (6)	0.0221 (15)
O1	−0.3722 (7)	1.0278 (8)	−0.1115 (6)	0.0481 (16)
C4	0.0733 (8)	0.8192 (10)	−0.3509 (7)	0.0326 (18)
H4A	0.0817	0.7106	−0.3677	0.039*
O4	−0.0449 (5)	0.6019 (7)	−0.1107 (5)	0.0300 (12)
O5	0.1633 (6)	0.6756 (8)	−0.0173 (6)	0.0455 (16)
O6	0.1087 (6)	0.4447 (7)	−0.1130 (6)	0.0412 (15)
N3	0.0782 (6)	0.5747 (8)	−0.0796 (6)	0.0272 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.0362 (4)	0.0246 (4)	0.0392 (4)	−0.0039 (3)	0.0176 (3)	−0.0010 (3)
Ag2	0.0466 (4)	0.0470 (5)	0.0422 (4)	0.0069 (3)	0.0214 (3)	−0.0104 (3)
S1	0.0274 (10)	0.0197 (9)	0.0274 (9)	−0.0011 (7)	0.0165 (8)	−0.0016 (7)
C5	0.038 (4)	0.020 (4)	0.027 (4)	−0.002 (3)	0.019 (3)	−0.003 (3)
O3	0.049 (4)	0.037 (3)	0.058 (4)	0.015 (3)	0.034 (3)	0.016 (3)
N1	0.033 (4)	0.035 (4)	0.030 (4)	0.004 (3)	0.022 (3)	0.002 (3)
N2	0.033 (4)	0.020 (3)	0.042 (4)	−0.001 (3)	0.023 (3)	0.006 (3)
C2	0.035 (4)	0.021 (4)	0.034 (4)	−0.002 (3)	0.021 (4)	−0.004 (3)
O2	0.077 (5)	0.042 (4)	0.046 (4)	0.004 (3)	0.042 (4)	−0.009 (3)
C3	0.035 (4)	0.041 (5)	0.029 (4)	−0.004 (4)	0.019 (4)	0.000 (4)
C1	0.027 (4)	0.024 (4)	0.019 (3)	−0.001 (3)	0.013 (3)	−0.006 (3)
O1	0.072 (5)	0.041 (4)	0.041 (4)	0.016 (3)	0.034 (3)	0.013 (3)
C4	0.041 (5)	0.026 (4)	0.034 (4)	0.010 (4)	0.020 (4)	0.001 (3)
O4	0.028 (3)	0.036 (3)	0.029 (3)	0.005 (2)	0.015 (2)	0.000 (2)
O5	0.035 (3)	0.049 (4)	0.056 (4)	−0.014 (3)	0.024 (3)	−0.023 (3)
O6	0.048 (4)	0.034 (3)	0.052 (4)	0.004 (3)	0.032 (3)	−0.010 (3)
N3	0.033 (4)	0.028 (3)	0.023 (3)	0.002 (3)	0.016 (3)	0.003 (3)

Geometric parameters (Å, º)

Ag1—S1^i	2.4870 (19)	O3—N2	1.273 (8)
Ag1—O1	2.494 (6)	N1—C4	1.339 (10)
Ag1—O4^ii	2.538 (6)	N1—C3	1.345 (11)
Ag1—S1	2.5791 (19)	N1—H1A	0.8600
Ag1—Ag2	3.0492 (10)	N2—O2	1.230 (8)
Ag2—O4	2.356 (5)	N2—O1	1.234 (9)
Ag2—O3	2.412 (6)	C2—C3	1.367 (11)
Ag2—S1^iii	2.5992 (19)	C2—C1	1.399 (10)
Ag2—S1	2.848 (2)	C2—H2A	0.9300
Ag2—Ag2^iii	2.8889 (16)	C3—H3A	0.9300
S1—C1	1.763 (7)	C4—H4A	0.9300
S1—Ag1^ii	2.4870 (19)	O4—N3	1.275 (8)
S1—Ag2^iii	2.5992 (19)	O4—Ag1^i	2.538 (6)
C5—C4	1.378 (11)	O5—N3	1.237 (9)
C5—C1	1.404 (10)	O6—N3	1.242 (8)
C5—H5A	0.9300
S1^i—Ag1—O1	119.89 (16)	Ag1^ii—S1—Ag2	140.19 (7)
S1^i—Ag1—O4^ii	123.17 (13)	Ag1—S1—Ag2	68.15 (5)
O1—Ag1—O4^ii	77.18 (18)	Ag2^iii—S1—Ag2	63.86 (5)
S1^i—Ag1—S1	145.35 (5)	C4—C5—C1	120.3 (7)
O1—Ag1—S1	85.40 (17)	C4—C5—H5A	119.9
O4^ii—Ag1—S1	83.13 (13)	C1—C5—H5A	119.9
S1^i—Ag1—Ag2	100.39 (5)	N2—O3—Ag2	115.7 (4)
O1—Ag1—Ag2	76.87 (15)	C4—N1—C3	122.7 (7)
O4^ii—Ag1—Ag2	136.16 (12)	C4—N1—H1A	118.6
S1—Ag1—Ag2	60.12 (5)	C3—N1—H1A	118.6
O4—Ag2—O3	111.1 (2)	O2—N2—O1	120.7 (7)
O4—Ag2—S1^iii	120.16 (14)	O2—N2—O3	119.7 (7)
O3—Ag2—S1^iii	102.59 (17)	O1—N2—O3	119.6 (7)
O4—Ag2—S1	102.58 (13)	C3—C2—C1	119.6 (7)
O3—Ag2—S1	103.16 (15)	C3—C2—H2A	120.2
S1^iii—Ag2—S1	116.14 (5)	C1—C2—H2A	120.2
O4—Ag2—Ag2^iii	131.82 (13)	N1—C3—C2	120.2 (8)
O3—Ag2—Ag2^iii	114.86 (15)	N1—C3—H3A	119.9
S1^iii—Ag2—Ag2^iii	62.27 (5)	C2—C3—H3A	119.9
S1—Ag2—Ag2^iii	53.87 (4)	C2—C1—C5	118.0 (6)
O4—Ag2—Ag1	79.97 (13)	C2—C1—S1	122.5 (6)
O3—Ag2—Ag1	69.09 (16)	C5—C1—S1	119.4 (6)
S1^iii—Ag2—Ag1	159.74 (5)	N2—O1—Ag1	115.1 (5)
S1—Ag2—Ag1	51.73 (4)	N1—C4—C5	119.0 (7)
Ag2^iii—Ag2—Ag1	103.49 (4)	N1—C4—H4A	120.5
C1—S1—Ag1^ii	108.8 (3)	C5—C4—H4A	120.5
C1—S1—Ag1	110.0 (2)	N3—O4—Ag2	108.5 (4)
Ag1^ii—S1—Ag1	117.28 (7)	N3—O4—Ag1^i	110.3 (4)
C1—S1—Ag2^iii	99.5 (2)	Ag2—O4—Ag1^i	141.0 (2)
Ag1^ii—S1—Ag2^iii	89.96 (6)	O5—N3—O6	122.0 (7)
Ag1—S1—Ag2^iii	128.50 (7)	O5—N3—O4	120.0 (6)
C1—S1—Ag2	105.0 (3)	O6—N3—O4	118.0 (7)

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