Polymeric (3-amino-2-chloropyridine)nitratosilver(I)

In the title compound {alternative name: poly­[silver(I)-[mu]-(3-­amino-2-chloro­pyridine)-[mu]-nitr­ato]}, [Ag(NO₃)(C₅H₅ClN₂)]_n the Ag^I atom is in an irregular AgN₂O₃ geometry, surrounded by one pyridyl N atom [Ag-N 2.283 (5) Å], one amine N atom [Ag-N 2.364 (6) Å] and three O atoms from different nitrate ions [Ag-O 2.510 (6)-2.707 (6) Å]. The Ag ions are bridged by the 3-amino-2-chloro­pyridine ligands into helical chains. Adjacent uniform chiral chains are further interlinked through the NO₃ bridges into an interesting two-dimensional coordination network in the solid.

S1. Comment

The field of metal-organic coordination polymers has recently attracted great interest, because such supramolecular architectures have potential as smart optoelectronic, magnetic or microporous materials (Abrahams et al., 1994; Biradha et al., 1999; Braga et al., 1998; Fujita et al., 1994; Gardner et al., 1995; Kahn, 2000; Russell et al., 1997). The structures of coordination polymers are highly influenced by factors such as the coordination nature of the metal ion, the structural characteristics of the polydentate organic ligand, the metal-ligand ratio and possible counter-ion influence. A subtle alteration in any of these factors can lead to new extended network structures. Thus, a great variety of supramolecular architectures have been ingeniously constructed. These not only have aesthetic appeal, but occasionally exhibit interesting functions. We are interested in the preparation of one-, two- and three-dimensional coordination polymers with potential applications in optoelectronics and adsorption (Tong et al., 1999; Zheng, Tong, Fu et al., 2001; Zheng, Tong, Tan et al., 2001 Is this the correct place to cite both these references?). We report here the preparation and crystal structure of a chiral two-dimensional coordination polymer constructed from an achiral building block, [Ag(µ-2-Clnpy)(µ-NO₃)], (I) (2-Clnpy is 3-amino-2-chloropyridine). \sch

The crystal structure of (I) comprises a chiral two-dimensional coordination network. As shown in Fig. 1, each Ag^I atom is coordinated in an irregular geometry, with one pyridyl N atom and one amine N atom from two different 2-Clnpy ligands and three O atoms from different nitrate ions (Table 1). The Ag—N(pyridyl) distances in (I) are slightly longer than those in bis(3-amino-2-chloropyridine)silver(I) perchlorate [2.179 (4)–2.199 (4) Å; Li et al., 2002] and that in bis(4-aminopyridine)silver(I) nitrate [2.122 (3) Å; Kristiansson, 2000]. The Ag^I atoms are bridged by µ-2-Clnpy ligands to form polymeric helical motifs along the c axis direction. Adjacent uniform infinite helical motifs are further interlinked through the µ-NO₃ bridges into chiral two-dimensional layers (Fig. 2). Within each layer, there are hydrogen-bonding interactions between adjacent NO₃^- and amine groups (Table 2).

It should be also noted that π···π stacking interactions play a role in consolidating the solid state structure of (I). Adjacent coordination layers are stacked via interlayer pyridyl groups with a face-to-face separation of 3.38–3.58 Å, resulting in a three-dimensional supramolecular architecture (Fig. 3).

S2. Experimental

To a solution of AgNO₃ (1.0 mmol) in MeCN/H₂O [10 ml; 1:1 (v/v)], a solution of 2-Clnpy (1.0 mmol) in MeOH (5 ml) was slowly added and stirred for 15 min at 333 K. Colourless polyhedral crystals of (I) were deposited within 2 d (75% yield).

S3. Refinement

The amino H atoms were located and refined subject to N—H = 0.85 (1) Å and H···H = 1.39 (1) Å, with U_iso(H) = 1.2U_eq(N). The carbon-bound H atoms were generated geometrically, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: XSCANS (Siemens, 1990); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A view of the coordination environment in (I). Displacement ellipsoids are drawn at the 35% probability level and dashed lines indicate weak interactions [symmetry code: (i) 3/2 - x, y - 1/2, -z].
	Fig. 2. A view of the two-dimensional coordination layer of (I). Ag and Cl atoms are shown hatched.
	Fig. 3. The three-dimensional supramolecular architecture of (I) viewed along the c axis.

(I)

Crystal data

[Ag(C5H5ClN2)]NO3	F(000) = 576
Mr = 298.44	Dx = 2.294 Mg m^−3
Orthorhombic, P21212	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 25 reflections
a = 13.343 (5) Å	θ = 7–15°
b = 7.832 (2) Å	µ = 2.62 mm^−1
c = 8.270 (2) Å	T = 298 K
V = 864.2 (4) Å^3	Polyhedral, colourless
Z = 4	0.34 × 0.30 × 0.20 mm

Data collection

Siemens R3m four-circle diffractometer	1080 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.018
Graphite monochromator	θmax = 27.5°, θmin = 2.5°
ω scans	h = −1→17
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
Tmin = 0.427, Tmax = 0.593	l = 0→10
1268 measured reflections	2 standard reflections every 150 reflections
1248 independent reflections	intensity decay: none

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 atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.083	w = 1/[σ^2(Fo^2) + (0.0493P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
1248 reflections	Δρmax = 0.44 e Å^−3
124 parameters	Δρmin = −0.76 e Å^−3
3 restraints	Absolute structure: Flack (1983) with 74 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.20 (8)

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
Ag	0.76829 (4)	0.90000 (6)	0.19699 (6)	0.04304 (16)
Cl1	0.75176 (14)	0.9794 (3)	0.5906 (2)	0.0561 (5)
O1	0.6048 (5)	0.8701 (6)	−0.0330 (7)	0.0621 (15)
O2	0.7137 (4)	0.6722 (8)	0.0026 (7)	0.0710 (18)
O3	0.5947 (5)	0.6321 (8)	−0.1625 (8)	0.077 (2)
N1	0.6560 (4)	1.0693 (6)	0.3300 (6)	0.0389 (13)
N2	0.6022 (4)	1.2019 (8)	0.7496 (7)	0.0382 (13)
H2N1	0.619 (4)	1.109 (5)	0.797 (7)	0.046*
H2N2	0.552 (3)	1.244 (7)	0.799 (7)	0.046*
N3	0.6378 (4)	0.7258 (8)	−0.0638 (7)	0.0410 (13)
C1	0.5843 (6)	1.1559 (10)	0.2502 (9)	0.0466 (18)
H1	0.5823	1.1480	0.1380	0.056*
C2	0.5134 (6)	1.2562 (10)	0.3268 (8)	0.0513 (19)
H2	0.4652	1.3150	0.2678	0.062*
C3	0.5163 (5)	1.2667 (10)	0.4939 (9)	0.0436 (16)
H3	0.4684	1.3307	0.5486	0.052*
C4	0.5896 (5)	1.1829 (8)	0.5793 (8)	0.0331 (13)
C5	0.6575 (4)	1.0849 (8)	0.4903 (7)	0.0330 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag	0.0490 (3)	0.0409 (2)	0.0393 (2)	0.0027 (2)	−0.0012 (2)	−0.0025 (2)
Cl1	0.0584 (11)	0.0625 (10)	0.0475 (9)	0.0315 (10)	−0.0048 (8)	−0.0042 (8)
O1	0.087 (4)	0.041 (3)	0.059 (3)	0.017 (3)	0.008 (3)	−0.011 (3)
O2	0.057 (3)	0.090 (4)	0.066 (3)	0.031 (3)	−0.031 (3)	−0.022 (4)
O3	0.064 (3)	0.074 (4)	0.092 (5)	0.021 (3)	−0.043 (3)	−0.041 (4)
N1	0.045 (3)	0.033 (3)	0.039 (3)	−0.001 (2)	−0.002 (2)	−0.009 (2)
N2	0.040 (3)	0.037 (3)	0.037 (3)	0.007 (3)	0.009 (2)	0.000 (3)
N3	0.040 (3)	0.045 (3)	0.037 (3)	0.003 (3)	−0.004 (2)	−0.002 (3)
C1	0.053 (4)	0.045 (4)	0.042 (3)	0.001 (3)	−0.014 (3)	−0.006 (3)
C2	0.047 (4)	0.050 (4)	0.057 (4)	0.010 (4)	−0.019 (4)	0.002 (4)
C3	0.032 (3)	0.040 (4)	0.059 (4)	0.002 (3)	−0.002 (3)	−0.012 (4)
C4	0.034 (3)	0.026 (3)	0.038 (3)	−0.006 (3)	−0.001 (3)	0.000 (3)
C5	0.029 (3)	0.028 (3)	0.042 (3)	0.003 (3)	−0.003 (2)	0.001 (3)

Geometric parameters (Å, º)

Ag—N1	2.283 (5)	N2—C4	1.427 (9)
Ag—N2^i	2.364 (6)	N2—H2N1	0.86 (5)
Ag—O2	2.510 (6)	N2—H2N2	0.85 (5)
Ag—O3^ii	2.594 (6)	C1—C2	1.383 (10)
Cl1—C5	1.718 (6)	C1—H1	0.9300
O1—N3	1.240 (7)	C2—C3	1.385 (9)
O2—N3	1.226 (7)	C2—H2	0.9300
O2—Ag^iii	2.707 (6)	C3—C4	1.373 (10)
O3—N3	1.239 (8)	C3—H3	0.9300
N1—C5	1.332 (8)	C4—C5	1.397 (9)
N1—C1	1.346 (9)
N1—Ag—N2^i	140.44 (18)	O2—N3—O1	120.9 (6)
N1—Ag—O2	122.09 (18)	O2—N3—O3	118.4 (6)
N2^i—Ag—O2	82.25 (19)	O1—N3—O3	120.7 (6)
N1—Ag—O3^ii	96.2 (2)	N1—C1—C2	123.2 (6)
N2^i—Ag—O3^ii	88.0 (2)	N1—C1—H1	118.4
O2—Ag—O3^ii	129.2 (2)	C2—C1—H1	118.4
N3—O2—Ag	106.5 (5)	C3—C2—C1	118.2 (7)
N3—O2—Ag^iii	94.0 (4)	C3—C2—H2	120.9
Ag—O2—Ag^iii	157.6 (2)	C1—C2—H2	120.9
N3—O3—Ag^iii	99.2 (4)	C4—C3—C2	120.3 (7)
C5—N1—C1	116.9 (6)	C4—C3—H3	119.9
C5—N1—Ag	121.5 (4)	C2—C3—H3	119.9
C1—N1—Ag	121.5 (4)	C3—C4—C5	117.0 (6)
C4—N2—Ag^iv	109.8 (4)	C3—C4—N2	122.8 (6)
C4—N2—H2N1	113 (5)	C5—C4—N2	120.1 (6)
Ag^iv—N2—H2N1	107 (5)	N1—C5—C4	124.4 (6)
C4—N2—H2N2	115 (5)	N1—C5—Cl1	116.6 (5)
Ag^iv—N2—H2N2	103 (5)	C4—C5—Cl1	119.0 (5)
H2N1—N2—H2N2	108 (5)
N1—Ag—O2—N3	33.8 (5)	Ag^iii—O3—N3—O1	168.0 (5)
N2^i—Ag—O2—N3	−179.8 (5)	C5—N1—C1—C2	−0.7 (11)
O3^ii—Ag—O2—N3	−98.8 (5)	Ag—N1—C1—C2	178.3 (6)
N1—Ag—O2—Ag^iii	−170.8 (7)	N1—C1—C2—C3	−0.4 (13)
N2^i—Ag—O2—Ag^iii	−24.4 (7)	C1—C2—C3—C4	1.8 (13)
O3^ii—Ag—O2—Ag^iii	56.6 (8)	C2—C3—C4—C5	−1.8 (11)
N2^i—Ag—N1—C5	5.9 (7)	C2—C3—C4—N2	173.9 (7)
O2—Ag—N1—C5	126.5 (5)	Ag^iv—N2—C4—C3	−98.7 (7)
O3^ii—Ag—N1—C5	−88.5 (5)	Ag^iv—N2—C4—C5	76.9 (7)
N2^i—Ag—N1—C1	−173.1 (5)	C1—N1—C5—C4	0.6 (10)
O2—Ag—N1—C1	−52.5 (6)	Ag—N1—C5—C4	−178.4 (5)
O3^ii—Ag—N1—C1	92.5 (5)	C1—N1—C5—Cl1	−178.0 (5)
Ag—O2—N3—O1	2.2 (8)	Ag—N1—C5—Cl1	3.0 (7)
Ag^iii—O2—N3—O1	−168.6 (6)	C3—C4—C5—N1	0.6 (10)
Ag—O2—N3—O3	−177.7 (5)	N2—C4—C5—N1	−175.2 (6)
Ag^iii—O2—N3—O3	11.4 (7)	C3—C4—C5—Cl1	179.2 (5)
Ag^iii—O3—N3—O2	−12.1 (7)	N2—C4—C5—Cl1	3.4 (9)

Symmetry codes: (i) −x+3/2, y−1/2, −z+1; (ii) −x+3/2, y+1/2, −z; (iii) −x+3/2, y−1/2, −z; (iv) −x+3/2, y+1/2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N1···O1^v	0.86 (5)	2.35 (5)	3.160 (8)	159 (5)
N2—H2N2···O3^vi	0.85 (5)	2.20 (4)	3.020 (8)	160 (6)

Symmetry codes: (v) x, y, z+1; (vi) −x+1, −y+2, z+1.