catena-Poly­[[(benzoato-κO)silver(I)]-μ-2-amino­pyrimidine-κ²N¹:N³]

The title complex, [Ag(C₇H₅O₂)(C₄H₅N₃)]_n, is a polymer based on a mononuclear silver(I)-centered fragment. The Ag^I atom is trigonally coordinated by two N atoms from two 2-­amino­pyrimidine ligands and one O atom from one benzoate anion, giving zigzag polymeric chains with an [–Ag—N—C—N–]_n backbone running along the a axis. It is proposed that intermolecular hydrogen bonding drives the formation of the chain polymer.

S1. Comment

Inorganic supramolecular chemistry, and in particular the construction of polymeric silver(I) coordination networks, is an active area of research (Xu et al., 2001; Yaghi & Li, 1996; Khlobystov et al., 2001). The primary reason for interest in silver(I) compounds is their ability to afford functional solid materials with potentially controllable properties and novel molecular structures. Recent developments in supramolecular chemistry have made it possible to select building units for assembly into structures with specific network topologies (Blake et al., 2000; Melcer et al., 2001). Crystal engineering of coordination polymeric networks based on multidentate ligands is a growing area of coordination and supramolecular chemistry. Recently, we have focused our attention on the assembly of silver(I) ions with flexible ligands, since they can adopt diverse coordination modes according to the different geometric needs of the silver(I) ions (You et al., 2004a,b). As reported previously, we have used 2-aminopyridine as the bidentate ligand and the benzoate anion as the counter-ion to obtain a mononuclear silver(I) complex, (II), bis(2-aminopyridine-κN¹)(benzoato-κO)silver(I) (Zhu et al., 2003). In order to investigate the relationship between the starting materials and the resulting structures, in this work we used the tridentate ligand 2-aminopyrimidine instead of the bidentate ligand 2-aminopyridine to obtain the title compound, (I). As expected, the structure of (I) consists of one-dimensional chains and is thus entirely different from that of (II).

Complex (I) is a polymeric 2-aminopyrimidine–Ag^I compound (Fig. 1). The smallest repeat unit for the complex contains a 2-aminopyrimidine–Ag^I cation and a benzoate anion. The Ag^I atom is in a distorted trigonal coordination environment and is three-coordinated by two N atoms of two different but symmetry-related 2-aminopyrimidine ligands and by one O atom of one benzoate anion. The angles subtended at atom Ag1 [136.15 (15), 125.40 (16) and 98.38 (15)°, respectively; Table 1] are comparable to the corresponding values observed in (II). In (I), the smallest of these angles is O1–Ag1–N2, which lies inside a six-atom ring (including an H atom) closed by the N1—H1A···O1 hydrogen bond.

The mean Ag—N bond length is 2.291 (4) Å in (I) and 2.218 (4) Å in (II). The Ag—O bond length in (I) [2.313 (4) Å] is comparable to the value of 2.344 (4) Å in (II). The coordination geometry around the Ag atom in (II) is approximately trigonal, and thus is qualitatively the same pattern as that found for (I).

In the extended structure of (I), the 2-aminopyrimidine–Ag^I unit propagates as a zigzag chain along the a axis (Fig. 2), with the benzoate anions extending laterally, attached not only by the Ag—O bonds but also through intramolecular N—H···O hydrogen bonds (Table 2).

In (II), the layered structure is mediated by the formation of intermolecular hydrogen bonds. In contrast, in (I), the hydrogen bonds are located within each of the chains. The H atoms of the amine groups are disposed in such a way as to obviate a link to the O atoms of another chain. We propose that it is this fundamental difference in the arrangement of the non-covalent interactions in (I) that gives rise to a chain structure, rather than to discrete molecules in layers or another arrangement mediated by non-covalent interactions.

S2. Experimental

Ag₂O (0.1 mmol, 23.2 mg) and benzoic acid (0.2 mmol, 24.4 mg) were dissolved in a 30% aqueous ammonia solution (10 ml), and the resulting solution was stirred for ca 15 min to give a clear colorless solution. To this solution was added an acetonitrile (5 ml) solution of 2-aminopyrimidine (0.1 mmol, 9.5 mg), with stirring. The mixture was stirred for 1 h, and the resulting colorless solution was kept in the dark at room temperature for 8 d. Colorless block-shaped crystals formed with slow evaporation of the solvent.

S3. Refinement

All H atoms were placed in idealized positions and allowed to ride on their parent atoms (N—H = 0.90 Å, and C—H = 0.96 Å), with U_iso(H) values fixed at 0.08 Ų.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The structure and atom-numbering scheme of (I). Displacement ellipsoids are drawn at the 30% probability level. Atoms labelled with the suffix A are at symmetry position (1 + x, y, z).
	Fig. 2. The crystal packing of (I), viewed along the a axis.

catena-Poly[[(benzoato-κO)silver(I)]-µ-2-aminopyrimidine-κ²N¹:N³]

Crystal data

[Ag(C7H5O2)(C4H5N3)]	F(000) = 640
Mr = 324.09	Dx = 1.910 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1213 reflections
a = 6.457 (3) Å	θ = 2.2–25.3°
b = 25.594 (7) Å	µ = 1.78 mm^−1
c = 7.111 (3) Å	T = 293 K
β = 106.488 (3)°	Block, colorless
V = 1126.8 (8) Å^3	0.28 × 0.25 × 0.22 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	2297 independent reflections
Radiation source: fine-focus sealed tube	1870 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.041
ω scans	θmax = 26.5°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→8
Tmin = 0.636, Tmax = 0.695	k = −23→32
5115 measured reflections	l = −6→8

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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.125	H-atom parameters constrained
S = 1.18	w = 1/[σ^2(Fo^2) + (0.0468P)^2 + 0.8969P] where P = (Fo^2 + 2Fc^2)/3
2297 reflections	(Δ/σ)max < 0.001
154 parameters	Δρmax = 0.80 e Å^−3
0 restraints	Δρmin = −0.74 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
Ag1	0.52115 (7)	1.01761 (2)	0.23928 (7)	0.0440 (2)
O1	0.4556 (6)	0.94268 (16)	0.3950 (6)	0.0434 (10)
O2	0.7227 (8)	0.90684 (18)	0.3038 (8)	0.0600 (13)
N1	0.0326 (7)	0.9841 (2)	0.2855 (7)	0.0375 (12)
H1A	0.1656	0.9699	0.3209	0.080*
H1B	−0.0791	0.9668	0.3084	0.080*
N2	0.1758 (6)	1.05482 (18)	0.1696 (6)	0.0301 (10)
N3	−0.1999 (6)	1.05083 (19)	0.1508 (7)	0.0320 (10)
C1	0.5783 (9)	0.9050 (2)	0.3855 (8)	0.0377 (14)
C2	0.5458 (9)	0.8551 (2)	0.4845 (8)	0.0348 (12)
C3	0.7049 (10)	0.8166 (3)	0.5198 (11)	0.0491 (16)
H3B	0.8303	0.8211	0.4744	0.080*
C4	0.6857 (12)	0.7714 (3)	0.6203 (11)	0.0599 (19)
H4A	0.7979	0.7455	0.6477	0.080*
C5	0.5060 (13)	0.7641 (3)	0.6852 (12)	0.065 (2)
H5A	0.4936	0.7333	0.7579	0.080*
C6	0.3454 (12)	0.8011 (3)	0.6453 (11)	0.0562 (18)
H6A	0.2159	0.7947	0.6824	0.080*
C7	0.3649 (10)	0.8464 (3)	0.5474 (9)	0.0420 (15)
H7A	0.2541	0.8726	0.5260	0.080*
C8	0.0020 (8)	1.0308 (2)	0.2002 (7)	0.0278 (12)
C9	0.1408 (9)	1.1012 (2)	0.0839 (8)	0.0362 (13)
H9A	0.2607	1.1193	0.0594	0.080*
C10	−0.0609 (9)	1.1242 (2)	0.0238 (9)	0.0417 (14)
H10A	−0.0832	1.1579	−0.0380	0.080*
C11	−0.2266 (9)	1.0973 (2)	0.0608 (9)	0.0383 (14)
H11A	−0.3686	1.1124	0.0196	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.0264 (3)	0.0506 (3)	0.0584 (4)	0.0016 (2)	0.0176 (2)	0.0076 (2)
O1	0.035 (2)	0.038 (2)	0.053 (3)	0.0056 (19)	0.0055 (19)	0.0080 (19)
O2	0.063 (3)	0.054 (3)	0.081 (4)	0.000 (2)	0.049 (3)	0.006 (3)
N1	0.026 (2)	0.048 (3)	0.041 (3)	0.007 (2)	0.014 (2)	0.010 (2)
N2	0.021 (2)	0.043 (3)	0.027 (2)	0.001 (2)	0.0083 (18)	−0.002 (2)
N3	0.020 (2)	0.040 (3)	0.037 (3)	0.0033 (19)	0.0103 (19)	0.001 (2)
C1	0.034 (3)	0.043 (4)	0.033 (3)	−0.008 (3)	0.003 (3)	−0.007 (3)
C2	0.034 (3)	0.033 (3)	0.034 (3)	−0.005 (3)	0.005 (2)	−0.003 (2)
C3	0.037 (3)	0.043 (4)	0.067 (5)	−0.003 (3)	0.013 (3)	−0.007 (3)
C4	0.059 (4)	0.039 (4)	0.079 (6)	0.012 (3)	0.015 (4)	0.006 (4)
C5	0.094 (6)	0.041 (4)	0.061 (5)	−0.003 (4)	0.023 (5)	0.009 (3)
C6	0.062 (4)	0.053 (5)	0.063 (5)	−0.009 (4)	0.032 (4)	0.001 (4)
C7	0.039 (3)	0.046 (4)	0.040 (4)	−0.002 (3)	0.010 (3)	−0.004 (3)
C8	0.023 (3)	0.039 (3)	0.020 (3)	0.001 (2)	0.003 (2)	−0.006 (2)
C9	0.027 (3)	0.044 (4)	0.041 (3)	−0.003 (2)	0.016 (2)	0.001 (3)
C10	0.039 (3)	0.047 (4)	0.040 (3)	0.009 (3)	0.012 (3)	0.009 (3)
C11	0.028 (3)	0.047 (4)	0.042 (3)	0.009 (3)	0.013 (3)	−0.001 (3)

Geometric parameters (Å, º)

Ag1—N3^i	2.237 (4)	C3—C4	1.384 (9)
Ag1—O1	2.313 (4)	C3—H3B	0.9600
Ag1—N2	2.345 (4)	C4—C5	1.378 (10)
O1—C1	1.262 (7)	C4—H4A	0.9600
O2—C1	1.232 (7)	C5—C6	1.373 (10)
N1—C8	1.329 (8)	C5—H5A	0.9599
N1—H1A	0.9000	C6—C7	1.376 (9)
N1—H1B	0.9000	C6—H6A	0.9600
N2—C9	1.323 (7)	C7—H7A	0.9601
N2—C8	1.350 (6)	C9—C10	1.382 (8)
N3—C11	1.339 (7)	C9—H9A	0.9600
N3—C8	1.351 (6)	C10—C11	1.359 (8)
C1—C2	1.500 (8)	C10—H10A	0.9601
C2—C7	1.383 (8)	C11—H11A	0.9601
C2—C3	1.393 (8)
N3^i—Ag1—O1	136.15 (15)	C5—C4—H4A	119.8
N3^i—Ag1—N2	125.40 (16)	C3—C4—H4A	120.6
O1—Ag1—N2	98.38 (15)	C6—C5—C4	119.7 (7)
C1—O1—Ag1	113.9 (4)	C6—C5—H5A	120.3
C8—N1—H1A	119.8	C4—C5—H5A	120.0
C8—N1—H1B	120.2	C5—C6—C7	120.9 (7)
H1A—N1—H1B	120.0	C5—C6—H6A	119.4
C9—N2—C8	116.2 (4)	C7—C6—H6A	119.6
C9—N2—Ag1	119.3 (3)	C6—C7—C2	120.4 (6)
C8—N2—Ag1	124.4 (4)	C6—C7—H7A	119.8
C11—N3—C8	116.4 (5)	C2—C7—H7A	119.7
C11—N3—Ag1^ii	117.9 (3)	N1—C8—N2	117.4 (5)
C8—N3—Ag1^ii	125.2 (4)	N1—C8—N3	117.9 (5)
O2—C1—O1	124.5 (6)	N2—C8—N3	124.7 (5)
O2—C1—C2	118.7 (6)	N2—C9—C10	123.2 (5)
O1—C1—C2	116.9 (5)	N2—C9—H9A	118.4
C7—C2—C3	118.4 (6)	C10—C9—H9A	118.3
C7—C2—C1	122.2 (5)	C11—C10—C9	116.6 (6)
C3—C2—C1	119.5 (5)	C11—C10—H10A	121.3
C4—C3—C2	121.0 (6)	C9—C10—H10A	122.1
C4—C3—H3B	118.8	N3—C11—C10	122.8 (5)
C2—C3—H3B	120.3	N3—C11—H11A	118.9
C5—C4—C3	119.6 (7)	C10—C11—H11A	118.3

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2^ii	0.90	1.99	2.843 (7)	157
N1—H1A···O1	0.90	1.93	2.825 (6)	177

Symmetry code: (ii) x−1, y, z.