Bis(2-amino­pyridine-[kappa]N¹)(benzoato-[kappa]O)silver(I)

In the title compound, [Ag(C₇H₅O₂)(C₅H₆N₂)₂], the Ag^I atom is tricoordinated by two independent pyridine N atoms and one benzoate O atom in a nearly planar geometry. An intramolecular N-H...O hydrogen bond forms an S(8) graph ring. The packing is built from molecular layers stabilized by two types of N-H...O hydrogen bond. Intermolecular Ag...N and intramolecular Ag...O contacts were also observed, together with three weak intermolecular C-H...[pi] interactions.

S1. Comment

Over the past two decades, there has been considerable interest in monovalent coinage metal compounds because the rich coordination chemistry of these metals can be utilized in biomimetics, catalysis and materials science (Lehn, 1988). Many polyazamacrocyclic complexes containing Cu^II, Zn^II, Co^II,III and Ni^II have been described. As a heavy metal ion with a d¹⁰ configuration, Ag^I also exhibits rich coordination chemistry. Many factors, such as the nature of the ligands, solvents, anions etc., appear to influences the streochemistry and stoichiometry of Ag^I compounds. All the above factors make it difficult to isolate simple stable monomers or dimers. In previous studies, we obtained and characterized several oligo-Ag^I complexes (Zhu et al., 2001; Usman et al., 2003). In this work, we report the crystal structure analysis of the title complex, (I), which is a new oligo-mononuclear Ag^I complex which is stable to light.

The Ag1 atom in (I) is tricoordinated by two pyridine N atoms from two independent 2-aminopyridine moieties and by one O atom from the benzoate moiety (Fig. 1). The Ag—N bond lengths [Ag1—N1 = 2.230 (3) Å and Ag1—N3 = 2.205 (4) Å] are within acceptable values and are comparable with those in the silver complexes of aminopyridines [2.122 (3) Å (Kristiansson, 2000), 2.197 (4)–2.199 (4) Å (Li et al., 2002) and 2.283 (3)–2.364 (6) Å (Tong et al., 2002)], whereas the Ag—O bond distance [Ag1—O1 = 2.344 (4) Å] is slightly longer than that in terephthalatosilver(I) [2.175 (3) Å; Zhu et al., 2003]. The AgN₂O coordination is nearly planar, with atom Ag1 deviating by 0.217 (1) Å from the O1/N1/N3 plane; the bond angles around Ag1 are listed in Table 1. The planes of the two independent 2-aminopyridine moieties make a dihedral angle of 30.8 (3)°. Within the benzoate moiety, the carboxylate group (C7/O1/O2) is nearly coplanar to the aromatic ring; the dihedral angle between the C6/C7/O1/O2 plane and the plane of the aromatic ring is 4.8 (2)°.

In (I), there is one S(8) graph ring (Etter et al., 1990), viz. O2—C7—O1—Ag1—N3—C17—N4—H4A, maintained by the intramolecular N4—H4A···O2 hydrogen bond (Table 2). This graph ring is not planar and the dihedral angle between the C6/C7/O1/O2 and Ag1/N3/C17/N4 planes is 61.1 (1)°. There is an intramolecular short contact between atoms Ag1 and O2 of 2.863 (4) Å; this contact is shorter than other Ag···O contacts observed in a related structure [average 3.087 Å; Usman et al., 2003; please check – this reference contains no Ag].

In the packing, the molecules are interconnected into chains parallel to the a direction by intermolecular N2—H2B···O2ⁱ hydrogen bonds [symmetry code: (i) −x, y + 1/2, 1 − z]. The molecular chains are then interconnected by intermolecular N4—H4B···O1ⁱⁱ hydrogen bonds into layers [Fig. 2; symmetry code: (ii) x − 1, y, z]. The layers stack one above another along the c direction. In this manner, atom O2 facilitates a bifurcated system, and the amino N4—H4 bond acts as a multiple hydrogen-bond donor, in contrast to the N2—H2 bond, which is a single hydrogen-bond donor. The packing is also stabilized by Ag1···N4(x + 1, y, z) [3.737 (4) Å] contacts, together with three weak intermolecular C—H···π interactions involving the centroids of the aromatic rings of pyridine C8–C12/N1 (Cg1) and benzoate C1–C6 (Cg3) (details are given in Table 2).

S2. Experimental

Ag₂O (0.5 mmol, 116 mg) and benzoic acid (1 mmol, 122 mg) were dissolved in ammonium solution (10 ml), and the resulting solution was stirred for ca 10 min to obtain a clear solution. A solution of 2-Aminopyridine (2 mmol, 188 mg) in acetonitrile (2 ml) was added to the above solution. The resulting solution was kept in air for 2 d with ammonium gas escaping. Colorless crystals of (I) were collected and washed with water and acetonitrile in turn, and then dried in a vacuum desiccator over drying CaCl₂ (yield 63%). Analysis calculated for C₁₇H₁₇AgN₄O₂: C 48.94, H 4.11, N 13.43%; found: C 49.05, H 4.18, N 13.29%. IR spectrum: 3419 (w), 3205 (m), 3146 (m), 1633 (m), 1591 (s), 1561 (s), 1486 (s), 1441 (s), 1388 (versus), 1323 (m), 1271 (m), 1156 (m), 1004 (m), 839 (m), 772 (m), 722 (m), 678 (m).

S3. Refinement

All H atoms attached to C atoms were fixed geometrically and treated as riding atoms, with C—H = 0.93 Å and U_iso(H) = 1.2 U_eq(C), whereas all H atoms attached to N atoms were located from difference maps and were refined isotropically; the N—H distances are in the range 0.73 (6)–0.90 (7) Å. The absolute configuration of the asymmetric unit shown in Fig. 1 has been determined by the Flack (1983) parameter.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 2003).

Figures

	Fig. 1. The structure of the title complex, (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. Packing diagram for (I), viewed down the c axis, showing the layers parallel to the ab plane. The dashed lines denote intermolecular N—H···O interactions.

Bis(2-aminopyridine-κN¹)(benzoato-κO)silver(I)

Crystal data

[Ag(C7H5O2)(C5H6N2)2]	F(000) = 420
Mr = 417.22	Dx = 1.575 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 6.0261 (5) Å	Cell parameters from 3391 reflections
b = 12.0503 (10) Å	θ = 2.4–28.3°
c = 12.312 (1) Å	µ = 1.16 mm^−1
β = 100.274 (1)°	T = 293 K
V = 879.72 (13) Å^3	Slab, colorless
Z = 2	0.50 × 0.40 × 0.38 mm

Data collection

Siemens SMART CCD area-detector diffractometer	3019 independent reflections
Radiation source: fine-focus sealed tube	2671 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
Detector resolution: 8.33 pixels mm^-1	θmax = 28.3°, θmin = 2.4°
ω scans	h = −7→8
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −15→10
Tmin = 0.594, Tmax = 0.667	l = −14→16
5504 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 atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.0453P)^2 + 0.1717P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max < 0.001
3019 reflections	Δρmax = 0.88 e Å^−3
233 parameters	Δρmin = −0.44 e Å^−3
1 restraint	Absolute structure: Flack (1983), 741 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.01 (4)

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal-to-detector distance was 5 cm and the detector swing angle was −35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the intensity of duplicate reflections, and was found to be negligible.

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	0.01716 (5)	0.31525 (3)	0.33028 (3)	0.06638 (13)
O1	0.1113 (6)	0.1763 (3)	0.2133 (3)	0.0727 (9)
O2	−0.1845 (7)	0.1043 (3)	0.2679 (3)	0.0621 (9)
N1	0.3214 (5)	0.3137 (5)	0.4633 (2)	0.0522 (6)
N2	0.1833 (9)	0.4652 (5)	0.5447 (4)	0.0727 (12)
H2A	0.071 (10)	0.444 (6)	0.510 (5)	0.077 (19)*
H2B	0.173 (13)	0.519 (7)	0.593 (6)	0.11 (2)*
N3	−0.2567 (6)	0.4330 (3)	0.2687 (3)	0.0554 (8)
N4	−0.4855 (7)	0.2917 (4)	0.1887 (4)	0.0616 (13)
H4A	−0.383 (10)	0.240 (6)	0.217 (5)	0.066 (17)*
H4B	−0.608 (10)	0.282 (5)	0.179 (4)	0.065 (17)*
C1	0.1837 (8)	−0.0134 (5)	0.0948 (4)	0.0654 (12)
H1	0.2873	0.0443	0.0985	0.079*
C2	0.2152 (12)	−0.1079 (7)	0.0367 (4)	0.091 (2)
H2	0.3414	−0.1163	0.0036	0.110*
C3	0.0566 (14)	−0.1881 (11)	0.0294 (5)	0.110 (3)
H3	0.0720	−0.2511	−0.0123	0.131*
C4	−0.1289 (11)	−0.1801 (8)	0.0818 (4)	0.0880 (15)
H4	−0.2333	−0.2375	0.0766	0.106*
C5	−0.1557 (8)	−0.0884 (4)	0.1401 (4)	0.0615 (11)
H5	−0.2794	−0.0824	0.1754	0.074*
C6	−0.0001 (6)	−0.0024 (4)	0.1481 (3)	0.0461 (8)
C7	−0.0278 (7)	0.0995 (3)	0.2146 (3)	0.0455 (8)
C8	0.4912 (9)	0.2427 (5)	0.4588 (4)	0.0609 (11)
H8	0.4705	0.1882	0.4044	0.073*
C9	0.6936 (9)	0.2464 (5)	0.5303 (4)	0.0727 (13)
H9	0.8077	0.1959	0.5246	0.087*
C10	0.7226 (8)	0.3269 (8)	0.6104 (4)	0.0753 (15)
H10	0.8574	0.3306	0.6606	0.090*
C11	0.5547 (9)	0.4017 (5)	0.6170 (4)	0.0664 (12)
H11	0.5754	0.4569	0.6706	0.080*
C12	0.3506 (7)	0.3940 (4)	0.5416 (3)	0.0513 (9)
C13	−0.2252 (13)	0.5433 (5)	0.2913 (6)	0.0771 (16)
H13	−0.0832	0.5675	0.3253	0.092*
C14	−0.3919 (13)	0.6186 (6)	0.2661 (6)	0.0960 (19)
H14	−0.3662	0.6929	0.2845	0.115*
C15	−0.5992 (13)	0.5842 (6)	0.2131 (6)	0.0926 (19)
H15	−0.7159	0.6352	0.1951	0.111*
C16	−0.6345 (9)	0.4751 (5)	0.1868 (5)	0.0754 (14)
H16	−0.7746	0.4513	0.1500	0.091*
C17	−0.4605 (8)	0.4002 (5)	0.2153 (4)	0.0524 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.05793 (18)	0.0646 (2)	0.0690 (2)	0.0027 (2)	−0.00918 (12)	−0.0132 (2)
O1	0.072 (2)	0.063 (2)	0.086 (2)	−0.0204 (18)	0.0232 (17)	−0.0179 (18)
O2	0.081 (2)	0.0476 (19)	0.0655 (19)	0.0079 (17)	0.0336 (17)	0.0074 (14)
N1	0.0554 (15)	0.0495 (15)	0.0487 (13)	0.001 (3)	0.0010 (11)	−0.009 (2)
N2	0.072 (3)	0.076 (3)	0.070 (3)	−0.001 (3)	0.013 (2)	−0.025 (2)
N3	0.0519 (19)	0.048 (2)	0.064 (2)	−0.0014 (16)	0.0054 (16)	−0.0029 (16)
N4	0.045 (2)	0.056 (4)	0.081 (3)	−0.0054 (19)	0.0020 (16)	−0.005 (2)
C1	0.063 (3)	0.081 (4)	0.052 (2)	0.007 (2)	0.0103 (19)	−0.002 (2)
C2	0.100 (4)	0.111 (5)	0.060 (3)	0.043 (4)	0.006 (3)	−0.020 (3)
C3	0.151 (6)	0.094 (5)	0.064 (3)	0.035 (7)	−0.034 (3)	−0.038 (5)
C4	0.111 (4)	0.058 (3)	0.083 (3)	−0.006 (5)	−0.016 (3)	−0.010 (4)
C5	0.069 (3)	0.050 (2)	0.060 (2)	−0.007 (2)	−0.004 (2)	−0.0024 (19)
C6	0.050 (2)	0.047 (2)	0.0375 (17)	0.0078 (16)	−0.0004 (14)	0.0028 (15)
C7	0.055 (2)	0.042 (2)	0.0372 (17)	0.0033 (17)	0.0022 (15)	0.0067 (15)
C8	0.069 (3)	0.063 (3)	0.050 (2)	0.005 (2)	0.0064 (19)	−0.006 (2)
C9	0.063 (3)	0.080 (4)	0.072 (3)	0.013 (3)	0.003 (2)	0.007 (3)
C10	0.060 (2)	0.098 (4)	0.061 (2)	−0.012 (4)	−0.0097 (17)	0.007 (3)
C11	0.074 (3)	0.069 (3)	0.052 (2)	−0.021 (3)	0.001 (2)	−0.010 (2)
C12	0.058 (2)	0.053 (2)	0.0438 (18)	−0.0108 (19)	0.0114 (16)	−0.0053 (16)
C13	0.079 (4)	0.055 (3)	0.095 (4)	0.000 (3)	0.008 (3)	−0.013 (3)
C14	0.114 (5)	0.053 (3)	0.123 (5)	0.010 (3)	0.026 (4)	−0.007 (3)
C15	0.103 (5)	0.072 (4)	0.104 (4)	0.033 (4)	0.019 (4)	0.010 (3)
C16	0.057 (3)	0.086 (4)	0.082 (3)	0.017 (3)	0.009 (2)	−0.001 (3)
C17	0.049 (2)	0.059 (3)	0.051 (2)	0.003 (2)	0.0145 (18)	0.006 (2)

Geometric parameters (Å, º)

Ag1—N3	2.205 (4)	C4—C5	1.342 (10)
Ag1—N1	2.230 (3)	C4—H4	0.9300
Ag1—O1	2.344 (4)	C5—C6	1.389 (6)
O1—C7	1.250 (5)	C5—H5	0.9300
O2—C7	1.244 (5)	C6—C7	1.502 (6)
N1—C8	1.343 (7)	C8—C9	1.372 (7)
N1—C12	1.355 (6)	C8—H8	0.9300
N2—C12	1.329 (7)	C9—C10	1.371 (9)
N2—H2A	0.78 (6)	C9—H9	0.9300
N2—H2B	0.88 (8)	C10—C11	1.368 (9)
N3—C17	1.345 (6)	C10—H10	0.9300
N3—C13	1.365 (7)	C11—C12	1.405 (6)
N4—C17	1.349 (8)	C11—H11	0.9300
N4—H4A	0.90 (7)	C13—C14	1.348 (10)
N4—H4B	0.73 (6)	C13—H13	0.9300
C1—C2	1.377 (8)	C14—C15	1.366 (11)
C1—C6	1.390 (6)	C14—H14	0.9300
C1—H1	0.9300	C15—C16	1.362 (9)
C2—C3	1.351 (14)	C15—H15	0.9300
C2—H2	0.9300	C16—C17	1.381 (8)
C3—C4	1.390 (10)	C16—H16	0.9300
C3—H3	0.9300
N3—Ag1—N1	136.4 (2)	O2—C7—O1	123.1 (4)
N3—Ag1—O1	119.8 (2)	O2—C7—C6	119.6 (4)
N1—Ag1—O1	100.9 (2)	O1—C7—C6	117.3 (4)
C7—O1—Ag1	106.5 (3)	N1—C8—C9	123.3 (5)
C8—N1—C12	118.8 (3)	N1—C8—H8	118.3
C8—N1—Ag1	120.5 (3)	C9—C8—H8	118.3
C12—N1—Ag1	120.2 (3)	C10—C9—C8	118.0 (5)
C12—N2—H2A	111 (5)	C10—C9—H9	121.0
C12—N2—H2B	129 (5)	C8—C9—H9	121.0
H2A—N2—H2B	117 (7)	C11—C10—C9	120.5 (4)
C17—N3—C13	117.9 (5)	C11—C10—H10	119.8
C17—N3—Ag1	122.8 (3)	C9—C10—H10	119.8
C13—N3—Ag1	119.2 (4)	C10—C11—C12	119.1 (5)
C17—N4—H4A	122 (4)	C10—C11—H11	120.4
C17—N4—H4B	105 (5)	C12—C11—H11	120.4
H4A—N4—H4B	123 (6)	N2—C12—N1	118.6 (4)
C2—C1—C6	121.3 (6)	N2—C12—C11	121.2 (4)
C2—C1—H1	119.4	N1—C12—C11	120.3 (4)
C6—C1—H1	119.4	C14—C13—N3	122.6 (7)
C3—C2—C1	117.7 (6)	C14—C13—H13	118.7
C3—C2—H2	121.1	N3—C13—H13	118.7
C1—C2—H2	121.1	C13—C14—C15	119.1 (7)
C2—C3—C4	122.5 (8)	C13—C14—H14	120.5
C2—C3—H3	118.8	C15—C14—H14	120.5
C4—C3—H3	118.8	C16—C15—C14	119.8 (6)
C5—C4—C3	119.3 (8)	C16—C15—H15	120.1
C5—C4—H4	120.4	C14—C15—H15	120.1
C3—C4—H4	120.4	C15—C16—C17	119.5 (6)
C4—C5—C6	120.5 (5)	C15—C16—H16	120.3
C4—C5—H5	119.7	C17—C16—H16	120.3
C6—C5—H5	119.7	N3—C17—N4	117.1 (5)
C5—C6—C1	118.7 (5)	N3—C17—C16	121.2 (5)
C5—C6—C7	120.6 (4)	N4—C17—C16	121.7 (5)
C1—C6—C7	120.7 (4)
N3—Ag1—O1—C7	−81.5 (3)	C1—C6—C7—O1	4.9 (6)
N1—Ag1—O1—C7	114.9 (3)	C12—N1—C8—C9	0.6 (8)
N3—Ag1—N1—C8	−159.7 (4)	Ag1—N1—C8—C9	171.8 (4)
O1—Ag1—N1—C8	−0.5 (4)	N1—C8—C9—C10	0.1 (9)
N3—Ag1—N1—C12	11.4 (5)	C8—C9—C10—C11	−0.9 (9)
O1—Ag1—N1—C12	170.7 (3)	C9—C10—C11—C12	1.0 (8)
N1—Ag1—N3—C17	−154.7 (3)	C8—N1—C12—N2	179.0 (5)
O1—Ag1—N3—C17	48.9 (4)	Ag1—N1—C12—N2	7.7 (6)
N1—Ag1—N3—C13	21.0 (5)	C8—N1—C12—C11	−0.5 (7)
O1—Ag1—N3—C13	−135.3 (4)	Ag1—N1—C12—C11	−171.8 (3)
C6—C1—C2—C3	2.6 (9)	C10—C11—C12—N2	−179.7 (5)
C1—C2—C3—C4	−2.8 (11)	C10—C11—C12—N1	−0.3 (7)
C2—C3—C4—C5	1.5 (11)	C17—N3—C13—C14	2.7 (9)
C3—C4—C5—C6	0.0 (8)	Ag1—N3—C13—C14	−173.2 (5)
C4—C5—C6—C1	−0.1 (6)	N3—C13—C14—C15	−1.9 (11)
C4—C5—C6—C7	−179.1 (4)	C13—C14—C15—C16	0.1 (11)
C2—C1—C6—C5	−1.2 (7)	C14—C15—C16—C17	0.8 (10)
C2—C1—C6—C7	177.8 (4)	C13—N3—C17—N4	176.7 (5)
Ag1—O1—C7—O2	1.7 (5)	Ag1—N3—C17—N4	−7.5 (6)
Ag1—O1—C7—C6	−178.2 (2)	C13—N3—C17—C16	−1.8 (7)
C5—C6—C7—O2	4.0 (5)	Ag1—N3—C17—C16	174.0 (4)
C1—C6—C7—O2	−174.9 (4)	C15—C16—C17—N3	0.1 (8)
C5—C6—C7—O1	−176.1 (4)	C15—C16—C17—N4	−178.4 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O2^i	0.88 (8)	1.99 (8)	2.851 (6)	163 (7)
N4—H4A···O2	0.90 (7)	2.06 (7)	2.951 (6)	171 (6)
N4—H4B···O1^ii	0.73 (6)	2.22 (6)	2.862 (6)	147 (6)
C10—H10···Cg3^iii	0.93	3.17	3.855 (6)	132
C14—H14···Cg1^i	0.93	2.97	3.623 (6)	128
C16—H16···Cg3^iv	0.93	3.11	3.873 (6)	140

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