The title compound, [Ag
2(C
2F
3O
2)
2(C
5H
6N
2)
2], is a dinuclear Ag
I complex with inversion symmetry. Each Ag atom is three-coordinated by two N atoms from two different 2-aminopyridine ligands and by one O atom from a trifluoroacetate anion, giving an approximately trigonal coordination environment. In the crystal packing, molecules are connected by N-H
O and N-H
F hydrogen bonds, forming layers parallel to the (001) plane.
Supporting information
CCDC reference: 254908
All reagents and solvents were used as obtained without further purification. Silver trifluoroacetate (0.1 mmol, 22.1 mg) and 2-aminopyridine (0.1 mmol, 9.4 mg) were dissolved in an ammonia solution (10 ml, 30%). The mixture was stirred for about 20 min at room temperature to give a clear colorless solution. The resulting solution was kept in air and, after slow evaporation of the solvent for 10 d, crystals of (I) formed, which were isolated, washed three times with water and dried in a vacuum desiccator using anhydrous CaCl2 (yield 72%). Elemental analysis calculated: C 26.7, H 1.9, N 8.9%; found: C 26.5, H 2.0, N 8.9%.
The diffraction measured fraction θfull was low (0.94) as a result of an unexpected error of the X-ray diffraction instrument during data collection. All H atoms were placed in idealized positions and constrained to ride on their parent atoms, with N—H distances of 0.90 Å and C—H distances of 0.96 Å, and with Uiso(H) values fixed at 0.08 Å2.
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1997); software used to prepare material for publication: SHELXTL.
Bis(µ-2-aminopyridine)bis[(trifluoroacetato)silver(I)]
top
Crystal data top
[Ag2(C2F3O2)2(C5H6N2)2] | Z = 2 |
Mr = 315.01 | F(000) = 304 |
Triclinic, P1 | Dx = 2.286 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.791 (2) Å | Cell parameters from 872 reflections |
b = 7.731 (2) Å | θ = 2.2–23.7° |
c = 8.732 (2) Å | µ = 2.23 mm−1 |
α = 92.01 (3)° | T = 293 K |
β = 92.17 (3)° | Block, colorless |
γ = 91.09 (3)° | 0.31 × 0.22 × 0.20 mm |
V = 457.7 (2) Å3 | |
Data collection top
CCD area detector diffractometer | 1789 independent reflections |
Radiation source: fine-focus sealed tube | 1712 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.016 |
ω scans | θmax = 26.5°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −8→8 |
Tmin = 0.545, Tmax = 0.664 | k = −9→9 |
2109 measured reflections | l = −10→5 |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.031 | H-atom parameters constrained |
wR(F2) = 0.084 | w = 1/[σ2(Fo2) + (0.0577P)2 + 0.418P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
1789 reflections | Δρmax = 0.81 e Å−3 |
137 parameters | Δρmin = −0.87 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.159 (7) |
Crystal data top
[Ag2(C2F3O2)2(C5H6N2)2] | γ = 91.09 (3)° |
Mr = 315.01 | V = 457.7 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.791 (2) Å | Mo Kα radiation |
b = 7.731 (2) Å | µ = 2.23 mm−1 |
c = 8.732 (2) Å | T = 293 K |
α = 92.01 (3)° | 0.31 × 0.22 × 0.20 mm |
β = 92.17 (3)° | |
Data collection top
CCD area detector diffractometer | 1789 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1712 reflections with I > 2σ(I) |
Tmin = 0.545, Tmax = 0.664 | Rint = 0.016 |
2109 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.084 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.81 e Å−3 |
1789 reflections | Δρmin = −0.87 e Å−3 |
137 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Ag1 | 0.22514 (4) | 0.46197 (3) | 0.98705 (3) | 0.03766 (18) | |
F1 | 0.5069 (5) | 1.0916 (4) | 1.2199 (7) | 0.1096 (17) | |
F2 | 0.5786 (7) | 0.8982 (6) | 1.3736 (4) | 0.1031 (15) | |
F3 | 0.7260 (5) | 0.9128 (5) | 1.1700 (5) | 0.0821 (11) | |
O1 | 0.2279 (4) | 0.8668 (4) | 1.1347 (4) | 0.0444 (7) | |
O2 | 0.4504 (4) | 0.6560 (3) | 1.1249 (3) | 0.0415 (6) | |
N1 | 0.1615 (4) | 0.6045 (4) | 0.7684 (3) | 0.0325 (6) | |
N2 | −0.0733 (4) | 0.7615 (4) | 0.8968 (3) | 0.0312 (6) | |
H2A | −0.1638 | 0.8422 | 0.8771 | 0.080* | |
H2C | 0.0174 | 0.8099 | 0.9638 | 0.080* | |
C1 | 0.2574 (6) | 0.5642 (5) | 0.6406 (5) | 0.0407 (8) | |
H1A | 0.3629 | 0.4837 | 0.6475 | 0.080* | |
C2 | 0.2131 (6) | 0.6338 (5) | 0.5011 (5) | 0.0436 (9) | |
H2B | 0.2857 | 0.6022 | 0.4125 | 0.080* | |
C3 | 0.0613 (6) | 0.7495 (5) | 0.4918 (5) | 0.0431 (9) | |
H3A | 0.0236 | 0.7979 | 0.3955 | 0.080* | |
C4 | −0.0360 (6) | 0.7949 (5) | 0.6219 (4) | 0.0379 (8) | |
H4A | −0.1403 | 0.8769 | 0.6189 | 0.080* | |
C5 | 0.0200 (5) | 0.7198 (4) | 0.7591 (4) | 0.0293 (7) | |
C6 | 0.5519 (6) | 0.9291 (5) | 1.2281 (4) | 0.0384 (8) | |
C7 | 0.3927 (5) | 0.8054 (4) | 1.1527 (4) | 0.0301 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Ag1 | 0.0352 (2) | 0.0344 (2) | 0.0440 (2) | 0.00374 (12) | 0.00462 (12) | 0.00587 (13) |
F1 | 0.071 (2) | 0.0339 (15) | 0.219 (5) | −0.0004 (14) | −0.037 (3) | −0.019 (2) |
F2 | 0.119 (3) | 0.142 (4) | 0.0436 (16) | −0.063 (3) | −0.0158 (17) | −0.0068 (19) |
F3 | 0.0448 (16) | 0.098 (2) | 0.100 (2) | −0.0248 (15) | 0.0229 (16) | −0.044 (2) |
O1 | 0.0352 (14) | 0.0422 (15) | 0.0549 (16) | 0.0095 (12) | −0.0075 (12) | −0.0068 (13) |
O2 | 0.0369 (14) | 0.0325 (13) | 0.0543 (16) | 0.0049 (10) | −0.0033 (12) | −0.0055 (12) |
N1 | 0.0319 (15) | 0.0305 (14) | 0.0353 (15) | 0.0038 (11) | 0.0025 (11) | 0.0036 (12) |
N2 | 0.0325 (15) | 0.0282 (13) | 0.0331 (14) | 0.0037 (11) | 0.0015 (11) | 0.0001 (11) |
C1 | 0.039 (2) | 0.0382 (19) | 0.046 (2) | 0.0060 (15) | 0.0109 (16) | 0.0033 (16) |
C2 | 0.048 (2) | 0.045 (2) | 0.039 (2) | −0.0042 (17) | 0.0157 (17) | 0.0027 (17) |
C3 | 0.051 (2) | 0.040 (2) | 0.0384 (19) | −0.0032 (17) | 0.0008 (16) | 0.0097 (16) |
C4 | 0.041 (2) | 0.0299 (17) | 0.0427 (19) | 0.0032 (14) | −0.0023 (15) | 0.0062 (15) |
C5 | 0.0295 (16) | 0.0220 (14) | 0.0365 (17) | −0.0029 (12) | 0.0019 (13) | 0.0021 (13) |
C6 | 0.0340 (18) | 0.0368 (18) | 0.044 (2) | 0.0023 (14) | 0.0025 (15) | −0.0064 (16) |
C7 | 0.0311 (17) | 0.0310 (16) | 0.0284 (15) | 0.0030 (13) | 0.0022 (12) | 0.0014 (13) |
Geometric parameters (Å, º) top
Ag1—N1 | 2.269 (3) | N2—Ag1i | 2.283 (3) |
Ag1—N2i | 2.283 (3) | N2—H2A | 0.9001 |
Ag1—O2 | 2.384 (3) | N2—H2C | 0.9000 |
Ag1—Ag1i | 3.140 (2) | C1—C2 | 1.374 (6) |
F1—C6 | 1.303 (5) | C1—H1A | 0.9600 |
F2—C6 | 1.308 (5) | C2—C3 | 1.380 (6) |
F3—C6 | 1.311 (5) | C2—H2B | 0.9600 |
O1—C7 | 1.230 (4) | C3—C4 | 1.374 (6) |
O2—C7 | 1.246 (4) | C3—H3A | 0.9600 |
N1—C5 | 1.326 (4) | C4—C5 | 1.392 (5) |
N1—C1 | 1.343 (5) | C4—H4A | 0.9600 |
N2—C5 | 1.411 (4) | C6—C7 | 1.542 (5) |
| | | |
N1—Ag1—N2i | 134.02 (11) | C1—C2—H2B | 120.7 |
N1—Ag1—O2 | 102.19 (11) | C3—C2—H2B | 121.1 |
N2i—Ag1—O2 | 121.71 (10) | C4—C3—C2 | 119.3 (4) |
N1—Ag1—Ag1i | 78.51 (8) | C4—C3—H3A | 120.2 |
N2i—Ag1—Ag1i | 70.47 (8) | C2—C3—H3A | 120.4 |
O2—Ag1—Ag1i | 116.70 (7) | C3—C4—C5 | 118.7 (3) |
C7—O2—Ag1 | 116.9 (2) | C3—C4—H4A | 121.0 |
C5—N1—C1 | 117.9 (3) | C5—C4—H4A | 120.3 |
C5—N1—Ag1 | 121.5 (2) | N1—C5—C4 | 122.5 (3) |
C1—N1—Ag1 | 120.4 (2) | N1—C5—N2 | 116.0 (3) |
C5—N2—Ag1i | 116.5 (2) | C4—C5—N2 | 121.5 (3) |
C5—N2—H2A | 108.0 | F1—C6—F2 | 106.8 (4) |
Ag1i—N2—H2A | 108.2 | F1—C6—F3 | 106.7 (4) |
C5—N2—H2C | 108.2 | F2—C6—F3 | 105.1 (4) |
Ag1i—N2—H2C | 108.2 | F1—C6—C7 | 113.1 (3) |
H2A—N2—H2C | 107.4 | F2—C6—C7 | 110.7 (3) |
N1—C1—C2 | 123.3 (4) | F3—C6—C7 | 113.9 (3) |
N1—C1—H1A | 118.2 | O1—C7—O2 | 130.1 (3) |
C2—C1—H1A | 118.5 | O1—C7—C6 | 115.6 (3) |
C1—C2—C3 | 118.2 (4) | O2—C7—C6 | 114.2 (3) |
| | | |
N1—Ag1—O2—C7 | 57.9 (3) | C1—N1—C5—N2 | −178.4 (3) |
N2i—Ag1—O2—C7 | −107.8 (3) | Ag1—N1—C5—N2 | 6.5 (4) |
N2i—Ag1—N1—C5 | 76.0 (3) | C3—C4—C5—N1 | −1.0 (5) |
O2—Ag1—N1—C5 | −87.1 (3) | C3—C4—C5—N2 | 179.7 (3) |
N2i—Ag1—N1—C1 | −99.0 (3) | Ag1i—N2—C5—N1 | −59.4 (3) |
O2—Ag1—N1—C1 | 98.0 (3) | Ag1i—N2—C5—C4 | 120.0 (3) |
Ag1i—Ag1—N1—C1 | −146.9 (3) | Ag1—O2—C7—O1 | 8.7 (5) |
C5—N1—C1—C2 | −1.4 (6) | Ag1—O2—C7—C6 | −174.4 (2) |
Ag1—N1—C1—C2 | 173.7 (3) | F1—C6—C7—O1 | −19.4 (5) |
N1—C1—C2—C3 | −0.6 (6) | F2—C6—C7—O1 | 100.4 (4) |
C1—C2—C3—C4 | 1.9 (6) | F3—C6—C7—O1 | −141.5 (4) |
C2—C3—C4—C5 | −1.1 (6) | F1—C6—C7—O2 | 163.2 (4) |
C1—N1—C5—C4 | 2.2 (5) | F2—C6—C7—O2 | −77.0 (5) |
Ag1—N1—C5—C4 | −172.8 (3) | F3—C6—C7—O2 | 41.1 (5) |
Symmetry code: (i) −x, −y+1, −z+2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···O1ii | 0.90 | 2.30 | 3.095 (4) | 146 |
N2—H2A···F1ii | 0.90 | 2.52 | 3.314 (5) | 148 |
N2—H2C···O1 | 0.90 | 2.06 | 2.943 (4) | 167 |
Symmetry code: (ii) −x, −y+2, −z+2. |
Experimental details
Crystal data |
Chemical formula | [Ag2(C2F3O2)2(C5H6N2)2] |
Mr | 315.01 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 6.791 (2), 7.731 (2), 8.732 (2) |
α, β, γ (°) | 92.01 (3), 92.17 (3), 91.09 (3) |
V (Å3) | 457.7 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.23 |
Crystal size (mm) | 0.31 × 0.22 × 0.20 |
|
Data collection |
Diffractometer | CCD area detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.545, 0.664 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2109, 1789, 1712 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.627 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.084, 1.04 |
No. of reflections | 1789 |
No. of parameters | 137 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.81, −0.87 |
Selected geometric parameters (Å, º) topAg1—N1 | 2.269 (3) | Ag1—O2 | 2.384 (3) |
Ag1—N2i | 2.283 (3) | Ag1—Ag1i | 3.140 (2) |
| | | |
N1—Ag1—N2i | 134.02 (11) | N2i—Ag1—O2 | 121.71 (10) |
N1—Ag1—O2 | 102.19 (11) | | |
| | | |
N1—Ag1—O2—C7 | 57.9 (3) | N2i—Ag1—O2—C7 | −107.8 (3) |
Symmetry code: (i) −x, −y+1, −z+2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2A···O1ii | 0.90 | 2.30 | 3.095 (4) | 146 |
N2—H2A···F1ii | 0.90 | 2.52 | 3.314 (5) | 148 |
N2—H2C···O1 | 0.90 | 2.06 | 2.943 (4) | 167 |
Symmetry code: (ii) −x, −y+2, −z+2. |
AgI complexes with carboxylate anions as counterions or ligands are a group of metal compounds that, because of their wide usage in many fields, have been structurally characterized over the past 30 years (Smith et al., 1996; Kristiansson, 2001; Nomiya et al., 2000; Wei et al., 1998; Zheng et al., 2001). Studying the variety of products in the self-assembly processes between labile metal ions and flexible multidentate ligands is an interesting topic in supramolecular chemistry. The balance between the formation of different structures is often subtle. Factors that affect the coordination topology include not only the highly influential factors of metal and ligand coordination preferences but also anion-based influences. The latter factor is particularly notable in AgI coordination complexes (Erxleben, 2001; Khlobystov et al., 2001). Owing to the versatile coordination sphere of AgI, coordination numbers from two to six are possible, and because of the relatively weak nature of many AgI–ligand interactions, including some anion–Ag interactions, such compounds are particularly susceptible to the influence of weaker supramolecular forces. However, the different nucleophilicities and sizes of the anions must be a significant factor in recognizing the different molecular structures. More work needs to be done to understand better the controlling effect of anions, which is now becoming an interesting topic in supramolecular chemistry (Cai et al., 2002; Xu et al., 2001).
Recently, we have reported two AgI complexes with 2-aminopyridine and different counter-anions, viz. bis(2-aminopyridine-κN1)(benzoato-κO)silver(I), (II) (Zhu, Usman et al., 2003) and bis(µ-4-chlorobenzoato-κ2O:O)bis[(2-aminopyridine-κN)disilver(I)], (III) (Zhu et al., 2004). These are both three-coordinate AgI complexes, although (II) is mononuclear and (III) is O-bridged dinuclear. In order to study the effects of the couter-anions in the construction of AgI coordination polymers with 2-aminopyridine, the structure of the novel title compound, (I), is reported here.
Complex (I) is a dinuclear AgI complex, which exhibits inversion symmetry (Fig. 1). Each AgI ion in the complex is three-coordinated by two N atoms from two different 2-aminopyridine ligands and by one O atom from a trifluoroacetate anion, giving an approximately trigonal coordination environment (Table 1). Atom Ag1 deviates from the N1/O2/N2i [symmetry code: (i) −x, 1 − y, 2 − z] trigonal plane by 0.188 (3) Å. The Ag1—N1 bond length [2.269 (3) Å] is a little longer than the corresponding bond length [2.230 (3) Å] in (II) and is much longer than that [2.137 (4) Å] in (III). These differences are probably caused by the coordination of atom N2 to the other Ag ion in (I), which decreases the electron density around atom N1 and weakens the bond strength between atoms Ag1 and N1. The structure of the present complex, with an eight-membered ring, is very different from that of (II) and (III). In (I), both the amine N atoms and the pyridine N atoms contribute to the coordination of the Ag atoms; however, in (II) and (III), only the pyridine N atoms take part in the coordination, while the amine N atoms participate in the formation of intermolecular N—H···O hydrogen bonds and do not coordinate to the Ag atoms.
The structural differences between (I) and compounds (II) and (III) might be caused by the different counter-ions used in the preparation of the complexes. In (I), the counter-ion is the trifluoroacetate anion, while in (II) and (III), the counter-ions are, respectively, the benzoate and 4-chlorobenzoate anions. The Ag—O(carboxylate) bond in (I) is weakened by the electro-attracting effect of the trifluoromethyl group. In fact, the Ag1—O2 bond length in (I) is slightly longer than the corresponding bond length [2.344 (4) Å] observed in (II) but is much shorter than the Ag···O weak interaction [2.813 (4) Å] observed in another AgI trifluoroacetate complex, viz. bis(4-aminopyridine)silver(I) trifluoroacetate, (IV), which is a mononuclear complex with a linear N(py)—Ag—N(py) bond (Zhu, Zeng et al., 2003). In (I), atom O2 is coordinated to atom Ag1 through a strong chemical bond, while in (IV), the O atom is connected to the Ag atom via a weak interaction.
In (I), another eight-membered ring (Ag1/N1/C5/N2/H2C/O1/C7/O2) is formed through an intramolecular N—H···O hydrogen bond. Furthermore, the dinuclear complexes are linked via N—H···O/F hydrogen bonds (Table 2) to form layers parallel to the (001) plane (Fig. 2). There are also π–π interactions between the pyridine rings at (x, y, z) and (-x, 1 − y, 1 − z), with a centroid separation of 3.78 (s.u.?) Å and a plane-to-plane distance of 3.34 (s.u.?) Å.