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In the title compound, [Ag(C
4H
4N
2)]ClO
4, pyrazine ligands bridge two symmetry-related Ag atoms [Ag—N = 2.222 (3) Å] to form linear polycationic chains which run along the
c axis of the orthorhombic unit cell. The Ag
I ion has
m2
m site symmetry. The N atoms of the pyrazine ligand lie on a crystallographic mirror plane and each C atom of this ligand possesses crystallographically imposed disorder with two components of equal occupancy. The Cl atom of the perchlorate anion has
m2
m site symmetry and the two unique O atoms of this anion lie on a mirror plane. In addition, in the crystal structure, one-dimensional chains are linked through weak interactions involving perchlorate anions [Ag
O = 2.726 (2) Å] into a motif that can be described as a 4(4).6(2) sheet.
Supporting information
CCDC reference: 667142
Key indicators
- Single-crystal X-ray study
- T = 295 K
- Mean (l-O) = 0.003 Å
- Disorder in main residue
- R factor = 0.021
- wR factor = 0.052
- Data-to-parameter ratio = 10.7
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for Cl1
PLAT301_ALERT_3_B Main Residue Disorder ......................... 29.00 Perc.
Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.95
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.27 Ratio
Alert level G
FORMU01_ALERT_1_G There is a discrepancy between the atom counts in the
_chemical_formula_sum and _chemical_formula_moiety. This is
usually due to the moiety formula being in the wrong format.
Atom count from _chemical_formula_sum: C4 H4 Ag1 Cl1 N2 O4
Atom count from _chemical_formula_moiety:C4 H4 Ag1 Cl1 N2 O1
0 ALERT level A = In general: serious problem
2 ALERT level B = Potentially serious problem
2 ALERT level C = Check and explain
1 ALERT level G = General alerts; check
1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
1 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
2 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Silver perchlorate (0.207 g, 1 mmol), pyrazine (0.08 g, 1 mmol) and water (10 ml) were sealed in a Teflon-lined stainless-steel autoclave (20 ml capacity).
The autoclave was heated 433 K for 3 days. It was then cooled at 5 K h-1.
Colorless crystals were obtained in about 60% yield based on Ag.
The pyrazine molecule is disordered with respect to the carbon atoms, which were
refined as four atoms, each of half-site occupancy. The four carbon-bound H
atoms were placed at calculated positions (C–H 0.93 Å) and were included in
the refinement in the riding model approximation, with U(H) set to 1.2
times Ueq(C).
Structure description
top
Silver salts react with the bidentate pyrazine N-heterocycles to furnish
adducts that display a diverse range of architectures. The nitrate adduct
consists of a polycationic [Ag(C4H4N2)]∞ chain that is surrounded
by the nitrate anions, albeit at somewhat long distances (Vranka & Amma,
1966). In silver nitrite adduct, the anion is much closer to the metal atom,
the anion chelating to it (Blake et al., 1999) in the resulting
pyrazine-bridged chain. With the hexafluorophosphate counterion, the adduct
exists as a chain as the counterion is not Lewis-basic enough to have any
coordinating ability. One adduct shows the chain motif in whcih the silver
atom shows linear coordination; another is a cocrystal that has both
[Ag(C4H4N2)]∞ and [Ag2(C4H4N2)5]∞ chains (Carlucci
et al., 1995a). Another adduct has the silver in a
four-coordinate N4Ag environment (Carlucci et al., 1995b). The
silver tetrafluoroborate adduct exists in two forms. One form has polycationic
chains and non-interacting tetrafluoroborate anions; in other polymorphs, the
silver atom shows three- and four-coordinate heterocycle-linked silver
(Carlucci et al., 1995c).
For details of the silver nitrite–pyrazine, see Blake et al. (1999); for
the silver hexafluorophosphate–pyrazine, see Carlucci et al.
(1995a,b); for the silver tetrafluoroborate–pyrazine, see Carlucci
et al. (1995c); and for the silver nitrate–pyrazine adducts,
see Vranka & Amma (1966).
Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001) and OLEX (Dolomanov et al., 2003); software used to prepare material for publication: publCIF (Westrip, 2007).
catena-Poly[[silver(I)-µ-pyrazine-
κ2N:
N'] perchlorate]
top
Crystal data top
[Ag(C4H4N2)]ClO4 | F(000) = 552 |
Mr = 287.41 | Dx = 2.468 Mg m−3 |
Orthorhombic, Cmcm | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2c 2 | Cell parameters from 1486 reflections |
a = 7.4838 (2) Å | θ = 2.8–27.8° |
b = 7.1954 (2) Å | µ = 2.93 mm−1 |
c = 14.3623 (4) Å | T = 295 K |
V = 773.39 (4) Å3 | Block, colorless |
Z = 4 | 0.29 × 0.23 × 0.18 mm |
Data collection top
Bruker APEXII area-detector diffractometer | 493 independent reflections |
Radiation source: fine-focus sealed tube | 443 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.023 |
φ and ω scans | θmax = 27.5°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −8→9 |
Tmin = 0.489, Tmax = 0.621 | k = −9→7 |
2749 measured reflections | l = −18→16 |
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)] = 0.021 | H-atom parameters constrained |
wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.0321P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max = 0.001 |
493 reflections | Δρmax = 0.46 e Å−3 |
46 parameters | Δρmin = −0.36 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0057 (6) |
Crystal data top
[Ag(C4H4N2)]ClO4 | V = 773.39 (4) Å3 |
Mr = 287.41 | Z = 4 |
Orthorhombic, Cmcm | Mo Kα radiation |
a = 7.4838 (2) Å | µ = 2.93 mm−1 |
b = 7.1954 (2) Å | T = 295 K |
c = 14.3623 (4) Å | 0.29 × 0.23 × 0.18 mm |
Data collection top
Bruker APEXII area-detector diffractometer | 493 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 443 reflections with I > 2σ(I) |
Tmin = 0.489, Tmax = 0.621 | Rint = 0.023 |
2749 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.021 | 0 restraints |
wR(F2) = 0.052 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.46 e Å−3 |
493 reflections | Δρmin = −0.36 e Å−3 |
46 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Ag1 | 0.5000 | 0.05768 (4) | 0.2500 | 0.0418 (2) | |
Cl1 | 0.0000 | 0.0621 (1) | 0.2500 | 0.0397 (3) | |
O1 | 0.1546 (3) | 0.1779 (3) | 0.2500 | 0.0588 (7) | |
O2 | 0.0000 | −0.0517 (4) | 0.3301 (3) | 0.093 (1) | |
N1 | 0.5000 | 0.0229 (4) | 0.40375 (18) | 0.0366 (6) | |
C1 | 0.6234 (7) | −0.0790 (6) | 0.4472 (3) | 0.046 (1) | 0.50 |
H1 | 0.7133 | −0.1351 | 0.4125 | 0.055* | 0.50 |
C2 | 0.6208 (7) | −0.1030 (7) | 0.5424 (3) | 0.046 (1) | 0.50 |
H2 | 0.7071 | −0.1783 | 0.5697 | 0.055* | 0.50 |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Ag1 | 0.0551 (3) | 0.0518 (3) | 0.0186 (2) | 0.000 | 0.000 | 0.000 |
Cl1 | 0.0362 (6) | 0.0377 (6) | 0.0452 (7) | 0.000 | 0.000 | 0.000 |
O1 | 0.036 (2) | 0.056 (2) | 0.084 (2) | −0.007 (1) | 0.000 | 0.000 |
O2 | 0.085 (2) | 0.096 (3) | 0.097 (3) | 0.000 | 0.000 | 0.054 (2) |
N1 | 0.043 (1) | 0.044 (1) | 0.023 (1) | 0.000 | 0.000 | 0.003 (1) |
C1 | 0.046 (3) | 0.064 (3) | 0.028 (2) | 0.016 (2) | 0.005 (2) | −0.002 (2) |
C2 | 0.047 (3) | 0.061 (3) | 0.029 (2) | 0.020 (2) | 0.000 (2) | 0.005 (2) |
Geometric parameters (Å, º) top
Ag1—N1 | 2.222 (3) | N1—C2iv | 1.322 (5) |
Ag1—N1i | 2.222 (3) | N1—C2v | 1.322 (5) |
Ag1—O1 | 2.726 (2) | N1—C1ii | 1.334 (5) |
Ag1—O1ii | 2.726 (2) | N1—C1 | 1.334 (5) |
Cl1—O2i | 1.412 (3) | C1—C2 | 1.377 (7) |
Cl1—O2 | 1.412 (3) | C2—N1v | 1.322 (5) |
Cl1—O1 | 1.426 (2) | C1—H1 | 0.9300 |
Cl1—O1iii | 1.426 (2) | C2—H2 | 0.9300 |
| | | |
N1i—Ag1—N1 | 167.1 (1) | C2v—N1—C1ii | 59.5 (3) |
N1—Ag1—O1 | 92.05 (2) | C2iv—N1—C1 | 59.5 (3) |
N1—Ag1—O1ii | 92.05 (2) | C2v—N1—C1 | 116.0 (3) |
N1i—Ag1—O1 | 92.05 (2) | C1ii—N1—C1 | 87.6 (4) |
N1i—Ag1—O1ii | 92.05 (2) | C2iv—N1—Ag1 | 122.2 (2) |
O1—Ag1—O1ii | 143.0 (1) | C2v—N1—Ag1 | 122.2 (2) |
O1—Cl1—O1iii | 108.5 (2) | C1ii—N1—Ag1 | 121.8 (2) |
O1—Cl1—O2 | 109.8 (1) | C1—N1—Ag1 | 121.8 (2) |
O1—Cl1—O2i | 109.8 (1) | N1—C1—C2 | 121.6 (4) |
O1iii—Cl1—O2 | 109.8 (1) | N1v—C2—C1 | 122.4 (4) |
O1iii—Cl1—O2i | 109.8 (1) | N1—C1—H1 | 119.2 |
O2—Cl1—O2i | 109.1 (3) | C2—C1—H1 | 119.2 |
Cl1—O1—Ag1 | 125.8 (1) | N1v—C2—H2 | 118.8 |
C2iv—N1—C2v | 86.3 (5) | C1—C2—H2 | 118.8 |
C2iv—N1—C1ii | 116.0 (3) | | |
| | | |
O2i—Cl1—O1—Ag1 | −60.0 (2) | N1i—Ag1—N1—C1ii | −54.5 (3) |
O2—Cl1—O1—Ag1 | 60.0 (2) | O1ii—Ag1—N1—C1ii | −162.9 (3) |
O1iii—Cl1—O1—Ag1 | 180.0 | O1—Ag1—N1—C1ii | 53.9 (3) |
N1i—Ag1—O1—Cl1 | 83.87 (6) | N1i—Ag1—N1—C1 | 54.5 (3) |
N1—Ag1—O1—Cl1 | −83.87 (6) | O1ii—Ag1—N1—C1 | −53.9 (3) |
O1ii—Ag1—O1—Cl1 | 180.0 | O1—Ag1—N1—C1 | 162.9 (3) |
N1i—Ag1—N1—C2iv | 126.1 (3) | C2iv—N1—C1—C2 | 70.1 (4) |
O1ii—Ag1—N1—C2iv | 17.7 (3) | C2v—N1—C1—C2 | 1.9 (7) |
O1—Ag1—N1—C2iv | −125.5 (3) | C1ii—N1—C1—C2 | −52.2 (6) |
N1i—Ag1—N1—C2v | −126.1 (3) | Ag1—N1—C1—C2 | −178.7 (3) |
O1ii—Ag1—N1—C2v | 125.5 (3) | N1—C1—C2—N1v | −2.0 (8) |
O1—Ag1—N1—C2v | −17.7 (3) | | |
Symmetry codes: (i) x, y, −z+1/2; (ii) −x+1, y, z; (iii) −x, y, z; (iv) x, −y, −z+1; (v) −x+1, −y, −z+1. |
Experimental details
Crystal data |
Chemical formula | [Ag(C4H4N2)]ClO4 |
Mr | 287.41 |
Crystal system, space group | Orthorhombic, Cmcm |
Temperature (K) | 295 |
a, b, c (Å) | 7.4838 (2), 7.1954 (2), 14.3623 (4) |
V (Å3) | 773.39 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.93 |
Crystal size (mm) | 0.29 × 0.23 × 0.18 |
|
Data collection |
Diffractometer | Bruker APEXII area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.489, 0.621 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2749, 493, 443 |
Rint | 0.023 |
(sin θ/λ)max (Å−1) | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.021, 0.052, 1.08 |
No. of reflections | 493 |
No. of parameters | 46 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.46, −0.36 |
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Silver salts react with the bidentate pyrazine N-heterocycles to furnish adducts that display a diverse range of architectures. The nitrate adduct consists of a polycationic [Ag(C4H4N2)]∞ chain that is surrounded by the nitrate anions, albeit at somewhat long distances (Vranka & Amma, 1966). In silver nitrite adduct, the anion is much closer to the metal atom, the anion chelating to it (Blake et al., 1999) in the resulting pyrazine-bridged chain. With the hexafluorophosphate counterion, the adduct exists as a chain as the counterion is not Lewis-basic enough to have any coordinating ability. One adduct shows the chain motif in whcih the silver atom shows linear coordination; another is a cocrystal that has both [Ag(C4H4N2)]∞ and [Ag2(C4H4N2)5]∞ chains (Carlucci et al., 1995a). Another adduct has the silver in a four-coordinate N4Ag environment (Carlucci et al., 1995b). The silver tetrafluoroborate adduct exists in two forms. One form has polycationic chains and non-interacting tetrafluoroborate anions; in other polymorphs, the silver atom shows three- and four-coordinate heterocycle-linked silver (Carlucci et al., 1995c).