catena-Poly[1-ethyl-4-methyl­pyridinium [argentate(I)-di-μ-iodido]]

The title compound, {(C₈H₁₂N)[AgI₂]}_n, was synthesized by a self-assembling reaction of 1-ethyl-4-methyl­pyridinium iodide and silver(I) iodide. The anion adopts a one-dimensional chain structure with the Ag atom in the chain in a nearly regular tetra­hedral environment. The crystal packing is stabilized by electrostatic inter­actions and by a C—H...I hydrogen bond between a methyl­ene H atom of the ethyl substituent and an I atom.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.013 Å
• R factor = 0.036
• wR factor = 0.096
• Data-to-parameter ratio = 24.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.06
PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         14

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      1.056
            Tmax scaled      0.264 Tmin scaled      0.148
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.48
           From the CIF: _reflns_number_total               2749
           Count of symmetry unique reflns         1516
           Completeness (_total/calc)            181.33%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1233
           Fraction of Friedel pairs measured     0.813
           Are heavy atom types Z>Si present        yes
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   5 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 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

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S1. Comment

In the title compound, each silver atom coordinated by four iodine atoms forms [AgI₄] tetrahedrons (Fig. 1). The [AgI₄] tetrahedron is highly distorted with Ag—I distances and I—Ag—I angles compared to an ideal tetrahedron (Table 1). This trans edge-sharing [AgI₄] tetrahedron results in two types of one-dimensional [(AgI₂)^-]_n anion chains which are along the crystallographic c axis. The further stability comes from a weak C—H···I hydrogen bond (Horn et al., 2003) between a methylene H of the cation part and I atom of anion part to give a 3-D network (Table 2 & Fig. 2).

Related literature

For the crystal structure of four-coordinated [Ag₂I₄] chain compounds, see: Thackeray & Coetzer (1975), Peters et al. (1984), Alcock et al. (2003), Li et al. (2004) and Niu et al. (2005).

For related literature, see: Caitlin et al. (2003); Huang & Xie (1988); MaArdle (1995); Sheldrick (2001).

S2. Experimental

The title compound was synthesized by self-assembling reaction of silver iodide and N-ethyl-4-methylpyridinium iodide (Huang & Xie, 1988). N-Ethyl-4-methylpyridinium iodide (0.25 g, 1.0 mmol) and silver iodide (0.23 g, 1 mmol) were dissolved in DMF (15 ml). After being stirred at room temperature for 20 min. Finally, a kind of yellow clear solution was formed and filtered. Then the solution was allowed to evaporate at room temperature for one week. The title compound was obtained as a kind of yellow crystals [yield 0.15 g (31% based on Ag)]. Anal. Calcd. for C₈H₁₂NAgI₂ (483.86): C19.88, H 2.47, N 2.90%. Found: C,19.84, H 2.48, N 2.89%.

S3. Refinement

All H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93 Å for aromatic H atoms, 0.97 Å for methylene H atoms and 0.96 Å for methyl H atoms, respectively, and with U_iso(H) = 1.2Ueq(C) for aromatic and methylene H atoms, U_iso(H) = 1.5Ueq(C) for methyl H atoms. In the absence of significant anomalous scattering effects, Friedel pairs were merged.

Computing details

Data collection: TEXRAY (Molecular Structure Corporation, 1999); cell refinement: TEXRAY (Molecular Structure Corporation, 1999); data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The molecular structure of the title compound, showing displacement ellipsoides drawn at the 50% probability level. [Symmetry code: (i) 3/2 - y, 3/2 - x, z - 1/2 (ii) 1 - x, 2 - y, z (iii) y - 1/2, x + 1/2, z - 1/2 (iv) 1 - y, x + 1, z + 1/2 (v) -x, 2 - y, z (vi)y - 1, 1 - x, z + 1/2.]
	Fig. 2. The packing diagrame of title compound with C—H···I hydrogen bonds (dotted line).

catena-Poly[1-ethyl-4-methylpyridinium [argentate(I)-di-µ-iodido]]

Crystal data

(C8H12N)[AgI2]	Dx = 2.631 Mg m^−3
Mr = 483.86	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42bc	Cell parameters from 25 reflections
Hall symbol: P 4c -2ab	θ = 12–18°
a = 18.205 (3) Å	µ = 6.66 mm^−1
c = 7.371 (2) Å	T = 293 K
V = 2442.9 (9) Å^3	Club, yellow
Z = 8	0.30 × 0.22 × 0.20 mm
F(000) = 1760

Data collection

Rigaku Weissenberg IP diffractometer	2749 independent reflections
Radiation source: rotor target	2267 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.053
Detector resolution: None pixels mm^-1	θmax = 27.5°, θmin = 3.2°
scintillation counter scans	h = −23→23
Absorption correction: multi-scan (TEXRAY; Molecular Structure Corporation, 1999)	k = −23→23
Tmin = 0.140, Tmax = 0.250	l = −9→9
21995 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)] = 0.036	H-atom parameters constrained
wR(F^2) = 0.096	w = 1/[σ^2(Fo^2) + (0.0469P)^2 + 1.1814P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max < 0.001
2749 reflections	Δρmax = 0.55 e Å^−3
111 parameters	Δρmin = −0.75 e Å^−3
1 restraint	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.06 (6)

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
I1	0.38094 (3)	0.99613 (3)	1.14714 (10)	0.05327 (15)
I2	0.10725 (3)	0.94396 (3)	1.23364 (12)	0.05458 (15)
Ag1	0.5000	1.0000	0.8979 (2)	0.0671 (3)
Ag2	0.0000	1.0000	1.48388 (18)	0.0665 (3)
N	0.2267 (4)	0.8906 (4)	0.7893 (8)	0.0460 (15)
C1	0.1605 (4)	0.8590 (5)	0.7740 (11)	0.055 (2)
H1	0.1190	0.8872	0.7510	0.066*
C2	0.1552 (5)	0.7847 (5)	0.7928 (12)	0.058 (2)
H2	0.1092	0.7627	0.7835	0.069*
C3	0.2152 (5)	0.7414 (5)	0.8250 (11)	0.053 (2)
C4	0.2822 (5)	0.7770 (5)	0.8414 (12)	0.054 (2)
H4	0.3243	0.7499	0.8655	0.064*
C5	0.2870 (4)	0.8504 (5)	0.8227 (11)	0.0485 (18)
H5	0.3324	0.8735	0.8332	0.058*
C6	0.2094 (7)	0.6606 (6)	0.8389 (15)	0.080 (3)
H6A	0.1998	0.6471	0.9626	0.121*
H6B	0.2547	0.6386	0.8001	0.121*
H6C	0.1700	0.6436	0.7632	0.121*
C7	0.2338 (5)	0.9718 (5)	0.7626 (14)	0.062 (2)
H7A	0.1854	0.9936	0.7517	0.074*
H7B	0.2581	0.9935	0.8666	0.074*
C8	0.2772 (7)	0.9867 (5)	0.5952 (15)	0.078 (3)
H8A	0.2826	1.0388	0.5796	0.117*
H8B	0.2521	0.9664	0.4921	0.117*
H8C	0.3248	0.9645	0.6060	0.117*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0493 (2)	0.0602 (3)	0.0503 (3)	0.0061 (2)	−0.0008 (3)	−0.0007 (3)
I2	0.0519 (3)	0.0537 (3)	0.0581 (3)	0.0063 (2)	−0.0008 (3)	−0.0024 (3)
Ag1	0.0722 (8)	0.0698 (8)	0.0593 (5)	−0.0005 (5)	0.000	0.000
Ag2	0.0693 (7)	0.0660 (7)	0.0641 (6)	−0.0027 (8)	0.000	0.000
N	0.047 (3)	0.047 (3)	0.044 (4)	0.006 (3)	0.005 (3)	0.000 (3)
C1	0.042 (4)	0.066 (5)	0.058 (6)	0.005 (4)	0.009 (3)	−0.008 (4)
C2	0.044 (4)	0.066 (5)	0.063 (5)	−0.014 (4)	0.009 (4)	−0.008 (4)
C3	0.075 (6)	0.050 (4)	0.035 (3)	−0.013 (4)	−0.001 (4)	−0.001 (3)
C4	0.061 (5)	0.044 (4)	0.056 (5)	0.008 (4)	−0.013 (4)	0.001 (4)
C5	0.042 (4)	0.052 (4)	0.052 (4)	0.004 (3)	−0.007 (4)	−0.003 (4)
C6	0.116 (9)	0.056 (6)	0.070 (6)	−0.010 (6)	−0.029 (7)	0.008 (5)
C7	0.081 (6)	0.042 (4)	0.063 (5)	0.010 (4)	−0.002 (5)	−0.004 (4)
C8	0.109 (9)	0.049 (5)	0.076 (7)	−0.011 (5)	−0.001 (6)	0.009 (4)

Geometric parameters (Å, º)

Ag1—I1	2.842 (1)	C4—C5	1.35 (1)
Ag1—I1^i	2.849 (1)	C4—H4	0.9300
Ag2—I2	2.873 (1)	C5—H5	0.9300
Ag2—I2^ii	2.871 (1)	C6—H6A	0.9600
N—C1	1.34 (1)	C6—H6B	0.9600
N—C5	1.34 (1)	C6—H6C	0.9600
N—C7	1.50 (1)	C7—C8	1.490 (15)
C1—C2	1.36 (2)	C7—H7A	0.9700
C1—H1	0.9300	C7—H7B	0.9700
C2—C3	1.37 (1)	C8—H8A	0.9600
C2—H2	0.9300	C8—H8B	0.9600
C3—C4	1.39 (1)	C8—H8C	0.9600
C3—C6	1.48 (1)
I1^iii—Ag1—I1^i	117.20 (2)	C3—C4—H4	119.6
I1^iii—Ag1—I1	99.45 (6)	N—C5—C4	120.5 (8)
I1—Ag1—I1^i	112.43 (2)	N—C5—H5	119.8
I1^i—Ag1—I1^iv	99.13 (6)	C4—C5—H5	119.8
I2^ii—Ag2—I2^v	100.23 (5)	C3—C6—H6A	109.5
I2^v—Ag2—I2	114.31 (1)	C3—C6—H6B	109.5
I2^vi—Ag2—I2	100.12 (5)	H6A—C6—H6B	109.5
Ag1—I1—Ag1^vii	80.71 (2)	C3—C6—H6C	109.5
Ag2^viii—I2—Ag2	79.83 (2)	H6A—C6—H6C	109.5
C1—N—C5	121.1 (7)	H6B—C6—H6C	109.5
C1—N—C7	119.4 (7)	C8—C7—N	109.5 (7)
C5—N—C7	119.5 (7)	C8—C7—H7A	109.8
N—C1—C2	118.8 (8)	N—C7—H7A	109.8
N—C1—H1	120.6	C8—C7—H7B	109.8
C2—C1—H1	120.6	N—C7—H7B	109.8
C1—C2—C3	122.2 (8)	H7A—C7—H7B	108.2
C1—C2—H2	118.9	C7—C8—H8A	109.5
C3—C2—H2	118.9	C7—C8—H8B	109.5
C2—C3—C4	116.6 (8)	H8A—C8—H8B	109.5
C2—C3—C6	122.0 (9)	C7—C8—H8C	109.5
C4—C3—C6	121.5 (9)	H8A—C8—H8C	109.5
C5—C4—C3	120.8 (8)	H8B—C8—H8C	109.5
C5—C4—H4	119.6
Ag1^vii—I1—Ag1—I1^iii	0.0	C7—N—C1—C2	177.9 (8)
Ag1^vii—I1—Ag1—I1^i	124.75 (3)	C1—C2—C3—C6	−177.8 (9)
Ag1^vii—I1—Ag1—I1^iv	−121.36 (4)	C6—C3—C4—C5	177.9 (9)
Ag2^viii—I2—Ag2—I2^ii	−122.65 (3)	C7—N—C5—C4	−177.9 (8)
Ag2^viii—I2—Ag2—I2^v	122.65 (3)	C1—N—C7—C8	−113.0 (9)
Ag2^viii—I2—Ag2—I2^vi	0.0	C5—N—C7—C8	65.0 (11)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7B···I1	0.97	3.05	3.93 (1)	151