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The title compound, {(C4H12N)[AgBr2]}n, is isomorphous with its chloride analogue [Helgesson, Josefsson & Jagner (1988). Acta Cryst. C44, 1729–1731]. It displays a one-dimensional 1[Ag2Br4]n2n anionic chain structure accompanied by isolated tetra­methyl­ammonium cations. All the crystallographically independent non-H atoms lie on special positions, namely Ag on 2mm, Br on mm2 or m2m, N on mm2, and C on sites of symmetry ma or mb. The tetra­methyl­ammonium cations reside between these anionic chains, with weak C—H...Br hydrogen-bonding inter­actions forming a layer perpendicular to the c axis; these layers stack together along the c direction merely by van der Waals forces.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807046880/bg3057sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807046880/bg3057Isup2.hkl
Contains datablock I

CCDC reference: 663660

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](g-Br) = 0.001 Å
  • Some non-H atoms missing
  • R factor = 0.030
  • wR factor = 0.068
  • Data-to-parameter ratio = 16.5

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for N1
Alert level C CHEMW03_ALERT_2_C The ratio of given/expected molecular weight as calculated from the _atom_site* data lies outside the range 0.99 <> 1.01 From the CIF: _cell_formula_units_Z 4 From the CIF: _chemical_formula_weight 341.84 TEST: Calculate formula weight from _atom_site_* atom mass num sum C 12.01 4.00 48.04 H 1.01 16.00 16.13 N 14.01 1.00 14.01 Ag 107.87 1.00 107.87 Br 79.90 2.00 159.81 Calculated formula weight 345.85
Alert level G FORMU01_ALERT_2_G There is a discrepancy between the atom counts in the _chemical_formula_sum and the formula from the _atom_site* data. Atom count from _chemical_formula_sum:C4 H12 Ag1 Br2 N1 Atom count from the _atom_site data: C4 H16 Ag1 Br2 N1 CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected. CELLZ01_ALERT_1_G ALERT: Large difference may be due to a symmetry error - see SYMMG tests From the CIF: _cell_formula_units_Z 4 From the CIF: _chemical_formula_sum C4 H12 Ag Br2 N TEST: Compare cell contents of formula and atom_site data atom Z*formula cif sites diff C 16.00 16.00 0.00 H 48.00 64.00 -16.00 Ag 4.00 4.00 0.00 Br 8.00 8.00 0.00 N 4.00 4.00 0.00 PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K
0 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 5 ALERT level G = General alerts; check 4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 3 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

Great interest is presently being focused on the controllable preparation of silver-halide-organoamonium compounds due to their potential application in photographic, photothermal, and other imaging or printing modalities (Bringley et al., 2005, and references therein). In these photographic functional compounds, the [AgaXb]n– parts may serve as commercial photographic color developer molecules. The reactions of silver(I) cyanide with Me4NBr (tetramethylammonioum) in acetonitrile solution and then diffused with aether lead to a AgBr-based complex, [Me4N]2[Ag2Br4] (I), isomorphous to its Cl analogue, reported by Helgesson et al., 1988.

Compound (I) displays a one-dimensional 1[Ag2Br4]n2n– anionic chain structure accompanied with isolated [Me4N]+ cations. As shown in Figure 1, one crystallographically independent silver cation in the center of a slightly distorted tetrahedral geometry is coordinated by four µ-Br atoms. The Ag—Br bond distances range from 2.7006 (5) to 2.7221 (5) Å, and the Br—Ag—Br bond angels vary between 97.93 (2) to 112.947 (7) °, in agreement with those in the [AgaBrb]n– clusters (Stomberg, 1969; Helgesson & Jagner, 1991; Liu et al., 2006). The silver cations are double bridged by µ-Br atoms to form an one-dimensional 1[Ag2Br4]n2n– anionic chain along the a direction, which also can be regarded as the common chain formed by edge-sharing [AgBr4]3– tetrahedrons (Stomberg, 1969; Helgesson & Jagner, 1991). While the [Me4N]+ cations reside between these anionic chains with weak C—H···Br hydrogen bonding interactions (Steiner, 1996; Liu et al., 2005) to form a special layer along the a and b directions (Figure 2). These special layers further stack together along the c direction merely by Van der Waals forces.

Solid-state luminescence spectra show that comound I exhibits a broad strong blue emission band centered around 485 nm upon photo-excitation at 300 nm (Figure 3) and its lifetime was measured to be 3.3 µs, suggesting to be a potential candidate for luminescent material. Density of states (DOS) calculation sindicate that the top of valence bands (VBs) are mostly formed by Ag-4 d state mixing with Br-4p state, while the bottom of conduction bands (CBs) are almost contribution from the Br-4 s state, indicating the luminescent emission probably originated from metal-to-ligand charge transfer (MLCT) accompanied with hybridizations between Ag-4 d and Br-4p.

Related literature top

For related literature, see: Bringley et al. (2005), and references therein; Helgesson & Jagner (1991); Liu et al. (2005, 2006); Steiner (1996); Stomberg (1969).

For related literature, see: Johnson (1976).

Experimental top

A mixture of AgCN (238 mg, 1.8 mmol) and Me4NBr (139 mg, 0.9 mmol) in 10 ml of dry and distilled acetonitrile was sealed into a 25 ml polytetrafluoroethylene-lined stainless steel containers under autogenous pressure and heated at 120 °C for 3 days, followed by cooling to room temperature. The resulted solution was filtered in a small tube, which was loaded into a large vial containing 5 ml diethyl ether. The large vial was sealed and left undisturbed at room temperature, and colourless crystals of the title complex were obtained in 7 days. Yield: 40%. Calc. for C8H24Ag2Br4N2: C, 14.05; H, 3.54; N, 4.10; Found: C, 14.12; H, 3.60; N, 4.02.

Refinement top

Methyl H atoms were added geometrically and allowed to ride on their respective parent carbon atoms (C—H = 0.96 Å and Uiso(H) = 1.5Ueq(C)). The groups were also allowed to rotate around the N—C vector.

Structure description top

Great interest is presently being focused on the controllable preparation of silver-halide-organoamonium compounds due to their potential application in photographic, photothermal, and other imaging or printing modalities (Bringley et al., 2005, and references therein). In these photographic functional compounds, the [AgaXb]n– parts may serve as commercial photographic color developer molecules. The reactions of silver(I) cyanide with Me4NBr (tetramethylammonioum) in acetonitrile solution and then diffused with aether lead to a AgBr-based complex, [Me4N]2[Ag2Br4] (I), isomorphous to its Cl analogue, reported by Helgesson et al., 1988.

Compound (I) displays a one-dimensional 1[Ag2Br4]n2n– anionic chain structure accompanied with isolated [Me4N]+ cations. As shown in Figure 1, one crystallographically independent silver cation in the center of a slightly distorted tetrahedral geometry is coordinated by four µ-Br atoms. The Ag—Br bond distances range from 2.7006 (5) to 2.7221 (5) Å, and the Br—Ag—Br bond angels vary between 97.93 (2) to 112.947 (7) °, in agreement with those in the [AgaBrb]n– clusters (Stomberg, 1969; Helgesson & Jagner, 1991; Liu et al., 2006). The silver cations are double bridged by µ-Br atoms to form an one-dimensional 1[Ag2Br4]n2n– anionic chain along the a direction, which also can be regarded as the common chain formed by edge-sharing [AgBr4]3– tetrahedrons (Stomberg, 1969; Helgesson & Jagner, 1991). While the [Me4N]+ cations reside between these anionic chains with weak C—H···Br hydrogen bonding interactions (Steiner, 1996; Liu et al., 2005) to form a special layer along the a and b directions (Figure 2). These special layers further stack together along the c direction merely by Van der Waals forces.

Solid-state luminescence spectra show that comound I exhibits a broad strong blue emission band centered around 485 nm upon photo-excitation at 300 nm (Figure 3) and its lifetime was measured to be 3.3 µs, suggesting to be a potential candidate for luminescent material. Density of states (DOS) calculation sindicate that the top of valence bands (VBs) are mostly formed by Ag-4 d state mixing with Br-4p state, while the bottom of conduction bands (CBs) are almost contribution from the Br-4 s state, indicating the luminescent emission probably originated from metal-to-ligand charge transfer (MLCT) accompanied with hybridizations between Ag-4 d and Br-4p.

For related literature, see: Bringley et al. (2005), and references therein; Helgesson & Jagner (1991); Liu et al. (2005, 2006); Steiner (1996); Stomberg (1969).

For related literature, see: Johnson (1976).

Computing details top

Data collection: CrystalClear (Rigaku, 2002); cell refinement: CrystalClear (Rigaku, 2002); data reduction: CrystalClear (Rigaku, 2002); program(s) used to solve structure: SHELXTL (Siemens, 1994); program(s) used to refine structure: SHELXTL (Siemens, 1994); molecular graphics: SHELXTL (Siemens, 1994) and ORTEP (Johnson, 1976); software used to prepare material for publication: SHELXTL (Siemens, 1994).

Figures top
[Figure 1] Fig. 1. ORTEPII (Johnson, 1976) plot of I at 30% probability of thermal ellipsoids. All hydrogen atoms are omitted for clarity. Symmetry codes i: -1 - x, -y, 1 - z; ii: -2 - x, -y, 1 - z
[Figure 2] Fig. 2. A view of the weak C—H···Br hydrogen bonding interactions between the 1[Ag2Br4]n2n– anionic chains and [Me4N]+ cations, which are represented as dashed lines.
catena-Poly[tetramethylammonium [argentate(I)-di-µ-bromido]] top
Crystal data top
(C4H12N)[AgBr2]F(000) = 640
Mr = 341.84Dx = 2.429 Mg m3
Orthorhombic, ImmmMo Kα radiation, λ = 0.71073 Å
Hall symbol: -I 2 2Cell parameters from 972 reflections
a = 6.7817 (9) Åθ = 3.3–27.5°
b = 9.1535 (14) ŵ = 10.63 mm1
c = 15.057 (2) ÅT = 293 K
V = 934.7 (2) Å3Prism, colourless
Z = 40.20 × 0.20 × 0.16 mm
Data collection top
Rigaku Mercury CCD
diffractometer
494 independent reflections
Radiation source: rotating-anode generator459 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.031
ω scansθmax = 25.0°, θmin = 3.3°
Absorption correction: multi-scan
(SPHERE in CrystalClear; Rigaku, 2002)
h = 88
Tmin = 0.13, Tmax = 0.18k = 1010
2952 measured reflectionsl = 917
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.030H-atom parameters constrained
wR(F2) = 0.068 w = 1/[σ2(Fo2) + (0.0315P)2 + 4.8P]
where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max < 0.001
494 reflectionsΔρmax = 0.65 e Å3
30 parametersΔρmin = 0.77 e Å3
0 restraintsExtinction correction: SHELXTL (Siemens, 1994), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.00064 (14)
Crystal data top
(C4H12N)[AgBr2]V = 934.7 (2) Å3
Mr = 341.84Z = 4
Orthorhombic, ImmmMo Kα radiation
a = 6.7817 (9) ŵ = 10.63 mm1
b = 9.1535 (14) ÅT = 293 K
c = 15.057 (2) Å0.20 × 0.20 × 0.16 mm
Data collection top
Rigaku Mercury CCD
diffractometer
494 independent reflections
Absorption correction: multi-scan
(SPHERE in CrystalClear; Rigaku, 2002)
459 reflections with I > 2σ(I)
Tmin = 0.13, Tmax = 0.18Rint = 0.031
2952 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0300 restraints
wR(F2) = 0.068H-atom parameters constrained
S = 1.00Δρmax = 0.65 e Å3
494 reflectionsΔρmin = 0.77 e Å3
30 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
xyzUiso*/UeqOcc. (<1)
Ag10.26353 (6)0.50000.50000.05861 (12)
Br10.00000.50000.36364 (3)0.05356 (14)
Br20.50000.26262 (5)0.50000.05680 (15)
N10.50000.50000.1917 (3)0.0490 (11)
C10.3206 (6)0.50000.1370 (3)0.121 (2)
H1A0.32050.41560.09920.181*0.50
H1B0.31740.58680.10130.181*0.50
H1C0.20670.49760.17480.181*
C20.50000.6304 (4)0.2516 (3)0.0781 (14)
H2A0.61520.62820.28870.117*0.50
H2B0.38400.62880.28820.117*0.50
H2C0.50080.71790.21650.117*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ag10.0521 (2)0.0711 (2)0.0526 (2)0.0000.0000.000
Br10.0402 (2)0.0777 (3)0.0428 (2)0.0000.0000.000
Br20.0566 (3)0.0474 (3)0.0664 (3)0.0000.0000.000
N10.0416 (19)0.061 (2)0.044 (2)0.0000.0000.000
C10.064 (3)0.224 (7)0.073 (3)0.0000.035 (2)0.000
C20.072 (2)0.051 (2)0.111 (3)0.0000.0000.005 (2)
Geometric parameters (Å, º) top
Ag1—Br2i2.7006 (5)N1—C2iii1.496 (5)
Ag1—Br22.7006 (5)C1—H1A0.9600
Ag1—Br12.7221 (5)C1—H1B0.9600
Ag1—Br1ii2.7221 (5)C1—H1C0.9600
N1—C11.470 (5)C2—H2A0.9600
N1—C1iii1.470 (5)C2—H2B0.9600
N1—C21.496 (5)C2—H2C0.9600
Br2i—Ag1—Br2107.14 (2)C2—N1—C2iii105.9 (4)
Br2i—Ag1—Br1112.947 (7)N1—C1—H1A109.5
Br2—Ag1—Br1112.947 (7)N1—C1—H1B109.5
Br2i—Ag1—Br1ii112.947 (7)H1A—C1—H1B109.5
Br2—Ag1—Br1ii112.947 (7)N1—C1—H1C109.5
Br1—Ag1—Br1ii97.93 (2)H1A—C1—H1C110.5
Br2i—Ag1—Ag1i53.571 (11)H1B—C1—H1C108.5
Ag1—Br1—Ag1ii82.07 (2)N1—C2—H2A109.5
Ag1i—Br2—Ag172.86 (2)N1—C2—H2B109.5
C1—N1—C1iii111.8 (4)H2A—C2—H2B109.5
C1—N1—C2109.76 (13)N1—C2—H2C109.5
C1iii—N1—C2109.76 (13)H2A—C2—H2C109.5
C1—N1—C2iii109.76 (13)H2B—C2—H2C109.5
C1iii—N1—C2iii109.76 (13)
Br2i—Ag1—Br1—Ag1ii119.104 (11)Br2i—Ag1—Br2—Ag1i0.0
Br2—Ag1—Br1—Ag1ii119.104 (11)Br1—Ag1—Br2—Ag1i125.005 (12)
Br1ii—Ag1—Br1—Ag1ii0.0Br1ii—Ag1—Br2—Ag1i125.005 (12)
Ag1i—Ag1—Br1—Ag1ii180.0
Symmetry codes: (i) x+1, y+1, z+1; (ii) x, y+1, z+1; (iii) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2C···Br1iv0.962.853.802 (4)172
Symmetry code: (iv) x+1/2, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formula(C4H12N)[AgBr2]
Mr341.84
Crystal system, space groupOrthorhombic, Immm
Temperature (K)293
a, b, c (Å)6.7817 (9), 9.1535 (14), 15.057 (2)
V3)934.7 (2)
Z4
Radiation typeMo Kα
µ (mm1)10.63
Crystal size (mm)0.20 × 0.20 × 0.16
Data collection
DiffractometerRigaku Mercury CCD
Absorption correctionMulti-scan
(SPHERE in CrystalClear; Rigaku, 2002)
Tmin, Tmax0.13, 0.18
No. of measured, independent and
observed [I > 2σ(I)] reflections
2952, 494, 459
Rint0.031
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.030, 0.068, 1.00
No. of reflections494
No. of parameters30
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.65, 0.77

Computer programs: CrystalClear (Rigaku, 2002), SHELXTL (Siemens, 1994) and ORTEP (Johnson, 1976).

Selected geometric parameters (Å, º) top
Ag1—Br22.7006 (5)Ag1—Br12.7221 (5)
Br2i—Ag1—Br2107.14 (2)Br1—Ag1—Br1ii97.93 (2)
Br2—Ag1—Br1112.947 (7)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2C···Br1iii0.962.853.802 (4)171.6
Symmetry code: (iii) x+1/2, y+3/2, z+1/2.
 

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