2,3-Dimethyl­quinoxalinediium hexa­bromidostannate(IV) trihydrate

In the title compound, (C₁₀H₁₂N₂)[SnBr₆]·3H₂O, the asymmetric unit contains one cation, one anion and three water mol­ecules, and the Sn atom has a distorted octa­hedral environment. In the crystal structure, intra- and inter­molecular hydrogen bonds and Br...Br inter­actions [Br...Br = 3.6726 (19), 3.6913 (18) and 3.6517 (21) Å] lead to the formation of a supra­molecular architecture.

Key indicators

• Single-crystal X-ray study
• T = 84 K
• Mean [sigma](C-C) = 0.013 Å
• R factor = 0.062
• wR factor = 0.132
• Data-to-parameter ratio = 23.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT420_ALERT_2_B D-H Without Acceptor       O3W    -   H3W1   ...          ?

Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Sn1    -   Br5     ..       7.78 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Sn1
PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         13
PLAT432_ALERT_2_C Short Inter X...Y Contact  Br5    ..  C2      ..       3.34 Ang.
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          6
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              Br6 Sn

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Sn1         (4)       3.62

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 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
   1 ALERT type 5 Informative message, check

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S1. Comment

Noncovalent interactions play an important role in organizing structural units in both natural and artificial systems (Desiraju, 1997). In connection with ongoing studies (Ali et al., 2007; Ali & Al-Far, 2007; Al-Far & Ali, 2007a,b) of the structural aspects of bromo metal anions salts, we herein report the crystal structure of the title compound, (I).

The asymmetric unit of the title compound, (I), contains one cation, one anion and three water molecules, where the Sn atom has a distorted octahedral environment (Fig. 1, Table 1). The bond lengths and angles (Table 1) are generally within normal ranges (Allen et al., 1987). In the anion, the Sn1—Br1 [2.4406 (12) Å] and Sn1—Br3 [2.4605 (12) Å] bonds are shorter than the other Sn—Br bonds, in which they are within the range of Sn—Br bonds reported previously for compounds containing [SnBr₆]^2- anions (Ali & Al-Far, 2007; Al-Far & Ali, 2007a,b; Al-Far et al., 2007; Tudela & Khan, 1991; Willey et al., 1998). In the cation, the bond lengths and angles are in accordance with the corresponding values (Al-Far & Ali, 2007a,b; Ali et al., 2007). The cation is, of course, planar, in which C1 and C10 atoms are also coplanar.

The packing of the structure can be regarded as alternating layers of anions and cations (Fig. 2). The anions within each layer (Fig. 3) interact via Br1···Br3^iv = 3.6726 (19) Å [symmetry code: (iv) x, 3/2 + y, 1/2 + z] interactions parallel to c axis. Each anionic layer further interacts via Br2···Br6^v = 3.6913 (18) Å [symmetry code: (v) -x + 3, 1/2 + y, 1/2 - z] and Br4···Br4^vi = 3.6517 (21) Å [symmetry code: (vi) -x + 2, -y + 1, -z] interactions to form a two-dimensional anionic network parallel to ac plane (Fig. 3).

The crystal supramolecularity is represented in the significantly short hydrogen bonds (Table 2, Fig. 4) along with Br···Br interactions that allow the formation of supramolecular assembly of the anion, cation and water molecules in three-dimensional structure, in which they may be effective in the stabilization of the crystal structure.

Related literature

For related literature, see: Desiraju (1997); Ali et al. (2007); Ali & Al-Far (2007); Al-Far & Ali (2007a,b); Al-Far et al. (2007); Tudela & Khan (1991); Willey et al. (1998). For bond-length data, see: Allen et al. (1987).

S2. Experimental

For the preparation of (I), tin metal (0.119 mg, 1 mmol) dissolved in absolute ethanol (10 ml), HBr (60%, 5 ml) and liquid Br₂ (60%, 2 ml), was added dropwise to a stirred hot solution of 2,3-dimethylquinoxalinium (0.158 mg, 1 mmol) dissolved in ethanol (10 ml) and HBr (60%, 2 ml). After refluxing for 1 h, the mixture was filtered off, and then allowed to stand undisturbed at room temperature. The salt crystallized over 1 d as yellow crystals. Crystals were filtered off, washed with diethylether and dried under vacuum (yield; 0.750 mg; 92.4%).

S3. Refinement

H atoms were positioned geometrically, with O—H = 0.84–0.90 Å (for H₂O), N—H = 0.86 Å (for NH) and C—H = 0.95 and 0.98 Å, for aromatic and methylene H atoms, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C,O,N), where x = 1.2 for NH and aromatic H atoms, and x = 1.5 for all other H atoms.

Computing details

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; 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.

Figures

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are shown as dashed lines.
	Fig. 2. A partial packing diagram of (I). Hydrogen bonds and Br···Br interactions are shown as dashed lines. Viewed down c axis, where a and b axes are horizontal and vertical, respectively.
	Fig. 3. Anion network of Br···Br interactions. Viewed down b axis, where c and a axes are horizontal and vertical, respectively [Symmetry codes: (iv) x, 3/2 + y, 1/2 + z; (v) -x + 3, 1/2 + y, 1/2 - z; (vi) -x + 2, -y + 1, -z].
	Fig. 4. Anion, cation and water molecules intermolecular interactions. Sn—Br···H—O, H2O···H—OH, H2O···H—N and Br···Br (parallel to c axis) intermolecular interactions are shown as dashed lines. Viewed down b axis, where c and a axes are horizontal and vertical, respectively. H atoms are omitted for clarity. Oxygen atoms of water molecules shown as balls.

'2,3-Dimethylquinoxalinediium hexabromostannate(IV) trihydrate'

Crystal data

(C10H12N2)[SnBr6]·3H2O	F(000) = 1504
Mr = 812.37	Dx = 2.558 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71070 Å
Hall symbol: -P 2ybc	Cell parameters from 4210 reflections
a = 9.898 (3) Å	θ = 1.3–27.9°
b = 13.620 (5) Å	µ = 12.59 mm^−1
c = 16.098 (6) Å	T = 84 K
β = 103.599 (6)°	Needle, yellow
V = 2109.3 (13) Å^3	0.30 × 0.20 × 0.10 mm
Z = 4

Data collection

Rigaku Mercury CCD diffractometer	4633 independent reflections
Radiation source: fine-focus sealed tube	4210 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.045
Detector resolution: 14.6306 pixels mm^-1	θmax = 27.5°, θmin = 2.1°
dtintegrate.ref scans	h = −12→11
Absorption correction: multi-scan Shape Tracing Software	k = −17→17
Tmin = 0.055, Tmax = 0.277	l = −20→20
27021 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.132	H-atom parameters constrained
S = 1.20	w = 1/[σ^2(Fo^2) + (0.0478P)^2 + 7.030P] where P = (Fo^2 + 2Fc^2)/3
4633 reflections	(Δ/σ)max = 0.001
201 parameters	Δρmax = 1.41 e Å^−3
0 restraints	Δρmin = −1.11 e Å^−3

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
Sn1	1.23031 (5)	0.73783 (4)	0.15141 (3)	0.03598 (16)
Br1	1.17497 (9)	0.68693 (8)	0.28495 (5)	0.0562 (3)
Br2	1.41637 (10)	0.86480 (7)	0.24513 (6)	0.0600 (3)
Br3	1.28560 (9)	0.79729 (8)	0.01892 (5)	0.0594 (3)
Br4	1.04854 (9)	0.61509 (7)	0.05744 (6)	0.0573 (3)
Br5	1.02270 (9)	0.87143 (7)	0.11762 (6)	0.0538 (2)
Br6	1.43853 (9)	0.60996 (7)	0.18886 (6)	0.0529 (2)
O1W	0.5390 (9)	0.6748 (7)	0.4150 (5)	0.099 (3)
H1W1	0.5917	0.6271	0.4063	0.149*
H1W2	0.4568	0.6502	0.4107	0.149*
O2W	0.7208 (12)	0.5361 (8)	0.4048 (8)	0.150 (5)
H2W1	0.6941	0.4985	0.3624	0.226*
H2W2	0.7408	0.5002	0.4510	0.226*
O3W	0.9249 (12)	0.6547 (9)	0.3909 (5)	0.134 (4)
H3W1	0.9395	0.7059	0.4277	0.201*
H3W2	1.0060	0.6290	0.3961	0.201*
N1	0.6611 (6)	0.7296 (5)	0.5744 (4)	0.0432 (15)
H1N	0.6144	0.7109	0.5249	0.052*
N2	0.8084 (7)	0.7870 (5)	0.7326 (4)	0.0457 (16)
H2N	0.8534	0.8050	0.7827	0.055*
C1	0.6530 (10)	0.5601 (7)	0.6141 (7)	0.067 (3)
H1A	0.5879	0.5584	0.5579	0.101*
H1B	0.6076	0.5337	0.6572	0.101*
H1C	0.7349	0.5202	0.6126	0.101*
C2	0.6965 (8)	0.6629 (7)	0.6361 (6)	0.049 (2)
C3	0.6962 (7)	0.8271 (6)	0.5865 (5)	0.0399 (17)
C4	0.6556 (9)	0.8934 (7)	0.5197 (5)	0.050 (2)
H4	0.6045	0.8736	0.4646	0.060*
C5	0.6936 (10)	0.9891 (8)	0.5380 (7)	0.063 (3)
H5	0.6690	1.0367	0.4939	0.075*
C6	0.7682 (10)	1.0201 (7)	0.6201 (8)	0.067 (3)
H6	0.7899	1.0878	0.6289	0.080*
C8	0.7744 (7)	0.8569 (6)	0.6704 (5)	0.0399 (17)
C7	0.8110 (9)	0.9554 (7)	0.6884 (6)	0.055 (2)
H7	0.8613	0.9766	0.7432	0.066*
C9	0.7761 (8)	0.6942 (6)	0.7202 (5)	0.0453 (19)
C10	0.8231 (11)	0.6235 (8)	0.7927 (6)	0.073 (3)
H10A	0.7928	0.6469	0.8429	0.109*
H10B	0.9248	0.6186	0.8064	0.109*
H10C	0.7826	0.5587	0.7761	0.109*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.0316 (3)	0.0490 (3)	0.0301 (3)	−0.0024 (2)	0.0128 (2)	−0.0062 (2)
Br1	0.0512 (5)	0.0851 (7)	0.0392 (4)	0.0018 (4)	0.0247 (4)	0.0052 (4)
Br2	0.0516 (5)	0.0684 (6)	0.0626 (6)	−0.0193 (4)	0.0188 (4)	−0.0240 (5)
Br3	0.0540 (5)	0.0901 (7)	0.0412 (4)	−0.0031 (5)	0.0252 (4)	0.0099 (4)
Br4	0.0517 (5)	0.0687 (6)	0.0546 (5)	−0.0196 (4)	0.0184 (4)	−0.0223 (4)
Br5	0.0447 (5)	0.0622 (5)	0.0588 (5)	0.0063 (4)	0.0210 (4)	−0.0041 (4)
Br6	0.0473 (5)	0.0622 (5)	0.0540 (5)	0.0130 (4)	0.0217 (4)	0.0009 (4)
O1W	0.106 (6)	0.134 (7)	0.054 (4)	0.010 (6)	0.013 (4)	−0.019 (5)
O2W	0.175 (11)	0.107 (8)	0.209 (13)	−0.005 (7)	0.123 (10)	−0.016 (8)
O3W	0.151 (9)	0.206 (11)	0.043 (4)	0.017 (8)	0.016 (5)	0.017 (6)
N1	0.035 (3)	0.056 (4)	0.040 (3)	0.003 (3)	0.011 (3)	−0.004 (3)
N2	0.038 (4)	0.070 (5)	0.032 (3)	0.001 (3)	0.013 (3)	0.000 (3)
C1	0.059 (6)	0.056 (6)	0.094 (8)	−0.003 (5)	0.030 (5)	−0.005 (5)
C2	0.031 (4)	0.059 (5)	0.059 (5)	−0.001 (4)	0.016 (4)	0.011 (4)
C3	0.032 (4)	0.049 (4)	0.045 (4)	0.004 (3)	0.021 (3)	0.002 (4)
C4	0.046 (5)	0.065 (6)	0.042 (4)	0.007 (4)	0.017 (4)	0.012 (4)
C5	0.054 (6)	0.071 (7)	0.070 (6)	0.013 (5)	0.030 (5)	0.023 (5)
C6	0.065 (6)	0.047 (5)	0.103 (8)	0.003 (4)	0.049 (6)	0.001 (5)
C8	0.027 (4)	0.061 (5)	0.036 (4)	0.002 (3)	0.015 (3)	0.001 (3)
C7	0.049 (5)	0.061 (5)	0.065 (6)	−0.005 (4)	0.032 (4)	−0.015 (5)
C9	0.036 (4)	0.060 (5)	0.043 (4)	−0.001 (4)	0.017 (3)	0.007 (4)
C10	0.063 (6)	0.099 (8)	0.060 (6)	0.009 (6)	0.023 (5)	0.037 (6)

Geometric parameters (Å, º)

Sn1—Br1	2.4405 (12)	C1—H1A	0.9800
Sn1—Br3	2.4603 (12)	C1—H1B	0.9800
Sn1—Br4	2.6534 (11)	C1—H1C	0.9800
Sn1—Br6	2.6570 (12)	C2—C9	1.461 (12)
Sn1—Br5	2.7026 (12)	C3—C4	1.391 (11)
Sn1—Br2	2.7114 (11)	C3—C8	1.447 (11)
O1W—H1W1	0.8600	C4—C5	1.368 (13)
O1W—H1W2	0.8700	C4—H4	0.9500
O2W—H2W1	0.8400	C5—C6	1.418 (14)
O2W—H2W2	0.8700	C5—H5	0.9500
O3W—H3W1	0.9000	C6—C7	1.395 (14)
O3W—H3W2	0.8600	C6—H6	0.9500
N1—C2	1.330 (10)	C8—C7	1.403 (12)
N1—C3	1.375 (10)	C7—H7	0.9500
N1—H1N	0.8600	C9—C10	1.500 (11)
N2—C9	1.308 (11)	C10—H10A	0.9800
N2—C8	1.365 (10)	C10—H10B	0.9800
N2—H2N	0.8600	C10—H10C	0.9800
C1—C2	1.483 (13)
Br1—Sn1—Br3	177.29 (4)	N1—C2—C9	118.9 (8)
Br1—Sn1—Br4	93.48 (4)	N1—C2—C1	117.1 (8)
Br3—Sn1—Br4	88.41 (4)	C9—C2—C1	124.0 (8)
Br1—Sn1—Br6	86.37 (4)	N1—C3—C4	120.0 (8)
Br3—Sn1—Br6	95.38 (4)	N1—C3—C8	117.8 (7)
Br4—Sn1—Br6	95.87 (4)	C4—C3—C8	122.2 (7)
Br1—Sn1—Br5	92.93 (3)	C5—C4—C3	115.9 (8)
Br3—Sn1—Br5	85.26 (4)	C5—C4—H4	122.0
Br4—Sn1—Br5	85.87 (4)	C3—C4—H4	122.0
Br6—Sn1—Br5	178.17 (3)	C4—C5—C6	122.7 (9)
Br1—Sn1—Br2	87.41 (4)	C4—C5—H5	118.6
Br3—Sn1—Br2	90.69 (4)	C6—C5—H5	118.6
Br4—Sn1—Br2	179.08 (4)	C7—C6—C5	122.8 (9)
Br6—Sn1—Br2	84.41 (4)	C7—C6—H6	118.6
Br5—Sn1—Br2	93.86 (4)	C5—C6—H6	118.6
H1W1—O1W—H1W2	106.70	N2—C8—C7	120.5 (8)
H2W1—O2W—H2W2	108.30	N2—C8—C3	118.3 (7)
H3W1—O3W—H3W2	104.40	C7—C8—C3	121.1 (8)
C2—N1—C3	122.6 (7)	C6—C7—C8	115.2 (9)
C2—N1—H1N	118.7	C6—C7—H7	122.4
C3—N1—H1N	118.7	C8—C7—H7	122.4
C9—N2—C8	123.5 (7)	N2—C9—C2	118.9 (7)
C9—N2—H2N	118.2	N2—C9—C10	118.8 (8)
C8—N2—H2N	118.2	C2—C9—C10	122.4 (8)
C2—C1—H1A	109.5	C9—C10—H10A	109.5
C2—C1—H1B	109.5	C9—C10—H10B	109.5
H1A—C1—H1B	109.5	H10A—C10—H10B	109.5
C2—C1—H1C	109.5	C9—C10—H10C	109.5
H1A—C1—H1C	109.5	H10A—C10—H10C	109.5
H1B—C1—H1C	109.5	H10B—C10—H10C	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W1···O2W	0.86	1.78	2.640 (14)	170.00
O1W—H1W2···Br3^i	0.87	2.79	3.348 (9)	123.1 (5)
O2W—H2W1···Br2^ii	0.84	2.57	3.401 (12)	167.4 (7)
O2W—H2W2···Br3^ii	0.87	2.83	3.482 (11)	132.9 (7)
O3W—H3W2···Br1	0.86	2.83	3.349 (11)	120.00
N1—H1N···O1W	0.86	1.82	2.672 (10)	172
N2—H2N···O3W^iii	0.86	1.81	2.660 (11)	172

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