Hydrogen bonding in (2-bromo­benz­yl)­dimethyl­ammonium bromide

Ions of the title compound, C₉H₁₃BrN⁺·Br⁻, are linked by a strong N—H...Br⁻ hydrogen bond, and this unit is further linked to another three anion–cation units by weak C—H...Br⁻ contacts (H...Br range 2.95–3.09 Å), generating a two-dimensional layer parallel to the bc plane. The layers are stacked along the a axis without any inter­actions in the third dimension. The Br atom of the cation forms only an intra­molecular hydrogen bond (H...Br = 2.76 Å) with one of the methyl­ene H atoms.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.049
• wR factor = 0.110
• Data-to-parameter ratio = 17.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          9
PLAT480_ALERT_4_C Long H...A H-Bond Reported H8A    ..  BR2     ..       3.04 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H7B    ..  BR2     ..       3.09 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H7A    ..  BR2     ..       2.95 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H8B    ..  BR2     ..       3.02 Ang.

Alert level G
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
   5 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
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

In solid state, the anion-cation unit of the title compound is held together by a strong N—H···Br^- hydrogen bond [H1···Br2 = 2.83 Å] (Fig. 1). Another intramolecular H···Br contact is present between one hydrogen from the methylene group and the bromine bonded to the aromatic ring [H7B···Br1 = 2.76 Å]. The resulting C7—H7B···Br1 angle has a small value due to the rigid skeleton bearing both the donor and the acceptor part of the hydrogen bond-type contact.

The anion-cation unit forms eight weak intermolecular contacts through the two methylene hydrogen atoms, two other H atoms, each from one methyl group bonded to nitrogen, and the bromine anion with three neighboring units (Fig. 2). Four of these interactions are with another anion-cation unit result in zigzag polymers along the c axis and the remaining four contacts with two other units link the one-dimensional arrays, along the b axis, in a two-dimensional supramolecular layer-type arrangement (Varga et al., 2006; Varga & Silvestru, 2007) (Fig. 3). The layers are stacked together, with the aromatic rings intercalated, but with no contacts of any type on the third dimension (Fig. 4).

Related literature

For similar supramolecular structures formed through H···Br contacts, see: Varga et al. (2006); Varga & Silvestru (2007).

S2. Experimental

The title compound was obtained unintentionally as the decomposition product from the reaction between dibromo[2-(dimethylaminomethyl)phenyl][2-(dimethylammoniomethyl)phenyl]tin(IV) tetrabromo[2-(dimethylaminomethyl)phenyl]tin(IV) and excess of potassium hydroxide in a CHCl₃ / H₂O (1:1) mixture. Crystals suitable for single-crystal X-ray diffraction were obtained from a CHCl₃-n-hexane (1:4) mixture.

S3. Refinement

All hydrogen atoms were placed in calculated positions using a riding model, with C—H = 0.93–0.97 Å and with U_iso= 1.5U_eq (C) for methyl H and U_iso= 1.2U_eq (C) for aryl H. The methyl groups were allowed to rotate but not to tip. The hydrogen H1 atom bonded to N1 was found in a difference map and refined with a restrained N—H distance of 0.86 (2) Å

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker, 2000); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2007).

Figures

	Fig. 1. View of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen bond shown with dashed line.
	Fig. 2. The hydrogen bonding (dashed lines) in structure of the title compound. [Symmetry codes: (i) 2 - x, 2 - y, 2 - z; (ii) 2 - x, 1/2 + y, 1.5 - z; (iii) 2 - x, -1/2 + y, 1.5 - z.]
	Fig. 3. Supramolecular arrangement of the title compound (hydrogen bonds are shown as dashed lines), view along a axis.
	Fig. 4. Crystal packing of the title compound along the c axis.

(2-bromobenzyl)dimethylammonium bromide

Crystal data

C9H13BrN^+·Br^−	F(000) = 576
Mr = 295.02	Dx = 1.764 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3587 reflections
a = 8.6227 (8) Å	θ = 2.5–27.6°
b = 14.6503 (13) Å	µ = 7.25 mm^−1
c = 9.2118 (8) Å	T = 297 K
β = 107.339 (2)°	Block, colourless
V = 1110.80 (17) Å^3	0.23 × 0.21 × 0.10 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1957 independent reflections
Radiation source: fine-focus sealed tube	1700 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
φ and ω scans	θmax = 25.0°, θmin = 2.5°
Absorption correction: multi-scan (SHELXTL; Bruker, 2001)	h = −10→10
Tmin = 0.216, Tmax = 0.491	k = −17→17
7866 measured reflections	l = −10→10

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.110	H atoms treated by a mixture of independent and constrained refinement
S = 1.17	w = 1/[σ^2(Fo^2) + (0.0392P)^2 + 2.3199P] where P = (Fo^2 + 2Fc^2)/3
1957 reflections	(Δ/σ)max < 0.001
115 parameters	Δρmax = 0.70 e Å^−3
1 restraint	Δρmin = −0.51 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
Br2	1.01040 (8)	1.09349 (4)	0.77395 (7)	0.0421 (2)
Br1	0.55425 (9)	0.75580 (5)	0.50628 (9)	0.0672 (3)
C1	0.5417 (7)	0.8600 (4)	0.6257 (7)	0.0390 (13)
C2	0.6691 (6)	0.8827 (3)	0.7517 (6)	0.0301 (12)
C3	0.6466 (8)	0.9588 (4)	0.8348 (7)	0.0458 (15)
H3	0.7295	0.9760	0.9209	0.055*
C4	0.5061 (9)	1.0087 (5)	0.7931 (9)	0.0605 (19)
H4	0.4941	1.0589	0.8505	0.073*
C5	0.3849 (8)	0.9846 (5)	0.6678 (9)	0.0558 (18)
H5	0.2898	1.0188	0.6394	0.067*
C6	0.4001 (7)	0.9102 (5)	0.5814 (8)	0.0509 (16)
H6	0.3166	0.8941	0.4950	0.061*
C7	0.8256 (6)	0.8306 (4)	0.8117 (6)	0.0353 (13)
H7A	0.8518	0.8256	0.9214	0.042*
H7B	0.8110	0.7694	0.7697	0.042*
C8	1.1244 (7)	0.8408 (4)	0.8720 (7)	0.0432 (14)
H8A	1.1317	0.7763	0.8568	0.065*
H8B	1.1327	0.8525	0.9766	0.065*
H8C	1.2111	0.8714	0.8463	0.065*
C9	0.9548 (7)	0.8636 (4)	0.6101 (6)	0.0437 (14)
H9A	1.0388	0.8987	0.5876	0.066*
H9B	0.8506	0.8841	0.5474	0.066*
H9C	0.9683	0.8002	0.5901	0.066*
N1	0.9650 (5)	0.8755 (3)	0.7728 (5)	0.0311 (10)
H1	0.964 (8)	0.9336 (15)	0.783 (8)	0.06 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br2	0.0564 (4)	0.0284 (3)	0.0410 (3)	−0.0039 (3)	0.0136 (3)	−0.0004 (2)
Br1	0.0509 (5)	0.0714 (5)	0.0772 (6)	−0.0147 (4)	0.0156 (4)	−0.0333 (4)
C1	0.036 (3)	0.041 (3)	0.042 (3)	−0.004 (3)	0.014 (3)	0.003 (3)
C2	0.031 (3)	0.027 (3)	0.034 (3)	0.001 (2)	0.013 (2)	0.004 (2)
C3	0.047 (4)	0.052 (4)	0.040 (3)	0.001 (3)	0.016 (3)	0.001 (3)
C4	0.072 (5)	0.046 (4)	0.075 (5)	0.017 (4)	0.041 (4)	0.004 (3)
C5	0.039 (4)	0.060 (4)	0.076 (5)	0.020 (3)	0.029 (4)	0.027 (4)
C6	0.025 (3)	0.072 (5)	0.055 (4)	0.002 (3)	0.010 (3)	0.015 (3)
C7	0.035 (3)	0.033 (3)	0.039 (3)	0.001 (2)	0.011 (3)	0.004 (2)
C8	0.035 (3)	0.042 (3)	0.049 (4)	0.007 (3)	0.008 (3)	0.003 (3)
C9	0.041 (3)	0.055 (4)	0.037 (3)	−0.008 (3)	0.014 (3)	−0.004 (3)
N1	0.030 (2)	0.026 (2)	0.038 (3)	−0.0002 (19)	0.011 (2)	0.0012 (19)

Geometric parameters (Å, º)

Br2—H1	2.38 (3)	C7—N1	1.503 (7)
Br1—C1	1.904 (6)	C7—H7A	0.9700
C1—C6	1.378 (8)	C7—H7B	0.9700
C1—C2	1.380 (8)	C8—N1	1.494 (7)
C2—C3	1.398 (8)	C8—H8A	0.9600
C2—C7	1.504 (7)	C8—H8B	0.9600
C3—C4	1.368 (9)	C8—H8C	0.9600
C3—H3	0.9300	C9—N1	1.485 (7)
C4—C5	1.353 (10)	C9—H9A	0.9600
C4—H4	0.9300	C9—H9B	0.9600
C5—C6	1.379 (10)	C9—H9C	0.9600
C5—H5	0.9300	N1—H1	0.86 (2)
C6—H6	0.9300
C6—C1—C2	122.3 (6)	N1—C7—H7B	109.1
C6—C1—Br1	117.0 (5)	C2—C7—H7B	109.1
C2—C1—Br1	120.7 (4)	H7A—C7—H7B	107.8
C1—C2—C3	116.5 (5)	N1—C8—H8A	109.5
C1—C2—C7	126.1 (5)	N1—C8—H8B	109.5
C3—C2—C7	117.3 (5)	H8A—C8—H8B	109.5
C4—C3—C2	121.9 (6)	N1—C8—H8C	109.5
C4—C3—H3	119.1	H8A—C8—H8C	109.5
C2—C3—H3	119.1	H8B—C8—H8C	109.5
C5—C4—C3	119.6 (7)	N1—C9—H9A	109.5
C5—C4—H4	120.2	N1—C9—H9B	109.5
C3—C4—H4	120.2	H9A—C9—H9B	109.5
C4—C5—C6	121.1 (6)	N1—C9—H9C	109.5
C4—C5—H5	119.4	H9A—C9—H9C	109.5
C6—C5—H5	119.4	H9B—C9—H9C	109.5
C1—C6—C5	118.6 (6)	C9—N1—C8	110.1 (4)
C1—C6—H6	120.7	C9—N1—C7	112.2 (4)
C5—C6—H6	120.7	C8—N1—C7	111.2 (4)
N1—C7—C2	112.6 (4)	C9—N1—H1	103 (5)
N1—C7—H7A	109.1	C8—N1—H1	108 (5)
C2—C7—H7A	109.1	C7—N1—H1	112 (5)
C6—C1—C2—C3	1.0 (8)	C2—C1—C6—C5	−1.0 (9)
Br1—C1—C2—C3	−178.2 (4)	Br1—C1—C6—C5	178.2 (5)
C6—C1—C2—C7	178.0 (5)	C4—C5—C6—C1	0.4 (10)
Br1—C1—C2—C7	−1.2 (8)	C1—C2—C7—N1	103.2 (6)
C1—C2—C3—C4	−0.4 (8)	C3—C2—C7—N1	−79.9 (6)
C7—C2—C3—C4	−177.6 (5)	C2—C7—N1—C9	−74.2 (6)
C2—C3—C4—C5	−0.2 (10)	C2—C7—N1—C8	162.0 (5)
C3—C4—C5—C6	0.2 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br2	0.86 (2)	2.38 (2)	3.217 (4)	165 (6)
C7—H7B···Br1	0.97	2.76	3.266 (5)	113
C8—H8A···Br2^i	0.96	3.04	3.916 (6)	153
C7—H7B···Br2^i	0.97	3.09	3.918 (6)	144
C7—H7A···Br2^ii	0.97	2.95	3.819 (5)	150
C8—H8B···Br2^ii	0.96	3.02	3.895 (7)	152

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