organic compounds
[2,6-Bis(dimethylaminomethyl)phenyl]selenium bromide monohydrate
aFaculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos Str. no. 11, RO-400028, Cluj Napoca, Romania, and bDepartamento de Química Inorgánica, Instituto de Ciencia de, Materiales de Aragón, Universidad de Zaragoza–CSIC, E-50009 Zaragoza, Spain
*Correspondence e-mail: richy@chem.ubbcluj.ro
In the title hydrated molecular salt, C12H19N2Se+·Br−·H2O, the two independent bromide anions lie on a twofold rotation axis. Strong intramolecular N→Se interactions [2.185 (3) and 2.181 (3) Å] are established by both N atoms of the organic group in the cation, in trans positions to each other, with an N—Se—N angle of 161.6 (1)°, resulting in a T-shaped (C,N,N′)Se core. In the crystal, dimeric associations are formed by Br⋯Se [3.662 (2) Å] and Br⋯H interactions [2.56 (6) and 2.63 (7) Å] involving two bromide anions, two cations and two water molecules.
Related literature
For related selenium and tellurium compounds, see: Drake et al. (2001a,b); Deleanu et al. (2002); Kulcsar et al. (2005, 2007); Beleaga et al. (2009); Fujihara et al. (1995). For van der Waals radii, see: Emsley (1994).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2000); cell SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND 3 (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536810008019/dn2538sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810008019/dn2538Isup2.hkl
[2,6-(Me2NCH2)2C6H3]SeBr was obtained by oxidizing [2,6-(Me2NCH2)2C6H3]2Se2 with elemental bromine.
The attempt to grow crystals of [2,6-(Me2NCH2)2C6H3]SeBr from a methylene dichloride / n-hexane mixture (1:5, v/v) in open atmosphere led to the isolation of [2,6-(Me2NCH2)2C6H3]SeBr.H2O.
All hydrogen atoms were placed in calculated positions using a riding model, with C—H = 0.93-0.97 Å and with Uiso= 1.5Ueq (C) for methyl H and Uiso= 1.2Ueq (C) for aryl H. The methyl groups were allowed to rotate but not to tip. Hydrogen atoms from the water molecule were found from difference map and refined to O—H distances of 0.78 (6) Å.
Data collection: SMART (Bruker, 2000); cell
SAINT-Plus (Bruker, 2000); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND 3 (Brandenburg & Putz, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).C12H19N2Se+·Br−·H2O | F(000) = 1472 |
Mr = 368.18 | Dx = 1.619 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 3226 reflections |
a = 15.1494 (14) Å | θ = 2.3–25.2° |
b = 11.3182 (10) Å | µ = 5.12 mm−1 |
c = 18.8083 (17) Å | T = 297 K |
β = 110.475 (2)° | Block, colourless |
V = 3021.2 (5) Å3 | 0.31 × 0.29 × 0.09 mm |
Z = 8 |
Bruker SMART APEX CCD area-detector diffractometer | 3093 independent reflections |
Radiation source: fine-focus sealed tube | 2696 reflections with I > 2/s(I) |
Graphite monochromator | Rint = 0.050 |
phi and ω scans | θmax = 26.4°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −18→18 |
Tmin = 0.300, Tmax = 0.656 | k = −14→14 |
11856 measured reflections | l = −23→23 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.039 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0287P)2 + 3.8997P] where P = (Fo2 + 2Fc2)/3 |
3093 reflections | (Δ/σ)max = 0.001 |
167 parameters | Δρmax = 0.49 e Å−3 |
0 restraints | Δρmin = −0.53 e Å−3 |
C12H19N2Se+·Br−·H2O | V = 3021.2 (5) Å3 |
Mr = 368.18 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 15.1494 (14) Å | µ = 5.12 mm−1 |
b = 11.3182 (10) Å | T = 297 K |
c = 18.8083 (17) Å | 0.31 × 0.29 × 0.09 mm |
β = 110.475 (2)° |
Bruker SMART APEX CCD area-detector diffractometer | 3093 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 2696 reflections with I > 2/s(I) |
Tmin = 0.300, Tmax = 0.656 | Rint = 0.050 |
11856 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | Δρmax = 0.49 e Å−3 |
3093 reflections | Δρmin = −0.53 e Å−3 |
167 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.5000 | 0.26510 (5) | 0.7500 | 0.05461 (17) | |
Br2 | 0.5000 | 0.73811 (6) | 0.7500 | 0.0747 (2) | |
C1 | 0.3337 (2) | 0.9300 (3) | 0.93573 (18) | 0.0319 (7) | |
C2 | 0.3774 (2) | 0.9329 (3) | 1.01348 (18) | 0.0372 (7) | |
C6 | 0.2603 (2) | 1.0046 (3) | 0.89677 (19) | 0.0346 (7) | |
C10 | 0.2169 (2) | 0.9828 (3) | 0.81308 (19) | 0.0408 (8) | |
H10A | 0.1640 | 0.9290 | 0.8028 | 0.049* | |
H10B | 0.1939 | 1.0565 | 0.7868 | 0.049* | |
C7 | 0.4589 (3) | 0.8503 (3) | 1.04538 (19) | 0.0444 (8) | |
H7A | 0.5173 | 0.8906 | 1.0505 | 0.053* | |
H7B | 0.4622 | 0.8232 | 1.0952 | 0.053* | |
C8 | 0.3799 (3) | 0.6604 (3) | 1.0050 (3) | 0.0572 (11) | |
H8A | 0.4077 | 0.6257 | 1.0544 | 0.086* | |
H8B | 0.3677 | 0.5999 | 0.9670 | 0.086* | |
H8C | 0.3218 | 0.6984 | 1.0014 | 0.086* | |
C9 | 0.5358 (3) | 0.6906 (4) | 0.9999 (2) | 0.0561 (10) | |
H9A | 0.5780 | 0.7482 | 0.9919 | 0.084* | |
H9B | 0.5246 | 0.6294 | 0.9624 | 0.084* | |
H9C | 0.5635 | 0.6570 | 1.0496 | 0.084* | |
C12 | 0.3495 (3) | 1.0235 (3) | 0.7709 (2) | 0.0495 (9) | |
H12A | 0.4006 | 0.9872 | 0.7599 | 0.074* | |
H12B | 0.3744 | 1.0733 | 0.8147 | 0.074* | |
H12C | 0.3126 | 1.0702 | 0.7282 | 0.074* | |
C11 | 0.2469 (3) | 0.8570 (4) | 0.7181 (2) | 0.0525 (9) | |
H11A | 0.2098 | 0.9056 | 0.6767 | 0.079* | |
H11B | 0.2073 | 0.7982 | 0.7286 | 0.079* | |
H11C | 0.2957 | 0.8189 | 0.7050 | 0.079* | |
C5 | 0.2301 (3) | 1.0860 (3) | 0.9381 (2) | 0.0454 (9) | |
H5 | 0.1810 | 1.1374 | 0.9134 | 0.054* | |
C4 | 0.2730 (3) | 1.0911 (3) | 1.0160 (2) | 0.0505 (9) | |
H4 | 0.2525 | 1.1462 | 1.0434 | 0.061* | |
C3 | 0.3460 (3) | 1.0155 (3) | 1.0540 (2) | 0.0473 (9) | |
H3 | 0.3740 | 1.0198 | 1.1065 | 0.057* | |
N1 | 0.4453 (2) | 0.7484 (2) | 0.99307 (16) | 0.0385 (7) | |
N2 | 0.28962 (19) | 0.9310 (2) | 0.78604 (15) | 0.0372 (6) | |
O1 | 0.4714 (3) | 0.5053 (4) | 0.8489 (2) | 0.0793 (11) | |
Se1 | 0.37778 (2) | 0.82185 (3) | 0.879443 (18) | 0.03542 (12) | |
H1 | 0.480 (4) | 0.562 (5) | 0.828 (3) | 0.09 (2)* | |
H2 | 0.475 (5) | 0.451 (6) | 0.825 (4) | 0.12 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0623 (4) | 0.0495 (3) | 0.0552 (4) | 0.000 | 0.0246 (3) | 0.000 |
Br2 | 0.0914 (5) | 0.0596 (4) | 0.0986 (6) | 0.000 | 0.0651 (5) | 0.000 |
C1 | 0.0345 (17) | 0.0321 (16) | 0.0323 (17) | −0.0077 (13) | 0.0157 (14) | −0.0033 (13) |
C2 | 0.0410 (19) | 0.0415 (18) | 0.0301 (18) | −0.0085 (15) | 0.0139 (15) | 0.0012 (14) |
C6 | 0.0337 (17) | 0.0329 (16) | 0.0367 (18) | −0.0046 (13) | 0.0117 (14) | −0.0018 (13) |
C10 | 0.0355 (18) | 0.0434 (19) | 0.0379 (19) | 0.0018 (15) | 0.0057 (15) | 0.0008 (15) |
C7 | 0.043 (2) | 0.057 (2) | 0.0302 (18) | −0.0040 (17) | 0.0092 (15) | 0.0064 (16) |
C8 | 0.045 (2) | 0.050 (2) | 0.073 (3) | −0.0058 (17) | 0.016 (2) | 0.021 (2) |
C9 | 0.040 (2) | 0.065 (3) | 0.061 (3) | 0.0149 (19) | 0.0143 (19) | 0.014 (2) |
C12 | 0.056 (2) | 0.053 (2) | 0.040 (2) | −0.0079 (18) | 0.0165 (18) | 0.0080 (17) |
C11 | 0.058 (2) | 0.055 (2) | 0.036 (2) | −0.0003 (19) | 0.0076 (18) | −0.0115 (17) |
C5 | 0.047 (2) | 0.0364 (18) | 0.056 (2) | 0.0009 (16) | 0.0221 (18) | −0.0025 (16) |
C4 | 0.063 (2) | 0.043 (2) | 0.055 (2) | −0.0016 (19) | 0.033 (2) | −0.0114 (18) |
C3 | 0.060 (2) | 0.054 (2) | 0.0317 (19) | −0.0089 (19) | 0.0210 (18) | −0.0050 (16) |
N1 | 0.0319 (15) | 0.0426 (16) | 0.0395 (16) | 0.0017 (12) | 0.0108 (13) | 0.0081 (12) |
N2 | 0.0412 (16) | 0.0396 (15) | 0.0273 (14) | −0.0040 (12) | 0.0076 (12) | −0.0005 (12) |
O1 | 0.106 (3) | 0.077 (3) | 0.046 (2) | −0.007 (2) | 0.0145 (19) | 0.0004 (19) |
Se1 | 0.03654 (19) | 0.03788 (19) | 0.03126 (19) | 0.00273 (14) | 0.01113 (14) | −0.00128 (14) |
C1—C2 | 1.379 (4) | C9—H9B | 0.9600 |
C1—C6 | 1.384 (5) | C9—H9C | 0.9600 |
C1—Se1 | 1.887 (3) | C12—N2 | 1.478 (4) |
C2—C3 | 1.391 (5) | C12—H12A | 0.9600 |
C2—C7 | 1.497 (5) | C12—H12B | 0.9600 |
C6—C5 | 1.382 (5) | C12—H12C | 0.9600 |
C6—C10 | 1.499 (5) | C11—N2 | 1.474 (4) |
C10—N2 | 1.487 (4) | C11—H11A | 0.9600 |
C10—H10A | 0.9700 | C11—H11B | 0.9600 |
C10—H10B | 0.9700 | C11—H11C | 0.9600 |
C7—N1 | 1.483 (5) | C5—C4 | 1.381 (5) |
C7—H7A | 0.9700 | C5—H5 | 0.9300 |
C7—H7B | 0.9700 | C4—C3 | 1.383 (5) |
C8—N1 | 1.476 (4) | C4—H4 | 0.9300 |
C8—H8A | 0.9600 | C3—H3 | 0.9300 |
C8—H8B | 0.9600 | N1—Se1 | 2.185 (3) |
C8—H8C | 0.9600 | N2—Se1 | 2.180 (3) |
C9—N1 | 1.484 (5) | O1—H1 | 0.78 (6) |
C9—H9A | 0.9600 | O1—H2 | 0.78 (6) |
C2—C1—C6 | 123.1 (3) | H12A—C12—H12B | 109.5 |
C2—C1—Se1 | 118.5 (2) | N2—C12—H12C | 109.5 |
C6—C1—Se1 | 118.4 (2) | H12A—C12—H12C | 109.5 |
C1—C2—C3 | 117.9 (3) | H12B—C12—H12C | 109.5 |
C1—C2—C7 | 115.7 (3) | N2—C11—H11A | 109.5 |
C3—C2—C7 | 126.3 (3) | N2—C11—H11B | 109.5 |
C5—C6—C1 | 118.1 (3) | H11A—C11—H11B | 109.5 |
C5—C6—C10 | 126.1 (3) | N2—C11—H11C | 109.5 |
C1—C6—C10 | 115.6 (3) | H11A—C11—H11C | 109.5 |
N2—C10—C6 | 108.6 (3) | H11B—C11—H11C | 109.5 |
N2—C10—H10A | 110.0 | C4—C5—C6 | 119.9 (3) |
C6—C10—H10A | 110.0 | C4—C5—H5 | 120.1 |
N2—C10—H10B | 110.0 | C6—C5—H5 | 120.1 |
C6—C10—H10B | 110.0 | C5—C4—C3 | 121.2 (3) |
H10A—C10—H10B | 108.4 | C5—C4—H4 | 119.4 |
N1—C7—C2 | 108.4 (3) | C3—C4—H4 | 119.4 |
N1—C7—H7A | 110.0 | C4—C3—C2 | 119.8 (3) |
C2—C7—H7A | 110.0 | C4—C3—H3 | 120.1 |
N1—C7—H7B | 110.0 | C2—C3—H3 | 120.1 |
C2—C7—H7B | 110.0 | C8—N1—C7 | 111.6 (3) |
H7A—C7—H7B | 108.4 | C8—N1—C9 | 109.8 (3) |
N1—C8—H8A | 109.5 | C7—N1—C9 | 112.1 (3) |
N1—C8—H8B | 109.5 | C8—N1—Se1 | 107.2 (2) |
H8A—C8—H8B | 109.5 | C7—N1—Se1 | 105.19 (19) |
N1—C8—H8C | 109.5 | C9—N1—Se1 | 110.7 (2) |
H8A—C8—H8C | 109.5 | C11—N2—C12 | 110.4 (3) |
H8B—C8—H8C | 109.5 | C11—N2—C10 | 111.5 (3) |
N1—C9—H9A | 109.5 | C12—N2—C10 | 111.4 (3) |
N1—C9—H9B | 109.5 | C11—N2—Se1 | 109.6 (2) |
H9A—C9—H9B | 109.5 | C12—N2—Se1 | 108.2 (2) |
N1—C9—H9C | 109.5 | C10—N2—Se1 | 105.46 (19) |
H9A—C9—H9C | 109.5 | H1—O1—H2 | 107 (6) |
H9B—C9—H9C | 109.5 | C1—Se1—N2 | 81.21 (12) |
N2—C12—H12A | 109.5 | C1—Se1—N1 | 80.47 (12) |
N2—C12—H12B | 109.5 | N2—Se1—N1 | 161.56 (11) |
C6—C1—C2—C3 | −0.4 (5) | C2—C7—N1—Se1 | 34.9 (3) |
Se1—C1—C2—C3 | 178.1 (2) | C6—C10—N2—C11 | 152.9 (3) |
C6—C1—C2—C7 | −176.8 (3) | C6—C10—N2—C12 | −83.3 (3) |
Se1—C1—C2—C7 | 1.8 (4) | C6—C10—N2—Se1 | 33.9 (3) |
C2—C1—C6—C5 | 0.4 (5) | C2—C1—Se1—N2 | −166.9 (3) |
Se1—C1—C6—C5 | −178.1 (2) | C6—C1—Se1—N2 | 11.7 (2) |
C2—C1—C6—C10 | −175.7 (3) | C2—C1—Se1—N1 | 15.2 (2) |
Se1—C1—C6—C10 | 5.7 (4) | C6—C1—Se1—N1 | −166.2 (3) |
C5—C6—C10—N2 | 155.8 (3) | C11—N2—Se1—C1 | −146.0 (3) |
C1—C6—C10—N2 | −28.4 (4) | C12—N2—Se1—C1 | 93.5 (2) |
C1—C2—C7—N1 | −26.9 (4) | C10—N2—Se1—C1 | −25.8 (2) |
C3—C2—C7—N1 | 157.1 (3) | C11—N2—Se1—N1 | −139.3 (3) |
C1—C6—C5—C4 | −0.1 (5) | C12—N2—Se1—N1 | 100.2 (4) |
C10—C6—C5—C4 | 175.6 (3) | C10—N2—Se1—N1 | −19.1 (4) |
C6—C5—C4—C3 | −0.2 (6) | C8—N1—Se1—C1 | 90.8 (2) |
C5—C4—C3—C2 | 0.2 (6) | C7—N1—Se1—C1 | −28.1 (2) |
C1—C2—C3—C4 | 0.1 (5) | C9—N1—Se1—C1 | −149.4 (3) |
C7—C2—C3—C4 | 176.0 (3) | C8—N1—Se1—N2 | 84.2 (4) |
C2—C7—N1—C8 | −81.0 (3) | C7—N1—Se1—N2 | −34.8 (4) |
C2—C7—N1—C9 | 155.3 (3) | C9—N1—Se1—N2 | −156.1 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Br2 | 0.78 (6) | 2.56 (6) | 3.340 (5) | 175 (5) |
O1—H2···Br1 | 0.78 (6) | 2.63 (7) | 3.406 (5) | 176 (7) |
Experimental details
Crystal data | |
Chemical formula | C12H19N2Se+·Br−·H2O |
Mr | 368.18 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 297 |
a, b, c (Å) | 15.1494 (14), 11.3182 (10), 18.8083 (17) |
β (°) | 110.475 (2) |
V (Å3) | 3021.2 (5) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 5.12 |
Crystal size (mm) | 0.31 × 0.29 × 0.09 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.300, 0.656 |
No. of measured, independent and observed [I > 2/s(I)] reflections | 11856, 3093, 2696 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.086, 1.09 |
No. of reflections | 3093 |
No. of parameters | 167 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.49, −0.53 |
Computer programs: SMART (Bruker, 2000), SAINT-Plus (Bruker, 2000), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND 3 (Brandenburg & Putz, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Br2 | 0.78 (6) | 2.56 (6) | 3.340 (5) | 175 (5) |
O1—H2···Br1 | 0.78 (6) | 2.63 (7) | 3.406 (5) | 176 (7) |
Acknowledgements
This work was supported by the Romanian Ministery of Education and Research (PNII Program, grant 2404/2008). We also thank the National Center for X-ray Diffraction, Cluj-Napoca, for the structure determination.
References
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In the last years our interest was focused on the synthesis, structural characterization and chemical reactivity of some new hypervalent organoselenium and organotellurium derivatives containing aryl groups with pendant arms, e.g. 2-(Me2NCH2)C6H4, 2-[O(CH2CH2)2NCH2]C6H4 and 2-[MeN(CH2CH2)2NCH2]C6H4 (Drake et al., 2001a,b, Deleanu et al.,2002, Kulcsar et al., 2005, 2007, Beleaga et al., 2009).
The crystal of the title compound contains a mixture of [{2,6-(Me2NCH2)2C6H3}Se]+ cations and [Br]- anions and crystallizes with a water molecule. The two independent bromine anions lie on a two-fold rotation axis. Both pendant arms of the organic group attached to selenium establish strong intramolecular N→Se interactions [Se—N1 = 2.185 (3) Å, Se1—N2 = 2.181 (3) Å], trans one to the other [N1—Se1—N2 = 161.6 (1)°], thus resulting in the increase of the coordination number at Se to three (Fig. 1). The Se—N distances are of the same magnitude as found in the cation of [{2,6-(Me2NCH2)2C6H3}Se]+[PF6]- [Se1—N1 = 2.180 Å; Se1—N2 = 2.154 Å] (Fujihara et al., 1995). This results in a distorted T-shaped (C,N,N')Se core [C1—Se1—N1 = 80.5 (1)°, C1—Se1—N2 = 81.2 (1)°], the distortion being mainly due to the constraints imposed by the two SeC3N five-membered chelate rings.
An unusual dimer association is formed between two cations, two bromine atoms and two water molecules (Fig. 2). The Br2 atom is involved in bridging two selenium atoms and the interatomic Se1—Br2 distances [3.662 (2) Å] are much longer than the sum of the corresponding covalent radii [Σrcov(Se,Br) ca. 2.31 Å], but shorter than the sum of the van der Waals radii [ΣrvdW(Se,Br) ca. 3.95 Å] (Emsley, 1994), consistent with an electrostatic anion-cation interaction. This interaction is directed trans to the selenium-carbon bond in the cation [C1—Se1—Br2 = 154.4 (1)°], thus resulting in a distorted square-planar environment around the chalcogen atom. The water molecules bridge the Br1 and Br2 anions through Br···H hydrogen bonding [Br1···H1 = 2.56 (6) Å, Br2···H2 = 2.63 (7) Å].