supplementary materials


wm2739 scheme

Acta Cryst. (2013). E69, m302    [ doi:10.1107/S1600536813011884 ]

2-Amino-5-bromopyridin-1-ium (2-amino-5-bromopyridine-[kappa]N1)trichloridozincate

Fitriani, K. Hansongnern, N. Leesakul, C. Pakawatchai and S. Saithong

Abstract top

The structure of the title salt, (C5H6BrN2)[ZnCl3(C5H5BrN2)], consists of discrete 2-amino-5-bromopyridin-1-ium cations and distorted tetrahedral (2-amino-5-bromopyridine)trichloridozincate anions. In the crystal, the complex anions and cations are linked via N-H...Cl hydrogen bonds into layers parallel to (101). Short Br...Cl contacts of 3.4239 (11) and 3.4503 (12) Å are observed, as well as [pi]-[pi] stacking interactions between the pyridine and pyridinium rings, with alternating centroid-to-centroid distances of 3.653 (2) and 3.845 (2) Å.

Comment top

In recent years, pyridine and its derivatives were found to be suitable ligands for transition metal coordination compounds involving FeII, NiII (Janiak et al., 1999); CuII, CoII (Hubrich et al., 2010) and ZnII (Wei et al., 2012). Several pyridine derivatives play important roles in biological activities (Jo et al., 2004) or have interesting electrochemical properties (Xiao et al., 2012).

In the present work, 2-amino-5-bromopyridine was reacted with ZnCl2 in acidic solution, forming the pyridinium cation, [C5H6BrN2]+, accompanied by the complex anion, [ZnCl3(C5H5BrN2]- (Fig. 1). In the anion, the ZnII atom is in a distorted tetrahedral coordination geometry, bonded to the N atom of the pyridine ring of neutral 2-amino-5-bromopyridine and to three Cl atoms. The amino group is not involved in metal coordination. The Zn1—N1 bond length is 2.052 (3) Å, and the three Zn—Cl bond lengths are Zn1—Cl1 = 2.2494 (11) Å; Zn1—Cl2 = 2.2691 (11) Å; Zn1—Cl3 = 2.2499 (11) Å. The angles around the ZnII atom range from 104.99 (9) to 114.22 (4)°, indicating a slight deviation from the the ideal tetrahedral angles.

Both intra- and inter-molecular N—H···Cl hydrogen-bonding interactions are observed (Fig. 2). The only intramolecular hydrogen bond is in the complex anion, namely between the N2 atom of the amino group and the Cl1 atom [N2—H2A···Cl1, N2···Cl1 = 3.315 (4) Å]. The N2 donor is also connected to the Cl2i atom (i: -x + 3/2, y + 1/2, -z + 1/2) of an adjacent anionic complex as an inter-molecular interaction [N2—H2B···Cl2i, N2···Cl2i = 3.288 (4) Å]. Other inter-molecular hydrogen bonds are found between the N-amino group of the cation and Cl atoms of different anionic complexes [N4—H4A···Cl3iii, N4···Cl3iii = 3.328 (4) Å; iii: -x + 1, -y, -z + 1; N4—H4B···Cl2iv, N4···Cl2iv = 3.295 (4) Å; iv: x - 1/2, -y + 1/2, z + 1/2]. In addition, inter-molecular hydrogen bonding of the type N—H···Cl is also found among the protonated N atom of the cation and other two Cl atoms of two nearby anionic complexes [N3—H3A···Cl1ii, N3···Cl1ii = 3.309 (4) Å; ii: x - 1, y, z; N3—H3A···Cl1iii, N3···Cl1iii = 3.297 (4) Å]. All these inter-molecular hydrogen-bonding interactions generate a layer-like arrangement parallel to (101).

A short halogen···halogen contact of the type Br···Cl is found between the Br1 atom of the 2-amino-5-bromopyridine ligand of the complex anion and the Cl2 atom of an adjacent complex anion [Br1···Cl2 = 3.4239 (11) Å]. Furthermore, the Br2 atom of the neighbouring 2-amino-5-bromopyridinium cation also has a short contact to this Cl2 atom with a Br2···Cl2 distance of 3.4503 (12) Å as depicted in Fig. 3.

The crystal packing is futher stabilized by ππ stacking interactions between the pyridine ring (Cg1) of the anionic complex and the pyridinium ring (Cg2) with alternating centroid···centroid distances of Cg2···Cg1 = 3.653 (2) Å and Cg1···Cg2 = 3.845 (2) Å (Fig. 4). These interactions generate ππ stacking chains parallel to [101]. All in all, the stability of the crystal packing is governed by various interactions, including N—H···Cl hydrogen bonds, Br···Cl short contacts and ππ stacking, respectively.

Related literature top

For background to the chemistry of substituted pyridines, see: Janiak et al. (1999); Hubrich et al. (2010); Wei et al. (2012). For the biological activities and electrochemical properties of pyridine derivatives, see: Jo et al. (2004); Xiao et al. (2012).

Experimental top

The title compound was synthesized by dissolving zinc chloride (480 mg, 3 mmol) in methanol (10 ml) which was added to a methanolic solution of 2-amino-5-bromopyridine (519 mg, 3 mmol). The reaction mixture was stirred in the presence of a few drops of concentrated hydrochloric acid. The final pH of the solution was adjusted to 3. After stirring for 5 h, the resulting solution was filtered off and the filtrate was left for slow evaporation of the solvent at ambient temperature. After several days, brown crystals suitable for X-ray diffraction analysis were collected by filtration, washed several times with methanol and dried in a desiccator over silica gel.

The analytical data of the zinc(II) complex are given as follows. [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]-. Yield 0.42 g, 27%. m.p. 461–463 K. Anal. Calcd. for [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]-: C 23.15, H 2.14, N 10.80%. Found: C 23.31, H 2.09, N 10.64%.

Refinement top

All carbon H-atoms of were placed in calculated positions (C—H = 0.93 Å) and were included in the refinement in the riding-model approximation, with Uiso(H) = 1.2Ueq(C). The H atoms of all N atoms were located in a difference map and were restrained to N—H = 0.88 (2) Å with Uiso(H) = 1.2Ueq(N).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular entities of cation and anion in the structure of [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]-, drawn with anisotropic displacement ellipsoids at the 30% probability level.
[Figure 2] Fig. 2. The inter- and intra-molecular hydrogen bonding interactions in [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]-, as viewed down the a axis.
[Figure 3] Fig. 3. The Br···Cl short contacts in [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]-, as viewed down the a axis [symmetry code: (vi) -x + 2, -y, -z].
[Figure 4] Fig. 4. The one-dimensional inter-molecular ππ stacking in [C5H6BrN2]+.[ZnCl3(C5H5BrN2)]- [symmetry codes: (iv) x - 1/2, -y + 1/2, z + 1/2; (v) x + 1/2, -y + 1/2, z + 1/2).
2-Amino-5-bromopyridin-1-ium (2-amino-5-bromopyridine-κN1)trichloridozincate top
Crystal data top
(C5H6BrN2)[ZnCl3(C5H5BrN2)]F(000) = 1000
Mr = 518.77Dx = 2.037 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4332 reflections
a = 9.4238 (4) Åθ = 2.2–24.1°
b = 13.6544 (6) ŵ = 6.64 mm1
c = 13.5679 (6) ÅT = 293 K
β = 104.349 (1)°Block, brown
V = 1691.40 (13) Å30.26 × 0.16 × 0.08 mm
Z = 4
Data collection top
Bruker APEX CCD area-detector
diffractometer
2979 independent reflections
Radiation source: fine-focus sealed tube2491 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
0.3° ω scansθmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
h = 1111
Tmin = 0.286, Tmax = 0.576k = 1616
18043 measured reflectionsl = 1616
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086H atoms treated by a mixture of independent and constrained refinement
S = 1.02 w = 1/[σ2(Fo2) + (0.0386P)2 + 2.1357P]
where P = (Fo2 + 2Fc2)/3
2979 reflections(Δ/σ)max < 0.001
196 parametersΔρmax = 1.23 e Å3
5 restraintsΔρmin = 0.40 e Å3
Crystal data top
(C5H6BrN2)[ZnCl3(C5H5BrN2)]V = 1691.40 (13) Å3
Mr = 518.77Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.4238 (4) ŵ = 6.64 mm1
b = 13.6544 (6) ÅT = 293 K
c = 13.5679 (6) Å0.26 × 0.16 × 0.08 mm
β = 104.349 (1)°
Data collection top
Bruker APEX CCD area-detector
diffractometer
2979 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
2491 reflections with I > 2σ(I)
Tmin = 0.286, Tmax = 0.576Rint = 0.034
18043 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.033H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.086Δρmax = 1.23 e Å3
S = 1.02Δρmin = 0.40 e Å3
2979 reflectionsAbsolute structure: ?
196 parametersFlack parameter: ?
5 restraintsRogers parameter: ?
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*/Ueq
Zn10.84827 (5)0.03227 (3)0.27004 (3)0.04549 (14)
N10.9443 (3)0.1421 (2)0.2061 (2)0.0424 (7)
N20.8519 (5)0.2686 (3)0.2841 (3)0.0656 (10)
H2A0.816 (5)0.226 (3)0.320 (3)0.079*
H2B0.843 (5)0.3311 (17)0.295 (4)0.079*
N30.1587 (4)0.1505 (2)0.4873 (3)0.0519 (8)
H3A0.104 (4)0.112 (3)0.513 (3)0.062*
N40.0611 (5)0.2750 (3)0.5635 (3)0.0642 (10)
H4A0.019 (5)0.234 (3)0.597 (3)0.077*
H4B0.056 (5)0.3368 (17)0.579 (4)0.077*
Cl10.81449 (12)0.07487 (8)0.42275 (8)0.0559 (3)
Cl20.63220 (11)0.00231 (7)0.15590 (7)0.0509 (2)
Cl31.00795 (13)0.09311 (7)0.29181 (8)0.0589 (3)
C10.9311 (4)0.2387 (3)0.2208 (3)0.0461 (9)
C21.0012 (5)0.3065 (3)0.1699 (3)0.0588 (11)
H20.99330.37330.18100.071*
C31.0794 (5)0.2747 (3)0.1055 (3)0.0614 (12)
H31.12520.31910.07160.074*
C41.0908 (4)0.1746 (3)0.0904 (3)0.0521 (10)
C51.0238 (4)0.1116 (3)0.1420 (3)0.0461 (9)
H51.03330.04460.13260.055*
C60.1411 (4)0.2466 (3)0.5014 (3)0.0469 (9)
C70.2104 (5)0.3113 (3)0.4476 (3)0.0538 (10)
H70.20050.37860.45470.065*
C80.2913 (4)0.2767 (3)0.3856 (3)0.0552 (10)
H80.33660.31990.35010.066*
C90.3068 (4)0.1754 (3)0.3750 (3)0.0528 (10)
C100.2379 (5)0.1142 (3)0.4251 (3)0.0536 (10)
H100.24470.04690.41710.064*
Br11.19546 (6)0.12257 (4)0.00001 (4)0.07623 (18)
Br20.42174 (6)0.12277 (5)0.29263 (4)0.07970 (19)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.0510 (3)0.0391 (2)0.0496 (3)0.00250 (19)0.0187 (2)0.00095 (19)
N10.0439 (17)0.0370 (16)0.0489 (18)0.0010 (13)0.0163 (14)0.0004 (13)
N20.086 (3)0.040 (2)0.079 (3)0.0100 (19)0.036 (2)0.0003 (19)
N30.056 (2)0.0417 (19)0.061 (2)0.0096 (15)0.0204 (17)0.0032 (16)
N40.076 (3)0.055 (2)0.070 (2)0.005 (2)0.033 (2)0.006 (2)
Cl10.0633 (6)0.0595 (6)0.0492 (6)0.0011 (5)0.0218 (5)0.0012 (5)
Cl20.0517 (6)0.0443 (5)0.0568 (6)0.0039 (4)0.0137 (5)0.0020 (4)
Cl30.0694 (7)0.0455 (5)0.0646 (6)0.0112 (5)0.0219 (5)0.0063 (5)
C10.047 (2)0.039 (2)0.049 (2)0.0024 (16)0.0062 (18)0.0020 (17)
C20.072 (3)0.042 (2)0.060 (3)0.008 (2)0.011 (2)0.0033 (19)
C30.070 (3)0.054 (3)0.058 (3)0.019 (2)0.012 (2)0.011 (2)
C40.048 (2)0.065 (3)0.044 (2)0.0064 (19)0.0119 (18)0.0017 (19)
C50.047 (2)0.043 (2)0.049 (2)0.0042 (17)0.0143 (18)0.0007 (17)
C60.043 (2)0.045 (2)0.050 (2)0.0043 (17)0.0064 (18)0.0033 (17)
C70.058 (3)0.040 (2)0.062 (3)0.0053 (18)0.010 (2)0.0050 (19)
C80.051 (2)0.061 (3)0.055 (2)0.008 (2)0.014 (2)0.008 (2)
C90.039 (2)0.068 (3)0.052 (2)0.0020 (19)0.0130 (18)0.001 (2)
C100.052 (2)0.052 (2)0.057 (2)0.0014 (19)0.015 (2)0.005 (2)
Br10.0751 (3)0.1016 (4)0.0625 (3)0.0195 (3)0.0369 (3)0.0081 (3)
Br20.0638 (3)0.1060 (4)0.0769 (4)0.0159 (3)0.0318 (3)0.0004 (3)
Geometric parameters (Å, º) top
Zn1—N12.052 (3)C2—C31.347 (6)
Zn1—Cl12.2494 (11)C2—H20.9300
Zn1—Cl32.2499 (11)C3—C41.390 (6)
Zn1—Cl22.2691 (11)C3—H30.9300
N1—C11.344 (5)C4—C51.359 (5)
N1—C51.347 (5)C4—Br11.892 (4)
N2—C11.334 (5)C5—H50.9300
N2—H2A0.874 (19)C6—C71.406 (6)
N2—H2B0.873 (19)C7—C81.354 (6)
N3—C61.342 (5)C7—H70.9300
N3—C101.351 (5)C8—C91.401 (6)
N3—H3A0.868 (19)C8—H80.9300
N4—C61.320 (6)C9—C101.342 (6)
N4—H4A0.881 (19)C9—Br21.882 (4)
N4—H4B0.874 (19)C10—H100.9300
C1—C21.413 (6)
N1—Zn1—Cl1112.23 (9)C2—C3—C4119.2 (4)
N1—Zn1—Cl3105.12 (9)C2—C3—H3120.4
Cl1—Zn1—Cl3108.58 (4)C4—C3—H3120.4
N1—Zn1—Cl2104.99 (9)C5—C4—C3118.9 (4)
Cl1—Zn1—Cl2111.55 (4)C5—C4—Br1118.6 (3)
Cl3—Zn1—Cl2114.22 (4)C3—C4—Br1122.5 (3)
C1—N1—C5119.1 (3)N1—C5—C4122.7 (4)
C1—N1—Zn1126.0 (3)N1—C5—H5118.7
C5—N1—Zn1114.9 (2)C4—C5—H5118.7
C1—N2—H2A121 (3)N4—C6—N3119.3 (4)
C1—N2—H2B120 (3)N4—C6—C7123.9 (4)
H2A—N2—H2B119 (5)N3—C6—C7116.8 (4)
C6—N3—C10123.7 (4)C8—C7—C6120.6 (4)
C6—N3—H3A116 (3)C8—C7—H7119.7
C10—N3—H3A120 (3)C6—C7—H7119.7
C6—N4—H4A123 (3)C7—C8—C9119.8 (4)
C6—N4—H4B121 (3)C7—C8—H8120.1
H4A—N4—H4B115 (5)C9—C8—H8120.1
N2—C1—N1118.9 (4)C10—C9—C8119.2 (4)
N2—C1—C2121.2 (4)C10—C9—Br2119.0 (3)
N1—C1—C2120.0 (4)C8—C9—Br2121.9 (3)
C3—C2—C1120.1 (4)C9—C10—N3119.9 (4)
C3—C2—H2119.9C9—C10—H10120.0
C1—C2—H2119.9N3—C10—H10120.0
Cl1—Zn1—N1—C129.5 (3)C1—N1—C5—C40.6 (6)
Cl3—Zn1—N1—C1147.3 (3)Zn1—N1—C5—C4177.7 (3)
Cl2—Zn1—N1—C191.9 (3)C3—C4—C5—N11.2 (6)
Cl1—Zn1—N1—C5152.4 (2)Br1—C4—C5—N1178.5 (3)
Cl3—Zn1—N1—C534.5 (3)C10—N3—C6—N4179.7 (4)
Cl2—Zn1—N1—C586.3 (3)C10—N3—C6—C70.0 (6)
C5—N1—C1—N2179.8 (4)N4—C6—C7—C8179.7 (4)
Zn1—N1—C1—N21.7 (5)N3—C6—C7—C80.5 (6)
C5—N1—C1—C20.5 (5)C6—C7—C8—C90.2 (6)
Zn1—N1—C1—C2178.6 (3)C7—C8—C9—C101.5 (6)
N2—C1—C2—C3179.3 (4)C7—C8—C9—Br2178.4 (3)
N1—C1—C2—C31.0 (6)C8—C9—C10—N32.0 (6)
C1—C2—C3—C40.4 (7)Br2—C9—C10—N3177.8 (3)
C2—C3—C4—C50.7 (6)C6—N3—C10—C91.3 (6)
C2—C3—C4—Br1179.0 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···Cl10.87 (2)2.50 (3)3.315 (4)156 (4)
N2—H2B···Cl2i0.87 (2)2.43 (2)3.288 (4)169 (5)
N3—H3A···Cl1ii0.87 (2)2.75 (4)3.309 (4)124 (3)
N3—H3A···Cl1iii0.87 (2)2.74 (4)3.297 (4)123 (4)
N4—H4A···Cl3iii0.88 (2)2.49 (3)3.328 (4)159 (4)
N4—H4B···Cl2iv0.87 (2)2.46 (3)3.295 (4)160 (4)
Symmetry codes: (i) x+3/2, y+1/2, z+1/2; (ii) x1, y, z; (iii) x+1, y, z+1; (iv) x1/2, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···Cl10.874 (19)2.50 (3)3.315 (4)156 (4)
N2—H2B···Cl2i0.873 (19)2.43 (2)3.288 (4)169 (5)
N3—H3A···Cl1ii0.868 (19)2.75 (4)3.309 (4)124 (3)
N3—H3A···Cl1iii0.868 (19)2.74 (4)3.297 (4)123 (4)
N4—H4A···Cl3iii0.881 (19)2.49 (3)3.328 (4)159 (4)
N4—H4B···Cl2iv0.874 (19)2.46 (3)3.295 (4)160 (4)
Symmetry codes: (i) x+3/2, y+1/2, z+1/2; (ii) x1, y, z; (iii) x+1, y, z+1; (iv) x1/2, y+1/2, z+1/2.
Acknowledgements top

The authors express their gratitute to the Center for Innovation in Chemistry (PERCH–CIC) and the Graduate School, Prince of Songkla University, Thailand, for financial support. One of the authors (Fitriani) is grateful to the Directorate General of Higher Education (DGHE) of Indonesia and Brawijaya University, Indonesia, for financial assistance and a DGHE postgraduate scholarship.

references
References top

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