Salts of 2-amino-5-iodo­pyridinium

Compound 1 is the anhydrous form of the known crystal 2-amino-5-iodo­pyridinium bromide monohydrate and crystallizes in layers inclined ∼40° to the ab face. Hydrogen bonding between the amino and pyridinium ions to the bromide ion acceptor stabilizes the layers. Compound 2 is a salt of 2-amino-5-iodo­pyridium and a trihalidocobaltate(II) ion with one coordinated 2-amino-5-iodo­pyridine ligand. The halide ions are mixed Cl/Br with differing occupancies.

Abstract

Reaction of 2-amino-5-iodo­pyridine (5IAP) with concentrated HBr at room temperature yielded 2-amino-5-iodo­pyridinium bromide, C₅H₆IN₂⁺·Br⁻ or (5IAPH)Br. The complex formed pale-yellow crystals, which exhibit significant hydrogen bonding between the amino and pyridinium N—H donors and bromide ion acceptors. Halogen bonding is also observed. Similarly, reaction of 5IAP with cobalt(II) chloride in mixed HCl/HBr in 1-propanol yielded 2-amino-5-iodo­pyridinium (2-amino-5-iodo­pyridine-κN¹)bromido/chlorido­(0.51/2.48)cobalt(II), (C₅H₆IN₂)[CoBr_0.51Cl_2.48(C₅H₅IN₂)] or (5-IAPH)[(5IAP)CoCl_2.48Br_0.51], as blue block-shaped crystals. Two of the three halide positions exhibit mixed occupancy [Cl/Br = 0.797 (5):0.203 (5) and 0.689 (6):0.311 (6)], while the third position is occupied solely by a chloride ion. Extensive hydrogen and halogen bonding is observed.

1. Chemical context

The effects of randomness have been of particular inter­est in physics and chemistry. In particular, they have been considered regarding quantum information (Khrennikov, 2016 ▸), band theory (Coey et al., 2005 ▸) and perturbation of the crystal lattice (Mackenzie, 1964 ▸; Anderson, 1958 ▸). With respect to magnetism, studies have looked at the relationship between randomness and spin glasses (Toulouse, 1986 ▸), amorphous magnets (Coey, 1978 ▸) and valence-bond solids (Kimchi et al., 2018 ▸).

Superexchange in magnetic systems can be studied through the production of families of closely related compounds where small changes in the structure can be correlated with their effects on the magnetic properties of the materials. We have looked at the production of such complexes, especially those based upon salts of subsituted 2-amino­pyridine for some time (Araujo-Martinez et al., 2023 ▸; Coffey et al., 2000 ▸; Landee et al., 2001 ▸; Woodward et al., 2002 ▸). One such compound, 2-amino-5-iodo­pyridine, has been involved in the production of a magnetic ladder (Landee et al., 2001 ▸) and a family of Cu^II halides complexes (Huynh et al., 2023 ▸).

One difficulty in the studies of randomness in such materials is the introduction of randomness into an otherwise ordered system. Crystallization is intrinsically a self-purifying process and attempts to introduce randomness through introduction of dopants into a system may be frustrated by exclusion of the ‘impurity’ during crystallization (Fujiwara et al. 1995 ▸). We have recently discovered a system, based upon 2-amino-5-iodo­pyridine (5IAP), where randomness can be introduced to the system via introduction of a mixture of halide ions; (5IAPH)₂[CoCl_4–xBr_x]·H₂O (Mukda et al., 2024 ▸) where 5IAPH is 2-amino-5-iodo­pyridinium. In the course of those investigations, we isolated the related compound (5IAPH)[(5IAP)CoCl_3–xBr_x] and here report its structure and the structure of the related salt (5IAPH)Br.

2. Structural commentary

(5IAPH)Br (1) crystallized in the triclinic space group P and comprises one 5IAPH cation and one bromide anion in the asymmetric unit (Fig. 1 ▸). The 5IAPH ring is planar (mean deviation of constituent atoms = 0.012 Å) with the amino substituent lying 0.070 (1) Å out of that plane. The iodine atom is displaced significantly further out of the plane, 0.199 (1) Å, toward the same face. The amino substituent deviates only slightly from sp²-hybridization [sum of ∠s = 360 (2)°]. The plane of the NH₂ group is nearly co-planar with the 5IAPH ring [6.8 (15)°] as expected due to conjugation.

Figure 1.

The asymmetric unit of 1 shown as 50% probability ellipsoids (hydrogen atoms are shown as spheres of arbitrary size). Only those hydrogen atoms whose positions were refined are labeled.

(5IAPH)[(5IAP)CoCl_3–xBr_x] (2) crystallized in the monoclinic space group P2₁/n. The asymmetric unit is shown in Fig. 2 ▸ and comprises one 5IAPH cation and one [(5IAP)CoCl_3–xBr_x] anion. The 5IAPH cation is nearly identical to that observed in 1, with a high degree of planarity in the ring (±0.007 Å), the sum of the angles about the amino nitro­gen atom being 359 (2)° and the amino group being nearly co-planar with the 5IAPH ring [deviation = 8.9 (16)°]. As with 1, the amino nitro­gen atom [0.013 (5) Å] and iodine atom [0.086 (1) Å] are displaced slightly from the plane of the ring, again both toward the same face. The anionic unit comprises one Co^II ion with a 5IAP ring coordinated through the pyridine nitro­gen atom and three coordinated halide ions. The halide ions are mixed Cl/Br with refined occupancies of Cl1/Br1 [0.797 (5)/0.203 (5)] and Cl3/Br3 [0.689 (6)/0.311 (6)]. Attempts to refine the position of Cl2 as mixed Cl/Br resulted in an occupancy of Cl2 of 1.0 within error; no bromide ion was included in that position in the final refinement. The Co—X bond lengths are all similar (∼2.3 Å) regardless of halide ion (Table 1 ▸). The Co^II ion is only slightly distorted from tetra­hedral with bond angles ranging from 105.1 (3) to 116.9 (3)°. The 5IAP ring is comparable to the 5IAPH ring in terms of planarity (mean deviation = 0.006 Å) and displacement of N12 and I15 [0.09 (1) Å and 0.077 (1) Å, respectively]. The amino group is again planar, but inclined 17 (2)° relative to the 5IAP plane, likely to accommodate the intra­molecular N12—H12A⋯Cl2 hydrogen bond [D⋯A = 3.282 (6) Å; Table 3].

Figure 2.

The asymmetric unit of 2 shown as 50% probability ellipsoids (hydrogen atoms are shown as spheres of arbitrary size). Only those hydrogen atoms whose positions were refined are labeled.

Table 1. Selected geometric parameters (Å, °) for 2.

Co1—N11	2.034 (4)	Co1—Br1	2.328 (11)
Co1—Cl2	2.2648 (15)	Co1—Cl1	2.329 (6)
Co1—Cl3	2.306 (11)	Co1—Br3	2.342 (8)
N11—Co1—Cl2	111.63 (13)	N11—Co1—Cl1	105.87 (18)
N11—Co1—Cl3	105.1 (3)	Cl2—Co1—Cl1	109.17 (16)
Cl2—Co1—Cl3	108.0 (2)	Cl3—Co1—Cl1	116.9 (3)

3. Supra­molecular features

Compound 1. Extensive hydrogen (Table 2 ▸) and halogen bonding with the bromide ion as acceptor are present in the structure (Fig. 3 ▸). The hydrogen bonds are typical with D⋯A distances ranging from 3.2136 (12) to 3.4924 (13) Å and D—H⋯A angles of 150.8 (18) to 165.5 (18)°. Each bromide ion serves as an acceptor of three hydrogen bonds from the pyridinium N—H and both protons on the amino group. The latter generates inversion-related pairs of 5IAPH ions bridged by the bromide ions (Fig. 3 ▸). A Type II halogen bond is also present with parameters d_I15C⋯Br1 = 3.88 (1) Å and ∠_{C15—I15C⋯Br1} = 154.6 (4)°. Further halogen bonding is observed in the packing structure (Fig. 4 ▸). Sheets of 5IAPH and bromide ions are linked parallel to the a axis by Type I halogen bonds between inversion-related iodine atoms; d_I15⋯I15A = 3.81 (1) Å and ∠_{C15—I15⋯I15A} = 130.6 (3)° [symmetry code: (A) 1 − x, 1 − y, 1 − z].

Table 2. Hydrogen-bond geometry (Å, °) for 1.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11⋯Br1	0.80 (2)	2.49 (2)	3.2136 (12)	150.8 (18)
N12—H12A⋯Br1i	0.86 (2)	2.55 (2)	3.3556 (12)	155.5 (17)
N12—H12B⋯Br1ii	0.85 (2)	2.67 (2)	3.4924 (13)	165.5 (18)

Symmetry codes: (i) ; (ii) .

Figure 3.

Halogen and hydrogen bonding in 1 (atoms are shown as spheres of arbitrary size). Dashed lines represent hydrogen and halogen bonds. Only those atoms involved in halogen or hydrogen bonding are labeled. Symmetry codes: Br1A = −x, 1 − y, −z; Br1B = x, y + 1 z; N12B = −x, 2 − y, −z; I15C = 1 − x, y, z − 1.

Figure 4.

The structure of 1 viewed parallel to the b axis (atoms are shown as spheres of arbitrary size). Dashed lines represent hydrogen and halogen bonds.

Compound 2. As with 1, 2 exhibits multiple hydrogen (Table 3 ▸) and halogen bonds (Fig. 5 ▸). The hydrogen bonds are typical with d_D⋯A = 3.282 (6)–3.341 (10) Å and ∠_D—H⋯A = 151 (5)–176 (5)°. Type II halogen bonds are also observed between both the 5IAP ligand [d_I15⋯Cl1 = 3.464 (3) Å, ∠_{C15—I15⋯Cl1} = 171.8 (3)°] and the 5IAPH cation [d_I25⋯Cl1 = 3.511 (3) Å, ∠_{C15—I15⋯Cl1} = 175.5 (4)°. Unlike 1, no I⋯I halogen bonds are observed. Similar to 1, the structure forms layers of hydrogen and halogen bridged ions parallel to the ac face diagonal (Fig. 6 ▸). Unlike 1, there are no direct linkages between those layers.

Table 3. Hydrogen-bond geometry (Å, °) for 2.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N12—H12A⋯Cl2	0.85 (6)	2.47 (7)	3.282 (6)	160 (5)
N12—H12B⋯Br1i	0.86 (7)	2.44 (7)	3.291 (12)	170 (6)
N22—H22A⋯Br1ii	0.87 (7)	2.55 (7)	3.338 (12)	151 (5)
N22—H22B⋯Br3iii	0.97 (6)	2.37 (7)	3.341 (10)	176 (5)

Symmetry codes: (i) ; (ii) ; (iii) .

Figure 5.

Halogen and hydrogen bonding in 2 (atoms are shown as spheres of arbitrary size). Dashed lines represent hydrogen and halogen bonds. Only those atoms involved in halogen or hydrogen bonding are labeled. Symmetry codes: N12A =  − x, y + , −z − 0.5; N21E/N22E = 1 − x, 2 − y, −1 − z; N22C = x − ,  − y, z + 0.5; I15B = −x, 2 − y, −z.

Figure 6.

The structure of 2 viewed parallel to the b axis (atoms are shown as spheres of arbitrary size). Dashed lines represent hydrogen and halogen bonds.

4. Database survey

The structures of a few salts of 5-IAPH have been reported. Copper(II) complexes include (5IAPH)[CuCl₃(H₂O)₂]Cl (Abdalrahman et al., 2013 ▸), two polymorphs of (5IAPH)₂[CuCl₄] (Giantsidis et al., 2002 ▸) and (5IAPH)₂[CuBr₄]H₂O (Landee et al., 2001 ▸). Several Hg and Zn salts of 5IAPH have also been reported (Khavasi et al., 2020 ▸), along with an Mn^II salt (Carnevale et al., 2021 ▸). Copper complexes of 5IAP itself are also known including [(5IAP)₂CuX₂], X = Cl, Br, [(5IAP)₂CuBr₂]₂, [(5IAP)₃CuCl₂], (Huynh et al., 2023 ▸) and [(5IAP)₂CuBr(OMe)]₂ (Araujo-Martinez et al., 2023 ▸).

Compound 1 may be most conveniently compared to its corresponding hydrate and chloride analogue (Polson et al., 2013 ▸). The C—N bond lengths in 1 are slightly shorter than observed in the hydrated salt (∼0.01–0.12 Å) and chloride analogue. Bond angles in 1 vary ±2° compared to the hydrated bromide salt, but not in any regular fashion, while they are comparable to those observed in the chloride complex within error.

With respect to compound 2, although there no related compounds of 5-IAP, there are a number of reported structures including the [LMX₃]⁻ ion where L is a pyridine-based ligand. Several of these involve Pt^II (Adams et al., 2005 ▸; Bel’skii et al., 1990 ▸; Rochon & Melanson, 1980 ▸; Melanson & Rochon, 1976 ▸) or Co^II (Bogdanovic et al., 2001 ▸; Crane et al., 2004 ▸). The closest comparisons appear to be compounds of Cu^II (Healy et al., 1985 ▸; Savariault et al., 1988 ▸) or Co^II (Hahn et al., 1997 ▸) with the formulae (LH)[LMX₃] (L = phenazine or quinoline for Cu, pyridine for Co). Similar hydrogen bonding is observed in all three compounds, but the absence of the iodine atom on the L group eliminates the halogen bonding observed in both 1 and 2. Only in the quinolinium tri­chlorido­cuprate compound (Savariault et al., 1988 ▸) are all of the aromatic rings approximately parallel, but even so the overall structure is that of dimers, rather than the extended sheet structure seen in 1 and 2. With respect to the geometry at the metal ion, only the cobalt complex is similar with its slightly distorted tetra­hedral geometry (as compared to the two strongly Jahn–Teller-distorted Cu complexes) and slightly shorter Co—Cl bond lengths (average = 2.24 Å).

5. Synthesis and crystallization

Compound 1: 2-Amino-5-iodo­pyridine (0.842g, 3.83 mmol) was dissolved in 10 mL of 9 M HBr and left to evaporate. After about one month, crystals of 1 were isolated by filtration (0.623g, 56%).

Compound 2: HCl (0.0415 g, 12 M) and HBr (0.242 g. 9 M) were added to 2-amino-5-iodo­pyridine (0.439 g) creating a yellow solid. The solid was dissolved in 15 ml of 1-propanol and then cobalt(II) chloride hexa­hydrate (0.245 g) was added creating a dark-blue solution. After ten days, blue crystals were recovered by filtration. The crystals were predominantly lighter blue plates of (5IAPH)₂[CoCl_4–xBr_x]·H₂O (Mukda et al., 2024 ▸), with a few dark-blue rhombic prisms mixed in. The dark-blue prisms were separated by hand and identified as compound 2 by X-ray diffraction.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4 ▸. All non-hydrogen atoms were refined anisotropically. Hydrogen atoms bonded to carbon atoms were placed geometrically and refined with a riding model and U_iso(H) = 1.2U_eq(C). Hydrogen atoms bonded to nitro­gen atoms were located in a Fourier map and their positions refined with U_iso(H) = 1.2U_eq(N). Occupancies of the mixed halogen sites (X1 and X3) in 2 were allowed to refine freely. Mixed occupancy at the X2 site in 2 was initially assumed, but the bromide occupancy refined to zero within experimental error and the potential bromide ion was removed in the final refinement. Pseudo-isotropic restraints (ISOR) were applied to the lower occupancy ion, Br1.

Table 4. Experimental details.

	1	2
Crystal data
Chemical formula	C5H6IN2+·Br−	(C5H6IN2)[CoBr0.51Cl2.48(C5H5IN2)]
M r	300.93	629.20
Crystal system, space group	Triclinic, P	Monoclinic, P21/n
Temperature (K)	100	100
a, b, c (Å)	5.2152 (2), 7.8039 (3), 10.1294 (4)	9.6998 (7), 13.5527 (8), 13.8518 (11)
α, β, γ (°)	93.3762 (12), 104.1108 (11), 96.4297 (12)	90, 107.336 (3), 90
V (Å3)	395.71 (3)	1738.2 (2)
Z	2	4
Radiation type	Mo Kα	Mo Kα
μ (mm−1)	9.01	6.10
Crystal size (mm)	0.24 × 0.21 × 0.08	0.11 × 0.07 × 0.06
Data collection
Diffractometer	Bruker D8 Venture dual wavelength Mo/Cu	Bruker D8 Venture dual wavelength Mo/Cu
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 ▸)	Multi-scan (SADABS; Krause et al., 2015 ▸)
Tmin, Tmax	0.605, 0.746	0.413, 0.492
No. of measured, independent and observed [I > 2σ(I)] reflections	13418, 2412, 2346	15915, 4318, 3139
R int	0.025	0.048
(sin θ/λ)max (Å−1)	0.714	0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S	0.012, 0.029, 1.11	0.040, 0.090, 1.09
No. of reflections	2412	4318
No. of parameters	91	216
No. of restraints	0	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.48, −0.50	1.22, −0.78

Computer programs: APEX4 and SAINT (Bruker, 2022 ▸), SHELXS2014 (Sheldrick 2008 ▸) and SHELXL2019/2 (Sheldrick, 2015 ▸).

Supplementary Material

CCDC references: 2392716, 2392715

Additional supporting information: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

2-Amino-5-iodopyridinium bromide (1). Crystal data

C5H6IN2+·Br−	Z = 2
Mr = 300.93	F(000) = 276
Triclinic, P1	Dx = 2.526 Mg m−3
a = 5.2152 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.8039 (3) Å	Cell parameters from 9950 reflections
c = 10.1294 (4) Å	θ = 2.6–30.5°
α = 93.3762 (12)°	µ = 9.01 mm−1
β = 104.1108 (11)°	T = 100 K
γ = 96.4297 (12)°	Block, yellow
V = 395.71 (3) Å3	0.24 × 0.21 × 0.08 mm

2-Amino-5-iodopyridinium bromide (1). Data collection

Bruker D8 VENTURE dual wavelength Mo/Cu diffractometer	2412 independent reflections
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs 3.0	2346 reflections with I > 2σ(I)
HELIOS double bounce multilayer mirror monochromator	Rint = 0.025
φ and ω scans	θmax = 30.5°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −7→7
Tmin = 0.605, Tmax = 0.746	k = −11→11
13418 measured reflections	l = −14→13

2-Amino-5-iodopyridinium bromide (1). Refinement

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)] = 0.012	Hydrogen site location: mixed
wR(F2) = 0.029	H atoms treated by a mixture of independent and constrained refinement
S = 1.11	w = 1/[σ2(Fo2) + 0.2575P] where P = (Fo2 + 2Fc2)/3
2412 reflections	(Δ/σ)max = 0.002
91 parameters	Δρmax = 0.48 e Å−3
0 restraints	Δρmin = −0.50 e Å−3

2-Amino-5-iodopyridinium bromide (1). Special details

Experimental. Data collections for compounds 1 and 2 were carried out with a Bruker D8 Venture Photon III diffractometer employing Mo-Kα radiation (λ = 0.71073Å). The data were collected using Bruker Instrument Service v8.5.0.27 & APEX4 v2022.10-1 and reduced using Bruker SAINT v8.40b (Bruker, 2022). Absorption corrections were performed using SADABS (Krause, 2015). The structure was solved using SHELXS-2014 (Sheldrick, 2008) and refined using SHELXL-2019 (Sheldrick, 2015).

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.

2-Amino-5-iodopyridinium bromide (1). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N11	0.5947 (2)	0.68193 (15)	0.18178 (12)	0.0141 (2)
H11	0.482 (4)	0.603 (3)	0.145 (2)	0.017*
C12	0.5464 (3)	0.84605 (17)	0.16387 (13)	0.0128 (2)
N12	0.3196 (2)	0.87844 (17)	0.08228 (13)	0.0164 (2)
H12A	0.197 (4)	0.801 (3)	0.034 (2)	0.020*
H12B	0.292 (4)	0.983 (3)	0.081 (2)	0.020*
C13	0.7459 (3)	0.98060 (17)	0.23485 (14)	0.0141 (2)
H13	0.722951	1.097926	0.221414	0.017*
C14	0.9711 (3)	0.94205 (17)	0.32251 (14)	0.0146 (2)
H14	1.103592	1.032609	0.371018	0.017*
I15	1.33221 (2)	0.70519 (2)	0.48691 (2)	0.01678 (3)
C15	1.0075 (3)	0.76766 (17)	0.34127 (13)	0.0140 (2)
C16	0.8176 (3)	0.64035 (18)	0.26754 (14)	0.0149 (2)
H16	0.841544	0.522265	0.276282	0.018*
Br1	0.23627 (3)	0.31109 (2)	0.14445 (2)	0.01608 (4)

2-Amino-5-iodopyridinium bromide (1). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
N11	0.0168 (5)	0.0103 (5)	0.0141 (5)	−0.0016 (4)	0.0035 (4)	−0.0002 (4)
C12	0.0149 (6)	0.0121 (5)	0.0118 (5)	0.0003 (4)	0.0051 (4)	0.0005 (4)
N12	0.0150 (5)	0.0149 (5)	0.0171 (5)	0.0000 (4)	0.0008 (4)	0.0008 (4)
C13	0.0167 (6)	0.0106 (5)	0.0145 (6)	0.0010 (4)	0.0029 (5)	0.0020 (4)
C14	0.0149 (6)	0.0127 (6)	0.0147 (6)	−0.0005 (4)	0.0023 (5)	0.0007 (5)
I15	0.01575 (5)	0.01769 (5)	0.01789 (5)	0.00603 (3)	0.00364 (3)	0.00494 (3)
C15	0.0154 (6)	0.0144 (6)	0.0136 (6)	0.0035 (5)	0.0053 (5)	0.0033 (5)
C16	0.0193 (6)	0.0125 (6)	0.0145 (6)	0.0029 (5)	0.0063 (5)	0.0029 (5)
Br1	0.01538 (6)	0.01065 (6)	0.01964 (7)	−0.00109 (4)	0.00095 (5)	0.00055 (5)

2-Amino-5-iodopyridinium bromide (1). Geometric parameters (Å, º)

N11—C12	1.3469 (17)	C13—C14	1.3638 (19)
N11—C16	1.3553 (18)	C13—H13	0.9500
N11—H11	0.80 (2)	C14—C15	1.4125 (18)
C12—N12	1.3271 (18)	C14—H14	0.9500
C12—C13	1.4155 (18)	I15—C15	2.0815 (14)
N12—H12A	0.86 (2)	C15—C16	1.3628 (19)
N12—H12B	0.85 (2)	C16—H16	0.9500
C12—N11—C16	123.45 (12)	C12—C13—H13	120.0
C12—N11—H11	119.3 (14)	C13—C14—C15	120.09 (12)
C16—N11—H11	117.1 (14)	C13—C14—H14	120.0
N12—C12—N11	120.62 (13)	C15—C14—H14	120.0
N12—C12—C13	121.90 (12)	C16—C15—C14	118.68 (13)
N11—C12—C13	117.49 (12)	C16—C15—I15	120.29 (10)
C12—N12—H12A	124.8 (13)	C14—C15—I15	120.93 (10)
C12—N12—H12B	116.8 (14)	N11—C16—C15	120.10 (12)
H12A—N12—H12B	118.3 (19)	N11—C16—H16	119.9
C14—C13—C12	120.10 (12)	C15—C16—H16	119.9
C14—C13—H13	120.0
C16—N11—C12—N12	−177.42 (13)	C13—C14—C15—C16	1.8 (2)
C16—N11—C12—C13	2.67 (19)	C13—C14—C15—I15	−174.50 (10)
N12—C12—C13—C14	177.04 (13)	C12—N11—C16—C15	0.0 (2)
N11—C12—C13—C14	−3.05 (19)	C14—C15—C16—N11	−2.25 (19)
C12—C13—C14—C15	0.9 (2)	I15—C15—C16—N11	174.05 (10)

2-Amino-5-iodopyridinium bromide (1). Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N11—H11···Br1	0.80 (2)	2.49 (2)	3.2136 (12)	150.8 (18)
N12—H12A···Br1i	0.86 (2)	2.55 (2)	3.3556 (12)	155.5 (17)
N12—H12B···Br1ii	0.85 (2)	2.67 (2)	3.4924 (13)	165.5 (18)

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

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Crystal data

(C5H6IN2)[CoBr0.51Cl2.48(C5H5IN2)]	F(000) = 1169
Mr = 629.20	Dx = 2.404 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.6998 (7) Å	Cell parameters from 5517 reflections
b = 13.5527 (8) Å	θ = 2.7–28.3°
c = 13.8518 (11) Å	µ = 6.10 mm−1
β = 107.336 (3)°	T = 100 K
V = 1738.2 (2) Å3	Block, blue
Z = 4	0.11 × 0.07 × 0.06 mm

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Data collection

Bruker D8 VENTURE dual wavelength Mo/Cu diffractometer	4318 independent reflections
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs 3.0	3139 reflections with I > 2σ(I)
HELIOS double bounce multilayer mirror monochromator	Rint = 0.048
φ and ω scans	θmax = 28.3°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −12→10
Tmin = 0.413, Tmax = 0.492	k = −18→16
15915 measured reflections	l = −14→18

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Refinement

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)] = 0.040	Hydrogen site location: mixed
wR(F2) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ2(Fo2) + (0.0334P)2 + 3.1822P] where P = (Fo2 + 2Fc2)/3
4318 reflections	(Δ/σ)max = 0.001
216 parameters	Δρmax = 1.22 e Å−3
6 restraints	Δρmin = −0.77 e Å−3

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Special details

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.

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Co1	0.13812 (7)	0.97174 (5)	−0.26955 (6)	0.01941 (17)
Br1	0.3650 (11)	1.0006 (8)	−0.1556 (9)	0.034 (4)	0.203 (5)
Cl1	0.3649 (7)	0.9995 (3)	−0.1548 (5)	0.0174 (19)	0.797 (5)
Cl2	0.16479 (13)	0.92952 (9)	−0.42118 (10)	0.0202 (3)
Br3	−0.0247 (7)	1.1037 (7)	−0.2947 (4)	0.0155 (17)	0.311 (6)
Cl3	−0.0261 (11)	1.0994 (9)	−0.2955 (7)	0.039 (4)	0.689 (6)
N11	0.0486 (4)	0.8604 (3)	−0.2101 (3)	0.0177 (9)
N12	0.1448 (5)	0.7359 (4)	−0.2837 (4)	0.0255 (11)
H12A	0.170 (6)	0.779 (5)	−0.319 (5)	0.031*
H12B	0.146 (7)	0.677 (5)	−0.305 (5)	0.031*
C12	0.0668 (5)	0.7640 (4)	−0.2239 (4)	0.0205 (11)
C13	0.0025 (6)	0.6924 (4)	−0.1763 (4)	0.0250 (13)
H13	0.012753	0.624131	−0.188153	0.030*
C14	−0.0742 (5)	0.7219 (4)	−0.1134 (4)	0.0245 (12)
H14	−0.116299	0.674373	−0.080308	0.029*
I15	−0.19969 (4)	0.87761 (3)	−0.00022 (3)	0.02480 (11)
C15	−0.0903 (5)	0.8235 (4)	−0.0978 (4)	0.0221 (12)
C16	−0.0286 (5)	0.8888 (4)	−0.1475 (4)	0.0218 (12)
H16	−0.040037	0.957340	−0.137836	0.026*
N21	0.8337 (5)	0.8524 (3)	−0.4898 (4)	0.0220 (10)
H21	0.882 (6)	0.896 (4)	−0.522 (4)	0.026*
C22	0.8517 (5)	0.7548 (4)	−0.5034 (4)	0.0206 (11)
N22	0.9307 (5)	0.7271 (4)	−0.5612 (4)	0.0280 (11)
H22A	0.946 (7)	0.665 (5)	−0.571 (5)	0.034*
H22B	0.962 (6)	0.775 (5)	−0.602 (5)	0.034*
C23	0.7858 (5)	0.6896 (4)	−0.4513 (4)	0.0223 (12)
H23	0.796975	0.620461	−0.457159	0.027*
C24	0.7061 (5)	0.7247 (4)	−0.3925 (4)	0.0215 (12)
H24	0.662676	0.680358	−0.357108	0.026*
C25	0.6888 (5)	0.8281 (4)	−0.3847 (4)	0.0220 (12)
I25	0.56035 (4)	0.88657 (3)	−0.30094 (3)	0.02550 (11)
C26	0.7535 (5)	0.8891 (4)	−0.4331 (4)	0.0202 (11)
H26	0.743268	0.958429	−0.427857	0.024*

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Co1	0.0173 (3)	0.0176 (4)	0.0231 (4)	−0.0007 (3)	0.0057 (3)	0.0006 (3)
Br1	0.011 (5)	0.054 (6)	0.042 (8)	0.000 (4)	0.014 (4)	0.006 (5)
Cl1	0.026 (4)	0.0045 (18)	0.021 (3)	0.0005 (17)	0.006 (2)	−0.0007 (17)
Cl2	0.0173 (5)	0.0213 (7)	0.0214 (7)	0.0003 (5)	0.0050 (5)	0.0009 (5)
Br3	0.017 (3)	0.020 (3)	0.009 (2)	0.004 (2)	0.0037 (19)	0.002 (2)
Cl3	0.047 (6)	0.019 (4)	0.053 (6)	0.000 (3)	0.018 (4)	−0.001 (3)
N11	0.0156 (19)	0.015 (2)	0.021 (2)	−0.0005 (17)	0.0038 (17)	0.0003 (18)
N12	0.035 (3)	0.019 (3)	0.023 (3)	0.002 (2)	0.010 (2)	−0.002 (2)
C12	0.016 (2)	0.018 (3)	0.024 (3)	0.002 (2)	0.002 (2)	−0.005 (2)
C13	0.023 (3)	0.021 (3)	0.025 (3)	−0.001 (2)	−0.001 (2)	−0.003 (2)
C14	0.018 (2)	0.026 (3)	0.024 (3)	−0.008 (2)	−0.001 (2)	0.005 (2)
I15	0.02164 (18)	0.0306 (2)	0.0235 (2)	−0.00515 (15)	0.00868 (14)	−0.00071 (16)
C15	0.015 (2)	0.024 (3)	0.025 (3)	−0.003 (2)	0.002 (2)	−0.003 (2)
C16	0.019 (2)	0.020 (3)	0.024 (3)	−0.001 (2)	0.002 (2)	−0.002 (2)
N21	0.021 (2)	0.020 (2)	0.025 (3)	−0.0046 (19)	0.0050 (19)	−0.0008 (19)
C22	0.015 (2)	0.021 (3)	0.024 (3)	0.000 (2)	0.002 (2)	−0.003 (2)
N22	0.025 (2)	0.023 (3)	0.038 (3)	0.000 (2)	0.014 (2)	−0.003 (2)
C23	0.020 (2)	0.017 (3)	0.028 (3)	−0.003 (2)	0.003 (2)	0.001 (2)
C24	0.016 (2)	0.021 (3)	0.025 (3)	−0.004 (2)	0.003 (2)	0.003 (2)
C25	0.013 (2)	0.030 (3)	0.018 (3)	−0.001 (2)	−0.002 (2)	−0.004 (2)
I25	0.01950 (17)	0.0274 (2)	0.0308 (2)	0.00454 (15)	0.00938 (15)	0.00033 (16)
C26	0.018 (2)	0.017 (3)	0.025 (3)	0.003 (2)	0.005 (2)	−0.004 (2)

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Geometric parameters (Å, º)

Co1—N11	2.034 (4)	C15—C16	1.364 (8)
Co1—Cl2	2.2648 (15)	C16—H16	0.9500
Co1—Cl3	2.306 (11)	N21—C26	1.354 (7)
Co1—Br1	2.328 (11)	N21—C22	1.354 (7)
Co1—Cl1	2.329 (6)	N21—H21	0.95 (6)
Co1—Br3	2.342 (8)	C22—N22	1.318 (7)
N11—C12	1.339 (6)	C22—C23	1.409 (8)
N11—C16	1.359 (7)	N22—H22A	0.87 (7)
N12—C12	1.333 (7)	N22—H22B	0.97 (6)
N12—H12A	0.85 (6)	C23—C24	1.364 (8)
N12—H12B	0.86 (7)	C23—H23	0.9500
C12—C13	1.418 (8)	C24—C25	1.420 (8)
C13—C14	1.363 (8)	C24—H24	0.9500
C13—H13	0.9500	C25—C26	1.333 (8)
C14—C15	1.410 (8)	C25—I25	2.095 (6)
C14—H14	0.9500	C26—H26	0.9500
I15—C15	2.084 (6)
N11—Co1—Cl2	111.63 (13)	C16—C15—I15	118.9 (4)
N11—Co1—Cl3	105.1 (3)	C14—C15—I15	123.0 (4)
Cl2—Co1—Cl3	108.0 (2)	N11—C16—C15	123.1 (5)
N11—Co1—Br1	106.4 (3)	N11—C16—H16	118.4
Cl2—Co1—Br1	109.0 (3)	C15—C16—H16	118.4
N11—Co1—Cl1	105.87 (18)	C26—N21—C22	124.0 (5)
Cl2—Co1—Cl1	109.17 (16)	C26—N21—H21	120 (4)
Cl3—Co1—Cl1	116.9 (3)	C22—N21—H21	116 (4)
N11—Co1—Br3	106.1 (2)	N22—C22—N21	119.1 (5)
Cl2—Co1—Br3	108.25 (15)	N22—C22—C23	124.5 (5)
Br1—Co1—Br3	115.6 (3)	N21—C22—C23	116.4 (5)
C12—N11—C16	119.2 (5)	C22—N22—H22A	122 (4)
C12—N11—Co1	125.2 (4)	C22—N22—H22B	121 (4)
C16—N11—Co1	115.5 (3)	H22A—N22—H22B	117 (6)
C12—N12—H12A	119 (4)	C24—C23—C22	120.8 (5)
C12—N12—H12B	124 (4)	C24—C23—H23	119.6
H12A—N12—H12B	114 (6)	C22—C23—H23	119.6
N12—C12—N11	119.4 (5)	C23—C24—C25	119.4 (5)
N12—C12—C13	120.2 (5)	C23—C24—H24	120.3
N11—C12—C13	120.4 (5)	C25—C24—H24	120.3
C14—C13—C12	119.7 (5)	C26—C25—C24	119.3 (5)
C14—C13—H13	120.1	C26—C25—I25	119.4 (4)
C12—C13—H13	120.1	C24—C25—I25	121.2 (4)
C13—C14—C15	119.4 (5)	C25—C26—N21	120.1 (5)
C13—C14—H14	120.3	C25—C26—H26	119.9
C15—C14—H14	120.3	N21—C26—H26	119.9
C16—C15—C14	118.1 (5)
C16—N11—C12—N12	−178.7 (5)	I15—C15—C16—N11	177.9 (4)
Co1—N11—C12—N12	−2.5 (7)	C26—N21—C22—N22	179.2 (5)
C16—N11—C12—C13	1.9 (7)	C26—N21—C22—C23	−2.4 (7)
Co1—N11—C12—C13	178.2 (4)	N22—C22—C23—C24	179.7 (5)
N12—C12—C13—C14	178.4 (5)	N21—C22—C23—C24	1.3 (7)
N11—C12—C13—C14	−2.2 (8)	C22—C23—C24—C25	0.5 (8)
C12—C13—C14—C15	1.0 (8)	C23—C24—C25—C26	−1.5 (8)
C13—C14—C15—C16	0.4 (8)	C23—C24—C25—I25	177.2 (4)
C13—C14—C15—I15	−178.1 (4)	C24—C25—C26—N21	0.6 (8)
C12—N11—C16—C15	−0.5 (8)	I25—C25—C26—N21	−178.2 (4)
Co1—N11—C16—C15	−177.1 (4)	C22—N21—C26—C25	1.5 (8)
C14—C15—C16—N11	−0.7 (8)

2-Amino-5-iodopyridinium (2-amino-5-iodopyridine-κN¹)bromido/chlorido(0.51/2.48)cobalt(II) (2) . Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N12—H12A···Cl2	0.85 (6)	2.47 (7)	3.282 (6)	160 (5)
N12—H12B···Br1i	0.86 (7)	2.44 (7)	3.291 (12)	170 (6)
N22—H22A···Br1ii	0.87 (7)	2.55 (7)	3.338 (12)	151 (5)
N22—H22A···I15iii	0.87 (7)	3.33 (6)	3.711 (5)	110 (5)
N22—H22B···Br3iv	0.97 (6)	2.37 (7)	3.341 (10)	176 (5)

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

Funding Statement

Funding for this research was provided by: Gustaf H. Carlson Fund (grant to Mark M. Turnbull); Bernard and Vera Kopelman Fund (bursary to Benjamin A. Mukda).