Crystal structure of poly[bis­(μ-2-bromo­pyrazine)­tetra-μ2-cyanido-dicopper(I)iron(II)]: a bimetallic metal-organic framework

Kucheriv, O.I.; Tokmenko, I.I.; Matushko, I.P.; Tsapyuk, G.G.; Gural'skiy, I.A.

doi:10.1107/S2056989018016638

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Volume 74| Part 12| December 2018| Pages 1895-1898

https://doi.org/10.1107/S2056989018016638

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Crystal structure of poly[bis(μ-2-bromopyrazine)tetra-μ₂-cyanido-dicopper(I)iron(II)]: a bimetallic metal-organic framework

Olesia I. Kucheriv,^a,^b ^* Inna I. Tokmenko,^a Igor P. Matushko,^a Galyna G. Tsapyuk ^a and Il'ya A. Gural'skiy ^a,^b

^aDepartment of Chemistry, Taras Shevchenko National University of Kyiv, Volodymyrska St 64, Kyiv 01601, Ukraine, and ^bUkrOrgSyntez Ltd, Chervonotkatska St 67, Kyiv 02094, Ukraine
^*Correspondence e-mail: lesya.kucheriv@gmail.com

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 10 November 2018; accepted 22 November 2018; online 30 November 2018)

In the title metal-organic framework, [Fe(C₄H₃BrN₂)₂{Cu(CN)₂}₂]_n, the Fe^II cation is located on an inversion center and has a slightly elongated octahedral coordination environment [FeN₆], ligated by two pyrazine N atoms of symmetry-related bridging 2-bromopyrazine molecules in the axial positions and by four N atoms of pairs of symmetry-related cyanido groups in the equatorial positions. The Cu^I center has a fourfold coordination environment [CuC₃N], with an almost perfect trigonal–pyramidal geometry, formed by three cyanido C atoms and an N atom of a bridging 2-bromopyrazine molecule. Copper(I) centers related by a twofold rotation axis are bridged by two carbon atoms from a pair of μ-CN groups, resulting in Cu₂(CN)₂ units. Each Cu₂(CN)₂ unit is linked to six Fe^II cations via a pair of linear CN units, the pair of μ-CN groups and two bridging 2-bromopyrazine ligands, resulting in the formation of a metal–organic framework, which is additionally stabilized by the short Cu⋯Cu contacts of 2.4450 (7) Å.

Keywords: crystal structure; bromopyrazine; dicyanocuprate; iron(II); copper(I); bimetallic; metal-organic framework; MOF.

CCDC reference: 1880717

1. Chemical context

The rational design and synthesis of cyanide-based coordination materials is of key interest today. By using different approaches for their design and tunable structures, composition and porosity, various exciting properties of these compounds, such as catalytic, photoluminescent, magnetic, electrical and other can be achieved (Zhang et al., 2015 ; Catala & Mallah, 2017 ). The cyanide anion is an important ligand in coordination chemistry as it can be used for stabilization of coordination materials formed by diverse transition metals. Cyanide-containing coordination materials of very different topologies have been proposed, although attention is frequently paid to heterometallic complexes.

The first class of cyanide-based metallic complexes emerged in the 18th century with the discovery of Prussian blue. Later its analogues containing two types of metals were synthesized. The inclusion of different metals instead of iron resulted in the occurrence of various attractive physical properties of these materials, which allowed their use as molecular sieves, for nanoscale devices, for hydrogen storage, etc. (Newton et al., 2011 ). Prussian blue analogues form networks with general formula AM_A[M_B(CN)₆] (A = alkali metal ion, M_A and M_B = transition metal ions) (Keggin & Miles, 1936 ). These complexes have a cubic structure in which the metallic centers are bridged in an M_A—C≡N—M_B fashion, forming three-dimensional frameworks.

Another class of heterometallic cyanide coordination compounds that has attracted much attention is represented by f–d complexes composed of lanthanide(III) ions and d-block cyanometallates. This type of materials has been shown to have exceptional photoluminescent properties (Chorazy et al., 2017 ). In addition, polynuclear octacyanides form a different family of cyanide-based heterometallic complexes. Compounds of this class can adopt very different geometries creating 0, 1, 2 or 3D assemblies. These materials are known for photomagnetism, molecular magnetism, and the ability to create chiral networks (Sieklucka et al., 2011 ).

The Hofmann clathrate analogues of the general formula [M_A(L)_x{M_B(CN)_y}] constitute another prominent example of bimetallic cyanometallates (Hofmann & Küspert, 1897 ), which are famous for their switchable magnetic properties (Muñoz & Real, 2011 ). Here we describe the crystal structure of a new Hofmann clathrate analogue of general formula [Fe(Brpz)₂{Cu(CN)₂}₂]_n.

2. Structural commentary

A fragment of the structure of the title compound, illustrating the sixfold coordination environment of atom Fe1, is shown in Fig. 1. Selected geometrical parameters are given in Table 1. The Fe^II ion is located on an inversion centre and has a slightly elongated FeN₆ octahedral coordination environment. It is ligated by two N atoms of symmetry-related 2-bromopyrazine molecules in axial positions [Fe1—N3 = 1.980 (2) Å] and by four N atoms of symmetry related cyanido groups in the equatorial positions [Fe1—N1 = 1.958 (2) and Fe1—N2 = 1.952 (2) Å]. The Fe—N bond lengths clearly indicate that the Fe^II center is in the low-spin state at the temperature of the experiment, i.e. 296 K. The deviation from an ideal octahedron of the Fe^II center can be described by the octahedral distortion parameter Σ|90 − θ| = 23.36°, where θ is a cis-N—Fe—N angle. Notably, this sum is higher than that expected for a low-spin Fe^II ion. It is important to note, and should always be taken into account, that the octahedral distortion value cannot always be used to judge the spin state of a metallic center, it is rather a characteristic of the order level in the structure, the measurement temperature, etc.

Table 1
Selected geometric parameters (Å, °)

Cu1—Cu1ⁱ	2.4450 (7)	Cu1—C2^iv	2.181 (3)
Cu1—N4ⁱⁱ	2.152 (2)	Fe1—N1	1.958 (2)
Cu1—C1	1.924 (3)	Fe1—N2	1.952 (2)
Cu1—C2ⁱⁱⁱ	2.049 (3)	Fe1—N3	1.980 (2)

N4ⁱⁱ—Cu1—C2^iv	99.77 (10)	N3—Fe1—N3^v	180
C2ⁱⁱⁱ—Cu1—N4ⁱⁱ	94.29 (10)	N2^v—Fe1—N3	87.27 (9)
C2ⁱⁱⁱ—Cu1—C2^iv	104.00 (10)	N2—Fe1—N3	92.73 (9)
C1—Cu1—N4ⁱⁱ	109.09 (10)	N2^v—Fe1—N1	92.19 (9)
C1—Cu1—C2^iv	116.07 (11)	N2—Fe1—N1	87.81 (9)
C1—Cu1—C2ⁱⁱⁱ	128.08 (11)	N1—Fe1—N3	90.92 (9)
N1—Fe1—N1^v	180	N1^v—Fe1—N3	89.08 (9)
N2—Fe1—N2^v	180
Symmetry codes: (i) $[-x+1, y, -z+{\script{3\over 2}}]$ ; (ii) x, y-1, z; (iii) -x+1, -y, -z+1; (iv) $[x, -y, z+{\script{1\over 2}}]$ ; (v) $[-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, -z+1]$ .

Figure 1
A fragment of the crystal structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at 50% probability level [symmetry codes: (i) −x + $[{3\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1; (ii) −x + 1, −y, −z + 1; (iii) −x + 1, y, −z + $[{1\over 2}]$ ; (iv) x, −y, z + $[{1\over 2}]$ ].

Atom Cu1 has a fourfold CuC₃N coordination environment (Fig. 2, Table 1) with a τ₄ descriptor of 0.82, close to that for a perfect trigonal–pyramidal geometry (τ₄ = 0.00 for square-planar, 1.00 for tetrahedral and 0.85 for trigonal–pyramidal; Yang et al., 2007 ). It is ligated by three C atoms of the cyanido groups and an N atom of a bridging 2-bromopyrazine molecule [Cu1—C1 = 1.924 (3), Cu1—C2^iv = 2.181 (3), Cu1—C2ⁱⁱⁱ = 2.049 (3), Cu1—N4ⁱⁱ = 2.152 (2) Å]. Notably, the coordination to atom Fe1 occurs only via the more sterically accessible atom N3 of the pyrazine ring, while atom Cu1 binds to atom N4 of the pyrazine ring.

Figure 2
A view of the coordination environment of the Cu atoms in the title compound, with atom labelling [symmetry codes: (i) −x + 1, −y, −z + 1; (iii) x, −y, z + $[{1\over 2}]$ ; (iv) x, −y, z + $[{1\over 2}]$ ].

3. Supramolecular features

The crystal packing of the title compound is shown in Fig. 3. The coordination framework is made up of bridging 2-bromopyrazine ligands and Cu₂(CN)₂ moieties (Fig. 2). The latter are formed by a pair of copper atoms, centered about a twofold rotation axis, being bridged by two carbon atoms from a pair of μ-CN groups. Each Cu₂(CN)₂ unit is linked to six Fe^II cations via a pair of linear CN units, the pair of μ-CN groups and two bridging 2-bromopyrazine ligands, resulting in the formation of a metal–organic framework (Fig. 3). The framework is additionally stabilized by the short Cu1⋯Cu1ⁱ contact of 2.4550 (7) Å, which is significantly shorter than the sum of the corresponding van der Waals radii, viz. 2.8 Å. Additionally, within the framework there are weak Br⋯π contacts of 3.8298 (6) Å, that are of lone-pair⋯π origin.

Figure 3
A view normal to plane (110) of the crystal structure of the title compound, showing the Cu⋯Cu contacts as dashed lines. H atoms have been omitted for clarity. Colour code: Fe dark red, Cu light blue, C grey, N blue, Br orange.

4. Database survey

A search of the Cambridge Structural Database (CSD, version 5.39, last update August 2018; Groom et al., 2016 ) gave 15 hits for Fe—N≡C—Cu bimetallic structures supported mainly by substituted pyridines and pyrimidines. These include a number of variable temperature measurements of certain compounds in order to study their spin-crossover behaviour; for example, the two-dimensional coordination polymer catena-[bis[(μ³-cyano-C,C,N)(μ²-cyano-C,N)]tetrakis(3-cyanopyridyl)dicopper(I)iron(II)] (VEHHOG, VEHHOG01; Galet et al., 2006 ), and the framework structures catena-[tetrakis(μ²-cyano-C,N)bis(μ²-pyrimidine-N,N′)dicopper(I)iron(II)] (EHOQOH01, EHOQOH03; Agustí et al., 2008 ) and catena-[octakis(μ²-cyano)octakis(3-chloropyridine)tetracopper(I)diiron(II)] (YUBRET, YUBRET03; Agustí et al., 2009 ).

A search of the CSD for the bridging Cu₂(CN)₂ unit gave 27 hits. The majority of these are monometallic copper(I) metal–organic frameworks (MOFs). The Cu⋯Cu distances vary from ca 2.31 Å in the two-dimensional network structure catena-[bis(μ₃-cyano)tetrakis(μ₂-cyano)tris(N,N,N′,N′-tetramethylethylenediamine)hexacopper(I)] (HIWHUQ; Stocker et al., 1999 ) to ca 2.72 Å in the MOF catena-[tris(μ-cyano)tris(μ-cyano)diamminepentacopper] (OPODAA; Grifasi et al., 2016 ). Two particular compounds resemble the title MOF, namely catena-[bis(μ₃-cyano-C,C,N)(μ₂-cyano-C,N)(μ₂-2,3-dimethylpyrazine-N,N′)tricopper(I)] (FERWUV; Greve & Nather, 2004 ), which involves a bridging 2,3-dimethylpyrazine ligand, and catena-[(μ₃-cyano)(μ₂-4,4′-bipyridine)tris(μ₂-cyano)hexamethyldicopper(I)ditin(IV)] (NUMRUI; Ibrahim et al., 1998 ), which is a bimetallic MOF with a bridging 4,4′-bipyridine ligand. The respective Cu⋯Cu distances are ca 2.49 and 2.62 Å, compared to 2.4550 (7) Å in the title MOF.

5. Synthesis and crystallization

Crystals of the title compound were obtained by slow diffusion within three layers in a 3 ml glass tube. The first layer was a solution of K[Cu(CN)₂] (7.8 mg, 0.05 mmol) in 1 ml of water; the second layer was a water/ethanol mixture (1:1, 1 ml); the third layer was a solution of Fe(ClO₄)₂·6H₂O (9.1 mg, 0.025 mmol) and 2-bromopyrazine (8.0 mg, 0.05 mmol) in 0.5 ml of ethanol. After two weeks, brown crystals were formed in the middle layer. The crystals were kept under the mother solution prior to measurement.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. All the hydrogen atoms were placed geometrically and refined as riding: C—H = 0.93 Å with U_iso(H) = 1.2U_eq(C).

Table 2
Experimental details

Crystal data
Chemical formula	[Cu₂Fe(CN)₄(C₄H₃BrN₂)₂]
M_r	605.00
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	13.6143 (17), 9.3067 (11), 13.2101 (15)
β (°)	92.369 (4)
V (Å³)	1672.3 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	8.17
Crystal size (mm)	0.2 × 0.1 × 0.05

Data collection
Diffractometer	Bruker SMART
Absorption correction	Multi-scan (SADABS; Bruker, 2013 )
T_min, T_max	0.487, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	8711, 2023, 1799
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.661

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.063, 1.04
No. of reflections	2023
No. of parameters	115
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.08, −0.76
Computer programs: APEX2 and SAINT (Bruker, 2013), SHELXS (Sheldrick, 2008 ), SHELXL (Sheldrick, 2015 ), OLEX2 (Dolomanov et al., 2009 ) and DIAMOND (Brandenburg, 1999 ).

Supporting information

CCDC reference: 1880717

Crystal structure: contains datablocks I, Global. DOI: https://doi.org/10.1107/S2056989018016638/su5461sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018016638/su5461Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

poly[bis(µ-2-bromopyrazine)tetra-µ₂-cyanido-dicopper(I)iron(II)] top

Crystal data top

[Cu₂Fe(CN)₄(C₄H₃BrN₂)₂]	F(000) = 1152
M_r = 605.00	D_x = 2.403 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.6143 (17) Å	Cell parameters from 3458 reflections
b = 9.3067 (11) Å	θ = 2.7–28.0°
c = 13.2101 (15) Å	µ = 8.17 mm⁻¹
β = 92.369 (4)°	T = 296 K
V = 1672.3 (3) Å³	Plate, brown
Z = 4	0.2 × 0.1 × 0.05 mm

Data collection top

Bruker SMART diffractometer	1799 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.029
Absorption correction: multi-scan (SADABS; Bruker, 2013)	θ_max = 28.0°, θ_min = 2.7°
T_min = 0.487, T_max = 0.746	h = −17→17
8711 measured reflections	k = −12→12
2023 independent reflections	l = −17→17

Refinement top

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)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.063	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0308P)² + 4.9236P] where P = (F_o² + 2F_c²)/3
2023 reflections	(Δ/σ)_max = 0.001
115 parameters	Δρ_max = 1.08 e Å⁻³
0 restraints	Δρ_min = −0.76 e Å⁻³

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.58637 (3)	0.80466 (3)	0.43290 (2)	0.02782 (10)
Cu1	0.56339 (2)	−0.11583 (4)	0.68710 (2)	0.01446 (10)
Fe1	0.750000	0.250000	0.500000	0.00911 (12)
N2	0.64165 (17)	0.2082 (2)	0.40313 (17)	0.0125 (4)
N4	0.61897 (18)	0.6878 (3)	0.62526 (18)	0.0167 (5)
N3	0.68414 (17)	0.4233 (2)	0.55166 (16)	0.0131 (4)
N1	0.68406 (17)	0.1288 (2)	0.59751 (17)	0.0133 (4)
C6	0.6791 (2)	0.4482 (3)	0.6517 (2)	0.0179 (6)
H6	0.697279	0.376181	0.697551	0.022*
C2	0.5807 (2)	0.1643 (3)	0.3484 (2)	0.0144 (5)
C3	0.6541 (2)	0.5292 (3)	0.4890 (2)	0.0167 (5)
H3	0.654572	0.515097	0.419324	0.020*
C5	0.6474 (2)	0.5785 (3)	0.6873 (2)	0.0205 (6)
H5	0.645476	0.591957	0.756995	0.025*
C1	0.6393 (2)	0.0431 (3)	0.63961 (19)	0.0129 (5)
C4	0.6224 (2)	0.6594 (3)	0.5265 (2)	0.0164 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0441 (2)	0.02245 (17)	0.01682 (15)	0.01597 (14)	0.00049 (13)	0.00483 (11)
Cu1	0.01237 (17)	0.01466 (17)	0.01645 (17)	−0.00143 (13)	0.00172 (13)	0.00342 (13)
Fe1	0.0097 (3)	0.0095 (2)	0.0081 (2)	−0.00185 (19)	−0.00025 (19)	0.00029 (18)
N2	0.0139 (12)	0.0124 (10)	0.0114 (10)	0.0000 (9)	0.0031 (9)	0.0019 (8)
N4	0.0199 (13)	0.0148 (11)	0.0154 (11)	0.0042 (9)	0.0019 (10)	0.0007 (9)
N3	0.0124 (11)	0.0152 (11)	0.0118 (10)	−0.0003 (9)	0.0006 (9)	−0.0006 (9)
N1	0.0133 (11)	0.0142 (11)	0.0122 (10)	0.0002 (9)	−0.0011 (9)	−0.0018 (9)
C6	0.0245 (16)	0.0162 (13)	0.0130 (12)	0.0054 (11)	−0.0003 (11)	0.0026 (10)
C2	0.0162 (14)	0.0109 (11)	0.0158 (12)	0.0015 (10)	−0.0011 (10)	0.0019 (10)
C3	0.0193 (14)	0.0181 (13)	0.0126 (12)	0.0047 (11)	0.0005 (10)	−0.0022 (10)
C5	0.0302 (17)	0.0198 (14)	0.0115 (12)	0.0071 (12)	0.0019 (11)	0.0004 (11)
C1	0.0142 (13)	0.0144 (13)	0.0101 (11)	0.0008 (10)	−0.0001 (10)	0.0014 (9)
C4	0.0166 (14)	0.0173 (13)	0.0151 (13)	0.0054 (11)	−0.0003 (10)	0.0041 (10)

Geometric parameters (Å, º) top

Br1—C4	1.884 (3)	N2—C2	1.153 (4)
Cu1—Cu1ⁱ	2.4450 (7)	N4—C5	1.353 (4)
Cu1—N4ⁱⁱ	2.152 (2)	N4—C4	1.334 (4)
Cu1—C1	1.924 (3)	N3—C6	1.347 (3)
Cu1—C2ⁱⁱⁱ	2.049 (3)	N3—C3	1.340 (4)
Cu1—C2^iv	2.181 (3)	N1—C1	1.160 (4)
Fe1—N1	1.958 (2)	C6—H6	0.9300
Fe1—N2^v	1.952 (2)	C6—C5	1.376 (4)
Fe1—N2	1.952 (2)	C3—H3	0.9300
Fe1—N3	1.980 (2)	C3—C4	1.385 (4)
Fe1—N3^v	1.980 (2)	C5—H5	0.9300
Fe1—N1^v	1.958 (2)

N4ⁱⁱ—Cu1—Cu1ⁱ	121.81 (7)	C2—N2—Fe1	170.7 (2)
N4ⁱⁱ—Cu1—C2^iv	99.77 (10)	C5—N4—Cu1^vi	120.31 (19)
C2ⁱⁱⁱ—Cu1—Cu1ⁱ	57.25 (8)	C4—N4—Cu1^vi	124.53 (19)
C2^iv—Cu1—Cu1ⁱ	52.20 (8)	C4—N4—C5	115.0 (2)
C2ⁱⁱⁱ—Cu1—N4ⁱⁱ	94.29 (10)	C6—N3—Fe1	121.39 (19)
C2ⁱⁱⁱ—Cu1—C2^iv	104.00 (10)	C3—N3—Fe1	121.14 (18)
C1—Cu1—Cu1ⁱ	128.71 (8)	C3—N3—C6	116.9 (2)
C1—Cu1—N4ⁱⁱ	109.09 (10)	C1—N1—Fe1	167.4 (2)
C1—Cu1—C2^iv	116.07 (11)	N3—C6—H6	119.4
C1—Cu1—C2ⁱⁱⁱ	128.08 (11)	N3—C6—C5	121.1 (3)
N1—Fe1—N1^v	180	C5—C6—H6	119.4
N2—Fe1—N2^v	180	Cu1ⁱⁱⁱ—C2—Cu1^vii	70.56 (9)
N3—Fe1—N3^v	180	N2—C2—Cu1ⁱⁱⁱ	151.5 (2)
N2^v—Fe1—N3	87.27 (9)	N2—C2—Cu1^vii	137.1 (2)
N2^v—Fe1—N3^v	92.73 (9)	N3—C3—H3	119.5
N2—Fe1—N3	92.73 (9)	N3—C3—C4	120.9 (3)
N2—Fe1—N3^v	87.27 (9)	C4—C3—H3	119.5
N2^v—Fe1—N1	92.19 (9)	N4—C5—C6	122.7 (3)
N2—Fe1—N1	87.81 (9)	N4—C5—H5	118.6
N2—Fe1—N1^v	92.19 (9)	C6—C5—H5	118.6
N2^v—Fe1—N1^v	87.81 (9)	N1—C1—Cu1	170.1 (2)
N1—Fe1—N3	90.92 (9)	N4—C4—Br1	118.8 (2)
N1^v—Fe1—N3^v	90.92 (9)	N4—C4—C3	123.2 (3)
N1^v—Fe1—N3	89.08 (9)	C3—C4—Br1	118.0 (2)
N1—Fe1—N3^v	89.08 (9)

Cu1^vi—N4—C5—C6	176.8 (2)	N3—C3—C4—N4	−0.5 (5)
Cu1^vi—N4—C4—Br1	5.2 (3)	C6—N3—C3—C4	2.0 (4)
Cu1^vi—N4—C4—C3	−176.7 (2)	C3—N3—C6—C5	−2.0 (4)
Fe1—N3—C6—C5	169.6 (2)	C5—N4—C4—Br1	−179.1 (2)
Fe1—N3—C3—C4	−169.7 (2)	C5—N4—C4—C3	−1.0 (4)
N3—C6—C5—N4	0.6 (5)	C4—N4—C5—C6	1.0 (5)
N3—C3—C4—Br1	177.6 (2)

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

Acknowledgements

We are grateful to the Ministry of Education and Science of Ukraine and H2020 Marie Skłodowska-Curie Actions for financial support.

Funding information

Funding for this research was provided by: Ministry of Education and Science of Ukraine (grant No. DZ/55-2018); H2020 Marie Skłodowska-Curie Actions (grant No. 734322).

References

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