Bis(ethyl­enedi­ammonium) μ-ethyl­enedi­aminetetra­acetato-1κ3O,N,O′:2κ3O′′,N′,O′′′-bis­[tri­oxidomolybdate(VI)] tetra­hydrate

Yaffa, L.; Seye, D.; Kama, A.B.; Toure, A.; Diop, C.A.K.

doi:10.1107/S2414314624006679

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 9| Part 7| July 2024| x240667

https://doi.org/10.1107/S2414314624006679

Open

access

Bis(ethylenediammonium) μ-ethylenediaminetetraacetato-1κ³O,N,O′:2κ³O′′,N′,O′′′-bis[trioxidomolybdate(VI)] tetrahydrate

Lamine Yaffa,^a ^* Dame Seye,^b Antoine Blaise Kama,^c Assane Toure ^a and Cheikh Abdoul Khadir Diop ^a

^aLaboratoire de Chimie Minérale et Analytique (LACHIMIA), Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, ^bDepartment of Physics-Chemistry, UFR Science and Technology, Iba Der THIAM University of THIES, Senegal, and ^cUniversité Alioune Diop de Bambey, UFR Sciences Appliquées et Technologies de l'Information et de la Communication (SATIC), Équipe Chimie des Matériaux Inorganiques et Organiques (ECMIO), Senegal
^*Correspondence e-mail: lamine.yaffa@ucad.edu.sn

Edited by S. Bernès, Benemérita Universidad Autónoma de Puebla, México (Received 14 May 2024; accepted 8 July 2024; online 12 July 2024)

This article is part of a collection of articles to commemorate the founding of the African Crystallographic Association and the 75th anniversary of the IUCr.

The title compound, (C₂H₁₀N₂)₂[(C₁₀H₁₂N₂O₈)(MoO₃)₂]·4H₂O, which crystallizes in the monoclinic C2/c space group, was obtained by mixing molybdenum oxide, ethylenediamine and ethylenediaminetetraacetic acid (H₄edta) in a 2:4:1 ratio. The complex anion contains two MoO₃ units bridged by an edta⁴⁻ anion. The midpoint of the central C—C bond of the edta⁴⁻ anion is located on a crystallographic inversion centre. The independent Mo atom is tridentately coordinated by a nitrogen atom and two carboxylate groups of the edta⁴⁻ ligand, together with the three oxo ligands, producing a distorted octahedral coordination environment. In the three-dimensional supramolecular crystal structure, the dinuclear anions, the organoammonium counter-ions and the solvent water molecules are linked by N—H⋯O_w, N—H⋯O_edta and O—H⋯O hydrogen bonds.

Keywords: crystal structure; edta complex; molybdenum oxide; ethylenediaminetetraacetic acid.

CCDC reference: 2368916

Structure description

The advancement of materials science has meant that many well-established materials, such as metals, ceramics or plastics, cannot meet the demand for new applications (photovoltaic cells, field-effect transistors, etc.). This desire to design new functional materials demands enormous research effort. In order to overcome this challenge, scientists quickly understood that mixtures of materials could have properties superior to those of their pure counterparts, and thus meet this demand. Hybrid framework materials research is one of the fastest growing research fields.

Their unique hybrid nature enables the combination of properties from both inorganic and organic materials (Cheetham & Rao, 2007 ). As organic ligands, polycarboxylates are multidentate chelating agents, widespread in nature and industry, due to their ability to coordinate to various transition metals in different ratios. In this field, the study of molybdenum polycarboxylate complexes has led to thorough investigation over the past three decades. Some well-characterized mono-, bi- and polynuclear molybdenum and tungsten complexes have been reported, for example [(H₂TEMED)Mo₂O₆(H₂edta)]·H₂O (TMED = tetramethylethylenediamine; Kumar et al., 2012 ), Mo₂(O₂CCH₂OH)₄, M₂[MoO₃(C₂O₄)] (M = Na, K, Rb, Cs) and Na₂[MO₂(C₆H₆O₇)₂]·3H₂O (M = Mo, W; Cotton et al., 2002 ; Cindrić et al., 2000 ; Zhou et al., 1999 ), Na₂K₂[Mo₂O₆(edta)]·10H₂O and Na₄[W₂O₆(edta)]·8H₂O (Lin et al., 2006 ). In our study, the reaction of H₄edta (ethylenediaminetetraacetic acid) with molybdenum oxide has been investigated, and a new binuclear 2:1 Mo–edta complex, (C₂H₁₀N₂)₂[(C₁₀H₁₂N₂O₈)(MoO₃)₂]·4H₂O, including edta⁴⁻ as ligand has been isolated and structurally characterized.

The single-crystal structure shows that the 2:1 Mo–edta complex anion of the title compound is discrete (Fig. 1). All of the carboxylic groups of H₄edta are deprotonated, coordinating the molybdenum oxide groups by nitrogen and two oxygen atoms. The edta⁴⁻ ligand itself is a bridge between the two MoO₃ units, and the midpoint of the central C—C bond is situated on an inversion centre. In the 2:1 Mo–edta complex, the edta⁴⁻ ligand thus chelates a pair of Mo^VI centres, in a tridentate fashion, giving a trans configuration to the complex. Each Mo^VI ion is chelated by the edta⁴⁻ ligand, simultaneously forming two glycinato rings occupying contiguous vertices that define one face of the coordination polyhedron. The other three vertices of the opposite face are occupied by three terminal oxo atoms of the MoO₃ unit, completing the octahedral geometry. In the complex, the Mo—O bond lengths are in the range 1.7195 (16) to 1.7686 (15) Å for Mo=O_t groups (O_t are terminal oxygen atoms: O5, O6 and O7). The resulting bond angles O_t—Mo—O_t are 107.27 (7), 103.83 (7) and 106.75 (7)°, considerably larger than the expected value of 90° for a regular octahedron, confirming the distortion from octahedral geometry.

Figure 1
Molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. Unlabelled atoms are generated by inversion symmetry.

The crystal packing can be rationalized in terms of non-bonding interactions between the three tectons: the Mo–edta complex anion, two (C₂H₁₀N₂)⁺ cations and four lattice water molecules. These units are linked through hydrogen bonds of the type N—H⋯O_water, N—H⋯O_edta and O—H⋯O (Table 1). This interconnection leads to the supramolecular structure, as shown in Fig. 2.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2C⋯O1ⁱ	0.91	1.93	2.795 (2)	159
N2—H2D⋯O10	0.91	2.00	2.715 (4)	134
N2—H2D⋯O7ⁱⁱ	0.91	2.21	2.786 (2)	121
N2—H2E⋯O6ⁱⁱⁱ	0.91	1.84	2.748 (2)	172
N3—H3C⋯O9ⁱ	0.91	1.88	2.785 (3)	170
N3—H3D⋯O1^iv	0.91	1.98	2.838 (2)	156
N3—H3E⋯O5^v	0.91	1.84	2.753 (2)	177
O1—H1A⋯O5^vi	0.87	1.83	2.694 (2)	173
O1—H1B⋯O2	0.87	1.83	2.694 (2)	173
O10—H10A⋯O8	0.87	1.86	2.692 (4)	160
O10—H10B⋯O8ⁱ	0.87	2.13	2.978 (4)	166
Symmetry codes: (i) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (ii) ; (iii) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (iv) $[x+{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (v) ; (vi) .

Figure 2
Supramolecular arrangement of the title compound with hydrogen bonds shown as dotted lines.

Synthesis and crystallization

Solid molybdenum oxide (4 mmol) and ethylenediamine (4 mmol) were mixed in 30 ml of distilled water. To this mixture were slowly added 2 mmol of ethylenediamminetetraacetic acid (H₄edta) under vigorous stirring. The solution was then stirred for 2 h at room temperature. The colourless solution thus obtained was left at room temperature for slow evaporation of water. After a few days, colourless crystals (yield 13.6% based on Mo) were obtained.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	(C₂H₁₀N₂)₂[(C₁₀H₁₂N₂O₈)(MoO₃)₂]·4H₂O
M_r	772.40
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	22.5897 (14), 7.5100 (4), 16.3743 (10)
β (°)	94.716 (2)
V (Å³)	2768.5 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.00
Crystal size (mm)	0.17 × 0.17 × 0.13

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.691, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	24031, 3192, 2946
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.022, 0.060, 1.06
No. of reflections	3192
No. of parameters	189
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.67, −1.06
Computer programs: APEX2 and SAINT (Bruker, 2016 ), SHELXT2018/2 (Sheldrick, 2015a ), SHELXL2018/32 (Sheldrick, 2015b ), Mercury (Macrae et al., 2020 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 2368916

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314624006679/bh4085sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314624006679/bh4085Isup2.hkl

checkCIF report

Computing details top

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate top

Crystal data top

(C₂H₁₀N₂)₂[Mo₂(C₁₀H₁₂N₂O₈)O₆]·4H₂O	F(000) = 1576
M_r = 772.40	D_x = 1.853 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 22.5897 (14) Å	Cell parameters from 9873 reflections
b = 7.5100 (4) Å	θ = 2.9–27.5°
c = 16.3743 (10) Å	µ = 1.00 mm⁻¹
β = 94.716 (2)°	T = 150 K
V = 2768.5 (3) Å³	Block, colourless
Z = 4	0.17 × 0.17 × 0.13 mm

Data collection top

Bruker APEXII CCD diffractometer	2946 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.032
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 27.5°, θ_min = 1.8°
T_min = 0.691, T_max = 0.746	h = −29→29
24031 measured reflections	k = −9→9
3192 independent reflections	l = −20→21

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.060	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0247P)² + 9.3382P] where P = (F_o² + 2F_c²)/3
3192 reflections	(Δ/σ)_max = 0.001
189 parameters	Δρ_max = 0.67 e Å⁻³
0 restraints	Δρ_min = −1.06 e Å⁻³

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

	x	y	z	U_iso*/U_eq
Mo1	0.34131 (2)	0.30046 (2)	0.43898 (2)	0.01140 (6)
O2	0.38304 (7)	0.07064 (19)	0.38526 (10)	0.0184 (3)
O3	0.34930 (6)	0.3750 (2)	0.31149 (9)	0.0153 (3)
O5	0.32695 (7)	0.5278 (2)	0.45742 (9)	0.0167 (3)
O6	0.27328 (7)	0.1984 (2)	0.41260 (10)	0.0192 (3)
O7	0.36649 (7)	0.2195 (2)	0.53376 (10)	0.0199 (3)
O8	0.46292 (8)	−0.0988 (2)	0.38094 (12)	0.0305 (4)
O9	0.40393 (8)	0.4592 (3)	0.21238 (10)	0.0313 (4)
N1	0.44444 (7)	0.3699 (2)	0.42662 (10)	0.0110 (3)
N2	0.68095 (9)	−0.1480 (2)	0.31790 (11)	0.0180 (4)
H2C	0.682765	−0.194661	0.266874	0.022*
H2D	0.644495	−0.169814	0.335592	0.022*
H2E	0.709362	−0.199255	0.352923	0.022*
N3	0.68986 (8)	0.3285 (2)	0.39152 (11)	0.0166 (4)
H3C	0.662370	0.374203	0.353458	0.020*
H3D	0.726961	0.352136	0.376498	0.020*
H3E	0.685339	0.379149	0.441115	0.020*
C1	0.43883 (10)	0.0440 (3)	0.39471 (13)	0.0165 (4)
C2	0.46667 (9)	0.4795 (3)	0.49874 (12)	0.0136 (4)
H2A	0.458550	0.415662	0.549512	0.016*
H2B	0.444417	0.593202	0.497625	0.016*
C3	0.44903 (9)	0.4682 (3)	0.34868 (12)	0.0158 (4)
H3A	0.486764	0.435686	0.325738	0.019*
H3B	0.450105	0.597629	0.360192	0.019*
C4	0.68156 (10)	0.1326 (3)	0.39721 (13)	0.0181 (4)
H4A	0.640934	0.106237	0.412324	0.022*
H4B	0.710243	0.083077	0.440266	0.022*
C5	0.39759 (10)	0.4287 (3)	0.28535 (13)	0.0159 (4)
C6	0.47677 (9)	0.1985 (3)	0.42775 (15)	0.0184 (4)
H6A	0.492092	0.171560	0.484797	0.022*
H6B	0.511335	0.210675	0.394705	0.022*
C7	0.69112 (12)	0.0470 (3)	0.31517 (13)	0.0225 (5)
H7A	0.663501	0.100557	0.271922	0.027*
H7B	0.732207	0.070407	0.301180	0.027*
O1	0.30869 (7)	−0.2039 (2)	0.34909 (9)	0.0180 (3)
H1A	0.317459	−0.290614	0.383210	0.027*
H1B	0.333866	−0.120160	0.364109	0.027*
O10	0.56206 (14)	−0.0882 (7)	0.30040 (19)	0.1003 (14)
H10A	0.533675	−0.115649	0.330976	0.151*
H10B	0.549760	−0.103261	0.249098	0.151*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Mo1	0.01159 (9)	0.01140 (9)	0.01128 (9)	−0.00124 (6)	0.00129 (6)	−0.00028 (6)
O2	0.0146 (7)	0.0131 (7)	0.0272 (8)	−0.0018 (6)	−0.0006 (6)	−0.0051 (6)
O3	0.0139 (7)	0.0207 (7)	0.0113 (7)	−0.0022 (6)	−0.0005 (5)	0.0000 (6)
O5	0.0197 (8)	0.0149 (7)	0.0157 (7)	0.0013 (6)	0.0031 (6)	−0.0022 (6)
O6	0.0142 (7)	0.0206 (8)	0.0229 (8)	−0.0029 (6)	0.0024 (6)	−0.0023 (6)
O7	0.0201 (8)	0.0226 (8)	0.0172 (7)	−0.0033 (6)	0.0021 (6)	0.0059 (6)
O8	0.0238 (9)	0.0153 (8)	0.0507 (12)	0.0053 (7)	−0.0067 (8)	−0.0107 (8)
O9	0.0263 (9)	0.0548 (12)	0.0123 (7)	−0.0165 (8)	−0.0016 (7)	0.0047 (8)
N1	0.0129 (8)	0.0100 (7)	0.0097 (7)	−0.0009 (6)	−0.0016 (6)	−0.0013 (6)
N2	0.0225 (9)	0.0163 (9)	0.0152 (8)	0.0008 (7)	0.0019 (7)	0.0001 (7)
N3	0.0183 (9)	0.0176 (9)	0.0137 (8)	0.0017 (7)	−0.0007 (7)	−0.0025 (7)
C1	0.0174 (10)	0.0132 (9)	0.0185 (10)	0.0003 (8)	−0.0018 (8)	−0.0013 (8)
C2	0.0133 (10)	0.0156 (9)	0.0115 (9)	−0.0025 (7)	−0.0017 (7)	−0.0027 (7)
C3	0.0150 (10)	0.0198 (10)	0.0125 (9)	−0.0062 (8)	0.0001 (7)	0.0020 (8)
C4	0.0234 (11)	0.0170 (10)	0.0138 (9)	0.0003 (8)	0.0019 (8)	−0.0002 (8)
C5	0.0190 (10)	0.0160 (10)	0.0125 (9)	−0.0031 (8)	−0.0002 (8)	0.0000 (8)
C6	0.0130 (10)	0.0141 (10)	0.0273 (11)	0.0015 (8)	−0.0038 (8)	−0.0038 (8)
C7	0.0376 (13)	0.0159 (10)	0.0138 (10)	−0.0012 (9)	0.0013 (9)	−0.0001 (8)
O1	0.0207 (8)	0.0152 (7)	0.0175 (7)	−0.0052 (6)	−0.0025 (6)	0.0023 (6)
O10	0.0533 (18)	0.200 (4)	0.0469 (16)	0.015 (2)	0.0000 (14)	0.007 (2)

Geometric parameters (Å, º) top

Mo1—O2	2.1858 (15)	N3—C4	1.487 (3)
Mo1—O3	2.1831 (14)	C1—C6	1.516 (3)
Mo1—O5	1.7686 (15)	C2—C2ⁱ	1.534 (4)
Mo1—O6	1.7397 (15)	C2—H2A	0.9900
Mo1—O7	1.7195 (16)	C2—H2B	0.9900
Mo1—N1	2.4121 (17)	C3—H3A	0.9900
O2—C1	1.273 (3)	C3—H3B	0.9900
O3—C5	1.270 (3)	C3—C5	1.521 (3)
O8—C1	1.232 (3)	C4—H4A	0.9900
O9—C5	1.236 (3)	C4—H4B	0.9900
N1—C2	1.492 (2)	C4—C7	1.521 (3)
N1—C3	1.485 (3)	C6—H6A	0.9900
N1—C6	1.479 (3)	C6—H6B	0.9900
N2—H2C	0.9100	C7—H7A	0.9900
N2—H2D	0.9100	C7—H7B	0.9900
N2—H2E	0.9100	O1—H1A	0.8703
N2—C7	1.484 (3)	O1—H1B	0.8697
N3—H3C	0.9100	O10—H10A	0.8701
N3—H3D	0.9100	O10—H10B	0.8702
N3—H3E	0.9100

O2—Mo1—N1	71.68 (6)	O8—C1—C6	119.11 (19)
O3—Mo1—O2	75.25 (6)	N1—C2—C2ⁱ	113.4 (2)
O3—Mo1—N1	73.02 (5)	N1—C2—H2A	108.9
O5—Mo1—O2	157.26 (6)	N1—C2—H2B	108.9
O5—Mo1—O3	86.93 (6)	C2ⁱ—C2—H2A	108.9
O5—Mo1—N1	89.85 (6)	C2ⁱ—C2—H2B	108.9
O6—Mo1—O2	87.34 (6)	H2A—C2—H2B	107.7
O6—Mo1—O3	90.94 (7)	N1—C3—H3A	109.1
O6—Mo1—O5	107.27 (7)	N1—C3—H3B	109.1
O6—Mo1—N1	156.07 (6)	N1—C3—C5	112.68 (16)
O7—Mo1—O2	87.85 (7)	H3A—C3—H3B	107.8
O7—Mo1—O3	155.03 (7)	C5—C3—H3A	109.1
O7—Mo1—O5	103.83 (7)	C5—C3—H3B	109.1
O7—Mo1—O6	106.75 (7)	N3—C4—H4A	109.8
O7—Mo1—N1	84.38 (7)	N3—C4—H4B	109.8
C1—O2—Mo1	122.03 (13)	N3—C4—C7	109.60 (17)
C5—O3—Mo1	123.00 (13)	H4A—C4—H4B	108.2
C2—N1—Mo1	108.51 (11)	C7—C4—H4A	109.8
C3—N1—Mo1	108.40 (12)	C7—C4—H4B	109.8
C3—N1—C2	111.30 (15)	O3—C5—C3	117.47 (18)
C6—N1—Mo1	106.85 (12)	O9—C5—O3	123.7 (2)
C6—N1—C2	109.66 (16)	O9—C5—C3	118.68 (19)
C6—N1—C3	111.95 (16)	N1—C6—C1	113.43 (17)
H2C—N2—H2D	109.5	N1—C6—H6A	108.9
H2C—N2—H2E	109.5	N1—C6—H6B	108.9
H2D—N2—H2E	109.5	C1—C6—H6A	108.9
C7—N2—H2C	109.5	C1—C6—H6B	108.9
C7—N2—H2D	109.5	H6A—C6—H6B	107.7
C7—N2—H2E	109.5	N2—C7—C4	110.94 (18)
H3C—N3—H3D	109.5	N2—C7—H7A	109.5
H3C—N3—H3E	109.5	N2—C7—H7B	109.5
H3D—N3—H3E	109.5	C4—C7—H7A	109.5
C4—N3—H3C	109.5	C4—C7—H7B	109.5
C4—N3—H3D	109.5	H7A—C7—H7B	108.0
C4—N3—H3E	109.5	H1A—O1—H1B	104.5
O2—C1—C6	116.65 (18)	H10A—O10—H10B	109.4
O8—C1—O2	124.2 (2)

Mo1—O2—C1—O8	164.21 (18)	N1—C3—C5—O3	24.0 (3)
Mo1—O2—C1—C6	−13.7 (3)	N1—C3—C5—O9	−159.7 (2)
Mo1—O3—C5—O9	174.61 (18)	N3—C4—C7—N2	−177.90 (18)
Mo1—O3—C5—C3	−9.3 (3)	C2—N1—C3—C5	−143.96 (17)
Mo1—N1—C2—C2ⁱ	175.59 (18)	C2—N1—C6—C1	145.79 (18)
Mo1—N1—C3—C5	−24.7 (2)	C3—N1—C2—C2ⁱ	−65.2 (3)
Mo1—N1—C6—C1	28.4 (2)	C3—N1—C6—C1	−90.2 (2)
O2—C1—C6—N1	−13.0 (3)	C6—N1—C2—C2ⁱ	59.2 (3)
O8—C1—C6—N1	169.0 (2)	C6—N1—C3—C5	92.9 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2C···O1ⁱⁱ	0.91	1.93	2.795 (2)	159
N2—H2D···O10	0.91	2.00	2.715 (4)	134
N2—H2D···O7ⁱⁱⁱ	0.91	2.21	2.786 (2)	121
N2—H2E···O6^iv	0.91	1.84	2.748 (2)	172
N3—H3C···O9ⁱⁱ	0.91	1.88	2.785 (3)	170
N3—H3D···O1^v	0.91	1.98	2.838 (2)	156
N3—H3E···O5ⁱ	0.91	1.84	2.753 (2)	177
O1—H1A···O5^vi	0.87	1.83	2.694 (2)	173
O1—H1B···O2	0.87	1.83	2.694 (2)	173
O10—H10A···O8	0.87	1.86	2.692 (4)	160
O10—H10B···O8ⁱⁱ	0.87	2.13	2.978 (4)	166

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

Acknowledgements

The authors acknowledge the Cheikh Anta Diop University of Dakar (Senegal) for financial support.

References

Bruker (2016). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cheetham, A. K. & Rao, C. N. R. (2007). Science, 318, 58–59. Web of Science CrossRef PubMed CAS Google Scholar
Cindrić, M., Strukan, N., Vrdoljak, V., Devčić, M., Veksli, Z. & Kamenar, B. (2000). Inorg. Chim. Acta, 304, 260–267. Web of Science CSD CrossRef CAS Google Scholar
Cotton, F. A., Barnard, T. S., Daniels, L. M. & Murillo, C. A. (2002). Inorg. Chem. Commun. 5, 527–532. Web of Science CSD CrossRef CAS Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Kumar, D., Singh, M. & Ramanan, A. (2012). J. Mol. Struct. 1030, 89–94. Web of Science CSD CrossRef CAS Google Scholar
Lin, H. B., Chen, C. Y., Liao, X. L., Lin, T. R. & Zhou, Z. H. (2006). Synth. React. Inorg. Met.-Org. Nano-Met. Chem. 36, 411–414. Web of Science CSD CrossRef CAS Google Scholar
Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226–235. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zhou, Z.-H., Wan, H.-L. & Tsai, K.-R. (1999). J. Chem. Soc. Dalton Trans. pp. 4289–4290. Web of Science CSD CrossRef Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.