research communications
κN)bis(4-benzoylpyridine-κN)bis(isothiocyanato-κN)nickel(II)
synthesis and thermal properties of bis(acetonitrile-aInstitut für Anorganische Chemie, Universität Kiel, Max-Eyth. Strasse 2, 241128 Kiel, Germany
*Correspondence e-mail: cwellm@ac.uni-kiel.de
In the 2(CH3CN)2(C12H9NO)2] or Ni(NCS)2(4-benzoylpyridine)2(acetonitrile)2, the NiII ions are octahedrally coordinated by the N atoms of two thiocyanate anions, two 4-benzoylpyridine ligands and two acetonitrile molecules into discrete complexes that are located on centres of inversion. In the crystal, the discrete complexes are linked by centrosymmetric pairs of weak C—H⋯S hydrogen bonds into chains. Thermogravimetric measurements prove that, upon heating, the title complex loses the two acetonitrile ligands and transforms into a new crystalline modification of the chain compound [Ni(NCS)2(4-benzoylpyridine)2], which is different from that of the corresponding CoII, NiII and CdII coordination polymers reported in the literature. IR spectroscopic investigations indicate the presence of bridging thiocyanate anions but the powder pattern cannot be indexed and, therefore, this structure is unknown.
of the title compound, [Ni(NCS)1. Chemical context
In most cases, the synthesis of new coordination compounds is performed in solution, which in some cases leads to inhomogenous samples or some, e.g. metastable compounds, formed by which can easily be overlooked. There are, however, some alternative routes, like synthesis via molecular milling, molten synthesis, solid-gas reactions or thermal decomposition of suitable precursor compounds (Braga et al., 2005, 2006; Näther et al., 2013; Zurawski et al., 2012; Höller et al., 2008; Den et al., 2019). These methods can have several advantages because, in most cases, they are irreversible, the products are obtained in quantitative yield, no solvent is needed and sometimes metastable isomeric or polymorphic modifications can be obtained. This is especially the case for thiocyanate coordination polymers prepared by thermal decomposition of suitable precursor compounds that consist of complexes in which the anionic ligands are only terminally bonded and additionally coordinated by neutral N-donor co-ligands (Wöhlert et al., 2014; Werner et al., 2015). Upon heating, the co-ligands are stepwise removed, leading to new compounds in which the metal cations are linked by thiocyanate anions into chains or layers (Neumann et al., 2019). In this context, we have reported on coordination polymers based on 4-benzoylpyridine. In [M(NCS)2(4-benzoylpyridine)2] (M = Co and Ni) prepared in solution, a rare cis–cis–trans coordination is observed, in which the thiocyanate N and S atoms are each in cis positions, whereas the co-ligand is trans (Rams et al., 2017; Jochim et al., 2018). This is in contrast to all other linear chain compounds, in which the coordinating atoms always show an all-trans coordination. Surprisingly, this coordination is found in [Cd(NCS)2(4-benzoylpyridine)2] (Neumann et al., 2018). Therefore, the question arose if this form can be prepared with Ni by thermal decomposition using a suitable NiII precursor compound. One discrete complex with methanol has already been reported in the literature, but this compound cannot be prepared pure (Wellm & Näther, 2019a). In the course of this project, we were able to prepare crystals from acetonitrile, which were characterized by single-crystal structure analysis, which proves that the title compound consists of discrete complexes with the composition Ni(NCS)2(4-benzoylpyridine)2(acetonitrile)2. This compound can be prepared pure and is a promising precursor to prepare an NiII compound with bridging thiocyanate anions (Fig. S1 in the supporting information). Measurements using differential thermoanalysis and thermogravimetry (DTA–TG) prove that on heating two mass steps are observed that are accompanied by endothermic events in the DTA curve (Fig. 1). The experimental mass loss of 12.8% in the first step is in reasonable agreement with that calculated for the removal of two acetonitrile molecules of 13.1%, indicating the formation of a compound with the desired composition (Fig. 1). If the X-ray powder diffraction pattern of the residue formed after the first mass loss is compared with that calculated for [Ni(NCS)2(4-benzoylpyridine)2] reported in the literature, it is obvious that a crystalline phase has been formed (Fig. S1 in the supporting information). This new form is also different from [Cd(NCS)2(4-benzoylpyridine)2], indicating that a new isomeric or polymorphic form is obtained. The value of the CN stretching vibration of this form (2113 cm−1) is very different from that of the title compound (2080 cm−1) but comparable to that observed in the known modification of [Ni(NCS)2(4-benzoylpyridine)2] (2121 cm−1) reported in the literature (Jochim et al., 2018), which indicates a similar thiocyanate coordination (Figs. S2, S3 and S4 in the supporting information). However, this powder pattern cannot be indexed and thus the structure of this new form is unknown.
2. Structural commentary
The II ion that is located on a centre of inversion, as well as one thiocyanate anion, one 4-benzoylpyridine co-ligand and one acetonitrile ligand that occupy general positions (Fig. 2). The NiII ions are sixfold coordinated by the N atoms of two terminal thiocyanate anions, two 4-benzoylpyridine and two acetonitrile ligands (Fig. 2). The Ni—NCS bond length to the negatively charged anionic ligands of 2.038 (3) Å is shorter than the Ni—N(pyridine) and Ni—NCMe bond lengths of 2.108 (2) and 2.108 (2) Å, respectively (Table 1). The bond angles deviate only slightly from ideal values, which shows that the octahedra are only slightly distorted (Table 1). This is also obvious from the octahedral angle variance of 0.71 and the quadratic elongation of 1.0006 calculated according to a procedure published by Robinson et al. (1971). The dihedral angle between the carbonyl plane (C13/C16/C17/O11) and that of the phenyl (C17–C22) ring is 22.2 (2)°, and that between the planes of the pyridine ring (N11/C11–15) and the carbonyl group (C13/C16/C17/O11) is 33.7 (2)°, which shows that the 4-benzoylpyridine ligand is not coplanar.
of the title compound consists of one Ni3. Supramolecular features
The discrete complexes are arranged into columns that proceed along the crystallographic a axis (Fig. 3). Along the b axis they are linked into chains by centrosymmetric pairs of weak C—H⋯S hydrogen bonds between the acetonitrile H atoms and the thiocyanate S atoms (Fig. 3 and Table 2).
4. Database survey
There are already some compounds reported in the Cambridge Structural Database (Groom et al., 2016) that consist of transition-metal thiocyanates and 4-benzoylpyridine ligands. These are Zn(NCS)2(4-benzoylpyridine)2 with tetrahedrally coordinated ZnII cations (Neumann et al., 2018) and Cu(NCS)2(4-benzoylpyridine)2 in which the CuII cations are square-planar coordinated (Bai et al., 2011). There are also a number of discrete complexes with an octahedral metal coordination and terminal thiocyanate anions (Drew et al., 1985; Soliman et al., 2014; Wellm & Näther, 2018, 2019a,b; Neumann et al., 2018; Suckert et al., 2017). Finally, there are several coordination polymers with the composition [M(NCS)2(4-benzoylpyridine)2]n (M = CdII, NiII and CoII), in which the cations are linked by pairs of μ-1,3-coordinating thiocyanate anions into chains (Neumann et al., 2018; Rams et al., 2017; Jochim et al., 2018).
5. Synthesis and crystallization
Ba(SCN)2·3H2O and 4-benzoylpyridine were purchased from Alfa Aesar. Ni(SO4)·6H2O was purchased from Merck. All solvents and reactants were used without further purification.
Ni(NCS)2 was prepared by the reaction of equimolar amounts of Ni(SO4)·6H2O and Ba(SCN)2·3H2O in water. The resulting white precipitate of BaSO4 was filtered off, and the solvent was evaporated from the filtrate. The green solid was dried at room temperature.
5.1. Synthesis
Crystals of the title compound suitable for single-crystal X-ray diffraction were obtained by the reaction of Ni(NCS)2 (26.2 mg, 0.15 mmol) with 4-benzoylpyridine (27.5 mg, 0.15 mmol) in acetonitrile (1.5 ml) for 2 d at 354 K in a closed test tube. A polycrystalline powder was obtained by stirring a solution of Ni(NCS)2 (87.4 mg, 0.5 mmol) and 4-benzoylpyridine (183.2 mg, 1.0 mmol) in MeCN (3 ml) for 4 d.
5.2. Experimental details
Differential thermoanalysis and thermogravimetry (DTA–TG) were performed under a dynamic nitrogen atmosphere in Al2O3 crucibles using an STA PT1600 thermobalance from Linseis. The XRPD measurements were performed using a Stoe Transmission Powder Diffraction System (STADI P) with Cu Kα radiation that was equipped with a linear position-sensitive MYTHEN detector from Stoe & Cie. The IR data were measured using a Bruker Alpha-P ATR–IR spectrometer.
6. Refinement
The C—H hydrogens were positioned with idealized geometry (methyl H atoms allowed to rotate but not to tip) and refined with Uiso(H) = 1.2Ueq(C) (1.5 for methyl H atoms) using a riding model. Crystal data, data collection and structure details are summarized in Table 3.
|
Supporting information
https://doi.org/10.1107/S2056989019013756/lh5928sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989019013756/lh5928Isup2.hkl
Additional figures. DOI: https://doi.org/10.1107/S2056989019013756/lh5928sup3.pdf
Data collection: X-AREA (Stoe & Cie, 2008); cell
X-AREA (Stoe & Cie, 2008); data reduction: X-AREA (Stoe & Cie, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).[Ni(NCS)2(C2H2N21)2(C12H9NO)2] | Z = 1 |
Mr = 623.38 | F(000) = 322 |
Triclinic, P1 | Dx = 1.373 Mg m−3 |
a = 7.2716 (5) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.4868 (6) Å | Cell parameters from 9692 reflections |
c = 10.8677 (6) Å | θ = 2.1–25.2° |
α = 65.540 (4)° | µ = 0.82 mm−1 |
β = 88.893 (5)° | T = 200 K |
γ = 88.378 (5)° | Needle, blue |
V = 754.02 (8) Å3 | 0.14 × 0.05 × 0.04 mm |
Stoe IPDS-2 diffractometer | 2634 reflections with I > 2σ(I) |
ω scans | Rint = 0.041 |
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2008) | θmax = 27.0°, θmin = 2.1° |
Tmin = 0.837, Tmax = 0.966 | h = −9→9 |
9692 measured reflections | k = −13→13 |
3283 independent reflections | l = −13→13 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.046 | H-atom parameters constrained |
wR(F2) = 0.100 | w = 1/[σ2(Fo2) + (0.0383P)2 + 0.2958P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
3283 reflections | Δρmax = 0.28 e Å−3 |
188 parameters | Δρmin = −0.40 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
Ni1 | 1.0000 | 0.5000 | 1.0000 | 0.04329 (15) | |
N1 | 1.1925 (3) | 0.6472 (3) | 0.9052 (2) | 0.0544 (5) | |
C1 | 1.2695 (4) | 0.7524 (3) | 0.8535 (3) | 0.0476 (6) | |
S1 | 1.38122 (12) | 0.89701 (8) | 0.77890 (9) | 0.0675 (2) | |
N11 | 0.8623 (3) | 0.5571 (2) | 0.8151 (2) | 0.0470 (5) | |
C11 | 0.9542 (4) | 0.5796 (3) | 0.6999 (3) | 0.0511 (6) | |
H11 | 1.0844 | 0.5686 | 0.7029 | 0.061* | |
C12 | 0.8685 (4) | 0.6177 (3) | 0.5778 (3) | 0.0516 (6) | |
H12 | 0.9387 | 0.6322 | 0.4987 | 0.062* | |
C13 | 0.6780 (4) | 0.6350 (3) | 0.5711 (3) | 0.0476 (6) | |
C14 | 0.5829 (4) | 0.6119 (3) | 0.6894 (3) | 0.0501 (6) | |
H14 | 0.4527 | 0.6230 | 0.6889 | 0.060* | |
C15 | 0.6789 (3) | 0.5726 (3) | 0.8082 (3) | 0.0476 (6) | |
H15 | 0.6116 | 0.5558 | 0.8891 | 0.057* | |
C16 | 0.5863 (4) | 0.6676 (3) | 0.4381 (3) | 0.0538 (6) | |
C17 | 0.4134 (4) | 0.7550 (3) | 0.4013 (3) | 0.0553 (7) | |
C18 | 0.3648 (4) | 0.8489 (3) | 0.4564 (3) | 0.0615 (7) | |
H18 | 0.4388 | 0.8554 | 0.5246 | 0.074* | |
C19 | 0.2080 (5) | 0.9336 (4) | 0.4122 (4) | 0.0777 (10) | |
H19 | 0.1755 | 0.9989 | 0.4492 | 0.093* | |
C20 | 0.0997 (5) | 0.9225 (4) | 0.3144 (4) | 0.0886 (12) | |
H20 | −0.0074 | 0.9806 | 0.2840 | 0.106* | |
C21 | 0.1459 (5) | 0.8281 (4) | 0.2610 (4) | 0.0868 (12) | |
H21 | 0.0694 | 0.8199 | 0.1949 | 0.104* | |
C22 | 0.3025 (5) | 0.7452 (3) | 0.3024 (3) | 0.0700 (8) | |
H22 | 0.3350 | 0.6814 | 0.2637 | 0.084* | |
O11 | 0.6554 (3) | 0.6210 (2) | 0.3620 (2) | 0.0687 (6) | |
N2 | 0.8453 (3) | 0.6523 (2) | 1.0367 (2) | 0.0540 (6) | |
C2 | 0.7727 (4) | 0.7466 (3) | 1.0432 (3) | 0.0518 (6) | |
C3 | 0.6820 (5) | 0.8675 (3) | 1.0510 (3) | 0.0715 (9) | |
H3A | 0.7191 | 0.9524 | 0.9733 | 0.107* | |
H3B | 0.7171 | 0.8740 | 1.1348 | 0.107* | |
H3C | 0.5484 | 0.8581 | 1.0501 | 0.107* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.0442 (3) | 0.0443 (3) | 0.0446 (3) | 0.00743 (19) | −0.00183 (19) | −0.0221 (2) |
N1 | 0.0536 (13) | 0.0556 (13) | 0.0542 (14) | 0.0029 (11) | −0.0014 (11) | −0.0230 (11) |
C1 | 0.0488 (14) | 0.0509 (15) | 0.0481 (15) | 0.0079 (12) | −0.0038 (12) | −0.0259 (12) |
S1 | 0.0725 (5) | 0.0514 (4) | 0.0826 (6) | −0.0061 (4) | 0.0032 (4) | −0.0317 (4) |
N11 | 0.0465 (11) | 0.0490 (12) | 0.0479 (12) | 0.0070 (9) | −0.0016 (9) | −0.0230 (10) |
C11 | 0.0458 (13) | 0.0620 (16) | 0.0476 (15) | 0.0031 (12) | 0.0021 (11) | −0.0249 (13) |
C12 | 0.0515 (14) | 0.0575 (15) | 0.0472 (15) | 0.0018 (12) | 0.0033 (12) | −0.0233 (12) |
C13 | 0.0523 (14) | 0.0456 (13) | 0.0457 (14) | 0.0028 (11) | −0.0034 (11) | −0.0199 (11) |
C14 | 0.0475 (13) | 0.0547 (15) | 0.0508 (15) | 0.0052 (11) | −0.0033 (12) | −0.0249 (12) |
C15 | 0.0453 (13) | 0.0539 (14) | 0.0457 (14) | 0.0072 (11) | −0.0006 (11) | −0.0234 (12) |
C16 | 0.0590 (16) | 0.0534 (15) | 0.0479 (15) | −0.0010 (12) | −0.0051 (13) | −0.0197 (12) |
C17 | 0.0565 (15) | 0.0528 (15) | 0.0472 (15) | −0.0032 (12) | −0.0049 (12) | −0.0110 (12) |
C18 | 0.0587 (17) | 0.0571 (16) | 0.0586 (18) | 0.0031 (13) | −0.0003 (14) | −0.0141 (14) |
C19 | 0.069 (2) | 0.066 (2) | 0.080 (2) | 0.0120 (16) | 0.0040 (18) | −0.0139 (17) |
C20 | 0.061 (2) | 0.082 (2) | 0.089 (3) | 0.0105 (18) | −0.0111 (19) | −0.001 (2) |
C21 | 0.068 (2) | 0.089 (3) | 0.076 (2) | −0.0072 (19) | −0.0239 (19) | −0.006 (2) |
C22 | 0.074 (2) | 0.0656 (19) | 0.0601 (19) | −0.0066 (16) | −0.0159 (16) | −0.0149 (15) |
O11 | 0.0799 (14) | 0.0802 (14) | 0.0541 (12) | 0.0092 (11) | −0.0061 (11) | −0.0363 (11) |
N2 | 0.0574 (13) | 0.0568 (13) | 0.0527 (13) | 0.0123 (11) | −0.0055 (11) | −0.0282 (11) |
C2 | 0.0606 (16) | 0.0522 (15) | 0.0468 (15) | 0.0120 (13) | −0.0042 (12) | −0.0252 (12) |
C3 | 0.093 (2) | 0.0588 (17) | 0.067 (2) | 0.0288 (17) | −0.0073 (17) | −0.0328 (15) |
Ni1—N1i | 2.038 (3) | C16—O11 | 1.217 (3) |
Ni1—N1 | 2.038 (3) | C16—C17 | 1.494 (4) |
Ni1—N2 | 2.093 (2) | C17—C18 | 1.383 (4) |
Ni1—N2i | 2.093 (2) | C17—C22 | 1.395 (4) |
Ni1—N11i | 2.108 (2) | C18—C19 | 1.390 (4) |
Ni1—N11 | 2.108 (2) | C18—H18 | 0.9500 |
N1—C1 | 1.164 (3) | C19—C20 | 1.379 (5) |
C1—S1 | 1.626 (3) | C19—H19 | 0.9500 |
N11—C15 | 1.339 (3) | C20—C21 | 1.371 (6) |
N11—C11 | 1.343 (3) | C20—H20 | 0.9500 |
C11—C12 | 1.373 (4) | C21—C22 | 1.376 (5) |
C11—H11 | 0.9500 | C21—H21 | 0.9500 |
C12—C13 | 1.391 (4) | C22—H22 | 0.9500 |
C12—H12 | 0.9500 | N2—C2 | 1.135 (3) |
C13—C14 | 1.381 (4) | C2—C3 | 1.445 (4) |
C13—C16 | 1.505 (4) | C3—H3A | 0.9800 |
C14—C15 | 1.380 (4) | C3—H3B | 0.9800 |
C14—H14 | 0.9500 | C3—H3C | 0.9800 |
C15—H15 | 0.9500 | ||
N1i—Ni1—N1 | 180.0 | N11—C15—C14 | 123.2 (2) |
N1i—Ni1—N2 | 91.36 (9) | N11—C15—H15 | 118.4 |
N1—Ni1—N2 | 88.64 (9) | C14—C15—H15 | 118.4 |
N1i—Ni1—N2i | 88.64 (9) | O11—C16—C17 | 121.0 (3) |
N1—Ni1—N2i | 91.36 (9) | O11—C16—C13 | 118.7 (2) |
N2—Ni1—N2i | 180.0 | C17—C16—C13 | 120.3 (2) |
N1i—Ni1—N11i | 90.03 (9) | C18—C17—C22 | 119.4 (3) |
N1—Ni1—N11i | 89.97 (9) | C18—C17—C16 | 122.7 (3) |
N2—Ni1—N11i | 90.31 (8) | C22—C17—C16 | 117.9 (3) |
N2i—Ni1—N11i | 89.69 (8) | C17—C18—C19 | 120.1 (3) |
N1i—Ni1—N11 | 89.97 (9) | C17—C18—H18 | 120.0 |
N1—Ni1—N11 | 90.03 (9) | C19—C18—H18 | 120.0 |
N2—Ni1—N11 | 89.69 (8) | C20—C19—C18 | 119.8 (4) |
N2i—Ni1—N11 | 90.31 (8) | C20—C19—H19 | 120.1 |
N11i—Ni1—N11 | 180.0 | C18—C19—H19 | 120.1 |
C1—N1—Ni1 | 163.8 (2) | C21—C20—C19 | 120.3 (3) |
N1—C1—S1 | 178.2 (2) | C21—C20—H20 | 119.9 |
C15—N11—C11 | 117.3 (2) | C19—C20—H20 | 119.9 |
C15—N11—Ni1 | 121.05 (18) | C20—C21—C22 | 120.5 (4) |
C11—N11—Ni1 | 121.64 (17) | C20—C21—H21 | 119.8 |
N11—C11—C12 | 123.0 (2) | C22—C21—H21 | 119.8 |
N11—C11—H11 | 118.5 | C21—C22—C17 | 120.0 (4) |
C12—C11—H11 | 118.5 | C21—C22—H22 | 120.0 |
C11—C12—C13 | 119.4 (3) | C17—C22—H22 | 120.0 |
C11—C12—H12 | 120.3 | C2—N2—Ni1 | 171.5 (2) |
C13—C12—H12 | 120.3 | N2—C2—C3 | 179.4 (4) |
C14—C13—C12 | 117.8 (2) | C2—C3—H3A | 109.5 |
C14—C13—C16 | 123.6 (2) | C2—C3—H3B | 109.5 |
C12—C13—C16 | 118.4 (2) | H3A—C3—H3B | 109.5 |
C15—C14—C13 | 119.3 (2) | C2—C3—H3C | 109.5 |
C15—C14—H14 | 120.4 | H3A—C3—H3C | 109.5 |
C13—C14—H14 | 120.4 | H3B—C3—H3C | 109.5 |
Symmetry code: (i) −x+2, −y+1, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C3—H3B···S1ii | 0.98 | 2.98 | 3.662 (3) | 127 |
Symmetry code: (ii) −x+2, −y+2, −z+2. |
Acknowledgements
This project was supported by the Deutsche Forschungsgemeinschaft and the State of Schleswig-Holstein. We thank Professor Dr Wolfgang Bensch for access to his experimental facilities.
Funding information
Funding for this research was provided by: Deutsche Forschungsgemeinschaft (grant No. NA 720/5-2).
References
Bai, Y., Zheng, G.-S., Dang, D.-B., Zheng, Y.-N. & Ma, P.-T. (2011). Spectrochim. Acta A Mol. Biomol. Spectrosc. 79, 1338–1344. Web of Science CSD CrossRef CAS PubMed Google Scholar
Braga, D., Curzi, M., Grepioni, F. & Polito, M. (2005). Chem. Commun. pp. 2915–2917. CSD CrossRef Google Scholar
Braga, D., Giaffreda, S. L., Grepioni, F., Pettersen, A., Maini, L., Curzi, M. & Polito, M. (2006). Dalton Trans. pp. 1249–1263. CrossRef Google Scholar
Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Den, T., Usov, P. M., Kim, J., Hashizume, D., Ohtsu, H. & Kawano, M. (2019). Chem. Eur. J. 25, 11512–11520. CrossRef CAS PubMed Google Scholar
Drew, M. G. B., Gray, N. I., Cabral, M. F. & Cabral, J. deO. (1985). Acta Cryst. C41, 1434–1437. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Höller, C. J. & Müller-Buschbaum, K. (2008). Inorg. Chem. 47, 10141–10149. PubMed Google Scholar
Jochim, A., Rams, M., Neumann, T., Wellm, C., Reinsch, H., Wójtowicz, G. M. & Näther, C. (2018). Eur. J. Inorg. Chem. 2018, 4779–4789. CSD CrossRef CAS Google Scholar
Näther, C., Wöhlert, S., Boeckmann, J., Wriedt, M. & Jess, I. (2013). Z. Anorg. Allg. Chem. 639, 2696–2714. Google Scholar
Neumann, T., Jess, I., dos Santos Cunha, C., Terraschke, H. & Näther, C. (2018). Inorg. Chim. Acta, 478, 15–24. CSD CrossRef CAS Google Scholar
Neumann, T., Rams, M., Tomkowicz, Z., Jess, I. & Näther, C. (2019). Chem. Commun. 55, 2652–2655. Web of Science CSD CrossRef CAS Google Scholar
Rams, M., Tomkowicz, Z., Böhme, M., Plass, W., Suckert, S., Werner, J., Jess, I. & Näther, C. (2017). Phys. Chem. Chem. Phys. 19, 3232–3243. Web of Science CSD CrossRef CAS PubMed Google Scholar
Robinson, K., Gibbs, G. V. & Ribbe, P. H. (1971). Science, 172, 567–570. CrossRef PubMed CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Soliman, S. M., Elzawy, Z. B., Abu-Youssef, M. A. M., Albering, J., Gatterer, K., Öhrström, L. & Kettle, S. F. A. (2014). Acta Cryst. B70, 115–125. Web of Science CSD CrossRef IUCr Journals Google Scholar
Stoe & Cie (2008). X-AREA, X-RED32 and X-SHAPE. Stoe & Cie, Darmstadt, Germany. Google Scholar
Suckert, S., Werner, J., Jess, I. & Näther, C. (2017). Acta Cryst. E73, 365–368. Web of Science CSD CrossRef IUCr Journals Google Scholar
Wellm, C. & Näther, C. (2018). Acta Cryst. E74, 1899–1902. Web of Science CSD CrossRef IUCr Journals Google Scholar
Wellm, C. & Näther, C. (2019a). Acta Cryst. E75, 299–303. CSD CrossRef IUCr Journals Google Scholar
Wellm, C. & Näther, C. (2019b). Acta Cryst. E75, 917–920. CSD CrossRef IUCr Journals Google Scholar
Werner, J., Runčevski, T., Dinnebier, R., Ebbinghaus, S. G., Suckert, S. & Näther, C. (2015). Eur. J. Inorg. Chem. 2015, 3236–3245. CSD CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wöhlert, S., Runčevski, T., Dinnebier, T., Ebbinghaus, S. G. & Näther, C. (2014). Cryst. Growth Des. 14, 1902–1913. Google Scholar
Zurawski, A., Rybak, J. C., Meyer, L. V., Matthes, P. R., Stepanenko, V., Dannenbauer, N., Würthner, F. & Müller-Buschbaum, K. (2012). Dalton Trans. 41, 4067–4078. CSD CrossRef CAS PubMed 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.