Synthesis and crystal structure study of (R,R)-TMCDA ethanol derivatives doubly protonated with FeCl4− and Cl− as counter-ions

Klotz, F.D.; Alonso Felipe, C.; Villafañe, F.; Strohmann, C.

doi:10.1107/S2056989025003019

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 81| Part 5| May 2025|

https://doi.org/10.1107/S2056989025003019

Open

access

Synthesis and crystal structure study of (R,R)-TMCDA ethanol derivatives doubly protonated with FeCl₄⁻ and Cl⁻ as counter-ions

Franziska Dorothea Klotz,^a Clara Alonso Felipe,^b Fernando Villafañe ^b and Carsten Strohmann ^a ^*

^aInorganic Chemistry, TU Dortmund University, Otto-Hahn Str. 6, 44227 Dortmund, Germany, and ^bQuímica Inorgánica, Universidad de Valladolid, Paseo Belén 7, 47011 Valladolid, Spain
^*Correspondence e-mail: carsten.strohmann@tu-dortmund.de

Edited by A. Briceno, Venezuelan Institute of Scientific Research, Venezuela (Received 21 February 2025; accepted 3 April 2025; online 8 April 2025)

The synthesis and structural characterization of the crystal forms of (R,R)-TMCDA and its ethanol derivative, both doubly protonated with FeCl₄⁻ and Cl⁻ as counter-ions, are reported, namely, (R,R)-N¹,N¹,N²,N²-tetramethylcyclohexane-1,2-bis(aminium) tetrachloridoferrate chloride, (C₁₀H₂₄N₂)[FeCl₄]Cl (1a), and (R,R)-N¹-(2-hydroxyethyl)-N¹,N²,N²-trimethylcyclohexane-1,2-bis(aminium) tetrachloridoferrate chloride (C₁₁H₂₆N₂O)[FeCl₄]Cl (2a). A notable feature across both synthesized compounds is the presence of N—H⋯Cl hydrogen bonds of moderate strength in the solid state. In the case of the ethanol derivative of (R,R)-TMCDA, the structure also reveals the formation of intermolecular O—H⋯Cl hydrogen bonds.

Keywords: crystal structure; (R,R)-TMCDA; stereogenic carbon center; hydrogen bonds; (R,R)-TMCDA ethanol derivative.

CCDC references: 2440777; 2440778

1. Chemical context

Nitrogen-containing compounds have numerous applications in coordination chemistry. Of particular interest is the molecule (R,R)-TMCDA (1), which contains two stereogenic carbon centers, enabling it to function as a bidentate, chiral ligand.

Selective deprotonation reactions play a critical role in the functionalization of certain molecules, facilitating the incorporation of new functional groups and enhancing molecular properties.

In organolithium chemistry, polyamines are the only tertiary amines susceptible to deprotonation reactions. This is due to the fact that polyamines allow the formation of a complex in which the lithiated base gets pre-coordinated. This pre-coordination brings reactive groups into close proximity, allowing selective deprotonation reactions to take place (Gessner et al., 2010 ). This phenomenon is widely known as the complex-induced proximity effect (CIPE) (Gessner et al., 2010; Whisler et al., 2004 ; Breit, 2000 ; Hoveyda et al., 1993 ; Beak & Meyers, 1986 ).

Additionally, the synthesis of new ligands with stereogenic centers presents a persistent challenge. The inherent chirality of (R,R)-TMCDA (1) coupled with its high reactivity towards lithiated bases, renders this molecule a promising precursor for the synthesis of other novel ligands. A notable example is compound 2, which displays interesting characteristics including chirality and its function as an N,N,O-scorpionate ligand. In light of these characteristics, our research group has previously investigated compound 2 and related ligands (Gessner et al., 2010) as well as with (R,R)-TMCDA (Eckert et al., 2011 ; Strohmann & Gessner, 2008 ; Strohmann & Gessner, 2007 ). Building upon this foundation, compounds 1a and 2a, incorporating the aforementioned ligands, have been successfully synthesized and crystallized in this work.

2. Structural commentary

The structure of compound 1a, as depicted in Fig. 1, comprises a cation and two anions. The cation consists of a doubly protonated (R,R)-TMCDA molecule, with the cyclohexane ring adopting a chair conformation. The two counter-ions are a chloride anion, that forms two N—H⋯Cl hydrogen bonds, and a FeCl₄⁻ anion, in which the Fe³⁺ cation is coordinated by four chlorides in a tetrahedral geometry.

Figure 1
The molecular structure of compound 1a with the atom labelling and displacement ellipsoids drawn at the 50% probability level.

The distances of interest are shown in Table 1. Hydrogen bonds between the chloride and the hydrogen atoms bonded to either N1 or N2 were observed in the crystal structure, with N1—H1⋯Cl1 distances of 2.133 (19) Å and N2—H2⋯Cl1 distances of 2.135 (17) Å and N1—H1 distances of 0.891 (19) Å and N2—H2 distances of 0.900 (18) Å. These hydrogen bonds could be classified as moderate (Steiner, 2002 ).

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Cl1	0.891 (19)	2.133 (19)	3.0189 (11)	172.7 (19)
N2—H2⋯Cl1	0.900 (18)	2.135 (17)	3.0208 (10)	165 (14)

The structure of compound 2a, illustrated in Fig. 2, consists of a cation and two anions. The cation is derived from an ethanol-substituted, doubly protonated (R,R)-TMCDA molecule, characterized by a cyclohexane ring adopting a chair conformation. The two counter-ions include a chloride, which forms N—H⋯Cl hydrogen bonds, and a FeCl₄⁻ anion, wherein the Fe³⁺ cation is coordinated by four chlorides arranged in a tetrahedral geometry. The cation in this structure features three tetrahedral stereogenic centres: the two carbon atoms associated with the N-bonded cycle and the nitrogen atoms N1 or N2, which are bonded to the ethanol fragment. The nitrogen atoms have a labile configuration and both enantiomers (R_N and S_N) can occur in solid state and thus represent a further cause of the existing disorder. The more flexible CH₂-segments of the side chain contribute to the observed disorder of the –CH₂CH₂OH fragment as well. This is distributed at atom C2 over positions designated as A and C (CH₂ group) as well as B and D (CH₃ group) with occupancies of 0.6 and 0.4 respectively. Additionally, the C1 carbon is similarly disordered at positions A and C, also exhibiting occupancies of 0.6 and 0.4 respectively. The relevant distances are summarized in Table 2. The structural analysis reveals hydrogen bonds between the chloride anion and the hydrogen atoms attached to nitrogen atoms N1 and N2. The N2—H2⋯Cl1 distance is measured at 2.357 (3) Å, while the N1—H1⋯Cl1 distance is 2.221 (3) Å. Additionally, the N1—H1 distance is 0.855 (3) Å, and the N2—H2 distance is 0.878 (3) Å. These hydrogen bonds can be classified as moderate in strength, according to Steiner (Steiner, 2002). In contrast, no interaction is observed between the hydrogen atoms O1A—H1A or O1C—H1C and Cl1, as they are separated by a distance of 3.1245 (5) Å (H1A⋯Cl1) and 3.4958 (5) Å (H1C⋯Cl1).

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Cl1	0.855 (3)	2.221 (3)	3.0603 (14)	167 (3)
N2—H2⋯Cl1	0.878 (3)	2.357 (3)	3.1698 (16)	154 (3)
O1C—H1C⋯Cl1ⁱ	0.84	2.43	3.229 (3)	159
Symmetry code: (i) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ .

Figure 2
The molecular structure of compound 2a with the atom labelling. The structure exhibits a disorder of the –CH₂CH₂OH fragment at two positions, with occupancies of 0.4 and 0.6 and a disorder of C2, also at two positions with occupancies of 0.4 and 0.6.

3. Supramolecular features

To better understand the supramolecular interactions, a Hirshfeld surface analysis was performed for compound 1a. In Fig. 3, the Hirshfeld surface generated by CrystalExplorer21 (Spackman et al., 2021 ) is mapped over d_norm (Spackman & Jayatilaka, 2009 ) and red dots are used to represent close contacts between the hydrogen atoms H3, H1A and H10C with the chloride anion Cl1′. The following figure (Fig. 4) shows the Hirshfeld surface with external fragments.

Figure 3
Three-dimensional Hirshfeld surface of 1a mapped over d_norm (rescale surface property: −0.2124 − 1.4372).

Figure 4
Three-dimensional Hirshfeld surface of 1a mapped over d_norm with external fragments and atom labeling (rescale surface property: −0.2124 − 1.4372).

For further exploration of the intermolecular interactions, two-dimensional fingerprint plots (McKinnon et al., 2007 ) were generated as shown in Fig. 5. The H⋯Cl interaction with a contribution of 66.6% has the biggest impact on the packing in the solid state as well as the H⋯H bonds with 28.8%. Fe⋯H interactions with 0.9% and Cl⋯Fe interactions with 0.3% are less impactful in comparison.

Figure 5
Two-dimensional fingerprint plots for 1a showing (b) all interactions, and (a) and (c)–(d) delineated into contributions from other contacts (blue areas) [d_e and d_i represent the distances from a point on the Hirshfeld surface to the nearest atoms outside (external) and inside (internal) the surface, respectively].

In contrast, compound 2a forms O—H⋯Cl hydrogen bonds. These interactions connect two different moieties of compound 2a by a chloride, resulting in a supramolecular zigzag structure in the solid state, as shown in Fig. 6. They show distances of 2.43 Å (O1C—H1C⋯Cl1′) and the N2—H2⋯Cl1 distance is measured at 2.357 (3) Å, while the N1—H1⋯Cl1 distance is 2.221 (3) Å. In Fig. 6 the disorder with the lower occupancy is omitted for clarity, but shows the O1A—H1A⋯Cl1 hydrogen bond with a distance of 2.22 Å.

Figure 6
The supramolecular structure of compound 2a with the formed hydrogen bonds and the atom labelling of parts of interest. The disorder with the lower occupancy (O1A, H1A) was omitted for clarity. Hydrogen bonds are depicted by dashed lines.

4. Database survey

A search of the Cambridge Structural Database (CSD version 5.43, November 2021; Groom et al., 2016 ) for structures containing (R,R)-TMCDA and its ethanol derivative both doubly protonated leads to three relevant and similar structures in common CUZZEC, CUZZIG (Duesler et al., 1985 ) and POMMIO (Lian et al., 2009 ). In these three cases, the amine substituents are –CH₂COOH fragments. Also, in all three cases there is a single anion, being either CdCl₄²⁻, PdCl₄²⁻ or PtCl₄²⁻ and none of the compounds presents a space group that matches 1a or 2a. Another search of structures involving non-protonated (R,R)-TMCDA leads to several related structures, some of them being: FEJFAD, FEJFIL and FEJFOR (Eckert et al., 2013 ), KOBCAH (Eckert et al., 2014 ) and LECRUI (Eckert et al., 2012 ). FEJFAD and LECRUI show the same space group as 2a and KOBCAH with 1a. However, all the latter structures show direct coordination to the metal unlike compounds 1a and 2a.

5. Synthesis and crystallization

The syntheses of compounds 1a and 2a were conducted according to the previously established procedure (Gessner, 2009 ), which involves the mixing of equimolar amounts of FeCl₃·H₂O with (R,R)-TMCDA (1) and with 2-{[(1R,2R)-2-(dimethylamino)cyclohexyl](methyl)amino}ethan-1-ol (2), respectively, to yield each compound. In both instances, the reactions were performed in a 3:2 mixture of acetone and 2.5 M of HCl at room temperature (see Fig. 7). Upon complete dissolution of the reactants, a homogeneous yellow solution was obtained, which was then allowed to stand at room temperature until complete evaporation of the solvent. After one week, yellow crystals were formed; specifically, needle-shaped crystals were obtained for compound 1a, while prism-shaped crystals were obtained for compound 2a.

Figure 7
The synthesis of the title compounds.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. Hydrogen atoms except for the protons attached to the nitrogen and oxygen atoms in both structures were positioned geometrically (C—H = 0.95–1.00 Å) and were refined using a riding model, with U_iso(H) = 1.2U_eq(C) for CH₂ hydrogen atoms and U_iso(H) = 1.5U_eq(C) for CH₃ hydrogen atoms.

Table 3
Experimental details

	1a	2a
Crystal data
Chemical formula	(C₁₀H₂₄N₂)[FeCl₄]Cl	(C₁₁H₂₆N₂O)[FeCl₄]Cl
M_r	405.41	435.44
Crystal system, space group	Monoclinic, P2₁	Orthorhombic, P2₁2₁2₁
Temperature (K)	100	100
a, b, c (Å)	10.2322 (3), 9.2378 (5), 10.7384 (4)	7.6070 (5), 11.5870 (6), 21.8705 (13)
α, β, γ (°)	90, 116.797 (1), 90	90, 90, 90
V (Å³)	906.02 (7)	1927.7 (2)
Z	2	4
Radiation type	Mo Kα	Mo Kα
μ (mm⁻¹)	1.56	1.47
Crystal size (mm)	0.50 × 0.43 × 0.38	0.8 × 0.43 × 0.18

Data collection
Diffractometer	Bruker D8 VENTURE area detector	Bruker APEXII CCD
Absorption correction	–	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	–	0.472, 0.567
No. of measured, independent and observed [I > 2σ(I)] reflections	69005, 8763, 8442	144077, 8488, 8082
R_int	0.030	0.046
(sin θ/λ)_max (Å⁻¹)	0.834	0.807

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.018, 0.037, 1.06	0.026, 0.063, 1.07
No. of reflections	8763	8488
No. of parameters	175	231
No. of restraints	1	1
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
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.34	0.61, −0.48
Absolute structure	Flack x determined using 3826 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )	Flack x determined using 3373 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013)
Absolute structure parameter	−0.009 (3)	−0.013 (4)
Computer programs: APEX2 and SAINT (Bruker, 2016 ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC references: 2440777; 2440778

Crystal structure: contains datablocks 2a, 1a. DOI: https://doi.org/10.1107/S2056989025003019/zn2042sup1.cif

Structure factors: contains datablock 1a. DOI: https://doi.org/10.1107/S2056989025003019/zn20421asup2.hkl

Structure factors: contains datablock 2a. DOI: https://doi.org/10.1107/S2056989025003019/zn20422asup3.hkl

checkCIF report

Computing details top

(R,R)-N¹-(2-Hydroxyethyl)-N¹,N²,N²-trimethylcyclohexane-1,2-bis(aminium) tetrachloridoferrate chloride (2a) top

Crystal data top

(C₁₁H₂₆N₂O)[FeCl₄]Cl	D_x = 1.500 Mg m⁻³
M_r = 435.44	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 9581 reflections
a = 7.6070 (5) Å	θ = 2.6–34.8°
b = 11.5870 (6) Å	µ = 1.47 mm⁻¹
c = 21.8705 (13) Å	T = 100 K
V = 1927.7 (2) Å³	Needle, yellow
Z = 4	0.8 × 0.43 × 0.18 mm
F(000) = 900

Data collection top

Bruker APEXII CCD diffractometer	8488 independent reflections
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs	8082 reflections with I > 2σ(I)
HELIOS mirror optics monochromator	R_int = 0.046
Detector resolution: 10.4167 pixels mm^-1	θ_max = 35.0°, θ_min = 1.9°
φ and ω scans	h = −12→12
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	k = −18→18
T_min = 0.472, T_max = 0.567	l = −35→35
144077 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.026	w = 1/[σ²(F_o²) + (0.0263P)² + 0.5573P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.063	(Δ/σ)_max = 0.001
S = 1.07	Δρ_max = 0.61 e Å⁻³
8488 reflections	Δρ_min = −0.48 e Å⁻³
231 parameters	Absolute structure: Flack x determined using 3373 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
1 restraint	Absolute structure parameter: −0.013 (4)
Primary atom site location: dual

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	Occ. (<1)
Fe1	0.38908 (3)	0.32831 (2)	0.64131 (2)	0.02140 (5)
Cl1	0.32469 (6)	0.71475 (4)	0.52176 (2)	0.02393 (7)
Cl5	0.40990 (7)	0.16915 (4)	0.69535 (2)	0.03204 (10)
Cl4	0.63253 (7)	0.34762 (4)	0.58818 (2)	0.02908 (9)
Cl3	0.36082 (7)	0.47621 (5)	0.70394 (3)	0.03907 (12)
Cl2	0.16007 (8)	0.31529 (4)	0.58067 (3)	0.04136 (13)
N1	0.36655 (19)	0.80677 (11)	0.39141 (6)	0.0176 (2)
C4	0.49489 (19)	0.73202 (12)	0.35567 (7)	0.0167 (2)
H4	0.610719	0.734966	0.377232	0.020*
C9	0.4413 (2)	0.60442 (13)	0.35010 (7)	0.0190 (3)
H9	0.330578	0.600659	0.325512	0.023*
N2	0.4066 (2)	0.54577 (12)	0.41140 (7)	0.0229 (3)
C2A	0.1906 (10)	0.8308 (10)	0.3630 (5)	0.0204 (19)	0.6
H2AA	0.204658	0.886344	0.329535	0.031*	0.6
H2AB	0.111296	0.863005	0.393931	0.031*	0.6
H2AC	0.140939	0.758896	0.346966	0.031*	0.6
C8	0.5840 (3)	0.53894 (15)	0.31517 (9)	0.0285 (4)
H8A	0.695235	0.542237	0.338627	0.034*
H8B	0.549412	0.456878	0.311433	0.034*
C5	0.5215 (3)	0.78172 (17)	0.29127 (8)	0.0283 (4)
H5A	0.409277	0.777667	0.268459	0.034*
H5B	0.555774	0.863928	0.294475	0.034*
C7	0.6146 (3)	0.58882 (18)	0.25142 (9)	0.0329 (4)
H7A	0.710524	0.546051	0.230899	0.040*
H7B	0.506586	0.580115	0.226574	0.040*
C10	0.5676 (3)	0.51474 (19)	0.44679 (11)	0.0380 (5)
H10A	0.632514	0.454339	0.425011	0.057*
H10B	0.533646	0.486423	0.487323	0.057*
H10C	0.642387	0.583097	0.451261	0.057*
C6	0.6630 (3)	0.71594 (19)	0.25612 (10)	0.0360 (5)
H6A	0.675303	0.748989	0.214598	0.043*
H6B	0.777242	0.723985	0.277372	0.043*
C3	0.4494 (3)	0.92074 (14)	0.40779 (9)	0.0261 (3)
H3A	0.566736	0.907371	0.424913	0.039*
H3B	0.376186	0.960350	0.438098	0.039*
H3C	0.459308	0.968647	0.371023	0.039*
C2C	0.3030 (10)	0.4364 (7)	0.4077 (4)	0.0352 (15)	0.6
H2CA	0.353142	0.375708	0.434330	0.042*	0.6
H2CB	0.296099	0.407377	0.365179	0.042*	0.6
O1C	0.0357 (4)	0.5852 (2)	0.40633 (12)	0.0303 (5)	0.6
H1C	−0.026743	0.622278	0.431171	0.045*	0.6
O1A	0.0770 (5)	0.6464 (3)	0.40150 (16)	0.0268 (6)	0.4
H1A	0.015547	0.671492	0.430532	0.040*	0.4
C1C	0.0962 (5)	0.4832 (3)	0.43433 (15)	0.0273 (6)	0.6
H1CA	0.009140	0.421137	0.427170	0.033*	0.6
H1CB	0.103627	0.496020	0.479006	0.033*	0.6
C1A	0.0736 (6)	0.7274 (4)	0.3522 (2)	0.0242 (7)	0.4
H1AA	−0.047730	0.756592	0.346835	0.029*	0.4
H1AB	0.108667	0.688030	0.313934	0.029*	0.4
H2	0.351 (4)	0.594 (2)	0.4354 (13)	0.033 (7)*
C2D	0.2584 (14)	0.4516 (10)	0.3996 (6)	0.0256 (17)	0.4
H2DA	0.230905	0.448666	0.355885	0.038*	0.4
H2DB	0.152364	0.472246	0.422608	0.038*	0.4
H2DC	0.300608	0.375886	0.413154	0.038*	0.4
H1	0.342 (4)	0.774 (2)	0.4253 (13)	0.037 (7)*
C2B	0.1897 (17)	0.8228 (16)	0.3631 (7)	0.028 (4)	0.4
H2BA	0.125018	0.878280	0.389230	0.034*	0.4
H2BB	0.208584	0.861386	0.323279	0.034*	0.4

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Fe1	0.02100 (10)	0.02097 (10)	0.02223 (10)	−0.00210 (8)	−0.00138 (8)	−0.00180 (8)
Cl1	0.02587 (17)	0.03036 (18)	0.01556 (13)	−0.00029 (15)	0.00178 (13)	−0.00037 (13)
Cl5	0.0315 (2)	0.0350 (2)	0.02956 (19)	−0.00769 (18)	0.00039 (16)	0.01233 (18)
Cl4	0.0340 (2)	0.02166 (16)	0.03163 (19)	0.00026 (15)	0.01043 (17)	0.00573 (14)
Cl3	0.0339 (2)	0.0387 (2)	0.0446 (3)	−0.0104 (2)	0.0089 (2)	−0.0217 (2)
Cl2	0.0391 (3)	0.0284 (2)	0.0566 (3)	0.00584 (19)	−0.0261 (2)	−0.0091 (2)
N1	0.0228 (6)	0.0148 (5)	0.0151 (5)	0.0018 (4)	0.0004 (4)	−0.0001 (4)
C4	0.0181 (6)	0.0152 (5)	0.0168 (6)	−0.0002 (4)	0.0009 (5)	−0.0016 (5)
C9	0.0223 (6)	0.0177 (6)	0.0171 (6)	−0.0033 (5)	0.0017 (5)	−0.0042 (5)
N2	0.0330 (7)	0.0138 (5)	0.0220 (6)	−0.0028 (5)	0.0049 (6)	−0.0017 (5)
C2A	0.018 (3)	0.0139 (19)	0.030 (4)	0.0001 (17)	−0.006 (2)	0.0035 (19)
C8	0.0345 (9)	0.0208 (7)	0.0303 (8)	0.0009 (6)	0.0101 (7)	−0.0093 (6)
C5	0.0386 (10)	0.0254 (8)	0.0209 (7)	0.0002 (7)	0.0093 (7)	0.0029 (6)
C7	0.0374 (10)	0.0344 (9)	0.0270 (8)	−0.0042 (8)	0.0141 (8)	−0.0121 (7)
C10	0.0487 (13)	0.0285 (9)	0.0368 (10)	0.0111 (9)	−0.0049 (9)	0.0087 (8)
C6	0.0425 (11)	0.0328 (9)	0.0326 (9)	−0.0076 (9)	0.0215 (9)	−0.0044 (7)
C3	0.0321 (9)	0.0164 (6)	0.0299 (8)	0.0006 (6)	−0.0035 (7)	−0.0057 (6)
C2C	0.053 (5)	0.024 (3)	0.029 (2)	−0.019 (3)	0.004 (3)	−0.0007 (19)
O1C	0.0374 (13)	0.0201 (10)	0.0335 (12)	0.0007 (9)	0.0022 (10)	−0.0058 (9)
O1A	0.0258 (15)	0.0288 (17)	0.0258 (15)	0.0005 (13)	0.0024 (11)	−0.0015 (13)
C1C	0.0348 (15)	0.0202 (11)	0.0269 (13)	−0.0052 (11)	0.0076 (12)	−0.0023 (10)
C1A	0.0215 (17)	0.0282 (19)	0.0229 (17)	0.0013 (14)	−0.0015 (14)	−0.0029 (15)
C2D	0.030 (4)	0.011 (2)	0.035 (4)	−0.003 (2)	0.006 (3)	−0.001 (2)
C2B	0.027 (6)	0.035 (7)	0.023 (5)	0.008 (4)	0.011 (4)	−0.002 (4)

Geometric parameters (Å, º) top

Fe1—Cl5	2.1962 (5)	C7—H7A	0.9900
Fe1—Cl4	2.1976 (5)	C7—H7B	0.9900
Fe1—Cl3	2.2044 (5)	C7—C6	1.522 (3)
Fe1—Cl2	2.1946 (6)	C10—H10A	0.9800
N1—C4	1.521 (2)	C10—H10B	0.9800
N1—C2A	1.502 (7)	C10—H10C	0.9800
N1—C3	1.507 (2)	C6—H6A	0.9900
N1—H1	0.86 (3)	C6—H6B	0.9900
N1—C2B	1.492 (13)	C3—H3A	0.9800
C4—H4	1.0000	C3—H3B	0.9800
C4—C9	1.539 (2)	C3—H3C	0.9800
C4—C5	1.535 (2)	C2C—H2CA	0.9900
C9—H9	1.0000	C2C—H2CB	0.9900
C9—N2	1.526 (2)	C2C—C1C	1.763 (9)
C9—C8	1.529 (2)	O1C—H1C	0.8400
N2—C10	1.493 (3)	O1C—C1C	1.408 (4)
N2—C2C	1.494 (9)	O1A—H1A	0.8400
N2—H2	0.88 (3)	O1A—C1A	1.429 (6)
N2—C2D	1.590 (13)	C1C—H1CA	0.9900
C2A—H2AA	0.9800	C1C—H1CB	0.9900
C2A—H2AB	0.9800	C1A—H1AA	0.9900
C2A—H2AC	0.9800	C1A—H1AB	0.9900
C8—H8A	0.9900	C1A—C2B	1.435 (18)
C8—H8B	0.9900	C2D—H2DA	0.9800
C8—C7	1.527 (3)	C2D—H2DB	0.9800
C5—H5A	0.9900	C2D—H2DC	0.9800
C5—H5B	0.9900	C2B—H2BA	0.9900
C5—C6	1.526 (3)	C2B—H2BB	0.9900

Cl5—Fe1—Cl4	108.02 (2)	C8—C7—H7B	109.7
Cl5—Fe1—Cl3	108.99 (3)	H7A—C7—H7B	108.2
Cl4—Fe1—Cl3	109.37 (2)	C6—C7—C8	109.97 (16)
Cl2—Fe1—Cl5	108.95 (2)	C6—C7—H7A	109.7
Cl2—Fe1—Cl4	110.88 (3)	C6—C7—H7B	109.7
Cl2—Fe1—Cl3	110.58 (2)	N2—C10—H10A	109.5
C4—N1—H1	109 (2)	N2—C10—H10B	109.5
C2A—N1—C4	117.7 (4)	N2—C10—H10C	109.5
C2A—N1—C3	108.0 (4)	H10A—C10—H10B	109.5
C2A—N1—H1	104 (2)	H10A—C10—H10C	109.5
C3—N1—C4	110.65 (13)	H10B—C10—H10C	109.5
C3—N1—H1	106.0 (19)	C5—C6—H6A	109.6
C2B—N1—C4	115.9 (6)	C5—C6—H6B	109.6
C2B—N1—C3	111.5 (7)	C7—C6—C5	110.28 (17)
C2B—N1—H1	103 (2)	C7—C6—H6A	109.6
N1—C4—H4	107.7	C7—C6—H6B	109.6
N1—C4—C9	114.68 (12)	H6A—C6—H6B	108.1
N1—C4—C5	110.03 (13)	N1—C3—H3A	109.5
C9—C4—H4	107.7	N1—C3—H3B	109.5
C5—C4—H4	107.7	N1—C3—H3C	109.5
C5—C4—C9	108.84 (13)	H3A—C3—H3B	109.5
C4—C9—H9	107.9	H3A—C3—H3C	109.5
N2—C9—C4	113.85 (12)	H3B—C3—H3C	109.5
N2—C9—H9	107.9	N2—C2C—H2CA	111.6
N2—C9—C8	109.91 (14)	N2—C2C—H2CB	111.6
C8—C9—C4	109.14 (13)	N2—C2C—C1C	101.1 (5)
C8—C9—H9	107.9	H2CA—C2C—H2CB	109.4
C9—N2—H2	108.7 (18)	C1C—C2C—H2CA	111.6
C9—N2—C2D	106.6 (5)	C1C—C2C—H2CB	111.6
C10—N2—C9	114.90 (15)	C1C—O1C—H1C	109.5
C10—N2—C2C	104.9 (3)	C1A—O1A—H1A	109.5
C10—N2—H2	103.8 (18)	C2C—C1C—H1CA	108.8
C10—N2—C2D	120.0 (3)	C2C—C1C—H1CB	108.8
C2C—N2—C9	114.9 (4)	O1C—C1C—C2C	113.9 (3)
C2C—N2—H2	109.0 (18)	O1C—C1C—H1CA	108.8
C2D—N2—H2	101.4 (19)	O1C—C1C—H1CB	108.8
N1—C2A—H2AA	109.5	H1CA—C1C—H1CB	107.7
N1—C2A—H2AB	109.5	O1A—C1A—H1AA	109.3
N1—C2A—H2AC	109.5	O1A—C1A—H1AB	109.3
H2AA—C2A—H2AB	109.5	O1A—C1A—C2B	111.7 (7)
H2AA—C2A—H2AC	109.5	H1AA—C1A—H1AB	107.9
H2AB—C2A—H2AC	109.5	C2B—C1A—H1AA	109.3
C9—C8—H8A	109.2	C2B—C1A—H1AB	109.3
C9—C8—H8B	109.2	N2—C2D—H2DA	109.5
H8A—C8—H8B	107.9	N2—C2D—H2DB	109.5
C7—C8—C9	112.10 (16)	N2—C2D—H2DC	109.5
C7—C8—H8A	109.2	H2DA—C2D—H2DB	109.5
C7—C8—H8B	109.2	H2DA—C2D—H2DC	109.5
C4—C5—H5A	109.3	H2DB—C2D—H2DC	109.5
C4—C5—H5B	109.3	N1—C2B—H2BA	106.9
H5A—C5—H5B	108.0	N1—C2B—H2BB	106.9
C6—C5—C4	111.58 (16)	C1A—C2B—N1	121.8 (12)
C6—C5—H5A	109.3	C1A—C2B—H2BA	106.9
C6—C5—H5B	109.3	C1A—C2B—H2BB	106.9
C8—C7—H7A	109.7	H2BA—C2B—H2BB	106.7

N1—C4—C9—N2	−54.93 (18)	C2A—N1—C4—C5	53.8 (5)
N1—C4—C9—C8	−178.13 (14)	C8—C9—N2—C10	46.55 (19)
N1—C4—C5—C6	174.42 (16)	C8—C9—N2—C2C	−75.3 (4)
C4—N1—C2B—C1A	61.9 (12)	C8—C9—N2—C2D	−89.0 (4)
C4—C9—N2—C10	−76.24 (18)	C8—C7—C6—C5	−55.7 (3)
C4—C9—N2—C2C	161.9 (3)	C5—C4—C9—N2	−178.65 (14)
C4—C9—N2—C2D	148.2 (4)	C5—C4—C9—C8	58.15 (18)
C4—C9—C8—C7	−58.7 (2)	C10—N2—C2C—C1C	128.1 (3)
C4—C5—C6—C7	58.1 (2)	C3—N1—C4—C9	165.95 (13)
C9—C4—C5—C6	−59.1 (2)	C3—N1—C4—C5	−70.97 (17)
C9—N2—C2C—C1C	−104.8 (4)	C3—N1—C2B—C1A	−170.3 (8)
C9—C8—C7—C6	57.3 (2)	O1A—C1A—C2B—N1	40.0 (12)
N2—C9—C8—C7	175.82 (15)	C2B—N1—C4—C9	−65.9 (8)
N2—C2C—C1C—O1C	48.6 (5)	C2B—N1—C4—C5	57.2 (8)
C2A—N1—C4—C9	−69.3 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1	0.855 (3)	2.221 (3)	3.0603 (14)	167 (3)
N2—H2···Cl1	0.878 (3)	2.357 (3)	3.1698 (16)	154 (3)
O1C—H1C···Cl1ⁱ	0.84	2.43	3.229 (3)	159

Symmetry code: (i) x−1/2, −y+3/2, −z+1.

(R,R)-N¹,N¹,N²,N²-Tetramethylcyclohexane-1,2-bis(aminium) tetrachloridoferrate chloride (1a) top

Crystal data top

(C₁₀H₂₄N₂)[FeCl₄]Cl	F(000) = 418
M_r = 405.41	D_x = 1.486 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 10.2322 (3) Å	Cell parameters from 1350 reflections
b = 9.2378 (5) Å	θ = 4.3–31.7°
c = 10.7384 (4) Å	µ = 1.56 mm⁻¹
β = 116.797 (1)°	T = 100 K
V = 906.02 (7) Å³	Prism, yellow
Z = 2	0.50 × 0.43 × 0.38 mm

Data collection top

Bruker D8 VENTURE area detector diffractometer	8442 reflections with I > 2σ(I)
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs	R_int = 0.030
HELIOS mirror optics monochromator	θ_max = 36.3°, θ_min = 2.1°
Detector resolution: 10.4167 pixels mm^-1	h = −13→17
ω and φ scans	k = −15→15
69005 measured reflections	l = −17→17
8763 independent reflections

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.018	w = 1/[σ²(F_o²) + (0.0156P)² + 0.078P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.037	(Δ/σ)_max = 0.001
S = 1.06	Δρ_max = 0.23 e Å⁻³
8763 reflections	Δρ_min = −0.33 e Å⁻³
175 parameters	Absolute structure: Flack x determined using 3826 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
1 restraint	Absolute structure parameter: −0.009 (3)
Primary atom site location: dual

Special details top

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

	x	y	z	U_iso*/U_eq
Fe1	0.73543 (2)	0.37018 (2)	0.11080 (2)	0.01357 (3)
Cl2	0.76183 (3)	0.51878 (3)	0.28052 (3)	0.01944 (5)
Cl5	0.76963 (3)	0.49518 (3)	−0.04548 (3)	0.01960 (5)
Cl1	0.35677 (3)	0.17053 (3)	0.42055 (3)	0.01882 (5)
Cl3	0.52216 (3)	0.26207 (4)	0.02175 (3)	0.02597 (6)
Cl4	0.90709 (3)	0.20084 (3)	0.19738 (3)	0.02248 (5)
N1	0.28286 (10)	0.44077 (10)	0.53384 (9)	0.01356 (15)
N2	0.26193 (10)	0.43743 (10)	0.23871 (9)	0.01275 (14)
C8	0.18173 (11)	0.54564 (11)	0.28693 (10)	0.01174 (15)
H8	0.0835	0.5042	0.2652	0.014*
C9	0.17020 (12)	0.38898 (13)	0.09145 (11)	0.01754 (19)
H9A	0.0722	0.3629	0.0790	0.026*
H9B	0.2159	0.3046	0.0717	0.026*
H9C	0.1625	0.4677	0.0274	0.026*
C7	0.15769 (13)	0.68716 (12)	0.20441 (11)	0.01745 (19)
H7A	0.2536	0.7251	0.2178	0.021*
H7B	0.0983	0.6667	0.1038	0.021*
C3	0.26269 (11)	0.57574 (11)	0.44544 (10)	0.01184 (15)
H3	0.3623	0.6133	0.4670	0.014*
C6	0.08042 (13)	0.80253 (12)	0.24935 (12)	0.01837 (19)
H6A	0.0700	0.8927	0.1958	0.022*
H6B	−0.0187	0.7685	0.2299	0.022*
C1	0.40538 (13)	0.45802 (15)	0.67836 (11)	0.0231 (2)
H1A	0.4946	0.4876	0.6728	0.035*
H1B	0.4226	0.3657	0.7282	0.035*
H1C	0.3790	0.5320	0.7284	0.035*
C5	0.16937 (13)	0.83247 (12)	0.40466 (12)	0.01787 (19)
H5A	0.1201	0.9077	0.4341	0.021*
H5B	0.2677	0.8686	0.4238	0.021*
C10	0.40958 (12)	0.48351 (14)	0.25595 (12)	0.0200 (2)
H10A	0.3979	0.5602	0.1887	0.030*
H10B	0.4595	0.4005	0.2396	0.030*
H10C	0.4679	0.5200	0.3509	0.030*
C4	0.18391 (12)	0.69326 (12)	0.48655 (11)	0.01606 (18)
H4A	0.0853	0.6584	0.4681	0.019*
H4B	0.2394	0.7133	0.5877	0.019*
C2	0.14826 (12)	0.38899 (13)	0.54129 (12)	0.0194 (2)
H2A	0.1253	0.4545	0.6005	0.029*
H2B	0.1651	0.2913	0.5810	0.029*
H2C	0.0661	0.3872	0.4473	0.029*
H1	0.3094 (18)	0.366 (2)	0.4978 (18)	0.025 (4)*
H2	0.2756 (17)	0.3539 (19)	0.2862 (17)	0.022 (4)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Fe1	0.01513 (6)	0.01373 (6)	0.01181 (6)	−0.00141 (5)	0.00605 (5)	−0.00101 (5)
Cl2	0.02272 (11)	0.01915 (11)	0.01510 (10)	0.00063 (9)	0.00734 (9)	−0.00412 (9)
Cl5	0.02426 (12)	0.01906 (12)	0.01887 (10)	0.00237 (10)	0.01270 (9)	0.00438 (9)
Cl1	0.02039 (11)	0.01434 (10)	0.02008 (11)	0.00533 (9)	0.00767 (9)	0.00351 (9)
Cl3	0.02241 (13)	0.03108 (15)	0.02344 (13)	−0.01235 (12)	0.00946 (11)	−0.00656 (11)
Cl4	0.02828 (13)	0.01860 (12)	0.02112 (11)	0.00725 (10)	0.01163 (10)	0.00335 (9)
N1	0.0145 (4)	0.0146 (4)	0.0109 (3)	0.0009 (3)	0.0052 (3)	0.0020 (3)
N2	0.0138 (3)	0.0133 (4)	0.0110 (3)	0.0011 (3)	0.0054 (3)	−0.0002 (3)
C8	0.0124 (4)	0.0121 (4)	0.0103 (3)	0.0013 (3)	0.0047 (3)	0.0003 (3)
C9	0.0200 (4)	0.0178 (5)	0.0126 (4)	−0.0006 (4)	0.0054 (3)	−0.0040 (3)
C7	0.0249 (5)	0.0150 (5)	0.0138 (4)	0.0053 (4)	0.0099 (4)	0.0039 (3)
C3	0.0131 (4)	0.0120 (4)	0.0101 (3)	−0.0003 (3)	0.0050 (3)	0.0010 (3)
C6	0.0229 (5)	0.0152 (4)	0.0172 (4)	0.0058 (4)	0.0092 (4)	0.0032 (4)
C1	0.0212 (5)	0.0290 (6)	0.0122 (4)	−0.0021 (4)	0.0015 (4)	0.0043 (4)
C5	0.0241 (5)	0.0123 (4)	0.0190 (5)	0.0013 (4)	0.0112 (4)	−0.0005 (3)
C10	0.0150 (4)	0.0256 (5)	0.0216 (5)	−0.0018 (4)	0.0101 (4)	−0.0058 (4)
C4	0.0217 (5)	0.0143 (4)	0.0151 (4)	0.0019 (4)	0.0109 (4)	−0.0003 (3)
C2	0.0190 (4)	0.0194 (5)	0.0216 (5)	−0.0018 (4)	0.0106 (4)	0.0053 (4)

Geometric parameters (Å, º) top

Fe1—Cl2	2.1989 (3)	C7—C6	1.5290 (15)
Fe1—Cl5	2.1913 (3)	C3—H3	1.0000
Fe1—Cl3	2.1891 (3)	C3—C4	1.5310 (14)
Fe1—Cl4	2.2191 (3)	C6—H6A	0.9900
N1—C3	1.5237 (13)	C6—H6B	0.9900
N1—C1	1.5004 (14)	C6—C5	1.5224 (16)
N1—C2	1.4939 (13)	C1—H1A	0.9800
N1—H1	0.891 (19)	C1—H1B	0.9800
N2—C8	1.5245 (13)	C1—H1C	0.9800
N2—C9	1.4978 (13)	C5—H5A	0.9900
N2—C10	1.4985 (14)	C5—H5B	0.9900
N2—H2	0.900 (18)	C5—C4	1.5269 (15)
C8—H8	1.0000	C10—H10A	0.9800
C8—C7	1.5358 (14)	C10—H10B	0.9800
C8—C3	1.5458 (13)	C10—H10C	0.9800
C9—H9A	0.9800	C4—H4A	0.9900
C9—H9B	0.9800	C4—H4B	0.9900
C9—H9C	0.9800	C2—H2A	0.9800
C7—H7A	0.9900	C2—H2B	0.9800
C7—H7B	0.9900	C2—H2C	0.9800

Cl2—Fe1—Cl4	108.335 (12)	C8—C3—H3	107.6
Cl5—Fe1—Cl2	107.664 (13)	C4—C3—C8	110.77 (8)
Cl5—Fe1—Cl4	108.833 (12)	C4—C3—H3	107.6
Cl3—Fe1—Cl2	111.878 (13)	C7—C6—H6A	109.8
Cl3—Fe1—Cl5	112.196 (13)	C7—C6—H6B	109.8
Cl3—Fe1—Cl4	107.837 (15)	H6A—C6—H6B	108.2
C3—N1—H1	110.2 (11)	C5—C6—C7	109.49 (9)
C1—N1—C3	111.89 (9)	C5—C6—H6A	109.8
C1—N1—H1	104.8 (11)	C5—C6—H6B	109.8
C2—N1—C3	115.23 (8)	N1—C1—H1A	109.5
C2—N1—C1	109.82 (9)	N1—C1—H1B	109.5
C2—N1—H1	104.1 (11)	N1—C1—H1C	109.5
C8—N2—H2	109.8 (10)	H1A—C1—H1B	109.5
C9—N2—C8	112.18 (8)	H1A—C1—H1C	109.5
C9—N2—C10	109.41 (8)	H1B—C1—H1C	109.5
C9—N2—H2	101.9 (11)	C6—C5—H5A	109.8
C10—N2—C8	116.03 (8)	C6—C5—H5B	109.8
C10—N2—H2	106.4 (10)	C6—C5—C4	109.44 (9)
N2—C8—H8	108.0	H5A—C5—H5B	108.2
N2—C8—C7	109.45 (8)	C4—C5—H5A	109.8
N2—C8—C3	112.87 (8)	C4—C5—H5B	109.8
C7—C8—H8	108.0	N2—C10—H10A	109.5
C7—C8—C3	110.43 (8)	N2—C10—H10B	109.5
C3—C8—H8	108.0	N2—C10—H10C	109.5
N2—C9—H9A	109.5	H10A—C10—H10B	109.5
N2—C9—H9B	109.5	H10A—C10—H10C	109.5
N2—C9—H9C	109.5	H10B—C10—H10C	109.5
H9A—C9—H9B	109.5	C3—C4—H4A	109.4
H9A—C9—H9C	109.5	C3—C4—H4B	109.4
H9B—C9—H9C	109.5	C5—C4—C3	111.00 (8)
C8—C7—H7A	109.1	C5—C4—H4A	109.4
C8—C7—H7B	109.1	C5—C4—H4B	109.4
H7A—C7—H7B	107.8	H4A—C4—H4B	108.0
C6—C7—C8	112.48 (9)	N1—C2—H2A	109.5
C6—C7—H7A	109.1	N1—C2—H2B	109.5
C6—C7—H7B	109.1	N1—C2—H2C	109.5
N1—C3—C8	113.18 (8)	H2A—C2—H2B	109.5
N1—C3—H3	107.6	H2A—C2—H2C	109.5
N1—C3—C4	109.98 (8)	H2B—C2—H2C	109.5

N1—C3—C4—C5	177.07 (8)	C7—C6—C5—C4	−59.87 (12)
N2—C8—C7—C6	−178.78 (9)	C3—C8—C7—C6	−53.93 (12)
N2—C8—C3—N1	−60.24 (11)	C6—C5—C4—C3	60.65 (12)
N2—C8—C3—C4	175.71 (8)	C1—N1—C3—C8	158.64 (9)
C8—C7—C6—C5	57.65 (13)	C1—N1—C3—C4	−76.88 (11)
C8—C3—C4—C5	−57.08 (11)	C10—N2—C8—C7	59.79 (11)
C9—N2—C8—C7	−66.97 (11)	C10—N2—C8—C3	−63.63 (11)
C9—N2—C8—C3	169.61 (9)	C2—N1—C3—C8	−74.97 (11)
C7—C8—C3—N1	176.89 (8)	C2—N1—C3—C4	49.51 (11)
C7—C8—C3—C4	52.84 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1	0.891 (19)	2.133 (19)	3.0189 (11)	172.7 (19)
N2—H2···Cl1	0.900 (18)	2.135 (17)	3.0208 (10)	165 (14)

Funding information

Funding for this research was provided by a scholarship from the Studienstiftung des Deutschen Volkes to FK.

References

Beak, P. & Meyers, A. I. (1986). Acc. Chem. Res. 19, 356–363. CrossRef CAS Google Scholar
Breit, B. (2000). Chem. Eur. J. 6, 1519–1524. CrossRef PubMed CAS Google Scholar
Bruker (2016). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Duesler, E. N., Tapscott, R. E., Garcia-Basallote, M. & Gonzalez-Vílchez, F. (1985). Acta Cryst. C41, 678–681. CSD CrossRef CAS IUCr Journals Google Scholar
Eckert, P. K., Gessner, V. H., Knorr, M. & Strohmann, C. (2012). Inorg. Chem. 51, 8516–8523. CSD CrossRef CAS PubMed Google Scholar
Eckert, P. K., Schill, V. & Strohmann, C. (2011). Inorg. Chim. Acta, 376, 634–637. CSD CrossRef CAS Google Scholar
Eckert, P. K., Schnura, B. & Strohmann, C. (2014). Chem. Commun. 50, 2532–2534. Web of Science CSD CrossRef CAS Google Scholar
Eckert, P. K., dos Santos Vieira, I., Gessner, V. H., Borner, J., Strohmann, C. & Herres-Pawlis, S. (2013). Polyhedron, 49, 151–157. CSD CrossRef CAS Google Scholar
Gessner, V. H. (2009). Dissertation, TU Dortmund University. Google Scholar
Gessner, V. H., Fröhlich, B. & Strohmann, C. (2010). Eur. J. Inorg. Chem. pp. 5640–5649. Web of Science CSD CrossRef 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
Hoveyda, A. H., Evans, D. A. & Fu, G. C. (1993). Chem. Rev. 93, 1307–1370. 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
Lian, P., Hu, Q.-S., Xie, Y.-R. & Guo, H.-X. (2009). Acta Cryst. E65, m32–m33. CSD CrossRef IUCr Journals Google Scholar
McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. pp. 3814–3816. Web of Science CrossRef Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CSD 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
Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19–32. Web of Science CrossRef CAS Google Scholar
Spackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006–1011. Web of Science CrossRef CAS IUCr Journals Google Scholar
Steiner, T. (2002). Angew. Chem. Int. Ed. 41, 48–76. Web of Science CrossRef CAS Google Scholar
Strohmann, C. & Gessner, V. H. (2007). Angew. Chem. Int. Ed. 46, 8281–8283. CSD CrossRef CAS Google Scholar
Strohmann, C. & Gessner, V. H. (2008). J. Am. Chem. Soc. 130, 11719–11725. Web of Science CSD CrossRef PubMed CAS Google Scholar
Whisler, M. C., MacNeil, S., Snieckus, V. & Beak, P. (2004). Angew. Chem. Int. Ed. 43, 2206–2225. CrossRef CAS 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.

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 81| Part 5| May 2025|

https://doi.org/10.1107/S2056989025003019

Open

access

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text
		Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Plain Text
		Text

Search IUCr Journals		doi		Advanced search
Author		volume	page

research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)