(2-Amino­ethan-1-aminium-κN2)tri­chlorido­zinc(II)

Diop, A.; Ndoye, D.; Tinnemans, P.; Zangrando, E.; Diop, C.A.K.

doi:10.1107/S2414314625007710

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 10| Part 9| September 2025| x250771

https://doi.org/10.1107/S2414314625007710

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(2-Aminoethan-1-aminium-κN²)trichloridozinc(II)

Aboubacar Diop,^a ^* Daouda Ndoye,^a Paul Tinnemans,^b Ennio Zangrando ^c and Cheikh Abdoul Khadir Diop ^d

^aInorganic and Analytical Chemistry Laboratory, Department of Chemistry, Faculty of Science and Technology, Cheikh Anta Diop University, Dakar, Senegal, ^bInstitute for Molecules & Materials (IMM), Solid State Chemistry, Faculty of Science, Radboud University, Nijmegen, The Netherlands, ^cDepartement of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy, and ^dInorganic and Analytical Chemistry Laboratory, Departement of Chemistry, Faculty of Science and Technology, Cheikh Anta Diop University, Dakar, Senegal
^*Correspondence e-mail: [email protected]

Edited by M. Weil, Vienna University of Technology, Austria (Received 14 August 2025; accepted 29 August 2025; online 5 September 2025)

The mononuclear zwitterionic Zn^II complex, [ZnCl₃(C₂H₉N₂)], contains a monodentate 2-ammonioethylamine moiety and three chloride anions coordinating to the central zinc atom in form of a distorted tetrahedron. The molecular packing shows amine and ammonium groups interacting through hydrogen-bonding interactions with chlorine atoms of symmetry-related complexes to form a supramolecular framework structure.

Keywords: crystal structure; zinc(II); zwitterionic complex; ethylenediamine.

CCDC reference: 2483701

Structure description

Zwitterionic trichloridozinc(II) complexes with the metal additionally ligated in a monodentate manner by a protonated organic molecule are known (Clemente et al., 2002 ; Maixner & Zachová, 1993 ; Purnell & Hodgson, 1976 ; Sheldrick, 1982 ; Steffen & Palenik, 1978 ; Zhu et al., 2002 ), including a protonated quinine ligand (Kang et al., 2013 ). The commonly used ethylenediamine (en) ligand acts primarily as a chelating ligand, and monodentate (Fanshawe et al., 2000 ) or bridging forms (Çolak et al., 2008 ) of en are rather rare. An example of a protonated and monodentate en ligand has been reported within a germanotungstate polyanion composed of two [GeW₉O₃₄]^10– moieties sandwiching a rhomboid-like Zn₄ cluster, in which two central Zn^II atoms are coordinated by the N atom of the non-protonated amino group (Wang et al. 2010 ). In this context, we synthesized the title complex [ZnCl₃(C₂H₉N₂)] using en, hydrochloric acid and zinc chloride as starting materials.

The molecular structure of [ZnCl₃(C₂H₉N₂)] is characterized by a protonated en ligand, monodentately binding through the amine N atom (N1) to the central Zn^II atom. The tetrahedral coordination environment is completed by three Cl⁻ ligands (Fig. 1). The Zn—N bond length is 2.0345 (10) Å, much shorter than the values found in the Zn^II complexes with chelating ethylendiamine (en) ligands, for example [Zn(en)(acetate)₂] (Kim et al., 2007 ) where the Zn—N distance is 2.0784 (16) Å, or in the complex octahedral cation [Zn(en)₃]²⁺ (Cheng et al., 2008 ) with distances between 2.159 (2) and 2.220 (2). The present Zn—N bond length is also considerably shorter than in the germanotungstate cluster comprising a Zn^II atom bound to a monodentate en ligand [2.121 (16) Å; Wang et al., 2010]. The three Zn—Cl bond lengths in the title complex range from 2.2600 (3) to 2.2686 (3) Å, which is comparable to those previously reported in the complexes having a ZnCl₃ moiety mentioned above. The present Cl—Zn—Cl and N—Zn—Cl bond angles vary from 104.52 (3) to 115.969 (12)°, indicating a considerable distortion from an ideal tetrahedron. The protonated en ligand has an anti-conformation with an N1—C1—C2—N2 torsion angle of 178.18 (10)°.

Figure 1
Molecular structure of the title complex with displacement ellipsoids drawn at the 50% probability level.

The molecular packing is stabilized by an intricate framework of intermolecular N—H⋯Cl hydrogen bonds involving both the amine (N1) and ammonium (N2) groups as donors and all three Cl ligands as acceptor atoms (Table 1). Part of the crystal packing is illustrated in Fig. 2.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Cl1ⁱ	0.883 (18)	2.636 (17)	3.3733 (11)	141.7 (14)
N1—H1B⋯Cl2ⁱⁱ	0.828 (17)	2.678 (18)	3.4620 (11)	158.6 (17)
N2—H2A⋯Cl3ⁱⁱ	0.85 (2)	2.46 (2)	3.2188 (12)	149.2 (17)
N2—H2B⋯Cl1ⁱⁱⁱ	0.87 (2)	2.566 (19)	3.2449 (11)	135.2 (16)
N2—H2C⋯Cl2ⁱ	0.81 (2)	2.70 (2)	3.4526 (12)	154.2 (19)
Symmetry codes: (i) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (iii) .

Figure 2
Partial view of the molecular packing in the crystal of the title complex with N—H⋯Cl hydrogen bonds indicated as dashed lines

Synthesis and crystallization

The title complex was obtained by addition of a methanolic solution (10 ml) of ZnCl₂ (0.136 g, 1 mmol) to a flask containing 10 ml of a methanolic solution of ethylenediamine, C₂H₈N₂ (0.06 g, 1 mmol) and 5 ml of hydrochloric acid HCl (1 N). The resulting mixture was stirred for 2 h at room temperature. A clear solution was obtained and left to evaporate slowly at room temperature, leading to colorless single crystals suitable for single-crystal X-ray diffraction after 24 h.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula	[ZnCl₃(C₂H₉N₂)]
M_r	232.83
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	150
a, b, c (Å)	6.6669 (4), 8.1192 (4), 14.7559 (7)
V (Å³)	798.74 (7)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.99
Crystal size (mm)	0.24 × 0.13 × 0.11

Data collection
Diffractometer	Bruker APEX CCD area-detector
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.407, 0.520
No. of measured, independent and observed [I > 2σ(I)] reflections	11232, 3036, 3017
R_int	0.020
(sin θ/λ)_max (Å⁻¹)	0.770

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.012, 0.026, 1.12
No. of reflections	3036
No. of parameters	101
H-atom treatment	Only H-atom coordinates refined
Δρ_max, Δρ_min (e Å⁻³)	0.29, −0.33
Absolute structure	Refined as an inversion twin Parsons et al., 2013 ]
Absolute structure parameter	0.374 (5)
Computer programs: SMART and SAINT (Bruker, 2000 ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), DIAMOND (Brandenburg & Putz, 1999 ) and WinGX (Farrugia, 2012 ).

Structural data

CCDC reference: 2483701

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314625007710/wm4235sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314625007710/wm4235Isup3.hkl

checkCIF report

Computing details top

(2-Aminoethan-1-aminium-κN²)trichloridozinc(II) top

Crystal data top

[ZnCl₃(C₂H₉N₂)]	D_x = 1.936 Mg m⁻³
M_r = 232.83	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2₁	Cell parameters from 7854 reflections
a = 6.6669 (4) Å	θ = 1.9–25.0°
b = 8.1192 (4) Å	µ = 3.99 mm⁻¹
c = 14.7559 (7) Å	T = 150 K
V = 798.74 (7) Å³	Block, colorless
Z = 4	0.24 × 0.13 × 0.11 mm
F(000) = 464

Data collection top

Bruker APEX CCD area-detector diffractometer	3036 independent reflections
Radiation source: fine-focus sealed tube	3017 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.020
ω scans	θ_max = 33.2°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −9→10
T_min = 0.407, T_max = 0.520	k = −12→12
11232 measured reflections	l = −22→22

Refinement top

Refinement on F²	Hydrogen site location: difference Fourier map
Least-squares matrix: full	Only H-atom coordinates refined
R[F² > 2σ(F²)] = 0.012	w = 1/[σ²(F_o²) + (0.0075P)² + 0.0649P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.026	(Δ/σ)_max = 0.002
S = 1.12	Δρ_max = 0.28 e Å⁻³
3036 reflections	Δρ_min = −0.33 e Å⁻³
101 parameters	Absolute structure: Refined as an inversion twin Parsons et al., 2013]
0 restraints	Absolute structure parameter: 0.374 (5)

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.

Refinement. Refined as a 2-component inversion twin. H atoms were freely refined with U_iso(H) 1.2× or 1.5×U_eq of the parent atom. The crystal structure was refined as a two-component inversion twin [Flack parameter = 0.374 (5); Parsons et al., 2013].

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

	x	y	z	U_iso*/U_eq
Zn1	0.45714 (2)	0.91365 (2)	0.38549 (2)	0.01331 (3)
Cl1	0.29829 (4)	0.98873 (3)	0.25628 (2)	0.01659 (5)
Cl2	0.79364 (4)	0.95070 (4)	0.37517 (2)	0.01909 (5)
Cl3	0.30307 (5)	1.04462 (3)	0.50133 (2)	0.01698 (5)
N1	0.42319 (16)	0.66776 (12)	0.40719 (7)	0.01523 (18)
H1A	0.535 (3)	0.620 (2)	0.3886 (11)	0.018*
H1B	0.427 (3)	0.642 (2)	0.4615 (12)	0.018*
N2	0.08625 (17)	0.31486 (12)	0.33981 (8)	0.0185 (2)
H2A	−0.023 (3)	0.342 (2)	0.3659 (12)	0.028*
H2B	0.105 (3)	0.209 (2)	0.3455 (12)	0.028*
H2C	0.074 (3)	0.338 (2)	0.2865 (14)	0.028*
C1	0.25042 (17)	0.58592 (14)	0.36385 (7)	0.01499 (19)
H1C	0.260 (3)	0.612 (2)	0.2975 (11)	0.018*
H1D	0.129 (3)	0.631 (2)	0.3899 (11)	0.018*
C2	0.26187 (17)	0.40102 (13)	0.38011 (8)	0.01628 (19)
H2E	0.374 (3)	0.356 (2)	0.3522 (11)	0.020*
H2D	0.265 (3)	0.3787 (19)	0.4438 (12)	0.020*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.01369 (6)	0.01376 (5)	0.01250 (5)	−0.00133 (4)	−0.00035 (5)	0.00047 (4)
Cl1	0.01636 (12)	0.02048 (10)	0.01292 (10)	0.00025 (10)	−0.00161 (9)	0.00117 (8)
Cl2	0.01381 (11)	0.02772 (12)	0.01575 (11)	−0.00389 (10)	−0.00020 (9)	0.00146 (9)
Cl3	0.01857 (12)	0.01778 (10)	0.01460 (10)	−0.00088 (9)	0.00209 (9)	−0.00156 (8)
N1	0.0162 (5)	0.0142 (4)	0.0153 (4)	−0.0002 (3)	−0.0010 (3)	0.0007 (3)
N2	0.0190 (5)	0.0143 (4)	0.0222 (5)	−0.0001 (3)	−0.0010 (4)	−0.0024 (4)
C1	0.0161 (5)	0.0123 (4)	0.0165 (4)	0.0001 (4)	−0.0016 (3)	0.0011 (4)
C2	0.0162 (5)	0.0128 (4)	0.0198 (5)	−0.0001 (3)	−0.0024 (4)	0.0012 (4)

Geometric parameters (Å, º) top

Zn1—N1	2.0345 (10)	N2—H2A	0.85 (2)
Zn1—Cl3	2.2600 (3)	N2—H2B	0.87 (2)
Zn1—Cl1	2.2646 (3)	N2—H2C	0.81 (2)
Zn1—Cl2	2.2686 (3)	C1—C2	1.5222 (15)
N1—C1	1.4755 (15)	C1—H1C	1.003 (16)
N1—H1A	0.883 (18)	C1—H1D	0.967 (18)
N1—H1B	0.828 (17)	C2—H2E	0.930 (18)
N2—C2	1.4879 (16)	C2—H2D	0.958 (17)

N1—Zn1—Cl3	106.99 (3)	C2—N2—H2C	110.9 (14)
N1—Zn1—Cl1	110.15 (3)	H2A—N2—H2C	107.2 (19)
Cl3—Zn1—Cl1	107.313 (12)	H2B—N2—H2C	109.4 (18)
N1—Zn1—Cl2	104.52 (3)	N1—C1—C2	109.68 (9)
Cl3—Zn1—Cl2	115.969 (12)	N1—C1—H1C	106.1 (10)
Cl1—Zn1—Cl2	111.728 (11)	C2—C1—H1C	110.9 (9)
C1—N1—Zn1	117.43 (7)	N1—C1—H1D	108.1 (10)
C1—N1—H1A	109.2 (11)	C2—C1—H1D	110.6 (10)
Zn1—N1—H1A	106.5 (11)	H1C—C1—H1D	111.2 (14)
C1—N1—H1B	109.4 (13)	N2—C2—C1	111.18 (9)
Zn1—N1—H1B	113.2 (11)	N2—C2—H2E	105.8 (11)
H1A—N1—H1B	99.6 (16)	C1—C2—H2E	111.0 (11)
C2—N2—H2A	112.0 (13)	N2—C2—H2D	108.7 (11)
C2—N2—H2B	108.0 (14)	C1—C2—H2D	110.0 (10)
H2A—N2—H2B	109.3 (19)	H2E—C2—H2D	110.1 (16)

Zn1—N1—C1—C2	174.46 (7)	N1—C1—C2—N2	178.18 (10)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl1ⁱ	0.883 (18)	2.636 (17)	3.3733 (11)	141.7 (14)
N1—H1B···Cl2ⁱⁱ	0.828 (17)	2.678 (18)	3.4620 (11)	158.6 (17)
N2—H2A···Cl3ⁱⁱ	0.85 (2)	2.46 (2)	3.2188 (12)	149.2 (17)
N2—H2B···Cl1ⁱⁱⁱ	0.87 (2)	2.566 (19)	3.2449 (11)	135.2 (16)
N2—H2C···Cl2ⁱ	0.81 (2)	2.70 (2)	3.4526 (12)	154.2 (19)

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

Acknowledgements

The authors thank the Solid State Chemistry Department of the Institute for Molecules and Materials (IMM), Radboud University, The Netherlands.

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