(N-{Amino­[(di­amino­methyl­idene)amino]­methyl­idene}-N-methyl­methanaminium)tri­bromido­zinc(II)

Germán-Acacio, J.M.; Rivas Arzate, C.; Cardenas-Valencia, Z.; Flores-Alamo, M.; Morales-Morales, D.

doi:10.1107/S2414314616008555

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 6| June 2016| x160855

doi:10.1107/S2414314616008555

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(N-{Amino[(diaminomethylidene)amino]methylidene}-N-methylmethanaminium)tribromidozinc(II)

Juan M. Germán-Acacio,^a Chrystian Rivas Arzate,^a Zeus Cardenas-Valencia,^a Marcos Flores-Alamo ^b ^* and David Morales-Morales ^c

^aResearch Support Network, Instituto Nacional de Ciencias Médicas y Nutrición SZ-Universidad Nacional Autónoma de México (CIC-UNAM), México D.F. Mexico, ^bFacultad de Química, Universidad, Nacional Autónoma de México, CDMX 04510, Mexico, and ^cInstituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, CDMX 04510, Mexico
^*Correspondence e-mail: mfa@unam.mx

Edited by J. Simpson, University of Otago, New Zealand (Received 19 May 2016; accepted 26 May 2016; online 3 June 2016)

In the title compound, [ZnBr₃(C₄H₁₂N₅)], the Zn^II cation is tetrahedrally coordinated by three bromide ions and the (N-{amino[(diaminomethylene)amino]methylene}-N-methylmethanaminium) cation that binds through the central N atom. The complex is of interest as a potential antidiabetic drug of the biguanide family. The crystal structure is stabilized by an extensive series of N—H⋯Br and C—H⋯Br hydrogen bonds, which combine to form a three-dimensional structure.

Keywords: crystal; structure MetforminH+; zinc-complex; hydrogen bonds.

CCDC reference: 1482160

Structure description

The title compound is a complex with a ligand derived from hypoglycaemic agent Metformin, N,N-dimethylimidodicarbonimidic diamide. This has potential applications as an oral antidiabetic drug of the biguanide family (Welton, 1999 ; Pérez-Fernández et al., 2013 ). The asymmetric unit (Fig. 1) consists of a zinc(II) metal atom, tetrahedrally coordinated to the (N-{amino[(diaminomethylene)amino]methylene}-N-methylmethanaminium) cation (MetforminH+) and three bromide ions. A rearrangement of the protonated Metformin molecule results in the N2 atom carrying a positive charge and the MetforminH+ ligand binds through atom N1. Bond lengths and angles (Table 1) confirm a tetrahedral coordination environment for the zinc(II) atom. The MetforminH+ ligand has two planar segments, N1—C4—N4—N5 and N1—C1—N3—N2—C2—C3 inclined to one another at an angle of 65.5 (9)°.

Table 1
Selected geometric parameters (Å, °)

Br1—Zn1	2.3659 (12)	Br3—Zn1	2.3461 (14)
Br2—Zn1	2.3499 (15)	N1—Zn1	2.077 (6)

N1—Zn1—Br1	107.40 (17)	Br3—Zn1—Br1	116.16 (5)
N1—Zn1—Br2	103.87 (19)	Br2—Zn1—Br1	110.13 (6)
N1—Zn1—Br3	106.84 (19)	Br3—Zn1—Br2	111.57 (6)

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as circles of arbitrary size.

In the crystal structure, N3—H3F⋯Br1 and N5—H5G⋯Br3 hydrogen bonds, Table 2, form an R₂²(10) motif while the N3—H3F⋯Br1 and N3—H3G⋯Br1 contacts generate R₄²(8) rings. Atoms Br2 and Br3 act as bifurcated acceptors, forming N5—H5F⋯Br2 and C3—H3C⋯Br2 together with N4—H4G⋯Br3 and N5—H5G⋯Br3 hydrogen bonds that enclose R₂¹(8) and R₂¹(6) rings, respectively. These numerous interactions combine to produce an infinite three-dimensional network structure (Fig. 2).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3F⋯Br1ⁱ	0.91 (2)	2.67 (5)	3.500 (8)	152 (8)
N3—H3G⋯Br1ⁱⁱ	0.91 (2)	2.85 (8)	3.416 (7)	122 (7)
C3—H3D⋯Br2ⁱⁱ	0.96	3.04	3.959 (13)	160
C3—H3C⋯Br2ⁱⁱⁱ	0.96	2.98	3.665 (12)	130
C2—H2A⋯Br2^iv	0.96	2.84	3.747 (10)	157
N5—H5G⋯Br3ⁱ	0.91 (2)	2.68 (5)	3.526 (7)	155 (8)
N4—H4G⋯Br3ⁱ	0.92 (2)	2.65 (6)	3.446 (7)	146 (8)
Symmetry codes: (i) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (ii) $[-x+2, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) x, y+1, z; (iv) $[x, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ .

Figure 2
Part of the crystal packing of the title compound showing N—H⋯Br hydrogen bonds forming the R₂²(10), R₄²(8) and R₂¹(6) ring motifs.

Synthesis and crystallization

A mixture of ZnBr₂ (100 mg, 0.44 mmol) and MetforminH+ hydrochloride (73.61 mg, 0.44 mmol) in 20 ml of an ethanol/water (1:1) solvent mixture was refluxed for 3 h. The resulting solution was evaporated using a rotary evaporator affording a microcrystalline white solid powder that was washed with 20 ml cold ethanol and dried under vacuum to produce the title product in a 52.76% yield, m.p. 170–172°C. CHN analysis: found C: 12.90%; H: 3.17%; N: 17.70%. Calculated, C: 12.29%; H: 3.10%; N: 17.92%. Crystals suitable for analysis by X-ray diffraction were grown from a saturated ethanol solution of the title compound at 4°C.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3.

Table 3
Experimental details

Crystal data
Chemical formula	[ZnBr₃(C₄H₁₂N₅)]
M_r	435.29
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	12.8934 (9), 7.6576 (4), 13.2374 (9)
β (°)	113.580 (8)
V (Å³)	1197.83 (15)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	12.03
Crystal size (mm)	0.26 × 0.23 × 0.15

Data collection
Diffractometer	Agilent Xcalibur Atlas Gemini
Absorption correction	Analytical (CrysAlis RED; Agilent, 2013 )
T_min, T_max	0.094, 0.215
No. of measured, independent and observed [I > 2σ(I)] reflections	11024, 2985, 2312
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.693

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.206, 1.08
No. of reflections	2985
No. of parameters	138
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	2.95, −2.33
Computer programs: CrysAlis PRO (Agilent, 2013), SHELXS2014 (Sheldrick, 2008 ), SHELXS2014 (Sheldrick, 2015 ), Mercury (Macrae et al., 2008 ) and WinGX (Farrugia, 2012 ).

Structural data

CCDC reference: 1482160

Crystal structure: contains datablocks global, I, New_Global_Publ_Block. DOI: 10.1107/S2414314616008555/sj4040sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616008555/sj4040Isup2.hkl

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXS2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 2012).

(N-{Amino[(diaminomethylidene)amino]methylidene}-N-methylmethanaminium)tribromidozinc(II) top

Crystal data top

[ZnBr₃(C₄H₁₂N₅)]	F(000) = 824
M_r = 435.29	D_x = 2.414 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3360 reflections
a = 12.8934 (9) Å	θ = 3.5–29.5°
b = 7.6576 (4) Å	µ = 12.03 mm⁻¹
c = 13.2374 (9) Å	T = 298 K
β = 113.580 (8)°	Block, colourless
V = 1197.83 (15) Å³	0.26 × 0.23 × 0.15 mm
Z = 4

Data collection top

Agilent Xcalibur Atlas Gemini diffractometer	2985 independent reflections
Graphite monochromator	2312 reflections with I > 2σ(I)
Detector resolution: 10.4685 pixels mm^-1	R_int = 0.032
ω scans	θ_max = 29.5°, θ_min = 3.5°
Absorption correction: analytical (CrysAlis RED; Agilent, 2013)	h = −17→16
T_min = 0.094, T_max = 0.215	k = −10→10
11024 measured reflections	l = −15→17

Refinement top

Refinement on F²	6 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.062	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.206	w = 1/[σ²(F_o²) + (0.1109P)² + 10.4971P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max < 0.001
2985 reflections	Δρ_max = 2.95 e Å⁻³
138 parameters	Δρ_min = −2.33 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.

Refinement. PROBLEM: Check Calcd Positive Residual Density on Zn1 3.07 eA3 RESPONSE: Residual close to Br1 (0.6 A), possible consequence of an unresolved disorder.

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

	x	y	z	U_iso*/U_eq
C1	0.8091 (6)	0.9864 (9)	0.6725 (6)	0.0231 (14)
C2	0.7232 (9)	1.0786 (14)	0.7966 (8)	0.044 (2)
H2A	0.7472	1.0422	0.872	0.067*
H2B	0.6625	1.0051	0.7504	0.067*
H2C	0.6977	1.1975	0.7894	0.067*
C3	0.9242 (10)	1.1520 (14)	0.8330 (9)	0.056 (3)
H3C	0.9363	1.2516	0.795	0.085*
H3D	0.9864	1.0723	0.8501	0.085*
H3E	0.9189	1.1893	0.9	0.085*
C4	0.6535 (7)	0.9019 (10)	0.5127 (6)	0.0259 (15)
Br1	0.87048 (8)	0.66446 (14)	0.87937 (7)	0.0410 (3)
Br2	0.77575 (13)	0.43610 (16)	0.59611 (10)	0.0639 (4)
Br3	0.54231 (9)	0.58951 (16)	0.69159 (8)	0.0485 (3)
N1	0.7192 (5)	0.8762 (8)	0.6202 (5)	0.0225 (12)
N2	0.8191 (6)	1.0647 (9)	0.7628 (5)	0.0279 (14)
N3	0.8886 (7)	0.9994 (10)	0.6327 (7)	0.0356 (16)
N4	0.5913 (7)	0.7710 (11)	0.4543 (6)	0.0398 (18)
N5	0.6419 (7)	1.0577 (10)	0.4666 (6)	0.0375 (17)
Zn1	0.72516 (8)	0.64108 (11)	0.70055 (7)	0.0245 (3)
H3F	0.874 (8)	0.923 (10)	0.576 (5)	0.029*
H3G	0.942 (6)	1.076 (10)	0.674 (6)	0.029*
H5F	0.645 (8)	1.163 (6)	0.500 (7)	0.029*
H5G	0.606 (7)	1.055 (13)	0.3919 (19)	0.029*
H4F	0.617 (8)	0.663 (6)	0.483 (7)	0.029*
H4G	0.547 (7)	0.808 (12)	0.385 (3)	0.029*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.025 (3)	0.017 (3)	0.025 (3)	−0.001 (3)	0.008 (3)	0.006 (3)
C2	0.055 (6)	0.045 (5)	0.040 (5)	0.008 (5)	0.025 (5)	−0.012 (4)
C3	0.055 (6)	0.040 (5)	0.045 (6)	−0.017 (5)	−0.010 (5)	−0.015 (4)
C4	0.025 (4)	0.027 (4)	0.025 (4)	−0.001 (3)	0.010 (3)	0.002 (3)
Br1	0.0369 (5)	0.0498 (6)	0.0317 (5)	0.0027 (4)	0.0088 (4)	0.0037 (4)
Br2	0.0919 (10)	0.0437 (6)	0.0574 (7)	0.0084 (6)	0.0312 (7)	−0.0042 (5)
Br3	0.0416 (6)	0.0593 (7)	0.0437 (6)	−0.0129 (5)	0.0161 (4)	−0.0027 (5)
N1	0.026 (3)	0.016 (3)	0.021 (3)	−0.005 (2)	0.004 (2)	0.003 (2)
N2	0.032 (3)	0.024 (3)	0.022 (3)	−0.003 (3)	0.005 (3)	−0.005 (3)
N3	0.034 (4)	0.037 (4)	0.043 (4)	−0.006 (3)	0.022 (3)	−0.005 (3)
N4	0.048 (4)	0.039 (4)	0.021 (3)	−0.009 (4)	0.003 (3)	0.002 (3)
N5	0.047 (4)	0.030 (4)	0.024 (3)	0.004 (3)	0.002 (3)	0.006 (3)
Zn1	0.0285 (5)	0.0213 (4)	0.0225 (4)	−0.0033 (3)	0.0089 (4)	0.0012 (3)

Geometric parameters (Å, º) top

C1—N2	1.297 (10)	C4—N4	1.322 (11)
C1—N3	1.330 (10)	C4—N1	1.348 (10)
C1—N1	1.376 (9)	Br1—Zn1	2.3659 (12)
C2—N2	1.477 (12)	Br2—Zn1	2.3499 (15)
C2—H2A	0.96	Br3—Zn1	2.3461 (14)
C2—H2B	0.96	N1—Zn1	2.077 (6)
C2—H2C	0.96	N3—H3F	0.91 (2)
C3—N2	1.463 (11)	N3—H3G	0.91 (2)
C3—H3C	0.96	N4—H4F	0.91 (2)
C3—H3D	0.96	N4—H4G	0.92 (2)
C3—H3E	0.96	N5—H5F	0.91 (2)
C4—N5	1.322 (11)	N5—H5G	0.91 (2)

N2—C1—N3	121.5 (7)	C1—N1—Zn1	115.0 (5)
N2—C1—N1	120.0 (7)	C1—N2—C3	121.5 (8)
N3—C1—N1	118.3 (7)	C1—N2—C2	121.7 (7)
N2—C2—H2A	109.5	C3—N2—C2	116.7 (8)
N2—C2—H2B	109.5	C1—N3—H3F	110 (6)
H2A—C2—H2B	109.5	C1—N3—H3G	110 (6)
N2—C2—H2C	109.5	H3F—N3—H3G	140 (9)
H2A—C2—H2C	109.5	C4—N4—H4F	114 (6)
H2B—C2—H2C	109.5	C4—N4—H4G	110 (6)
N2—C3—H3C	109.5	H4F—N4—H4G	133 (9)
N2—C3—H3D	109.5	C4—N5—H5F	127 (6)
H3C—C3—H3D	109.5	C4—N5—H5G	113 (6)
N2—C3—H3E	109.5	H5F—N5—H5G	117 (9)
H3C—C3—H3E	109.5	N1—Zn1—Br1	107.40 (17)
H3D—C3—H3E	109.5	N1—Zn1—Br2	103.87 (19)
N5—C4—N4	119.0 (7)	N1—Zn1—Br3	106.84 (19)
N5—C4—N1	121.7 (7)	Br3—Zn1—Br1	116.16 (5)
N4—C4—N1	119.0 (7)	Br2—Zn1—Br1	110.13 (6)
C4—N1—C1	119.3 (6)	Br3—Zn1—Br2	111.57 (6)
C4—N1—Zn1	123.1 (5)

N5—C4—N1—C1	−26.7 (12)	N2—C1—N1—Zn1	−71.2 (8)
N4—C4—N1—C1	159.3 (8)	N3—C1—N1—Zn1	103.8 (7)
N5—C4—N1—Zn1	172.5 (6)	N3—C1—N2—C3	−8.1 (12)
N4—C4—N1—Zn1	−1.5 (11)	N1—C1—N2—C3	166.7 (8)
N2—C1—N1—C4	126.5 (8)	N3—C1—N2—C2	168.4 (8)
N3—C1—N1—C4	−58.5 (10)	N1—C1—N2—C2	−16.8 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3F···Br1ⁱ	0.91 (2)	2.67 (5)	3.500 (8)	152 (8)
N3—H3G···Br1ⁱⁱ	0.91 (2)	2.85 (8)	3.416 (7)	122 (7)
C3—H3D···Br2ⁱⁱ	0.96	3.04	3.959 (13)	160
C3—H3C···Br2ⁱⁱⁱ	0.96	2.98	3.665 (12)	130
C2—H2A···Br2^iv	0.96	2.84	3.747 (10)	157
N5—H5G···Br3ⁱ	0.91 (2)	2.68 (5)	3.526 (7)	155 (8)
N4—H4G···Br3ⁱ	0.92 (2)	2.65 (6)	3.446 (7)	146 (8)

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

Acknowledgements

The financial support of our research by CONACYT (247089) and PAPIIT (IA202315) is gratefully acknowledged.

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