catena-Poly[[dichloro­zinc(II)]-μ-cyano­guanidine]

Ritche, L.K.; Harrison, W.T.A.

doi:10.1107/S1600536807003807

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 63| Part 2| February 2007| Pages m617-m618

https://doi.org/10.1107/S1600536807003807

catena-Poly[[dichlorozinc(II)]-μ-cyanoguanidine]

Lyndsey K. Ritche ^a and William T. A. Harrison ^a ^*

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
^*Correspondence e-mail: w.harrison@abdn.ac.uk

(Received 22 January 2007; accepted 23 January 2007; online 31 January 2007)

The one-dimensional title compound, [ZnCl₂(C₂H₄N₄)]_n, contains ZnCl₂N₂ tetraheda linked by N,N-bridging cyanoguanidine molecules. A network of N—H⋯Cl hydrogen bonds help to establish the crystal packing.

Comment

The title compound, (I) (Fig. 1), is a one-dimensional coordination polymer containing cyanoguanidine molecules, Zn²⁺ ions and Cl⁻ ions. The Zn²⁺ cation is tetrahedrally coordinated by two terminal Cl⁻ ions and two cyanoguanidine molecules (Table 1), one bonded through the cyanide atom N4 and one from the imine atom N3. The C1—N3—C2 bond angle in (I) is 116.22 (15)°, compared with the corresponding angle of 118.38 (2)° in the free ligand (Hirshfeld & Hope, 1980 ). The C1—N3 [1.370 (2) Å] and C2—N3 [1.308 (3) Å] bond lengths in (I) indicate that the conventional Lewis structure shown in the chemical scheme (C1=N3 a formal double bond and C2—N3 a formal single bond) is only a very approximate representation of the actual electron distribution in the molecule (Hughes, 1940 ; Hirshfeld & Hope, 1980).

The connectivity of the building units in (I) results in a polymeric chain of stoichiometry Zn(C₂H₄N₄)Cl₂ (Fig. 2), which propagates in the polar [001] direction. The chain conformation is reinforced by an intra-chain N1—H2⋯Cl1 hydrogen bond. Further N—H⋯Cl bonds cross-link the polymeric strands (Table 2). Atom H1 has no nearby Cl⁻ ions but possibly forms a weak bifurcated N—H⋯(Cl,Cl) interaction (bond angle sum for H1 = 359°).

Two polymorphs of the molecular compound Zn(C₂H₄N₄)₂Cl₂ have been reported by Pickardt & Kuhn (1995 ) and Fowkes & Harrison (2005 ). These both contain ZnCl₂N₂ tetrahedra, with the two cyanoguanidine molecules both bonding through their cyanide N atoms. Other compounds with the stoichiometry of the title compound, M(C₂H₄N₄)X₂ (M is a divalent metal cation and X is a halide) include Hg(C₂H₄N₄)Cl₂ and Cd(C₂H₄N₄)Br₂ (Pickardt & Kuhn, 1996 ). The mercury compound contains N,N-bonded cyanoguanidine molecues, as seen here in (I), but the Cl⁻ ions also act as μ₂ bridges between the irregularly-coordinated Hg²⁺ ions, leading to a layered polymeric network. The cadmium compound features cyanide-N-bonded cyanoguanidine molecules and bridging Br⁻ ions, leading to one-dimensional chains of distorted tetrahedral CdN₂Br₂ units.

Figure 1
The asymmetric unit of (I)

, expanded to show the polymeric connectivity (open bonds) of the chain. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radius. The intra-chain hydrogen bond is indicated by a double-dashed line. [Symmetry codes: (i) 1 − x, −y, z − $[{1\over 2}]$ , (ii) 1 − x, −y, z + $[{1\over 2}]$ .]

Figure 2
Part of an [001] polymeric chain in (I)

. [Symmetry codes: (ii) 1 − x, −y, z + $[{1\over 2}]$ , (iii) x, y, z + 1.]

Experimental

An aqueous solution (10 ml) of cyanoguanidine (0.73 M) and a methanolic solution (10 ml) of ZnCl₂ (0.73 M) were mixed at 293 K in a Petri dish, resulting in a colourless mixture. Colourless blocks and slabs of (I) grew over the course of a few days as the water/methanol evaporated at 293 K.

Crystal data

[ZnCl₂(C₂H₄N₄)]
M_r = 220.36
Orthorhombic, P c a 2₁
a = 13.6756 (8) Å
b = 7.3710 (5) Å
c = 7.4200 (5) Å
V = 747.96 (8) Å³
Z = 4
D_x = 1.957 Mg m⁻³
Mo Kα radiation
μ = 3.92 mm⁻¹
T = 293 (2) K
Slab, colourless
0.51 × 0.49 × 0.09 mm

Data collection

Bruker SMART1000 CCD area-detector diffractometer
ω scans
Absorption correction: multi-scan (SADABS; Bruker, 1999 ) T_min = 0.240, T_max = 0.720
9597 measured reflections
2612 independent reflections
2481 reflections with I > 2σ(I)
R_int = 0.039
θ_max = 32.5°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.026
wR(F²) = 0.071
S = 1.05
2612 reflections
83 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.047P)²] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.57 e Å⁻³
Extinction correction: SHELXL97 (Sheldrick, 1997 )
Extinction coefficient: 0.0218 (16)
Absolute structure: Flack (1983 ), with 1163 Friedel pairs
Flack parameter: 0.027 (11)

Table 1
Selected bond lengths (Å)

Zn1—N4^iv	1.985 (2)
Zn1—N3	2.0887 (14)
Zn1—Cl2	2.2238 (7)
Zn1—Cl1	2.2252 (7)
Symmetry code: (iv) $[-x+1, -y, z-{\script{1\over 2}}]$ .

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Cl1^v	0.86	2.92	3.6437 (18)	144
N1—H1⋯Cl2^vi	0.86	2.92	3.389 (2)	116
N1—H2⋯Cl1	0.86	2.48	3.3050 (18)	161
N2—H3⋯Cl1^v	0.86	2.42	3.262 (2)	166
N2—H4⋯Cl2^vii	0.86	2.50	3.289 (2)	153
Symmetry codes: (v) $[x+{\script{1\over 2}}, -y+1, z]$ ; (vi) $[-x+1, -y+1, z-{\script{1\over 2}}]$ ; (vii) $[x+{\script{1\over 2}}, -y, z]$ .

H atoms were placed in idealized locations, with N—H = 0.86 Å, and refined as riding, with U_iso(H) = 1.2U_eq(N).

Data collection: SMART (Bruker, 1999); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536807003807/pk2001sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807003807/pk2001Isup2.hkl

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

catena-Poly[[dichlorozinc(II)]-µ-cyanoguanidine] top

Crystal data top

[ZnCl₂(C₂H₄N₄)]	F(000) = 432
M_r = 220.36	D_x = 1.957 Mg m⁻³
Orthorhombic, Pca2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 6450 reflections
a = 13.6756 (8) Å	θ = 2.8–32.5°
b = 7.3710 (5) Å	µ = 3.92 mm⁻¹
c = 7.4200 (5) Å	T = 293 K
V = 747.96 (8) Å³	Slab, colourless
Z = 4	0.51 × 0.49 × 0.09 mm

Data collection top

Bruker SMART1000 CCD area-detector diffractometer	2612 independent reflections
Radiation source: fine-focus sealed tube	2481 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
ω scans	θ_max = 32.5°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −20→20
T_min = 0.240, T_max = 0.720	k = −10→11
9597 measured reflections	l = −11→9

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.026	w = 1/[σ²(F_o²) + (0.047P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.071	(Δ/σ)_max < 0.001
S = 1.05	Δρ_max = 0.49 e Å⁻³
2612 reflections	Δρ_min = −0.57 e Å⁻³
83 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.0218 (16)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), with 1163 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.027 (11)

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
Zn1	0.424511 (14)	0.23356 (3)	0.72398 (5)	0.02943 (8)
Cl1	0.40928 (4)	0.51909 (9)	0.63074 (11)	0.04953 (16)
Cl2	0.33515 (4)	0.15972 (8)	0.96339 (10)	0.04576 (14)
C1	0.65364 (13)	0.2735 (2)	0.7454 (3)	0.0276 (4)
C2	0.58011 (11)	0.0556 (3)	0.9148 (3)	0.0307 (4)
N1	0.64494 (13)	0.4213 (3)	0.6480 (3)	0.0420 (4)
H1	0.6963	0.4784	0.6126	0.050*
H2	0.5879	0.4611	0.6196	0.050*
N2	0.74078 (13)	0.2115 (3)	0.7896 (3)	0.0390 (4)
H3	0.7924	0.2680	0.7545	0.047*
H4	0.7460	0.1146	0.8534	0.047*
N3	0.56986 (10)	0.1852 (2)	0.7959 (2)	0.0265 (3)
N4	0.58423 (12)	−0.0587 (4)	1.0211 (4)	0.0471 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.02959 (11)	0.02627 (11)	0.03243 (13)	0.00409 (6)	−0.00139 (11)	−0.00518 (13)
Cl1	0.0527 (3)	0.0378 (3)	0.0581 (4)	0.0195 (2)	0.0104 (3)	0.0144 (3)
Cl2	0.0439 (2)	0.0449 (3)	0.0484 (3)	−0.0134 (2)	0.0135 (2)	−0.0086 (3)
C1	0.0270 (7)	0.0267 (7)	0.0291 (11)	−0.0018 (5)	0.0025 (6)	0.0031 (7)
C2	0.0255 (7)	0.0336 (10)	0.0330 (10)	−0.0001 (6)	0.0009 (6)	0.0073 (8)
N1	0.0390 (8)	0.0353 (9)	0.0515 (12)	0.0006 (7)	0.0059 (8)	0.0180 (9)
N2	0.0247 (7)	0.0397 (9)	0.0525 (12)	−0.0014 (7)	−0.0001 (7)	0.0112 (8)
N3	0.0253 (6)	0.0253 (7)	0.0290 (8)	−0.0018 (5)	−0.0008 (5)	0.0043 (6)
N4	0.0321 (8)	0.0528 (13)	0.0563 (15)	0.0059 (7)	0.0077 (7)	0.0275 (11)

Geometric parameters (Å, º) top

Zn1—N4ⁱ	1.985 (2)	C2—N4	1.156 (3)
Zn1—N3	2.0887 (14)	C2—N3	1.308 (3)
Zn1—Cl2	2.2238 (7)	N1—H1	0.8600
Zn1—Cl1	2.2252 (7)	N1—H2	0.8600
C1—N1	1.313 (3)	N2—H3	0.8600
C1—N2	1.318 (3)	N2—H4	0.8600
C1—N3	1.370 (2)	N4—Zn1ⁱⁱ	1.985 (2)

N4ⁱ—Zn1—N3	98.07 (7)	C1—N1—H1	120.0
N4ⁱ—Zn1—Cl2	114.44 (8)	C1—N1—H2	120.0
N3—Zn1—Cl2	106.09 (5)	H1—N1—H2	120.0
N4ⁱ—Zn1—Cl1	111.87 (9)	C1—N2—H3	120.0
N3—Zn1—Cl1	109.26 (5)	C1—N2—H4	120.0
Cl2—Zn1—Cl1	115.37 (3)	H3—N2—H4	120.0
N1—C1—N2	120.42 (18)	C2—N3—C1	116.22 (15)
N1—C1—N3	117.97 (17)	C2—N3—Zn1	113.50 (11)
N2—C1—N3	121.60 (18)	C1—N3—Zn1	130.18 (14)
N4—C2—N3	176.63 (17)	C2—N4—Zn1ⁱⁱ	171.1 (2)

N1—C1—N3—C2	−169.9 (2)	Cl2—Zn1—N3—C2	29.17 (17)
N2—C1—N3—C2	11.4 (3)	Cl1—Zn1—N3—C2	154.14 (16)
N1—C1—N3—Zn1	6.2 (3)	N4ⁱ—Zn1—N3—C1	94.6 (2)
N2—C1—N3—Zn1	−172.58 (18)	Cl2—Zn1—N3—C1	−146.97 (18)
N4ⁱ—Zn1—N3—C2	−89.24 (19)	Cl1—Zn1—N3—C1	−22.0 (2)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1ⁱⁱⁱ	0.86	2.92	3.6437 (18)	144
N1—H1···Cl2^iv	0.86	2.92	3.389 (2)	116
N1—H2···Cl1	0.86	2.48	3.3050 (18)	161
N2—H3···Cl1ⁱⁱⁱ	0.86	2.42	3.262 (2)	166
N2—H4···Cl2^v	0.86	2.50	3.289 (2)	153

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

References

Bruker (1999). SMART (Version 5.624), SAINT-Plus (Version 6.02a) and SADABS (Version 2.03). Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Fowkes, A. & Harrison, W. T. A. (2005). Acta Cryst. E61, m2021–m2022. Web of Science CSD CrossRef IUCr Journals Google Scholar
Hirshfeld, F. L. & Hope, H. (1980). Acta Cryst. B36, 406–415. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Hughes, E. W. (1940). J. Am. Chem. Soc. 62, 1258–1267. CrossRef CAS Google Scholar
Pickardt, J. & Kuhn, B. (1995). Z. Kristallogr. 210, 901–901. CrossRef CAS Web of Science Google Scholar
Pickardt, J. & Kuhn, B. (1996). Z. Naturforsch. Teil B, 51, 1701–1706. CAS Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar

© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.