Dichloridobis(4-fluoro­aniline-κN)zinc

Ashokkumar Subashini; Kandasamy Ramamurthi; Helen Stoeckli-Evans

doi:10.1107/S1600536812033922

. 2012 Aug 4;68(Pt 9):m1152. doi: 10.1107/S1600536812033922

Dichloridobis(4-fluoroaniline-κN)zinc

Ashokkumar Subashini ^a, Kandasamy Ramamurthi ^a,^*, Helen Stoeckli-Evans ^b,^*

PMCID: PMC3435581 PMID: 22969454

Abstract

In the title compound, [ZnCl₂(C₆H₆FN)₂], the Zn^II atom has a slightly distorted tetrahedral geometry, being coordinated by the N atoms of two 4-fluoroaniline molecules and the two Cl⁻ anions. The two benzene rings are almost perpendicular to one another, making a dihedral angle of 89.96 (13)°. In the crystal, molecules are linked via pairs of N—H⋯Cl hydrogen bonds, forming chains propagating along the b axis. These chains are in turn linked via a second pair of N—H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to the ab plane. The title compound crystallizes in the space group Pca2₁ and exhibits weak second harmonic generation (SHG) properties.

Related literature

For the measurement of second harmonic generation (SHG) conversion efficiency, see: Kurtz & Perry (1968 ▶). For the crystal structure of dichlorido-bis(p-chloroaniline)zinc, see: Subashini et al. (2012a ▶) and for the crystal structure of dichlorodo-bis(p-bromoaniline)zinc, see: Subashini et al. (2012b ▶); Feng et al. (2003 ▶).

Experimental

Crystal data

[ZnCl₂(C₆H₆FN)₂]
M _r = 358.51
Orthorhombic,
a = 11.6817 (5) Å
b = 4.7080 (2) Å
c = 25.2056 (15) Å
V = 1386.24 (12) Å³
Z = 4
Mo Kα radiation
μ = 2.17 mm⁻¹
T = 173 K
0.45 × 0.22 × 0.10 mm

Data collection

Stoe IPDS 2 diffractometer
Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009 ▶) T _min = 0.742, T _max = 0.805
7963 measured reflections
2613 independent reflections
2465 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.020
wR(F ²) = 0.043
S = 1.02
2613 reflections
172 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.32 e Å⁻³
Absolute structure: Flack (1983 ▶), 1273 Friedel pairs
Flack parameter: 0.013 (10)

Data collection: X-AREA (Stoe & Cie, 2009 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2009 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97, PLATON and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812033922/is5178sup1.cif

e-68-m1152-sup1.cif^{(23.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033922/is5178Isup2.hkl

e-68-m1152-Isup2.hkl^{(128.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯Cl2ⁱ	0.92	2.63	3.436 (2)	147
N2—H2B⋯Cl1ⁱ	0.92	2.55	3.380 (2)	151
N1—H1A⋯Cl2ⁱⁱ	0.92	2.59	3.479 (2)	162
N2—H2A⋯Cl1ⁱⁱⁱ	0.92	2.55	3.439 (2)	162

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

AS thanks the University Grants Commission, India, for the award of a Research Fellowship in Sciences for Meritorious Students [File No. 4–1/2008 (BSR)]. HSE thanks the XRD Application Laboratory, CSEM, Neuchâtel, for access to the X-ray diffraction equipment.

supplementary crystallographic information

Comment

In our search for compounds exhibiting second harmonic generation (SHG) properties we have synthesized a series of ZnCl₂ complexes of p-halogen substituted anilines. The title compound, the ZnCl₂ complex of p-fluoroaniline crystallized in the noncentrosymmetric orthorhombic space group Pca2₁, while the p-chloroaniline (Subashini et al., 2012a) and p-bromoaniline (Subashini et al., 2012b; Feng et al., 2003) ZnCl₂ complexes crystallized in the centrosymmetric monoclinic space group C2/c and both molecules have crystallographic 2-fold rotation symmetry.

In the title compound (Fig. 1), the zinc atom has a slightly distorted tetrahedral geometry, being coordinated by the atoms N1 and N2 of two p-fluoroaniline molecules and the two Cl^- anions. The two benzene rings (C1—C6 and C7—C12) are perpendicular to one another with a dihedral angle of 89.96 (13)°. In the p-chloroaniline and p-bromoaniline ZnCl₂ complexes mentioned above the same angles are 80.65 (16) and 80.0 (3)°, respectively.

In the crystal of the title compound, molecules are linked via a pair of N—H···Cl hydrogen bonds forming chains propagating along the b axis direction. These chains are in turn linked via a second pair of N—H···Cl hydrogen bonds to form a two-dimensional network lying parallel to the ab plane (Table 1 and Fig. 2). This contrasts with the packing in the crystals of the p-chloroaniline and p-bromoaniline ZnCl₂ complexes. There molecules are linked by four N—H···halogen bonds to form chains propagating along [010], with no significant interactions between the chains.

As the title compound crystallized in a noncentrosymmetric space group it was decided to measure the second harmonic generation (SHG) properties of all three compounds; dichloro-bis(p-fluoroaniline)zinc, dichloro-bis(p-chloroaniline)zinc and dichloro-bis(p-bromoaniline)zinc. The SHG conversion efficiency was determined by the powder technique developed by (Kurtz & Perry, 1968). The crystals were powdered and the fine powdered samples were inserted in a micro-capillary tube and then subjected to a Q-switched Nd: YAG laser emitting 1064 nm radiation with 3.9 mJ/pulse. The frequency doubling was confirmed by the emission of green radiation of wavelength 532 nm collected by a monochromator after separating the 1064 nm pump beam with an IR-blocking filter. A detector connected to a power meter was used to detect the second harmonic intensity.

The output beam voltage produced by dichloro-bis(p-fluoroaniline)zinc, dichloro-bis(p-chloroaniline)zinc and dichloro-bis(p-bromoaniline)zinc derivatives were 15, 3 and 10 mV, respectively. The same quantity of crystalline KDP (potassium dihydrogen phosphate) powder, used as a reference material, produced 140 mV as output beam voltage. Hence the three samples exhibits SHG efficiency of only ca 0.11, 0.02 and 0.07 times that of the KDP.

Experimental

The title compound was prepared by the condensation reaction of p-fluoroaniline with ZnCl₂ in a 1:1 molar ratio. The reaction mixture was dissolved in methanol and heated under reflux for 6 h. The resulting solution was filtered and allowed to evaporate. Colourless rod-like crystals of the title compound, suitable for X-ray diffraction analysis, were obtained in a period of ca 7 days. The same method was used for the preparation of the p-chloroaniline and p-bromoaniline ZnCl₂ complexes.