Crystal structure of di-μ-chlorido-bis(chlorido­{N 1-phenyl-N 4-[(pyridin-2-yl-κN)methyl­idene]benzene-1,4-di­amine-κN 4}mercury(II))

Md Serajul Haque Faizi; Elena V Prisyazhnaya

doi:10.1107/S2056989015015790

. 2015 Aug 29;71(Pt 9):m175–m176. doi: 10.1107/S2056989015015790

Crystal structure of di-μ-chlorido-bis(chlorido{N ¹-phenyl-N ⁴-[(pyridin-2-yl-κN)methylidene]benzene-1,4-diamine-κN ⁴}mercury(II))

Md Serajul Haque Faizi ^a, Elena V Prisyazhnaya ^b,^*

PMCID: PMC4555402 PMID: 26396873

Abstract

The whole molecule of the title complex, [Hg₂Cl₄(C₁₈H₁₅N₃)₂], is generated by inversion symmetry. It was synthesized from the pyridine-derived Schiff base N-phenyl-N′-[(pyridin-2-yl)methylidene]benzene-1,4-diamine (PPMBD). The five-coordinated Hg²⁺ ions have a distorted square-pyramidal environment defined by two N atoms, viz. the imine and the other pyridyl [Hg—N = 2.467 (6) and 2.310 (6) Å, respectively] belonging to the bidentate iminopyridine ligand, and three Cl atoms [Hg—Cl = 2.407 (2), 2.447 (2) and 3.031 (2) Å]. The longest Hg—Cl bond is bridging about the inversion centre. In the ligand, the central ring and pyridine ring are oriented at a dihedral angle of 8.1 (4)°, while the planes of the pyridine ring and the terminal phenyl ring are oriented at a dihedral angle of 53.8 (4)°. In the crystal, molecules are linked by N—H⋯Cl and C—H⋯Cl hydrogen bonds, forming sheets parallel to (001).

Keywords: crystal structure, mercury(II), Schiff base, bidentate ligand, inversion symmetry, hydrogen bonding

Related literature

For applications of pyridincarbaldehyde and related structures, see: Baul et al. (2004 ▸); Das et al. (2013 ▸); Faizi & Sen (2014 ▸); Hughes & Prince (1978 ▸); Jursic et al. (2002 ▸); Kasselouri et al. (1993 ▸); Mandal et al. (2012 ▸); Motswainyana et al. (2013 ▸); Song et al. (2011 ▸). graphic file with name e-71-0m175-scheme1.jpg

Experimental

Crystal data

[Hg₂Cl₄(C₁₈H₁₅N₃)₂]
M _r = 1089.64
Monoclinic,
a = 11.7507 (14) Å
b = 8.9026 (11) Å
c = 17.050 (2) Å
β = 90.194 (8)°
V = 1783.6 (4) Å³
Z = 2
Mo Kα radiation
μ = 8.93 mm⁻¹
T = 100 K
0.18 × 0.15 × 0.12 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▸) T _min = 0.296, T _max = 0.414
19428 measured reflections
4451 independent reflections
2451 reflections with I > 2σ(I)
R _int = 0.098

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.124
S = 0.96
4451 reflections
220 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.78 e Å⁻³
Δρ_min = −1.13 e Å⁻³

Data collection: SMART (Bruker, 2003 ▸); cell refinement: SAINT (Bruker, 2003 ▸); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: SHELXL2014 and PLATON (Spek, 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015015790/su5192sup1.cif

e-71-0m175-sup1.cif^{(602.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015015790/su5192Isup2.hkl

e-71-0m175-Isup2.hkl^{(354.6KB, hkl)}

Click here for additional data file.^{(1.4MB, tif)}

x y z . DOI: 10.1107/S2056989015015790/su5192fig1.tif

The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The unlabelled atoms are related to the labelled atoms by inversion symmetry (symmetry code: −x + 1, −y + 1, −z + 1).

Click here for additional data file.^{(1.9MB, tif)}

c . DOI: 10.1107/S2056989015015790/su5192fig2.tif

The crystal packing of the title compound viewed along the c axis. The hydrogen bonds are shown as dashed lines (see Table 1 for details), and for clarity only the H atoms involved in hydrogen bonding are shown.

CCDC reference: 1420119

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N3H3NCl2ⁱ	0.87(2)	2.67(3)	3.510(7)	161(7)
C1H1Cl1ⁱⁱ	0.95	2.74	3.493(9)	136
C6H6Cl1ⁱⁱⁱ	0.95	2.82	3.526(9)	132

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

Acknowledgments

The authors are grateful to the Department of Chemistry, College of Science, Sultan Qaboos University, Sultanate of Oman, for financial support.

supplementary crystallographic information

S1. Comment

Mercury is one of the most prevalent toxic metals in the environment and gains access to the body orally or dermally, causing cell dysfunction that consequently leads to health problems (Mandal et al., 2012). Schiff base complexes of 2-pyridinecarboxaldehyde and its derivatives have been found to be good herbicides and used for the protection of plants (Hughes & Prince, 1978). Transition metal complexes of pyridyl Schiff bases have found applications in catalysis (Kasselouri et al., 1993), Pyridyl derivatives of Schiff bases are important building blocks of many important compounds widely used in biological applications such as antioxidative,anticancer, fluorescent probe agents in industry, in coordination chemistry and in catalysis (Motswainyana et al., 2013; Das et al. , 2013; Song et al. 2011; Jursic et al., 2002). The synthesis of a complex of mercury(II) using the 2-pyridincarbaldehyde derivative of the Schiff base N-phenyl-N'-pyridin-2-ylmethylene benzene-1,4-diamine (PPMBD) has not previously been reported. We report herein the crystal structure of a new mercury(II) complex of this ligand.

The whole molecule of the title complex, Fig. 1, is generated by inversion symmetry. The Schiff base derived PPMBD ligand coordinates to the Hg^II atom as a bidentate ligand through the N atoms of the imine group and pyridine ring. Also two bridging and one terminal chloride anions are present in the coordination environment of the Hg^II atom (Baul et al., 2004). The five-coordinated Hg²⁺ ions have a distorted square-pyramidal geometry defined by two N atoms viz. one imine, the other pyridyl [Hg–N = 2.467 (6) and 2.310 (6) Å, respectively], belonging to the bidentate iminopyridine ligand and three Cl atoms [Hg—Cl = 2.407 (2), 2.447 (2) and 3.031 (2) Å]. The longest Hg—Cl distance, Hg1···Cl1ⁱ = 3.031 (2) Å, is bridging about the centre of inversion (symmetry code: (i) -x+1, -y+1, -z+1). The observed Hg—Cl and Hg—N bond lengths and bond angles are considered normal for this type of Hg^II complex (Faizi & Sen, 2014). The central ring and pyridine ring are oriented at a dihedral angle of 8.10 (6)°. The pyridine ring and terminal phenyl ring are oriented at a dihedral angle of 53.78 (6)°.

In the crystal, molecules are linked by N—H···Cl and C—H···Cl hydrogen bonds forming sheets parallel to (001); see Fig. 2 and Table 1.

S2. Synthesis and crystallization

The iminopyridyl compound N-phenyl-N'-pyridin-2-ylmethylene benzene-1,4-diamine (PPMBD) was prepared by adding drop wise pyridine-2-carbaldehyde (0.29 g, 2.71 mmol) to a methanolic solution (50 ml) of N-phenyl-p-phenylenediamine (0.50 g, 2.71 mmol). The reaction mixture was stirred for 3 h at room temperature and filtered. The resulting yellow solid powder was washed with methanol (2 × 3 ml) and hexane (3 × 10 ml), respectively. The compound was recrystallized from in hot MeOH to give yellow crystals, which were dried in a vacuum desiccator to give the pure product (yield: 0.60 g, 80%; m.p.: 410-142 K). UV/vis (MeOH): λmax, nm (ε, M^-1 cm^-1): 205 (40,000), 280 (18,000), 398 (18,000). IR (KBr, cm^-1): ν(N—H) 3259, ν(HC=N) 1618. ¹H NMR (400 MHz DMSO-d₆) δ (ppm) 8.67 (¹H, d, J = 4.8 Hz), 8.41 (¹H, s, HC=N), 8.12 (¹H, d, J = 4.4 Hz), 7.90 (¹H, t, J = 8.0 Hz), 7.46 (¹H, t, J = 7.6 Hz ) 7.35 (²H, d, J = 3.6 Hz), 7.25 (²H, t, J = 3.6 Hz), 7.2 (²H, m, J = 7.2), 7.12 (²H, m), 6.86 (¹H, t). HRMS (ESI) m/z [M+H]+ calcd for C₁₈H₁₅N₃: 274.1339 found: 274.1349.

The title compound was prepared by reacting (PPMBD) (0.100 g, 0.37 mmol) with mercury(II) chloride (0.099 g, 0.37 mmol) in methanol (5 ml), with vigorous stirring for 2 h at room temperature The yellow precipitate that formed was filtered off and redissolved in dimethylformamide. Crystals of the title complex suitable for X-ray analysis was obtained within 3 days by slow evaporation of the dimethylformamide. The yellow crystals of the title compound were isolated (yield: 0.31 g, 77.1%; m.p.: 520 K).

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The NH H-atom was located in difference Fourier map and refined with a distance restraint: N—H = 0.88 (2) Å with U_iso(H) = 1.2U_eq(N). The C-bound H-atoms were positioned geometrically and refined using a riding model: C—H = 0.95 Å with U_iso(H) = 1.2U_eq(C).