catena-Poly[[di­chlorido­mercury(II)]-μ-1,4-bis­[2-(pyridin-4-yl)ethyn­yl]benzene-κ²N:N′]

In the polymeric title compound, [HgCl₂(C₂₀H₁₂N₂)]_n, the Hg^II atom is located on a twofold rotation axis and the benzene ring of the bidentate bridging 1,4-bis­[2-(pyridin-4-yl)ethyn­yl]benzene (L) ligand is located about a twofold rotation axis. The Hg^II atom is coordinated by two N atoms of two different L ligands and by two chloride ions in a distorted tetra­hedral geometry. The dihedral angle between the coordinating pyridine and the benzene ring is 12.8 (2)°. The result of the bridging is the formation of a zigzag chain running parallel to [102]. The chains pack with no specific inter­molecular inter­actions between them.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.028
• wR factor = 0.070
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT125_ALERT_4_C No '_symmetry_space_group_name_Hall' Given .....     Please Do !
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.595          8 Why ?
PLAT971_ALERT_2_C Check Calcd Residual Density  0.98A From     Hg1       2.24 eA-3
PLAT971_ALERT_2_C Check Calcd Residual Density  0.84A From     Hg1       2.09 eA-3
PLAT971_ALERT_2_C Check Calcd Residual Density  1.06A From     Hg1       1.61 eA-3
PLAT972_ALERT_2_C Check Calcd Residual Density  1.10A From     Hg1      -1.76 eA-3
PLAT972_ALERT_2_C Check Calcd Residual Density  0.86A From     Hg1      -1.72 eA-3

Alert level G
PLAT004_ALERT_5_G Polymeric Structure Found with Dimension .......          1 Info
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF     Please Do !
PLAT066_ALERT_1_G Predicted and Reported Tmin&Tmax Range Identical          ? Check
PLAT371_ALERT_2_G Long   C(sp2)-C(sp1) Bond  C3     -   C6     ...       1.42 Ang.
PLAT371_ALERT_2_G Long   C(sp2)-C(sp1) Bond  C7     -   C8     ...       1.43 Ang.
PLAT804_ALERT_5_G Number of ARU-Code Packing Problem(s) in PLATON           8 Info
PLAT909_ALERT_3_G Percentage of Observed Data at Theta(Max) still          92 %
PLAT910_ALERT_3_G Missing # of FCF Reflections Below Th(Min) .....          1 Why ?
PLAT961_ALERT_5_G Dataset Contains no Negative Intensities .......     Please Check

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   7 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   9 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   7 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   4 ALERT type 5 Informative message, check

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S1. Structural commentary

Recently, a large number of coordination polymers assembled from pyridyl-based ligands have been extensively investigated. Most of these coordination polymers are constructed from 4,4'-bi­pyridyl but other examples of bridging ligands are known, such as with 1,4-bis­(pyridin-4-ylethynyl)benzene (Yamada et al., 2011). Mercury coordination polymers are known (Xie et al., 2007)

In this work, an linear pyridyl-based ligand, 1,4-bis­(pyridin-4-ylethynyl)benzene, was employed to react with HgCl₂ to afford the title complex, [Hg(C₂₀H₁₂N₂₎Cl_2]]_n (I). In I, the Hg(II) center is coordinated by two N atoms of two different 1,4-bis­(pyridin-4-ylethynyl)benzene ligands and two chloride ions in a distorted tetra­hedral geometry (Fig. 1). The Hg(II) centers are linked by 1,4-bis­(pyridin-4-ylethynyl)benzene ligands to form a one-dimensional zigzag chain and the chain is parallel to [102] (Fig. 2). The dihedral angles between coordinated pyridine rings and benzene ring are ca. 12.8 (2)°.

S2. Synthesis and crystallization

The ligand 1,4-bis­(pyridin-4-ylethynyl)benzene (bpyb) was synthesized from the reaction between 4-(prop-1-yn-1-yl)pyridine and 1,4-di­iodo­benzene following the reported procedure (Fasina et al., 2004). A methanol (3 ml) solution of HgCl₂ (0.1 mmol, 27 mg) was layered upon a chloro­form solution (3 ml) of bpyp (0.2 mmol, 56 mg). After three days, colourless crystals of the title complex suitable for X-ray analysis were obtained.

S3. Refinement

Hydrogen atoms were included in calculated positions and treated as riding on their parent C atoms with C—H = 0.95Å and U_iso(H) = 1.2U_eq(C). The maximum and minimum residual electron density peaks of 2.15 and 1.73 eÅ^-3, respectively, were located 0.93 Å and 1.00 Å from the Hg atom.

Related literature

For examples of 1,4-bis[2-(pyridin-4-yl)ethynyl]benzene-containing polymers, see: Yamada et al. (2011). For examples of Hg-containing polymers, see: Xie & Wu (2007). For the synthesis of the ligand, see: Fasina et al. (2004).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The coordination mode of the title complex, with displacement ellipsoids drawn at the 50% probability level. All H atoms have been omitted for clarity. [Symmetry codes: (#1) -x+1, y, -z+1/2; (#2) -x, -y+3, z+1.]
	Fig. 2. The zigzag chain of the complex. View down the c axis, with displacement ellipsoids drawn at the 50% probability level. All hydrogen atoms are omitted for clarity.

catena-Poly[[dichloridomercury(II)]-µ-1,4-bis[2-(pyridin-4-yl)ethynyl]benzene-κ²N:N']

Crystal data

[HgCl2(C20H12N2)]	Z = 2
Mr = 551.81	F(000) = 520
Monoclinic, P2/c	Dx = 2.035 Mg m^−3
a = 12.285 (3) Å	Mo Kα radiation, λ = 0.71073 Å
b = 4.8482 (10) Å	µ = 8.85 mm^−1
c = 15.271 (3) Å	T = 173 K
β = 98.00 (3)°	Block, colourless
V = 900.7 (3) Å^3	0.18 × 0.16 × 0.16 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	1585 independent reflections
Radiation source: fine-focus sealed tube	1512 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
ω and phi scan	θmax = 25.0°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1995)	h = −11→14
Tmin = 0.222, Tmax = 0.243	k = −5→5
4238 measured reflections	l = −18→17

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.070	H-atom parameters constrained
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0394P)^2 + 2.093P] where P = (Fo^2 + 2Fc^2)/3
1585 reflections	(Δ/σ)max < 0.001
114 parameters	Δρmax = 2.15 e Å^−3
0 restraints	Δρmin = −1.73 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Hg1	0.5000	−0.01536 (4)	0.2500	0.01426 (13)
Cl1	0.61049 (9)	−0.1178 (2)	0.38614 (6)	0.0215 (3)
C6	0.1775 (4)	0.9118 (11)	0.3998 (3)	0.0188 (9)
C5	0.3948 (4)	0.3872 (9)	0.3923 (3)	0.0178 (9)
H5	0.4536	0.3071	0.4310	0.021*
C3	0.2446 (3)	0.7051 (9)	0.3688 (3)	0.0161 (9)
C2	0.2249 (4)	0.6136 (9)	0.2821 (3)	0.0193 (9)
H2	0.1656	0.6871	0.2425	0.023*
C7	0.1230 (4)	1.0887 (10)	0.4276 (3)	0.0179 (9)
C8	0.0599 (3)	1.2960 (8)	0.4641 (3)	0.0156 (8)
C4	0.3310 (4)	0.5860 (11)	0.4251 (3)	0.0196 (9)
H4	0.3457	0.6411	0.4853	0.024*
C1	0.2929 (4)	0.4134 (11)	0.2537 (3)	0.0197 (9)
H1	0.2795	0.3527	0.1940	0.024*
C10	0.1000 (4)	1.4112 (11)	0.5461 (3)	0.0205 (9)
H10	0.1682	1.3511	0.5772	0.025*
C9	−0.0398 (4)	1.3864 (10)	0.4180 (3)	0.0197 (9)
H9	−0.0665	1.3092	0.3619	0.024*
N1	0.3772 (3)	0.3030 (7)	0.3080 (2)	0.0141 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.01265 (19)	0.01679 (18)	0.01374 (17)	0.000	0.00326 (11)	0.000
Cl1	0.0189 (6)	0.0284 (7)	0.0167 (5)	0.0057 (4)	0.0013 (4)	0.0040 (4)
C6	0.018 (3)	0.019 (2)	0.020 (2)	−0.001 (2)	0.0039 (19)	0.0006 (19)
C5	0.014 (2)	0.020 (2)	0.018 (2)	0.0032 (18)	0.0009 (17)	−0.0011 (17)
C3	0.016 (2)	0.015 (2)	0.018 (2)	−0.0011 (17)	0.0063 (16)	−0.0011 (16)
C2	0.018 (2)	0.020 (3)	0.019 (2)	0.0059 (19)	0.0012 (18)	0.0001 (18)
C7	0.018 (3)	0.020 (2)	0.016 (2)	−0.002 (2)	0.0014 (18)	0.0005 (19)
C8	0.017 (2)	0.015 (2)	0.0162 (19)	−0.0015 (17)	0.0068 (16)	0.0019 (16)
C4	0.018 (3)	0.023 (2)	0.018 (2)	0.001 (2)	0.0053 (18)	−0.005 (2)
C1	0.020 (3)	0.024 (2)	0.017 (2)	0.002 (2)	0.0060 (19)	−0.0011 (19)
C10	0.019 (3)	0.022 (2)	0.020 (2)	0.004 (2)	0.0039 (19)	0.002 (2)
C9	0.020 (2)	0.021 (2)	0.018 (2)	0.0003 (19)	0.0041 (18)	−0.0036 (18)
N1	0.0115 (18)	0.0172 (18)	0.0145 (16)	−0.0012 (14)	0.0053 (13)	−0.0004 (14)

Geometric parameters (Å, º)

Hg1—Cl1^i	2.3719 (12)	C2—H2	0.9500
Hg1—Cl1	2.3719 (12)	C7—C8	1.428 (6)
Hg1—N1^i	2.412 (3)	C8—C9	1.396 (6)
Hg1—N1	2.412 (3)	C8—C10	1.397 (6)
C6—C7	1.202 (8)	C4—H4	0.9500
C6—C3	1.420 (6)	C1—N1	1.344 (6)
C5—N1	1.339 (5)	C1—H1	0.9500
C5—C4	1.380 (7)	C10—C9^ii	1.386 (7)
C5—H5	0.9500	C10—H10	0.9500
C3—C2	1.385 (6)	C9—C10^ii	1.386 (7)
C3—C4	1.395 (6)	C9—H9	0.9500
C2—C1	1.389 (7)
Cl1^i—Hg1—Cl1	155.82 (6)	C9—C8—C7	120.7 (4)
Cl1^i—Hg1—N1^i	97.08 (8)	C10—C8—C7	119.2 (4)
Cl1—Hg1—N1^i	98.33 (8)	C5—C4—C3	119.1 (4)
Cl1^i—Hg1—N1	98.33 (8)	C5—C4—H4	120.4
Cl1—Hg1—N1	97.08 (8)	C3—C4—H4	120.4
N1^i—Hg1—N1	100.42 (16)	N1—C1—C2	122.1 (4)
C7—C6—C3	178.3 (5)	N1—C1—H1	119.0
N1—C5—C4	122.5 (4)	C2—C1—H1	119.0
N1—C5—H5	118.7	C9^ii—C10—C8	119.8 (4)
C4—C5—H5	118.7	C9^ii—C10—H10	120.1
C2—C3—C4	118.3 (4)	C8—C10—H10	120.1
C2—C3—C6	120.8 (4)	C10^ii—C9—C8	120.1 (4)
C4—C3—C6	120.9 (4)	C10^ii—C9—H9	120.0
C3—C2—C1	119.3 (4)	C8—C9—H9	120.0
C3—C2—H2	120.3	C5—N1—C1	118.6 (4)
C1—C2—H2	120.3	C5—N1—Hg1	121.5 (3)
C6—C7—C8	177.8 (5)	C1—N1—Hg1	119.7 (3)
C9—C8—C10	120.1 (4)
C4—C3—C2—C1	−1.6 (7)	C4—C5—N1—C1	−1.0 (7)
C6—C3—C2—C1	179.3 (5)	C4—C5—N1—Hg1	174.6 (4)
N1—C5—C4—C3	−0.1 (8)	C2—C1—N1—C5	0.8 (7)
C2—C3—C4—C5	1.4 (7)	C2—C1—N1—Hg1	−174.9 (4)
C6—C3—C4—C5	−179.5 (5)	Cl1^i—Hg1—N1—C5	168.6 (3)
C3—C2—C1—N1	0.6 (8)	Cl1—Hg1—N1—C5	7.3 (3)
C9—C8—C10—C9^ii	0.7 (8)	N1^i—Hg1—N1—C5	−92.5 (3)
C7—C8—C10—C9^ii	179.7 (5)	Cl1^i—Hg1—N1—C1	−15.8 (3)
C10—C8—C9—C10^ii	−0.7 (8)	Cl1—Hg1—N1—C1	−177.1 (3)
C7—C8—C9—C10^ii	−179.7 (5)	N1^i—Hg1—N1—C1	83.0 (3)

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