Dibromidobis(pyridine-3-carbonitrile-κN ¹)mercury(II)

Abstract

In the crystal structure of the title compound, [HgBr₂(C₆H₄N₂)₂], the Hg atom is four coordinated by two pyridine N atoms and two Br⁻ anions in a considerably distorted tetrahedral environment. π–π inter­actions between adjacent pyridine rings [centroid–centroid distance of 3.648 (3) Å] stabilize the crystal structure.

Related literature

For related structures, see: Ghiasi (2011 ▶); Steffen & Palenik (1977 ▶); Li et al. (2004 ▶).

Experimental

Crystal data

• [HgBr₂(C₆H₄N₂)₂]

• M _r = 568.61

• Triclinic,

• a = 8.5823 (6) Å

• b = 9.4069 (6) Å

• c = 9.8562 (7) Å

• α = 81.935 (5)°

• β = 71.435 (6)°

• γ = 80.508 (6)°

• V = 740.70 (9) ų

• Z = 2

• Mo Kα radiation

• μ = 15.78 mm⁻¹

• T = 120 K

• 0.45 × 0.22 × 0.20 mm

Data collection

• Bruker SMART CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.033, T _max = 0.052

• 8486 measured reflections

• 3967 independent reflections

• 3751 reflections with I > 2σ(I)

• R _int = 0.043

Refinement

• R[F ² > 2σ(F ²)] = 0.030

• wR(F ²) = 0.084

• S = 1.18

• 3967 reflections

• 172 parameters

• H-atom parameters constrained

• Δρ_max = 1.13 e Å⁻³

• Δρ_min = −2.48 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT (Bruker, 1998 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

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

supplementary crystallographic information

Comment

Recently, the crystal satructure of dibromozinc(II)-di-3-pyridine-carbonitrile have been reported, (Ghiasi, 2011). On the other hand there are several complexes, with formula, [MX₂L₂], such as [ZnCl₂(4-cypy)₂], (Steffen & Palenik, 1977), [CuBr₂(3-Cypy)₂], (Li et al. 2004), [where py is pyridine, 4-cypy is 4-cyanopyridine and 3-cypy is 3-cyanopyridine] have been synthesized and characterized by single-crystal X-ray diffraction methods. The molecular structure of the title compound is shown in Fig. 1. The Hg^II atom is four-coordinated in a slightly distorted tetrahedral configuration by two N atoms from two pyridine rings and two Br^- anions. The Hg—Br and Hg—N bond distances and angles (Table 1) are within normal ranges. π-π interactions between adjacent pyridine rings [centroid···centroid distance of 3.648 (3) Å, symmetry code: –x,1-y,1-z] stabilize the packing of the crystal structure.

Experimental

Mercury(II) bromide (0.72 gr, 2 mmol) was disolved in methanol (12 ml) and the solution was mixed with a methanolic solution (10 ml) of 3-pyridinecarbonitrile (0.42 g, 4 mmol). This solution was left to evaporate slowly at room temperature. After one week, colorless prismatic crystals of the title compound were isolated (yield 0.64 g, 56.0%, m.p. < 570 K).

Refinement

All H atoms were positioned geometrically, with C—H=0.96Å aromatics hydrogen atoms and constrained to ride on their parent atoms, with U_iso(H)=1.2U_eq.

Figures

Fig. 1.

The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Fig. 2.

Unit-cell packing diagram for (I).

Crystal data

[HgBr2(C6H4N2)2]	Z = 2
Mr = 568.61	F(000) = 516
Triclinic, P1	Dx = 2.549 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.5823 (6) Å	Cell parameters from 8405 reflections
b = 9.4069 (6) Å	θ = 2.2–29.2°
c = 9.8562 (7) Å	µ = 15.78 mm−1
α = 81.935 (5)°	T = 120 K
β = 71.435 (6)°	Prism, colorless
γ = 80.508 (6)°	0.45 × 0.22 × 0.2 mm
V = 740.70 (9) Å3

Data collection

Bruker SMART CCD diffractometer	3751 reflections with I > 2σ(I)
graphite	Rint = 0.043
phi and ω scans	θmax = 29.2°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 1998)	h = −11→11
Tmin = 0.033, Tmax = 0.052	k = −12→12
8486 measured reflections	l = −13→13
3967 independent reflections

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.084	H-atom parameters constrained
S = 1.18	w = 1/[σ2(Fo2) + (0.0481P)2 + 0.8751P] where P = (Fo2 + 2Fc2)/3
3967 reflections	(Δ/σ)max = 0.013
172 parameters	Δρmax = 1.13 e Å−3
0 restraints	Δρmin = −2.48 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
C1	0.0093 (6)	0.7134 (5)	0.4103 (5)	0.0225 (9)
H1	0.0187	0.784	0.4635	0.027*
C2	−0.1379 (6)	0.6544 (5)	0.4499 (6)	0.0239 (9)
H2	−0.2248	0.6851	0.5286	0.029*
C3	−0.1559 (7)	0.5491 (5)	0.3719 (5)	0.0241 (9)
H3	−0.2534	0.5073	0.3971	0.029*
C4	−0.0218 (6)	0.5089 (5)	0.2548 (5)	0.0224 (9)
C5	−0.0290 (6)	0.4010 (5)	0.1668 (6)	0.0241 (9)
C6	0.1248 (7)	0.5712 (5)	0.2222 (5)	0.0227 (9)
H6	0.2146	0.5409	0.1454	0.027*
C7	0.2284 (7)	1.0208 (6)	−0.0244 (6)	0.0277 (10)
H7	0.1906	1.0754	0.0541	0.033*
C8	0.1848 (9)	1.0747 (6)	−0.1468 (6)	0.0355 (13)
H8	0.1204	1.1641	−0.1508	0.043*
C9	0.2387 (8)	0.9933 (6)	−0.2636 (6)	0.0308 (11)
H9	0.2099	1.0259	−0.347	0.037*
C10	0.3368 (6)	0.8616 (5)	−0.2530 (5)	0.0221 (9)
C11	0.3959 (7)	0.7725 (6)	−0.3706 (6)	0.0265 (10)
C12	0.3758 (7)	0.8154 (5)	−0.1251 (5)	0.0237 (9)
H12	0.4413	0.7271	−0.118	0.028*
Br1	0.59621 (7)	0.60216 (6)	0.12550 (6)	0.02802 (12)
Br2	0.25093 (7)	1.02533 (5)	0.34027 (6)	0.02714 (12)
Hg1	0.38539 (2)	0.805335 (18)	0.216864 (18)	0.02106 (7)
N1	0.1397 (5)	0.6727 (5)	0.2979 (4)	0.0223 (8)
N2	−0.0327 (6)	0.3162 (5)	0.0956 (6)	0.0311 (10)
N3	0.3219 (6)	0.8943 (5)	−0.0129 (5)	0.0238 (8)
N4	0.4417 (7)	0.7012 (5)	−0.4646 (6)	0.0351 (11)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.027 (2)	0.019 (2)	0.022 (2)	0.0020 (17)	−0.0076 (19)	−0.0081 (17)
C2	0.020 (2)	0.025 (2)	0.024 (2)	0.0023 (17)	−0.0048 (18)	−0.0038 (18)
C3	0.027 (2)	0.022 (2)	0.021 (2)	−0.0032 (18)	−0.0052 (19)	0.0010 (18)
C4	0.025 (2)	0.022 (2)	0.021 (2)	−0.0013 (18)	−0.0076 (18)	−0.0055 (17)
C5	0.024 (2)	0.024 (2)	0.025 (2)	−0.0017 (18)	−0.0073 (19)	−0.0041 (18)
C6	0.025 (2)	0.022 (2)	0.020 (2)	−0.0005 (17)	−0.0043 (18)	−0.0075 (17)
C7	0.035 (3)	0.024 (2)	0.025 (2)	0.002 (2)	−0.010 (2)	−0.0065 (19)
C8	0.055 (4)	0.025 (2)	0.026 (3)	0.010 (2)	−0.017 (3)	−0.007 (2)
C9	0.043 (3)	0.025 (2)	0.026 (2)	0.004 (2)	−0.016 (2)	−0.005 (2)
C10	0.025 (2)	0.021 (2)	0.020 (2)	−0.0017 (17)	−0.0062 (18)	−0.0037 (17)
C11	0.031 (3)	0.025 (2)	0.024 (2)	0.0001 (19)	−0.011 (2)	−0.0036 (19)
C12	0.027 (2)	0.021 (2)	0.024 (2)	−0.0018 (18)	−0.010 (2)	−0.0032 (18)
Br1	0.0268 (2)	0.0291 (2)	0.0289 (3)	0.00759 (19)	−0.0111 (2)	−0.01227 (19)
Br2	0.0334 (3)	0.0236 (2)	0.0239 (2)	0.00029 (19)	−0.0065 (2)	−0.01056 (18)
Hg1	0.02188 (10)	0.02100 (10)	0.02036 (10)	0.00031 (7)	−0.00584 (7)	−0.00698 (7)
N1	0.024 (2)	0.0245 (19)	0.0182 (18)	−0.0005 (15)	−0.0058 (16)	−0.0068 (15)
N2	0.030 (2)	0.029 (2)	0.034 (2)	−0.0031 (18)	−0.007 (2)	−0.0104 (19)
N3	0.023 (2)	0.0250 (19)	0.022 (2)	0.0014 (16)	−0.0068 (16)	−0.0052 (16)
N4	0.044 (3)	0.031 (2)	0.031 (2)	−0.001 (2)	−0.010 (2)	−0.009 (2)

Geometric parameters (Å, °)

C1—N1	1.347 (6)	C7—H7	0.93
C1—C2	1.384 (7)	C8—C9	1.385 (8)
C1—H1	0.93	C8—H8	0.93
C2—C3	1.391 (7)	C9—C10	1.389 (7)
C2—H2	0.93	C9—H9	0.93
C3—C4	1.390 (7)	C10—C12	1.399 (7)
C3—H3	0.93	C10—C11	1.436 (7)
C4—C6	1.401 (7)	C11—N4	1.148 (7)
C4—C5	1.446 (7)	C12—N3	1.334 (7)
C5—N2	1.144 (7)	C12—H12	0.93
C6—N1	1.337 (6)	Br1—Hg1	2.4581 (5)
C6—H6	0.93	Br2—Hg1	2.4736 (5)
C7—N3	1.333 (7)	Hg1—N1	2.481 (4)
C7—C8	1.381 (8)	Hg1—N3	2.496 (4)
N1—C1—C2	122.7 (5)	C8—C9—C10	118.4 (5)
N1—C1—H1	118.7	C8—C9—H9	120.8
C2—C1—H1	118.7	C10—C9—H9	120.8
C1—C2—C3	120.0 (5)	C9—C10—C12	119.1 (5)
C1—C2—H2	120	C9—C10—C11	120.7 (5)
C3—C2—H2	120	C12—C10—C11	120.1 (4)
C4—C3—C2	117.1 (5)	N4—C11—C10	179.3 (6)
C4—C3—H3	121.4	N3—C12—C10	121.9 (5)
C2—C3—H3	121.4	N3—C12—H12	119
C3—C4—C6	120.0 (5)	C10—C12—H12	119
C3—C4—C5	121.2 (5)	Br1—Hg1—Br2	159.99 (2)
C6—C4—C5	118.8 (5)	Br1—Hg1—N1	98.01 (10)
N2—C5—C4	179.0 (6)	Br2—Hg1—N1	97.02 (10)
N1—C6—C4	122.1 (5)	Br1—Hg1—N3	97.22 (10)
N1—C6—H6	119	Br2—Hg1—N3	95.88 (10)
C4—C6—H6	119	N1—Hg1—N3	90.10 (14)
N3—C7—C8	123.4 (5)	C6—N1—C1	118.1 (4)
N3—C7—H7	118.3	C6—N1—Hg1	121.2 (3)
C8—C7—H7	118.3	C1—N1—Hg1	120.3 (3)
C7—C8—C9	118.7 (5)	C7—N3—C12	118.5 (5)
C7—C8—H8	120.6	C7—N3—Hg1	120.3 (3)
C9—C8—H8	120.6	C12—N3—Hg1	121.2 (3)
N1—C1—C2—C3	−0.3 (8)	C2—C1—N1—C6	0.0 (7)
C1—C2—C3—C4	−0.5 (7)	C2—C1—N1—Hg1	172.5 (4)
C2—C3—C4—C6	1.7 (7)	Br1—Hg1—N1—C6	−38.3 (4)
C2—C3—C4—C5	−179.7 (5)	Br2—Hg1—N1—C6	155.0 (4)
C3—C4—C5—N2	16E1(4)	N3—Hg1—N1—C6	59.0 (4)
C6—C4—C5—N2	−2E1(4)	Br1—Hg1—N1—C1	149.5 (4)
C3—C4—C6—N1	−2.1 (8)	Br2—Hg1—N1—C1	−17.2 (4)
C5—C4—C6—N1	179.3 (5)	N3—Hg1—N1—C1	−113.2 (4)
N3—C7—C8—C9	0.8 (10)	C8—C7—N3—C12	−0.2 (9)
C7—C8—C9—C10	−1.0 (10)	C8—C7—N3—Hg1	−178.2 (5)
C8—C9—C10—C12	0.7 (9)	C10—C12—N3—C7	−0.1 (8)
C8—C9—C10—C11	179.9 (6)	C10—C12—N3—Hg1	177.9 (4)
C9—C10—C11—N4	−6E1(5)	Br1—Hg1—N3—C7	−169.9 (4)
C12—C10—C11—N4	12E1(5)	Br2—Hg1—N3—C7	−5.0 (4)
C9—C10—C12—N3	−0.2 (8)	N1—Hg1—N3—C7	92.1 (4)
C11—C10—C12—N3	−179.3 (5)	Br1—Hg1—N3—C12	12.2 (4)
C4—C6—N1—C1	1.2 (7)	Br2—Hg1—N3—C12	177.1 (4)
C4—C6—N1—Hg1	−171.2 (4)	N1—Hg1—N3—C12	−85.9 (4)