(4,4′-Dimethyl-2,2′-bipyridine-κ²N,N′)diiodidomercury(II)

In the mol­ecule of the title compound, [HgI₂(C₁₂H₁₂N₂)], the Hg^II atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from the 4,4′-dimethyl-2,2′-bipyridine ligand and by two I atoms. There is a π–π contact between the pyridine rings [centroid–centroid distance = 3.775 (6) Å].

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.015 Å
• R factor = 0.048
• wR factor = 0.159
• Data-to-parameter ratio = 26.6

checkCIF/PLATON results

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Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Hg1    --  I1      ..       5.09 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Hg1    --  I2      ..       5.79 su
PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         15
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        800 Deg.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

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

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S1. Comment

Recently, we reported the syntheses and crystal structures of [Zn(5,5'-dmbpy)Cl₂], (II), (Khalighi et al., 2008), [Cd(5,5'-dmbpy)(µ-Cl)₂]_n, (III), (Ahmadi et al., 2008) and {[HgCl(dm4bt)]₂(µ-Cl)₂}, (IV), (Khavasi et al., 2008) [where 5,5'-dmbpy is 5,5'-dimethyl-2,2'-bipyridine and dm4bt is 2,2'-dimethyl-4,4' -bithiazole]. There are several Hg^II complexes, with formula, [HgI₂(N-N)], such as [HgI₂(bipy)], (V), [HgI₂(phen)], (VI), [HgI₂(2,9-dmphen)], (VII), (Freire et al., 1999), [HgI₂(bipy)][HgI₂], (VIII), (Chen et al., 2006) and [HgI₂(TMDA)], (IX), (Htoon & Ladd, 1976) [where bipy is 2,2'-bipyridine, phen is 1,10-phenanthroline, dmphen is 2,9-dimethyl-1,10-phenanthroline and TMDA is tetramethylethylenediamine] have been synthesized and characterized by single-crystal X-ray diffraction methods. We report herein the synthesis and crystal structure of the title compound, (I).

In the title compound, (I), (Fig. 1), the Hg^II atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from 4,4'-dimethyl-2,2'-bipyridine and two I atoms. The Hg—I and Hg—N bond lengths and angles (Table 1) are within normal ranges, as in (V) and (VI).

In the crystal structure, the π–π contact (Fig. 2) between the pyridine rings, Cg2···Cg3ⁱ [symmetry code: (i) 1 - x, -y, -z, where Cg2 and Cg3 are the centroids of the rings (N1/C1–C3/C5/C6) and (N2/C7–C9/C11/C12), respectively] may stabilize the structure, with centroid–centroid distance of 3.775 (6) Å.

Related literature

For related literature, see: Khalighi et al. (2008); Ahmadi et al. (2008); Khavasi et al. (2008); Freire et al. (1999); Chen et al. (2006); Htoon & Ladd (1976).

S2. Experimental

For the preparation of the title compound, (I), a solution of 4,4'-dimethyl-2,2'-bipyridine (0.25 g, 1.33 mmol) in methanol (20 ml) was added to a solution of HgI₂ (0.61 g, 1.33 mmol) in acetonitrile (50 ml) and the resulting colorless solution was stirred for 20 min at room temperature, and then it was left to evaporate slowly. After one week, colorless block crystals of (I) were isolated (yield; 0.61 g, 71.8%).

S3. Refinement

H atoms were positioned geometrically, with C—H = 0.93 and 0.96 Å for aromatic and methyl H, respectively, and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C).

Computing details

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

Figures

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level.
	Fig. 2. A packing diagram of the title compound.

(4,4'-Dimethyl-2,2'-bipyridine-κ²N,N')diiodidomercury(II)

Crystal data

[HgI2(C12H12N2)]	Z = 2
Mr = 638.63	F(000) = 568
Triclinic, P1	Dx = 2.761 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.4214 (9) Å	Cell parameters from 2145 reflections
b = 9.8391 (10) Å	θ = 2.1–29.2°
c = 10.2983 (10) Å	µ = 14.02 mm^−1
α = 69.383 (8)°	T = 298 K
β = 88.448 (8)°	Block, colourless
γ = 74.670 (8)°	0.38 × 0.25 × 0.12 mm
V = 768.18 (14) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	4123 independent reflections
Radiation source: fine-focus sealed tube	3467 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.091
ϕ and ω scans	θmax = 29.2°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1998)	h = −11→11
Tmin = 0.022, Tmax = 0.183	k = −13→13
8874 measured reflections	l = −14→14

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.048	H-atom parameters constrained
wR(F^2) = 0.159	w = 1/[σ^2(Fo^2) + (0.108P)^2 + 1.3499P] where P = (Fo^2 + 2Fc^2)/3
S = 0.95	(Δ/σ)max = 0.002
4123 reflections	Δρmax = 1.95 e Å^−3
155 parameters	Δρmin = −1.38 e Å^−3
0 restraints	Extinction correction: SHELXTL (Sheldrick, 1998), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0071 (13)

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	0.31760 (5)	0.15247 (5)	0.30109 (4)	0.05970 (19)
I1	0.03155 (9)	0.31134 (10)	0.35551 (9)	0.0704 (2)
I2	0.63357 (8)	0.13618 (9)	0.35681 (7)	0.0594 (2)
N1	0.3481 (10)	0.2223 (10)	0.0514 (8)	0.0520 (16)
N2	0.2438 (12)	−0.0160 (12)	0.2073 (9)	0.0595 (19)
C1	0.3943 (12)	0.3461 (12)	−0.0232 (12)	0.058 (2)
H1	0.4209	0.4042	0.0227	0.069*
C2	0.4037 (14)	0.3905 (12)	−0.1657 (13)	0.064 (3)
H2	0.4374	0.4763	−0.2141	0.077*
C3	0.3630 (12)	0.3066 (10)	−0.2355 (10)	0.053 (2)
C4	0.368 (2)	0.3537 (19)	−0.3901 (13)	0.080 (4)
H4A	0.2607	0.3701	−0.4313	0.096*
H4B	0.4460	0.2758	−0.4127	0.096*
H4C	0.4015	0.4454	−0.4256	0.096*
C5	0.3166 (12)	0.1780 (10)	−0.1574 (9)	0.0512 (18)
H5	0.2901	0.1178	−0.2009	0.061*
C6	0.3098 (10)	0.1393 (10)	−0.0149 (9)	0.0461 (16)
C7	0.2537 (10)	0.0050 (9)	0.0721 (9)	0.0438 (15)
C8	0.2150 (11)	−0.0932 (10)	0.0177 (10)	0.0488 (17)
H8	0.2260	−0.0777	−0.0762	0.059*
C9	0.1602 (11)	−0.2137 (10)	0.1003 (11)	0.0525 (19)
C10	0.1200 (14)	−0.3201 (12)	0.0393 (13)	0.065 (2)
H10A	0.2170	−0.3670	0.0034	0.079*
H10B	0.0348	−0.2648	−0.0346	0.079*
H10C	0.0825	−0.3962	0.1103	0.079*
C11	0.1411 (15)	−0.2305 (14)	0.2394 (12)	0.065 (3)
H11	0.1004	−0.3078	0.2981	0.078*
C12	0.1831 (16)	−0.1319 (15)	0.2875 (11)	0.066 (3)
H12	0.1698	−0.1438	0.3805	0.079*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.0532 (2)	0.0783 (3)	0.0614 (3)	−0.02592 (18)	0.01400 (15)	−0.0362 (2)
I1	0.0537 (4)	0.0824 (5)	0.0729 (4)	−0.0159 (3)	0.0167 (3)	−0.0280 (4)
I2	0.0539 (3)	0.0771 (4)	0.0543 (3)	−0.0294 (3)	0.0096 (2)	−0.0241 (3)
N1	0.056 (4)	0.058 (4)	0.049 (3)	−0.022 (3)	0.010 (3)	−0.022 (3)
N2	0.063 (5)	0.077 (5)	0.047 (4)	−0.029 (4)	0.011 (3)	−0.026 (4)
C1	0.054 (5)	0.052 (5)	0.074 (6)	−0.023 (4)	0.005 (4)	−0.025 (4)
C2	0.061 (5)	0.047 (5)	0.079 (7)	−0.021 (4)	0.010 (5)	−0.013 (4)
C3	0.054 (5)	0.044 (4)	0.056 (5)	−0.013 (3)	0.006 (4)	−0.012 (3)
C4	0.089 (9)	0.089 (9)	0.056 (5)	−0.033 (7)	0.013 (5)	−0.013 (6)
C5	0.057 (5)	0.048 (4)	0.048 (4)	−0.015 (4)	0.009 (3)	−0.016 (3)
C6	0.041 (4)	0.044 (4)	0.052 (4)	−0.011 (3)	0.013 (3)	−0.017 (3)
C7	0.039 (3)	0.042 (3)	0.048 (4)	−0.010 (3)	0.008 (3)	−0.016 (3)
C8	0.047 (4)	0.048 (4)	0.053 (4)	−0.014 (3)	0.012 (3)	−0.020 (3)
C9	0.043 (4)	0.048 (4)	0.061 (5)	−0.012 (3)	0.004 (3)	−0.014 (3)
C10	0.067 (5)	0.049 (5)	0.078 (6)	−0.014 (4)	0.010 (5)	−0.021 (4)
C11	0.071 (6)	0.070 (6)	0.060 (5)	−0.040 (5)	0.007 (5)	−0.013 (5)
C12	0.075 (7)	0.079 (7)	0.050 (4)	−0.040 (5)	0.015 (4)	−0.017 (4)

Geometric parameters (Å, º)

Hg1—I1	2.6671 (9)	C6—N1	1.334 (12)
Hg1—I2	2.6885 (8)	C6—C7	1.498 (12)
N1—Hg1	2.442 (8)	C7—N2	1.337 (12)
N2—Hg1	2.402 (10)	C7—C8	1.383 (13)
C1—N1	1.342 (13)	C8—C9	1.378 (13)
C1—C2	1.382 (17)	C8—H8	0.9300
C1—H1	0.9300	C9—C11	1.392 (16)
C2—C3	1.377 (17)	C9—C10	1.506 (16)
C2—H2	0.9300	C10—H10A	0.9600
C3—C5	1.389 (13)	C10—H10B	0.9600
C3—C4	1.497 (16)	C10—H10C	0.9600
C4—H4A	0.9600	C11—C12	1.357 (18)
C4—H4B	0.9600	C11—H11	0.9300
C4—H4C	0.9600	C12—N2	1.366 (15)
C5—C6	1.384 (12)	C12—H12	0.9300
C5—H5	0.9300
I1—Hg1—I2	132.56 (3)	C6—C5—C3	120.2 (9)
N1—Hg1—I1	111.9 (2)	C6—C5—H5	119.7
N1—Hg1—I2	92.87 (19)	C3—C5—H5	120.2
N2—Hg1—N1	67.3 (3)	N1—C6—C5	121.6 (8)
N2—Hg1—I1	104.9 (2)	N1—C6—C7	116.6 (8)
N2—Hg1—I2	122.2 (2)	C5—C6—C7	121.7 (8)
C1—N1—Hg1	122.2 (7)	N2—C7—C8	121.2 (8)
C6—N1—Hg1	119.2 (6)	N2—C7—C6	116.1 (8)
C6—N1—C1	118.6 (8)	C8—C7—C6	122.6 (8)
C7—N2—Hg1	120.8 (7)	C9—C8—C7	121.0 (9)
C7—N2—C12	117.4 (9)	C9—C8—H8	119.4
C12—N2—Hg1	121.7 (7)	C7—C8—H8	119.6
N1—C1—C2	122.5 (10)	C8—C9—C11	117.7 (10)
N1—C1—H1	118.7	C8—C9—C10	120.2 (10)
C2—C1—H1	118.8	C11—C9—C10	122.1 (9)
C3—C2—C1	119.5 (10)	C9—C10—H10A	109.2
C3—C2—H2	120.1	C9—C10—H10B	109.6
C1—C2—H2	120.4	H10A—C10—H10B	109.5
C2—C3—C5	117.6 (10)	C9—C10—H10C	109.6
C2—C3—C4	120.8 (11)	H10A—C10—H10C	109.5
C5—C3—C4	121.6 (11)	H10B—C10—H10C	109.5
C3—C4—H4A	109.3	C12—C11—C9	118.7 (10)
C3—C4—H4B	109.5	C12—C11—H11	120.7
H4A—C4—H4B	109.5	C9—C11—H11	120.6
C3—C4—H4C	109.6	N2—C12—C11	123.8 (10)
H4A—C4—H4C	109.5	N2—C12—H12	118.1
H4B—C4—H4C	109.5	C11—C12—H12	118.2
C1—N1—Hg1—I1	79.7 (8)	C5—C6—N1—Hg1	176.7 (6)
C1—N1—Hg1—I2	−58.9 (7)	C7—C6—N1—Hg1	−1.4 (10)
C1—N1—Hg1—N2	177.2 (8)	C5—C6—N1—C1	−0.1 (13)
C6—N1—Hg1—I1	−96.9 (7)	C7—C6—N1—C1	−178.1 (8)
C6—N1—Hg1—I2	124.5 (7)	N1—C6—C7—N2	1.6 (11)
C6—N1—Hg1—N2	0.6 (7)	C5—C6—C7—N2	−176.5 (9)
C7—N2—Hg1—I1	108.1 (7)	N1—C6—C7—C8	−178.0 (8)
C7—N2—Hg1—I2	−78.2 (8)	C5—C6—C7—C8	4.0 (12)
C7—N2—Hg1—N1	0.2 (7)	C6—C7—N2—Hg1	−1.0 (10)
C12—N2—Hg1—I1	−68.7 (9)	C8—C7—N2—Hg1	178.6 (6)
C12—N2—Hg1—I2	104.9 (9)	C6—C7—N2—C12	176.0 (9)
C12—N2—Hg1—N1	−176.6 (10)	C8—C7—N2—C12	−4.5 (14)
C2—C1—N1—C6	−0.1 (15)	N2—C7—C8—C9	1.9 (13)
C2—C1—N1—Hg1	−176.7 (8)	C6—C7—C8—C9	−178.6 (8)
N1—C1—C2—C3	0.7 (16)	C7—C8—C9—C11	1.7 (13)
C1—C2—C3—C5	−1.2 (16)	C7—C8—C9—C10	−179.5 (8)
C1—C2—C3—C4	178.6 (11)	C8—C9—C11—C12	−2.5 (16)
C2—C3—C5—C6	1.1 (14)	C10—C9—C11—C12	178.7 (11)
C4—C3—C5—C6	−178.7 (10)	C9—C11—C12—N2	−0.1 (19)
C3—C5—C6—N1	−0.5 (14)	C11—C12—N2—Hg1	−179.4 (10)
C3—C5—C6—C7	177.4 (8)	C11—C12—N2—C7	3.6 (18)