Dibromido(di-2-pyridylamine-κ²N,N′)mercury(II)

In the mol­ecule of the title compound, [HgBr₂(C₁₀H₉N₃)], the Hg^II atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from the chelating di-2-pyridylamine ligand and by two Br atoms. In the crystal structure, inter­molecular N—H...Br hydrogen bonds link the mol­ecules into centrosymmetric dimers. There are π–π contacts between the pyridine rings [centroid–centroid distances = 3.9662 (5) and 3.9321 (4) Å]. There also exists a C—H...π contact between the pyridine CH group and a pyridine ring.

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.014 Å
• R factor = 0.053
• wR factor = 0.140
• Data-to-parameter ratio = 23.1

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   120.000
            Value of melting point given =     0.000
DIFMN02_ALERT_2_C  The minimum difference density is < -0.1*ZMAX*0.75
            _refine_diff_density_min given =     -6.537
            Test value =     -6.000
DIFMN03_ALERT_1_C  The minimum difference density is < -0.1*ZMAX*0.75
            The relevant atom site should be identified.
SHFSU01_ALERT_2_C  The absolute value of parameter shift to su ratio > 0.05
            Absolute value of the parameter shift to su ratio given   0.059
            Additional refinement cycles may be required.
PLAT080_ALERT_2_C Maximum Shift/Error ............................       0.06
PLAT098_ALERT_2_C Minimum (Negative) Residual Density ............      -6.54 eA-3
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Hg1    --  Br2     ..       5.44 su
PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         14
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)       3000 Deg.
PLAT737_ALERT_1_C D...A   Calc    3.472(8), Rep    3.472(3) ......       2.67 su-Ra
              N2   -BR2     1.555   2.657

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

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 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 [Hg(4,4'-dmbpy) I₂], (II), (Yousefi, Tadayon Pour et al., 2008), [Hg(5,5'-dmbpy)I₂], (III), (Tadayon Pour, et al., 2008), [Hg(dmphen)I₂], (IV), (Yousefi, Rashidi Vahid et al., 2008), {[HgCl(dm4bt)]₂(µ-Cl)₂}, (V), (Khavasi et al., 2008), [Hg(6-mbpy)Cl₂], (VI), (Ahmadi et al., 2008) and [{HgBr(4,4'-dmbpy)}₂(µ-Br)₂], (VII), (Kalateh et al., 2008) [where 4,4'-dmbpy is 4,4'-dimethyl-2,2'-bipyridine, 5,5'-dmbpy is 5,5'-dimethyl-2,2'- bipyridine, 6-mbpy is 6-methyl-2,2'-bipyridine, dmphen is 4,7-diphenyl-1,10- phenanthroline and dm4bt is 2,2'-dimethyl-4,4'-bithiazole]. There are two Hg^II complexes, with formula, [Hg(N—N)Br₂], such as [Hg(TPA)Br₂], (VIII), (Xie et al., 2004) and [Hg(TPD)Br₂], (IX), (Hughes et al., 1985) [where TPA is tris(2-pyridyl)amine and TPD is N,N,N',N'-Tetramethyl-o-phenylenediamine] 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, (Fig. 1), the Hg^II atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from di-2-pyridylamine and two Br atoms. The Hg-Br and Hg-N bond lengths and angles (Table 1) are within normal ranges, as in (VIII).

In the crystal structure, intermolecular N-H···Br hydrogen bonds link the molecules into centrosymmetric dimers (Fig. 2), in which they may be effective in the stabilization of the structure. The π-π contacts between the pyridine rings Cg2···Cg2ⁱ and Cg2···Cg3ⁱⁱ [symmetry codes: (i) x, -y, 2 - z, (ii) 1 - x,- y, 2 - z, where Cg2 and Cg3 are centroids of the rings A (N1/C1-C5) and B (N3/C6-C10), respectively] may further stabilize the structure, with centroid-centroid distances of 3.9662 (5) %A and 3.9321 (4) %A, respectively. There also exists a C—H···π contact (Table 1) between the pyridine CH group and pyridine ring.

Related literature

For related literature, see: Ahmadi et al. (2008); Kalateh et al. (2008); Khavasi et al. (2008); Tadayon Pour et al. (2008); Yousefi, Rashidi Vahid et al. (2008); Yousefi, Tadayon Pour et al. (2008). For related structures, see: Xie et al. (2004); Hughes et al. (1985).

S2. Experimental

For the preparation of the title compound, (I), a solution of di-2-pyridylamine (0.25 g, 1.43 mmol) in methanol (20 ml) was added to a solution of HgBr₂ (0.51 g, 1.43 mmol) in acetonitrile (20 ml) and the resulting colorless solution was stirred for 20 min at 313 K. This solution was left to evaporate slowly at room temperature. After one week, colorless prismatic crystals of the title compound were isolated (yield; 0.55 g, 72.3%).

S3. Refinement

H atoms were positioned geometrically, with N-H = 0.86 Å (for NH) and C-H = 0.93 Å for aromatic H and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C,N). The highest and lowest peaks are located 0.69 Å and 0.78 Å from Hg1 atom, respectively.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (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 50% probability level.
	Fig. 2. A partial packing diagram of the title compound.

Dibromido(di-2-pyridylamine-κ²N,N')mercury(II)

Crystal data

[HgBr2(C10H9N3)]	Z = 2
Mr = 531.59	F(000) = 480
Triclinic, P1	Dx = 2.820 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.1284 (16) Å	Cell parameters from 1657 reflections
b = 8.7645 (18) Å	θ = 2.3–29.2°
c = 9.912 (2) Å	µ = 18.65 mm^−1
α = 113.45 (3)°	T = 120 K
β = 98.41 (3)°	Prism, colorless
γ = 97.79 (3)°	0.40 × 0.35 × 0.25 mm
V = 626.1 (3) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	3350 independent reflections
Radiation source: fine-focus sealed tube	3234 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.087
ϕ and ω scans	θmax = 29.2°, θmin = 2.3°
Absorption correction: numerical (shape of crystal determined optically)	h = −11→11
Tmin = 0.016, Tmax = 0.080	k = −11→10
7839 measured reflections	l = −12→13

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)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.140	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0882P)^2 + 2.3955P] where P = (Fo^2 + 2Fc^2)/3
3350 reflections	(Δ/σ)max = 0.059
145 parameters	Δρmax = 4.33 e Å^−3
0 restraints	Δρmin = −6.54 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	0.28140 (3)	0.22806 (4)	0.84793 (3)	0.02226 (15)
Br1	0.03376 (10)	0.29535 (11)	0.71493 (10)	0.0259 (2)
Br2	0.58403 (10)	0.34148 (10)	0.83842 (9)	0.0219 (2)
N1	0.2053 (9)	0.1755 (9)	1.0425 (8)	0.0195 (12)
N2	0.3018 (9)	−0.0818 (8)	0.9915 (8)	0.0190 (12)
H2A	0.3426	−0.1362	1.0395	0.023*
N3	0.3006 (9)	−0.0591 (8)	0.7601 (8)	0.0192 (12)
C1	0.1347 (11)	0.2988 (10)	1.1369 (11)	0.0239 (15)
H1	0.1098	0.3845	1.1096	0.029*
C2	0.0991 (11)	0.3023 (11)	1.2678 (11)	0.0248 (16)
H2	0.0516	0.3881	1.3288	0.030*
C3	0.1363 (11)	0.1728 (11)	1.3080 (10)	0.0247 (15)
H3	0.1151	0.1727	1.3977	0.030*
C4	0.2037 (11)	0.0462 (11)	1.2157 (10)	0.0225 (14)
H4	0.2279	−0.0412	1.2407	0.027*
C5	0.2355 (9)	0.0519 (10)	1.0815 (9)	0.0178 (13)
C6	0.3175 (9)	−0.1477 (10)	0.8430 (9)	0.0172 (13)
C7	0.3535 (10)	−0.3113 (10)	0.7834 (10)	0.0215 (14)
H7	0.3679	−0.3693	0.8437	0.026*
C8	0.3671 (11)	−0.3850 (11)	0.6355 (10)	0.0249 (15)
H8	0.3886	−0.4940	0.5944	0.030*
C9	0.3485 (12)	−0.2952 (11)	0.5481 (10)	0.0262 (16)
H9	0.3575	−0.3414	0.4479	0.031*
C10	0.3158 (11)	−0.1340 (12)	0.6165 (10)	0.0248 (16)
H10	0.3034	−0.0731	0.5587	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.0242 (2)	0.0212 (2)	0.0290 (2)	0.00845 (13)	0.00573 (13)	0.01720 (14)
Br1	0.0239 (4)	0.0253 (4)	0.0341 (4)	0.0070 (3)	0.0012 (3)	0.0194 (3)
Br2	0.0237 (4)	0.0208 (4)	0.0267 (4)	0.0057 (3)	0.0061 (3)	0.0151 (3)
N1	0.023 (3)	0.016 (3)	0.019 (3)	0.006 (2)	0.001 (2)	0.008 (2)
N2	0.026 (3)	0.015 (3)	0.022 (3)	0.007 (2)	0.004 (2)	0.013 (2)
N3	0.024 (3)	0.016 (3)	0.018 (3)	0.005 (2)	0.002 (2)	0.009 (2)
C1	0.025 (4)	0.015 (3)	0.032 (4)	0.005 (3)	0.003 (3)	0.011 (3)
C2	0.024 (3)	0.020 (3)	0.030 (4)	0.007 (3)	0.007 (3)	0.009 (3)
C3	0.029 (4)	0.024 (4)	0.022 (3)	0.006 (3)	0.009 (3)	0.010 (3)
C4	0.026 (3)	0.021 (3)	0.024 (4)	0.005 (3)	0.003 (3)	0.012 (3)
C5	0.014 (3)	0.017 (3)	0.020 (3)	0.001 (2)	0.002 (2)	0.007 (3)
C6	0.013 (3)	0.016 (3)	0.020 (3)	−0.002 (2)	−0.002 (2)	0.009 (3)
C7	0.024 (3)	0.017 (3)	0.024 (4)	0.004 (3)	0.004 (3)	0.010 (3)
C8	0.027 (4)	0.022 (4)	0.023 (4)	0.005 (3)	0.002 (3)	0.008 (3)
C9	0.037 (4)	0.021 (4)	0.017 (3)	0.005 (3)	0.003 (3)	0.006 (3)
C10	0.030 (4)	0.029 (4)	0.020 (3)	0.008 (3)	0.004 (3)	0.015 (3)

Geometric parameters (Å, º)

Br1—Hg1	2.5106 (11)	C5—N1	1.327 (10)
Br2—Hg1	2.5549 (11)	C5—N2	1.393 (10)
N1—Hg1	2.301 (7)	C6—N3	1.342 (10)
N2—H2A	0.8600	C6—N2	1.384 (10)
N3—Hg1	2.350 (7)	C6—C7	1.408 (11)
C1—C2	1.360 (13)	C7—C8	1.376 (12)
C1—N1	1.376 (11)	C7—H7	0.9300
C1—H1	0.9300	C8—C9	1.389 (13)
C2—C3	1.398 (13)	C8—H8	0.9300
C2—H2	0.9300	C9—C10	1.385 (12)
C3—C4	1.368 (12)	C9—H9	0.9300
C3—H3	0.9300	C10—N3	1.342 (11)
C4—C5	1.410 (11)	C10—H10	0.9300
C4—H4	0.9300
N1—Hg1—N3	81.1 (2)	C2—C3—H3	119.9
N1—Hg1—Br1	109.13 (17)	C3—C4—C5	118.2 (8)
N3—Hg1—Br1	117.16 (17)	C3—C4—H4	120.9
N1—Hg1—Br2	125.41 (17)	C5—C4—H4	120.9
N3—Hg1—Br2	96.23 (18)	N1—C5—N2	121.7 (7)
Br1—Hg1—Br2	119.68 (3)	N1—C5—C4	122.9 (7)
C1—N1—Hg1	114.3 (5)	N2—C5—C4	115.4 (7)
C5—N1—Hg1	128.2 (6)	N3—C6—N2	121.6 (7)
C5—N1—C1	117.2 (7)	N3—C6—C7	121.6 (7)
C6—N2—C5	135.0 (7)	N2—C6—C7	116.9 (7)
C6—N2—H2A	112.5	C8—C7—C6	119.6 (8)
C5—N2—H2A	112.5	C8—C7—H7	120.2
C6—N3—Hg1	126.5 (5)	C6—C7—H7	120.2
C10—N3—Hg1	115.6 (6)	C7—C8—C9	119.4 (8)
C10—N3—C6	117.4 (7)	C7—C8—H8	120.3
C2—C1—N1	123.6 (8)	C9—C8—H8	120.3
C2—C1—H1	118.1	C8—C9—C10	117.2 (8)
N1—C1—H1	118.3	C8—C9—H9	121.4
C1—C2—C3	117.9 (8)	C10—C9—H9	121.4
C1—C2—H2	121.0	N3—C10—C9	124.8 (8)
C3—C2—H2	121.1	N3—C10—H10	117.5
C4—C3—C2	120.2 (8)	C9—C10—H10	117.7
C4—C3—H3	120.0
C1—N1—Hg1—N3	−166.6 (6)	C6—C7—C8—C9	1.3 (12)
C5—N1—Hg1—N3	20.2 (6)	C7—C8—C9—C10	−0.3 (13)
C1—N1—Hg1—Br1	−50.8 (6)	C8—C9—C10—N3	−0.1 (14)
C5—N1—Hg1—Br1	136.0 (6)	N2—C5—N1—C1	178.0 (7)
C1—N1—Hg1—Br2	102.0 (5)	C4—C5—N1—C1	−2.2 (11)
C5—N1—Hg1—Br2	−71.1 (7)	N2—C5—N1—Hg1	−9.0 (10)
C10—N3—Hg1—N1	168.0 (6)	C4—C5—N1—Hg1	170.8 (6)
C6—N3—Hg1—N1	−20.2 (6)	C2—C1—N1—C5	1.8 (12)
C6—N3—Hg1—Br1	−127.2 (6)	C2—C1—N1—Hg1	−172.2 (7)
C10—N3—Hg1—Br1	61.0 (6)	N3—C6—N2—C5	16.3 (13)
C6—N3—Hg1—Br2	104.8 (6)	C7—C6—N2—C5	−164.2 (8)
C10—N3—Hg1—Br2	−67.0 (6)	N1—C5—N2—C6	−16.8 (13)
N1—C1—C2—C3	−0.2 (13)	C4—C5—N2—C6	163.3 (8)
C1—C2—C3—C4	−1.0 (13)	C9—C10—N3—C6	−0.4 (13)
C2—C3—C4—C5	0.6 (12)	C9—C10—N3—Hg1	172.2 (7)
C3—C4—C5—N1	1.0 (12)	N2—C6—N3—C10	−179.2 (7)
C3—C4—C5—N2	−179.1 (7)	C7—C6—N3—C10	1.4 (11)
N3—C6—C7—C8	−1.8 (11)	N2—C6—N3—Hg1	9.2 (10)
N2—C6—C7—C8	178.7 (7)	C7—C6—N3—Hg1	−170.3 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···Br2^i	0.86	2.62	3.472 (3)	170
C2—H2···Cg3^ii	0.93	3.20	3.587 (3)	107

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