Dichloridobis(pyrazine-2-carboxamide-κN ⁴)zinc(II)

Abstract

In the crystal of the title compound, [ZnCl₂(C₅H₅N₃O)₂], the mol­ecule has m symmetry, with the Zn^II cation and Cl⁻ anions located on the mirror plane. The Zn^II cation is coordinated by two Cl⁻ anions and two pyrazine-2-carboxamide ligands in a distorted ZnCl₂N₂ tetra­hedral geometry. The two pyrazine rings are nearly perpendicular to each other [dihedral angle = 86.61 (10)°]. Inter­molecular N—H⋯O and N—H⋯N hydrogen bonds and weak C—H⋯O inter­actions stabilize the crystal packing.

Related literature  

For related structures, see: Abu-Youssef et al. (2006 ▶); Azhdari Tehrani et al. (2010 ▶); Goher & Mautner (2000 ▶); Kristiansson (2002 ▶); Mir Mohammad Sadegh et al. (2010 ▶); Munakata et al. (1997 ▶); Pacigova et al. (2008 ▶).

Experimental  

Crystal data  

• [ZnCl₂(C₅H₅N₃O)₂]

• M _r = 382.53

• Monoclinic,

• a = 5.4296 (5) Å

• b = 19.7629 (14) Å

• c = 6.8396 (5) Å

• β = 105.131 (7)°

• V = 708.48 (10) ų

• Z = 2

• Mo Kα radiation

• μ = 2.12 mm⁻¹

• T = 298 K

• 0.40 × 0.06 × 0.05 mm

Data collection  

• Bruker APEXII CCD area-detector’ diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.881, T _max = 0.902

• 5777 measured reflections

• 1441 independent reflections

• 1064 reflections with I > 2σ(I)

• R _int = 0.085

Refinement  

• R[F ² > 2σ(F ²)] = 0.045

• wR(F ²) = 0.093

• S = 0.97

• 1441 reflections

• 100 parameters

• H-atom parameters constrained

• Δρ_max = 0.78 e Å⁻³

• Δρ_min = −0.65 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Selected bond lengths (Å).

Zn1—N1	2.085 (3)
Zn1—Cl1	2.1945 (16)
Zn1—Cl2	2.1888 (16)

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3B⋯O1i	0.86	2.02	2.875 (5)	175
N3—H3C⋯N2ii	0.86	2.61	3.205 (5)	128
C3—H3⋯O1iii	0.93	2.44	3.357 (5)	170

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

supplementary crystallographic information

Comment

Pyrazine-2-carboxamide (pzc), is a good ligand, and a few complexes with pzc have been prepared, such as that of mercury (Azhdari Tehrani et al., 2010; Mir Mohammad Sadegh et al., 2010), vanadium (Pacigova et al., 2008), manganese (Abu-Youssef et al., 2006) and copper (Kristiansson, 2002; Munakata et al., 1997; Goher & Mautner, 2000). Here, we report the synthesis and structure of the title compound.

The asymmetric unit of the title compound, (Fig. 1), contains one Zn^II atom, two Cl atoms and one pyrazine-2-carboxamide ligand. The Zn^II atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from two pyrazine-2-carboxamide ligands and two terminal Cl atoms. The Zn—Cl and Zn—N bond lengths and angles are collected in Table 1.

In the crystal structure, intermolecular N—H···O, N—H···N and C—H···O hydrogen bonds (Table 2, Fig. 2) may stabilize the structure.

Experimental

A solution of pyrazine-2-carboxamide (0.25 g, 2.0 mmol) in methanol (10 ml) was added to a solution of ZnCl₂ (0.13 g, 1.0 mmol) in methanol (10 ml) and the resulting colorless solution was stirred for 15 min at room temperature. This solution was left to evaporate slowly at room temperature. After one week, colorless plate crystals of the title compound were isolated (yield 0.30 g, 78.4%).

Refinement

All H atoms were positioned geometrically, with C—H = 0.93 and N—H = 0.86 Å, and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C,N).

Figures

Fig. 1.

The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry codes: (a) x,1/2 - y,z].

Fig. 2.

Unit-cell packing diagram for title molecule. Hydrogen bonds are shown as dashed lines

Crystal data

[ZnCl2(C5H5N3O)2]	F(000) = 384
Mr = 382.53	Dx = 1.793 Mg m−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 5777 reflections
a = 5.4296 (5) Å	θ = 2.1–26.0°
b = 19.7629 (14) Å	µ = 2.12 mm−1
c = 6.8396 (5) Å	T = 298 K
β = 105.131 (7)°	Plate, colorless
V = 708.48 (10) Å3	0.40 × 0.06 × 0.05 mm
Z = 2

Data collection

Bruker APEXII CCD area-detector' diffractometer	1441 independent reflections
Radiation source: fine-focus sealed tube	1064 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.085
ω scans	θmax = 26.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −6→6
Tmin = 0.881, Tmax = 0.902	k = −21→24
5777 measured reflections	l = −8→8

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.093	H-atom parameters constrained
S = 0.97	w = 1/[σ2(Fo2) + (0.0467P)2] where P = (Fo2 + 2Fc2)/3
1441 reflections	(Δ/σ)max = 0.003
100 parameters	Δρmax = 0.78 e Å−3
0 restraints	Δρmin = −0.65 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	0.3963 (7)	0.3616 (2)	0.4810 (6)	0.0307 (9)
H1	0.2583	0.3512	0.3724	0.037*
C2	0.6226 (8)	0.3464 (2)	0.8085 (6)	0.0364 (10)
H2	0.6435	0.3262	0.9347	0.044*
C3	0.8016 (8)	0.3930 (2)	0.7802 (6)	0.0391 (10)
H3	0.9428	0.4022	0.8873	0.047*
C4	0.5722 (7)	0.4094 (2)	0.4563 (6)	0.0310 (8)
C5	0.5370 (8)	0.4445 (2)	0.2579 (6)	0.0366 (9)
N1	0.4213 (6)	0.33021 (16)	0.6574 (5)	0.0312 (7)
N2	0.7776 (6)	0.42473 (18)	0.6048 (5)	0.0366 (8)
N3	0.7336 (7)	0.4801 (2)	0.2331 (6)	0.0535 (11)
H3B	0.7210	0.5022	0.1226	0.064*
H3C	0.8736	0.4812	0.3276	0.064*
O1	0.3309 (6)	0.44069 (17)	0.1293 (4)	0.0506 (8)
Zn1	0.18582 (12)	0.2500	0.69002 (10)	0.0304 (2)
Cl1	0.1855 (3)	0.2500	1.0108 (2)	0.0480 (4)
Cl2	−0.1427 (3)	0.2500	0.4244 (2)	0.0416 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0264 (19)	0.030 (2)	0.034 (2)	−0.0008 (16)	0.0050 (17)	0.0030 (17)
C2	0.040 (2)	0.038 (2)	0.028 (2)	−0.0004 (18)	0.0041 (18)	0.0030 (18)
C3	0.036 (2)	0.046 (3)	0.030 (2)	−0.0092 (19)	−0.0004 (18)	0.0013 (19)
C4	0.0278 (19)	0.030 (2)	0.034 (2)	−0.0010 (16)	0.0063 (16)	−0.0002 (17)
C5	0.041 (2)	0.031 (2)	0.036 (2)	−0.0065 (18)	0.0050 (19)	0.0002 (18)
N1	0.0300 (16)	0.0295 (18)	0.0341 (19)	−0.0027 (14)	0.0081 (14)	−0.0011 (14)
N2	0.0325 (18)	0.037 (2)	0.037 (2)	−0.0053 (14)	0.0032 (15)	−0.0011 (15)
N3	0.041 (2)	0.073 (3)	0.042 (2)	−0.0229 (19)	0.0026 (17)	0.017 (2)
O1	0.0432 (17)	0.058 (2)	0.0413 (18)	−0.0198 (15)	−0.0053 (15)	0.0173 (16)
Zn1	0.0290 (3)	0.0313 (4)	0.0329 (4)	0.000	0.0114 (3)	0.000
Cl1	0.0570 (10)	0.0575 (11)	0.0328 (8)	0.000	0.0174 (7)	0.000
Cl2	0.0303 (7)	0.0525 (10)	0.0408 (8)	0.000	0.0069 (6)	0.000

Geometric parameters (Å, º)

C1—N1	1.332 (5)	C5—O1	1.232 (5)
C1—C4	1.384 (5)	C5—N3	1.326 (5)
C1—H1	0.9300	N1—Zn1	2.085 (3)
C2—N1	1.333 (5)	N3—H3B	0.8600
C2—C3	1.388 (6)	N3—H3C	0.8600
C2—H2	0.9300	Zn1—N1	2.085 (3)
C3—N2	1.330 (5)	Zn1—N1i	2.085 (3)
C3—H3	0.9300	Zn1—Cl1	2.1945 (16)
C4—N2	1.333 (5)	Zn1—Cl2	2.1888 (16)
C4—C5	1.491 (6)
N1—C1—C4	121.2 (4)	N3—C5—C4	116.6 (4)
N1—C1—H1	119.4	C1—N1—C2	117.4 (3)
C4—C1—H1	119.4	C1—N1—Zn1	122.1 (3)
N1—C2—C3	120.9 (4)	C2—N1—Zn1	120.1 (3)
N1—C2—H2	119.6	C3—N2—C4	116.4 (3)
C3—C2—H2	119.6	C5—N3—H3B	120.0
N2—C3—C2	122.1 (4)	C5—N3—H3C	120.0
N2—C3—H3	118.9	H3B—N3—H3C	120.0
C2—C3—H3	118.9	N1—Zn1—N1i	99.00 (18)
N2—C4—C1	121.9 (4)	N1—Zn1—Cl2	107.51 (10)
N2—C4—C5	118.1 (3)	N1i—Zn1—Cl2	107.51 (10)
C1—C4—C5	120.0 (3)	N1—Zn1—Cl1	105.53 (9)
O1—C5—N3	123.5 (4)	N1i—Zn1—Cl1	105.53 (9)
O1—C5—C4	119.9 (4)	Cl2—Zn1—Cl1	128.07 (6)
N1—C2—C3—N2	1.9 (7)	C3—C2—N1—Zn1	170.7 (3)
N1—C1—C4—N2	2.1 (6)	C2—C3—N2—C4	−0.2 (6)
N1—C1—C4—C5	−179.0 (4)	C1—C4—N2—C3	−1.7 (6)
N2—C4—C5—O1	−167.5 (4)	C5—C4—N2—C3	179.4 (4)
C1—C4—C5—O1	13.5 (6)	C1—N1—Zn1—N1i	96.5 (3)
N2—C4—C5—N3	10.8 (6)	C2—N1—Zn1—N1i	−75.5 (3)
C1—C4—C5—N3	−168.2 (4)	C1—N1—Zn1—Cl2	−15.2 (3)
C4—C1—N1—C2	−0.3 (6)	C2—N1—Zn1—Cl2	172.9 (3)
C4—C1—N1—Zn1	−172.5 (3)	C1—N1—Zn1—Cl1	−154.6 (3)
C3—C2—N1—C1	−1.5 (6)	C2—N1—Zn1—Cl1	33.5 (3)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3B···O1ii	0.86	2.02	2.875 (5)	175
N3—H3C···N2iii	0.86	2.61	3.205 (5)	128
C3—H3···O1iv	0.93	2.44	3.357 (5)	170

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