Bis(2-amino­pyrimidine-κN¹)dichloridozinc(II)

The title compound, [ZnCl₂(C₄H₅N₃)₂], contains a four-coordinate Zn^II atom in an approximately tetra­hedral environment. The Zn^II atom lies on a twofold rotation axis and is coordinated by two N atoms of two 2-amino­pyrimidine ligands and by two Cl⁻ anions. N—H...N hydrogen bonds connect the complex mol­ecules to form a one-dimensional supra­molecular structure along the c axis. The supra­molecular chains are parallel to each other and N—H...Cl hydrogen bonds link them into a two-dimensional network in the ac plane.

Key indicators

• Single-crystal X-ray study
• T = 302 K
• Mean [sigma](C-C) = 0.008 Å
• R factor = 0.065
• wR factor = 0.174
• Data-to-parameter ratio = 16.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.05
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Zn1    -   Cl1     ..       7.75 su
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          8
PLAT731_ALERT_1_C Bond    Calc     0.87(6), Rep     0.87(2) ......       3.00 su-Ra
              N1   -H1A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.85(5), Rep     0.85(2) ......       2.50 su-Ra
              N1   -H1B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.87(6), Rep     0.87(2) ......       3.00 su-Ra
              N1   -H1A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(5), Rep     0.85(2) ......       2.50 su-Ra
              N1   -H1B     1.555   1.555

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Zn1         (2)       1.85
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2

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

   4 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
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Aminopyrimidine is an active component of antibiotics, antimicrobials, anticonvulsants, antispasmatics, antineoplastics and antidiabetogenics, and many derivatives have been used in seed dressings, crop-disease control and veterinary drugs etc (Cookson et al., 1993, Katritzky et al., 1984, Santra et al., 1999). In coordination chemistry, the meta-related nitrogen in pyrimidine has played an important role in connecting different metal atoms, transmitting antiferromagnetic interactions and for obtaining magnetic systems of high nuclearity (Munno et la, 1998; Groen et al., 1998). Because of the peripheral N heteroatom, the excited state of the pyrimidine moiety undergoes protonation in aqueous solution and the complexes exhibit proton-dependent photophysics and photochemistry. Recently, the design of molecular architecture with aminopyrimidine and bipyrimidine has aroused interest in the fields of coordination, bioinorganic and magnetochemistry (Arwaroli,1997). We report here a new bichlorobis(2-aminopyrimidine) zinc(II) complex(I), (C₄H₅N₃)₂ZnCl₂.

In the crystal structure of the title complex(I), the Zn^II atom lies on a twofold rotation axis, the asymmetric unit is composed of a Zn^II ion, two 2-aminopyrimidine ligands and two Cl anions. The molecular structure of (I) is shown in Fig. 1. The Zn^II ion is four-coordinated in an approximately tetrahedral environment by two N atoms[N2 and N2ⁱ; symmetry code: (i) x- 1, y- 1, z] of two 2-aminopyrimidine ligands and two Cl anions [Cl1 and Cl1ⁱ]. The bond distances and angles around the zinc atoms are quite normal. [Zn—N 2.056 (2)Å and Zn—Cl 2.249 (3) Å].

The 2-aminopyrimidine molecules are planar within experimental error (pyrimidine ring the greatest deviation C3 within 0.0119 (3) Å)) and the amino N atoms lie approximately in the corresponding molecular planes (N1 off of the pyrimidine ring plane within 0.0183 (3) Å). The bond distances and angles of the 2-aminopyrimidine ligand are similar to those found in other complexes (Kennard et al., 1985; Etter et al., 1990; Zanchini et al., 1990;Lumme et al., 1996).

A large number of N—H···N hydrogen bonds and N—H···Cl hydrogen bonds (Table 2) help to establish the crystal packing. The N—H···N hydrogen bonds bind the complex molecules to form a one-dimensional supramolecular structure along the c axis. The supramolecular chains are parallel to each other and the N—H···Cl hydrogen bonds link them into a two-dimensional network into the ac plane. There are only weaker van der Waals interactions in the b axis (Fig.2).

Related literature

For related literature, see: Arwaroli et al. (1997); Cookson & Tiekink (1993); Etter et al. (1990); Groen et al. (1998); Katritzky et al. (1984); Kennard et al. (1985); Lumme et al. (1996); Munno et al. (1998); Santra et al. (1999); Zanchini & Willett (1990).

S2. Experimental

A solution of ZnCl₂ (0.5 mmol) in ethanol (10 ml) and 2-aminopyrimidine (1.0 mmol) was stirred at room temperature for 12 h and then filtered. The filtrate was kept at room temperature in the dark for two weeks, affording white crystals of (I). The crystals were isolated, washed three times with ethanol and dried in a vacuum desiccator using anhydrous CaCl₂. Analysis calculated for C₈N₆H₁₀ Zn Cl₂: C 29.43, N 25.74, H 3.09%; found: C 29.11, N 25.34,H 3.22%.

S3. Refinement

The H atoms bonded to the C atoms were placed in calculated positions, and were allowed to ride on their parent atoms, with a C—H distance of 0.93 Å for aromatic H atoms and U_iso(H) = 1.2 times of its parent atom. The H atom positions of the NH₂ group were obtained from a Fourier difference map and were refined with a restrained N—H distance of 0.86 (0.02) Å. The isotropic displacement parameters were set equal to 1.2U_eq(parent atom). The highest and lowest residual density peaks are 0.94 Å and 0.77 Å respectively from the Zn atom.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SMART; data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 19907a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Sheldrick, 1997b).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes:(i) -x, y, -z + 1/2]
	Fig. 2. Crystal packing of (I) viewing along the a axis. The N–H···N and N—H···Cl hydrogen bonding interactions are shown as dashed lines.

Bis(2-aminopyrimidine-κN¹)dichloridozinc(II)

Crystal data

[ZnCl2(C4H5N3)2]	F(000) = 656
Mr = 326.49	Dx = 1.716 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2860 reflections
a = 10.744 (4) Å	θ = 2.0–28.3°
b = 13.454 (5) Å	µ = 2.35 mm^−1
c = 8.806 (3) Å	T = 302 K
β = 97.012 (6)°	Block, white
V = 1263.4 (8) Å^3	0.28 × 0.18 × 0.16 mm
Z = 4

Data collection

Siemens SMART CCD area-detector diffractometer	1378 independent reflections
Radiation source: fine-focus sealed tube	1140 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.045
φ and ω scans	θmax = 27.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −13→12
Tmin = 0.512, Tmax = 0.685	k = −17→17
4933 measured reflections	l = −11→11

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)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.174	H atoms treated by a mixture of independent and constrained refinement
S = 1.14	w = 1/[σ^2(Fo^2) + (0.0993P)^2 + 1.9733P] where P = (Fo^2 + 2Fc^2)/3
1378 reflections	(Δ/σ)max = 0.002
84 parameters	Δρmax = 1.35 e Å^−3
2 restraints	Δρmin = −0.66 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 > 2σ(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
Zn1	0.0000	0.24505 (6)	0.2500	0.0411 (3)
C1	0.0696 (5)	0.3725 (4)	−0.0120 (5)	0.0419 (11)
C2	0.2323 (5)	0.3378 (4)	0.1742 (6)	0.0494 (13)
H2	0.2627	0.3089	0.2673	0.059*
C3	0.3158 (6)	0.3857 (5)	0.0918 (7)	0.0586 (15)
H3	0.4001	0.3929	0.1291	0.070*
C4	0.2666 (5)	0.4222 (4)	−0.0492 (6)	0.0521 (13)
H4	0.3210	0.4522	−0.1099	0.063*
Cl1	−0.12680 (12)	0.15173 (10)	0.08506 (13)	0.0479 (4)
N1	−0.0526 (4)	0.3712 (4)	−0.0641 (5)	0.0553 (12)
H1A	−0.108 (5)	0.340 (4)	−0.018 (7)	0.066*
H1B	−0.088 (5)	0.404 (4)	−0.140 (5)	0.066*
N2	0.1090 (4)	0.3313 (3)	0.1258 (4)	0.0403 (9)
N3	0.1469 (4)	0.4169 (3)	−0.1027 (5)	0.0491 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0449 (5)	0.0541 (6)	0.0248 (4)	0.000	0.0067 (3)	0.000
C1	0.056 (3)	0.047 (3)	0.025 (2)	0.001 (2)	0.0112 (19)	−0.0044 (17)
C2	0.052 (3)	0.065 (3)	0.030 (2)	−0.005 (2)	0.002 (2)	−0.003 (2)
C3	0.052 (3)	0.077 (4)	0.047 (3)	−0.020 (3)	0.003 (2)	−0.003 (3)
C4	0.058 (3)	0.057 (3)	0.044 (3)	−0.013 (2)	0.020 (2)	−0.006 (2)
Cl1	0.0497 (8)	0.0568 (8)	0.0362 (6)	−0.0088 (5)	0.0012 (5)	−0.0068 (5)
N1	0.047 (3)	0.083 (4)	0.037 (2)	0.005 (2)	0.0075 (19)	0.013 (2)
N2	0.046 (2)	0.052 (2)	0.0238 (18)	−0.0043 (18)	0.0078 (15)	−0.0017 (15)
N3	0.062 (3)	0.057 (3)	0.030 (2)	−0.007 (2)	0.0117 (19)	−0.0010 (17)

Geometric parameters (Å, º)

Zn1—N2	2.056 (4)	C2—C3	1.380 (8)
Zn1—N2^i	2.056 (4)	C2—H2	0.9300
Zn1—Cl1	2.2492 (13)	C3—C4	1.380 (8)
Zn1—Cl1^i	2.2492 (13)	C3—H3	0.9300
C1—N1	1.337 (7)	C4—N3	1.316 (7)
C1—N2	1.355 (6)	C4—H4	0.9300
C1—N3	1.358 (6)	N1—H1A	0.87 (2)
C2—N2	1.344 (6)	N1—H1B	0.85 (2)
N2—Zn1—N2^i	111.3 (2)	C4—C3—H3	122.0
N2—Zn1—Cl1	108.13 (11)	C2—C3—H3	122.0
N2^i—Zn1—Cl1	108.59 (12)	N3—C4—C3	123.5 (5)
N2—Zn1—Cl1^i	108.59 (12)	N3—C4—H4	118.2
N2^i—Zn1—Cl1^i	108.13 (11)	C3—C4—H4	118.2
Cl1—Zn1—Cl1^i	112.13 (8)	C1—N1—H1A	123 (4)
N1—C1—N2	119.2 (4)	C1—N1—H1B	126 (4)
N1—C1—N3	116.7 (4)	H1A—N1—H1B	111 (6)
N2—C1—N3	124.0 (5)	C2—N2—C1	116.5 (4)
N2—C2—C3	122.9 (5)	C2—N2—Zn1	118.2 (3)
N2—C2—H2	118.6	C1—N2—Zn1	124.8 (3)
C3—C2—H2	118.6	C4—N3—C1	117.1 (4)
C4—C3—C2	115.9 (5)
N2—C2—C3—C4	−3.6 (8)	Cl1—Zn1—N2—C2	−134.8 (3)
C2—C3—C4—N3	2.9 (9)	Cl1^i—Zn1—N2—C2	−12.9 (4)
C3—C2—N2—C1	1.5 (8)	N2^i—Zn1—N2—C1	−82.6 (4)
C3—C2—N2—Zn1	173.6 (4)	Cl1—Zn1—N2—C1	36.6 (4)
N1—C1—N2—C2	−177.9 (5)	Cl1^i—Zn1—N2—C1	158.5 (4)
N3—C1—N2—C2	1.6 (7)	C3—C4—N3—C1	−0.1 (8)
N1—C1—N2—Zn1	10.6 (7)	N1—C1—N3—C4	177.2 (5)
N3—C1—N2—Zn1	−169.9 (4)	N2—C1—N3—C4	−2.3 (7)
N2^i—Zn1—N2—C2	106.0 (4)

Symmetry code: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl1	0.87 (2)	2.70 (5)	3.367 (5)	134 (5)
N1—H1B···N3^ii	0.85 (2)	2.28 (4)	3.048 (6)	149 (6)

Symmetry code: (ii) −x, y, −z−1/2.