Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The title structure, [ZnBr2(C2H8N2)], is made up of infinite –ZnBr2–(en)–ZnBr2–(en)– zigzag chains. Each repeat unit contains a trans ethyl­enedi­amine ligand [N—C—C—N −179 (1)°], which bridges two approximately tetrahedral but crystallographically distinct Zn atoms. One Zn atom is bisected by a crystallographic twofold axis, whereas the other has mirror symmetry. Even though the crystal packing does not allow significant interaction between Zn and N atoms on adjacent chains, it does facilitate extensive inter­molecular N—H...Br hydrogen bonding (N...H 2.69–2.96 Å).

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101000567/na1500sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101000567/na1500Isup2.hkl
Contains datablock I

CCDC reference: 166958

Comment top

Prior to the present work, the only structural information concerning monoethylenediamine zinc dihalides had been obtained from vibrational spectroscopy. Raman and infrared studies of Zn(en)Cl2 (en is ethylenediamine) carried out by Newman & Powell (1961) and Krishnan & Plane (1966) indicated that the solid consists of infinite chains of Zn atoms bridged by en ligands, with N atoms trans to the C—C bond. The same studies concluded that both Cl atoms are attached to Zn, presumably completing a tetrahedral arrangement of bonds, c.f. the crystal structure of catena(µ-2-ethylenediamine)mercury(II) dibromide (Matkovic-Calogovic & Sikirica, 1990), in which a cationic -(en)-Hg-(en)-Hg- polymeric chain is accompanied by Br- anions. Repetition of the Zn(en)Cl2 work and its extension to Zn(en)Br2 by Iwamoto & Shriver (1971) indicated that both structures consist of polymeric Zn(en)X2 chains but, because of the complexity of the spectra, it was thought that the en moiety was probably in sites of low symmetry. More recent work by Bennett et al. (1990) also explained the vibrational spectra in terms of –ZnX2-(en)-ZnX2-(en)- polymeric chains, but with en in its symmetric trans form; however, they concluded that there was additional interaction between Zn and NH2 groups on neighbouring molecules, leading to an effective octahedral coordination around Zn.

The stucture of the title molecule, (I), reported herein confirms the existence of polymeric –ZnBr2-(en)-ZnBr2-(en)- chains and a trans en configuration but rules out intermolecular NH2···Zn contacts. Despite the en ligand having a trans configuration, its two N atoms are attached to Zn centres with different crystallographic symmetry and significantly different geometry, e.g. N1—Zn1—N1i 98.6 (8)° (mirror symmetry) and N2—Zn2—N2ii 111.6 (10)° (twofold axis) [symmetry codes: (i) 1/2 - x, y, z; (ii) 1 - x, -y, z]. The complexity of the vibrational spectra can therefore be related to asymmetric NH2 environments.

Interestingly, –HgI2-(en)-HgI2-(en)- (Matkovic-Calogovic & Sikirica, 1990), the only other zinc-group M(en)X2 complex to be characterized by single-crystal methods, also consists of zigzag chains, but in this case each en is centrosymmetric and hence crystallographically constrained to be trans.

Related literature top

For related literature, see: Bennett et al. (1990); Iwamoto & Shriver (1971); Krishnan & Plane (1966); Matkovic-Calogovic & Sikirica (1990); Newman & Powell (1961).

Experimental top

Suitable crystals of (I) were prepared by slow evaporation of a mixture of ZnCl2 (1 ml, 0.2 M) and en (1 ml, 0.2 M), both in methanol to which two drops of 35% w/w hydrogen peroxide had been added.

Refinement top

Please provide brief details of H-atom refinement.

Computing details top

Data collection: please give details; cell refinement: please give details; data reduction: please give details; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular view of (I) with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
catena-Poly[dibromozinc(II)-µ-ethylenediamine-N:N'] top
Crystal data top
[ZnBr2(C2H8N2)]F(000) = 1072
Mr = 285.29Dx = 2.721 Mg m3
Orthorhombic, Ima2Cu Kα radiation, λ = 1.54178 Å
Hall symbol: I 2 -2aCell parameters from 25 reflections
a = 19.270 (4) Åθ = 8.3–16.2°
b = 7.2111 (17) ŵ = 17.47 mm1
c = 10.025 (5) ÅT = 293 K
V = 1393.1 (8) Å3Needle, colourless
Z = 80.25 × 0.15 × 0.10 mm
Data collection top
Scintillation counter
diffractometer
Rint = 0.075
ω/2θ scansθmax = 65.0°, θmin = 4.6°
Absorption correction: ψ-scan
(North et al., 1968)
h = 022
Tmin = 0.062, Tmax = 0.174k = 88
1206 measured reflectionsl = 011
631 independent reflections3 standard reflections every 150 reflections
565 reflections with I > 2σ(I) intensity decay: 0.0%
Refinement top
Refinement on F2 w = 1/[σ2(Fo2) + (0.1171P)2]
where P = (Fo2 + 2Fc2)/3
Least-squares matrix: full(Δ/σ)max < 0.001
R[F2 > 2σ(F2)] = 0.053Δρmax = 1.22 e Å3
wR(F2) = 0.151Δρmin = 1.44 e Å3
S = 1.02Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
631 reflectionsExtinction coefficient: 0.00034 (4)
70 parametersAbsolute structure: Flack (1983)
1 restraintAbsolute structure parameter: 0.12 (14)
H-atom parameters constrained
Crystal data top
[ZnBr2(C2H8N2)]V = 1393.1 (8) Å3
Mr = 285.29Z = 8
Orthorhombic, Ima2Cu Kα radiation
a = 19.270 (4) ŵ = 17.47 mm1
b = 7.2111 (17) ÅT = 293 K
c = 10.025 (5) Å0.25 × 0.15 × 0.10 mm
Data collection top
Scintillation counter
diffractometer
565 reflections with I > 2σ(I)
Absorption correction: ψ-scan
(North et al., 1968)
Rint = 0.075
Tmin = 0.062, Tmax = 0.1743 standard reflections every 150 reflections
1206 measured reflections intensity decay: 0.0%
631 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.053H-atom parameters constrained
wR(F2) = 0.151Δρmax = 1.22 e Å3
S = 1.02Δρmin = 1.44 e Å3
631 reflectionsAbsolute structure: Flack (1983)
70 parametersAbsolute structure parameter: 0.12 (14)
1 restraint
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br11/40.9850 (3)0.4662 (3)0.0408 (8)
Br21/40.4999 (3)0.3284 (3)0.0403 (8)
Br30.54675 (9)0.2492 (3)0.9320 (3)0.0442 (7)
Zn11/40.6703 (4)0.5339 (4)0.0301 (7)
Zn21/200.8039 (4)0.0334 (9)
N10.3308 (6)0.5790 (16)0.6502 (15)0.031 (3)
H1A0.36850.64850.63280.037*
H1B0.31970.59550.73660.037*
N20.4222 (7)0.1127 (18)0.6882 (19)0.039 (3)
H2A0.43430.10140.6020.047*
H2B0.38340.04540.70050.047*
C10.3481 (7)0.3825 (19)0.6283 (18)0.030 (3)
H1C0.36110.3660.53560.036*
H1D0.30690.30850.64430.036*
C20.4055 (9)0.311 (2)0.7145 (17)0.034 (4)
H2C0.44670.38510.69960.041*
H2D0.39230.32470.80740.041*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0640 (19)0.0209 (13)0.0375 (16)000.0007 (10)
Br20.0468 (14)0.0330 (14)0.0409 (15)000.0052 (11)
Br30.0447 (9)0.0316 (9)0.0563 (13)0.0034 (8)0.0127 (9)0.0068 (8)
Zn10.0321 (13)0.0228 (14)0.0355 (15)000.0050 (14)
Zn20.0307 (15)0.0236 (14)0.046 (2)0.0072 (11)00
N10.034 (6)0.019 (6)0.039 (7)0.002 (5)0.000 (6)0.000 (6)
N20.029 (6)0.028 (7)0.061 (9)0.006 (5)0.012 (7)0.008 (7)
C10.028 (8)0.018 (6)0.043 (9)0.001 (6)0.006 (7)0.005 (7)
C20.037 (8)0.030 (9)0.036 (11)0.005 (7)0.004 (7)0.009 (7)
Geometric parameters (Å, º) top
Br1—Zn12.369 (4)Zn2—N22.063 (14)
Br2—Zn12.399 (5)Zn2—Br3ii2.386 (3)
Br3—Zn22.386 (3)N1—C11.47 (2)
Zn1—N12.053 (14)N2—C21.49 (2)
Zn1—N1i2.053 (14)C1—C21.50 (2)
Zn2—N2ii2.063 (14)
N1—Zn1—N1i98.6 (8)N2—Zn2—Br3106.3 (4)
N1—Zn1—Br1118.0 (4)N2ii—Zn2—Br3ii106.3 (4)
N1i—Zn1—Br1118.0 (3)N2—Zn2—Br3ii109.0 (4)
N1—Zn1—Br2108.9 (4)Br3—Zn2—Br3ii114.9 (2)
N1i—Zn1—Br2108.9 (4)C1—N1—Zn1113.3 (10)
Br1—Zn1—Br2104.2 (2)C2—N2—Zn2115.8 (10)
N2ii—Zn2—N2111.6 (10)N1—C1—C2114.4 (14)
N2ii—Zn2—Br3109.0 (4)N2—C2—C1112.9 (14)
N1i—Zn1—N1—C182.9 (12)Br3ii—Zn2—N2—C2118.4 (12)
Br1—Zn1—N1—C1148.8 (9)Zn1—N1—C1—C2178.4 (11)
Br2—Zn1—N1—C130.5 (12)Zn2—N2—C2—C1179.3 (11)
N2ii—Zn2—N2—C2124.6 (14)N1—C1—C2—N2179.2 (14)
Br3—Zn2—N2—C25.9 (14)
Symmetry codes: (i) x+1/2, y, z; (ii) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···Br3iii0.902.693.44 (1)142
N1—H1B···Br1iv0.902.733.56 (2)154
N2—H2A···Br3v0.902.963.65 (2)135
N2—H2B···Br2vi0.902.893.69 (1)149
Symmetry codes: (iii) x+1, y+1/2, z1/2; (iv) x, y+3/2, z+1/2; (v) x, y+1/2, z1/2; (vi) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula[ZnBr2(C2H8N2)]
Mr285.29
Crystal system, space groupOrthorhombic, Ima2
Temperature (K)293
a, b, c (Å)19.270 (4), 7.2111 (17), 10.025 (5)
V3)1393.1 (8)
Z8
Radiation typeCu Kα
µ (mm1)17.47
Crystal size (mm)0.25 × 0.15 × 0.10
Data collection
DiffractometerScintillation counter
diffractometer
Absorption correctionψ-scan
(North et al., 1968)
Tmin, Tmax0.062, 0.174
No. of measured, independent and
observed [I > 2σ(I)] reflections
1206, 631, 565
Rint0.075
(sin θ/λ)max1)0.588
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.151, 1.02
No. of reflections631
No. of parameters70
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.22, 1.44
Absolute structureFlack (1983)
Absolute structure parameter0.12 (14)

Computer programs: please give details, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Br1—Zn12.369 (4)Zn2—N22.063 (14)
Br2—Zn12.399 (5)N1—C11.47 (2)
Br3—Zn22.386 (3)N2—C21.49 (2)
Zn1—N12.053 (14)C1—C21.50 (2)
N1—Zn1—N1i98.6 (8)N2ii—Zn2—N2111.6 (10)
N1—Zn1—Br1118.0 (4)N2ii—Zn2—Br3109.0 (4)
N1—Zn1—Br2108.9 (4)N2—Zn2—Br3106.3 (4)
Br1—Zn1—Br2104.2 (2)Br3—Zn2—Br3ii114.9 (2)
Symmetry codes: (i) x+1/2, y, z; (ii) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···Br3iii0.902.693.44 (1)142
N1—H1B···Br1iv0.902.733.56 (2)154
N2—H2A···Br3v0.902.963.65 (2)135
N2—H2B···Br2vi0.902.893.69 (1)149
Symmetry codes: (iii) x+1, y+1/2, z1/2; (iv) x, y+3/2, z+1/2; (v) x, y+1/2, z1/2; (vi) x, y+1/2, z+1/2.
 

Subscribe to Acta Crystallographica Section C: Structural Chemistry

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds