Buy article online - an online subscription or single-article purchase is required to access this article.
The title structure, [ZnBr
2(C
2H
8N
2)], is made up of infinite –ZnBr
2–(en)–ZnBr
2–(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
CCDC reference: 166958
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.
Please provide brief details of H-atom refinement.
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).
catena-Poly[dibromozinc(II)-µ-ethylenediamine-N:
N']
top
Crystal data top
[ZnBr2(C2H8N2)] | F(000) = 1072 |
Mr = 285.29 | Dx = 2.721 Mg m−3 |
Orthorhombic, Ima2 | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: I 2 -2a | Cell parameters from 25 reflections |
a = 19.270 (4) Å | θ = 8.3–16.2° |
b = 7.2111 (17) Å | µ = 17.47 mm−1 |
c = 10.025 (5) Å | T = 293 K |
V = 1393.1 (8) Å3 | Needle, colourless |
Z = 8 | 0.25 × 0.15 × 0.10 mm |
Data collection top
Scintillation counter diffractometer | Rint = 0.075 |
ω/2θ scans | θmax = 65.0°, θmin = 4.6° |
Absorption correction: ψ-scan (North et al., 1968) | h = 0→22 |
Tmin = 0.062, Tmax = 0.174 | k = −8→8 |
1206 measured reflections | l = 0→11 |
631 independent reflections | 3 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)] = 0.053 | Δρmax = 1.22 e Å−3 |
wR(F2) = 0.151 | Δρmin = −1.44 e Å−3 |
S = 1.02 | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
631 reflections | Extinction coefficient: 0.00034 (4) |
70 parameters | Absolute structure: Flack (1983) |
1 restraint | Absolute structure parameter: 0.12 (14) |
H-atom parameters constrained | |
Crystal data top
[ZnBr2(C2H8N2)] | V = 1393.1 (8) Å3 |
Mr = 285.29 | Z = 8 |
Orthorhombic, Ima2 | Cu Kα radiation |
a = 19.270 (4) Å | µ = 17.47 mm−1 |
b = 7.2111 (17) Å | T = 293 K |
c = 10.025 (5) Å | 0.25 × 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 = 0.174 | 3 standard reflections every 150 reflections |
1206 measured reflections | intensity decay: 0.0% |
631 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.053 | H-atom parameters constrained |
wR(F2) = 0.151 | Δρmax = 1.22 e Å−3 |
S = 1.02 | Δρmin = −1.44 e Å−3 |
631 reflections | Absolute structure: Flack (1983) |
70 parameters | Absolute 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 | x | y | z | Uiso*/Ueq | |
Br1 | 1/4 | 0.9850 (3) | 0.4662 (3) | 0.0408 (8) | |
Br2 | 1/4 | 0.4999 (3) | 0.3284 (3) | 0.0403 (8) | |
Br3 | 0.54675 (9) | 0.2492 (3) | 0.9320 (3) | 0.0442 (7) | |
Zn1 | 1/4 | 0.6703 (4) | 0.5339 (4) | 0.0301 (7) | |
Zn2 | 1/2 | 0 | 0.8039 (4) | 0.0334 (9) | |
N1 | 0.3308 (6) | 0.5790 (16) | 0.6502 (15) | 0.031 (3) | |
H1A | 0.3685 | 0.6485 | 0.6328 | 0.037* | |
H1B | 0.3197 | 0.5955 | 0.7366 | 0.037* | |
N2 | 0.4222 (7) | 0.1127 (18) | 0.6882 (19) | 0.039 (3) | |
H2A | 0.4343 | 0.1014 | 0.602 | 0.047* | |
H2B | 0.3834 | 0.0454 | 0.7005 | 0.047* | |
C1 | 0.3481 (7) | 0.3825 (19) | 0.6283 (18) | 0.030 (3) | |
H1C | 0.3611 | 0.366 | 0.5356 | 0.036* | |
H1D | 0.3069 | 0.3085 | 0.6443 | 0.036* | |
C2 | 0.4055 (9) | 0.311 (2) | 0.7145 (17) | 0.034 (4) | |
H2C | 0.4467 | 0.3851 | 0.6996 | 0.041* | |
H2D | 0.3923 | 0.3247 | 0.8074 | 0.041* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Br1 | 0.0640 (19) | 0.0209 (13) | 0.0375 (16) | 0 | 0 | 0.0007 (10) |
Br2 | 0.0468 (14) | 0.0330 (14) | 0.0409 (15) | 0 | 0 | −0.0052 (11) |
Br3 | 0.0447 (9) | 0.0316 (9) | 0.0563 (13) | 0.0034 (8) | −0.0127 (9) | −0.0068 (8) |
Zn1 | 0.0321 (13) | 0.0228 (14) | 0.0355 (15) | 0 | 0 | 0.0050 (14) |
Zn2 | 0.0307 (15) | 0.0236 (14) | 0.046 (2) | 0.0072 (11) | 0 | 0 |
N1 | 0.034 (6) | 0.019 (6) | 0.039 (7) | 0.002 (5) | 0.000 (6) | 0.000 (6) |
N2 | 0.029 (6) | 0.028 (7) | 0.061 (9) | 0.006 (5) | −0.012 (7) | −0.008 (7) |
C1 | 0.028 (8) | 0.018 (6) | 0.043 (9) | 0.001 (6) | −0.006 (7) | 0.005 (7) |
C2 | 0.037 (8) | 0.030 (9) | 0.036 (11) | 0.005 (7) | −0.004 (7) | 0.009 (7) |
Geometric parameters (Å, º) top
Br1—Zn1 | 2.369 (4) | Zn2—N2 | 2.063 (14) |
Br2—Zn1 | 2.399 (5) | Zn2—Br3ii | 2.386 (3) |
Br3—Zn2 | 2.386 (3) | N1—C1 | 1.47 (2) |
Zn1—N1 | 2.053 (14) | N2—C2 | 1.49 (2) |
Zn1—N1i | 2.053 (14) | C1—C2 | 1.50 (2) |
Zn2—N2ii | 2.063 (14) | | |
| | | |
N1—Zn1—N1i | 98.6 (8) | N2—Zn2—Br3 | 106.3 (4) |
N1—Zn1—Br1 | 118.0 (4) | N2ii—Zn2—Br3ii | 106.3 (4) |
N1i—Zn1—Br1 | 118.0 (3) | N2—Zn2—Br3ii | 109.0 (4) |
N1—Zn1—Br2 | 108.9 (4) | Br3—Zn2—Br3ii | 114.9 (2) |
N1i—Zn1—Br2 | 108.9 (4) | C1—N1—Zn1 | 113.3 (10) |
Br1—Zn1—Br2 | 104.2 (2) | C2—N2—Zn2 | 115.8 (10) |
N2ii—Zn2—N2 | 111.6 (10) | N1—C1—C2 | 114.4 (14) |
N2ii—Zn2—Br3 | 109.0 (4) | N2—C2—C1 | 112.9 (14) |
| | | |
N1i—Zn1—N1—C1 | 82.9 (12) | Br3ii—Zn2—N2—C2 | 118.4 (12) |
Br1—Zn1—N1—C1 | −148.8 (9) | Zn1—N1—C1—C2 | −178.4 (11) |
Br2—Zn1—N1—C1 | −30.5 (12) | Zn2—N2—C2—C1 | −179.3 (11) |
N2ii—Zn2—N2—C2 | −124.6 (14) | N1—C1—C2—N2 | −179.2 (14) |
Br3—Zn2—N2—C2 | −5.9 (14) | | |
Symmetry codes: (i) −x+1/2, y, z; (ii) −x+1, −y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Br3iii | 0.90 | 2.69 | 3.44 (1) | 142 |
N1—H1B···Br1iv | 0.90 | 2.73 | 3.56 (2) | 154 |
N2—H2A···Br3v | 0.90 | 2.96 | 3.65 (2) | 135 |
N2—H2B···Br2vi | 0.90 | 2.89 | 3.69 (1) | 149 |
Symmetry codes: (iii) −x+1, y+1/2, z−1/2; (iv) x, −y+3/2, z+1/2; (v) x, −y+1/2, z−1/2; (vi) x, −y+1/2, z+1/2. |
Experimental details
Crystal data |
Chemical formula | [ZnBr2(C2H8N2)] |
Mr | 285.29 |
Crystal system, space group | Orthorhombic, Ima2 |
Temperature (K) | 293 |
a, b, c (Å) | 19.270 (4), 7.2111 (17), 10.025 (5) |
V (Å3) | 1393.1 (8) |
Z | 8 |
Radiation type | Cu Kα |
µ (mm−1) | 17.47 |
Crystal size (mm) | 0.25 × 0.15 × 0.10 |
|
Data collection |
Diffractometer | Scintillation counter diffractometer |
Absorption correction | ψ-scan (North et al., 1968) |
Tmin, Tmax | 0.062, 0.174 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1206, 631, 565 |
Rint | 0.075 |
(sin θ/λ)max (Å−1) | 0.588 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.053, 0.151, 1.02 |
No. of reflections | 631 |
No. of parameters | 70 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.22, −1.44 |
Absolute structure | Flack (1983) |
Absolute structure parameter | 0.12 (14) |
Selected geometric parameters (Å, º) topBr1—Zn1 | 2.369 (4) | Zn2—N2 | 2.063 (14) |
Br2—Zn1 | 2.399 (5) | N1—C1 | 1.47 (2) |
Br3—Zn2 | 2.386 (3) | N2—C2 | 1.49 (2) |
Zn1—N1 | 2.053 (14) | C1—C2 | 1.50 (2) |
| | | |
N1—Zn1—N1i | 98.6 (8) | N2ii—Zn2—N2 | 111.6 (10) |
N1—Zn1—Br1 | 118.0 (4) | N2ii—Zn2—Br3 | 109.0 (4) |
N1—Zn1—Br2 | 108.9 (4) | N2—Zn2—Br3 | 106.3 (4) |
Br1—Zn1—Br2 | 104.2 (2) | Br3—Zn2—Br3ii | 114.9 (2) |
Symmetry codes: (i) −x+1/2, y, z; (ii) −x+1, −y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···Br3iii | 0.90 | 2.69 | 3.44 (1) | 142 |
N1—H1B···Br1iv | 0.90 | 2.73 | 3.56 (2) | 154 |
N2—H2A···Br3v | 0.90 | 2.96 | 3.65 (2) | 135 |
N2—H2B···Br2vi | 0.90 | 2.89 | 3.69 (1) | 149 |
Symmetry codes: (iii) −x+1, y+1/2, z−1/2; (iv) x, −y+3/2, z+1/2; (v) x, −y+1/2, z−1/2; (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.
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.