Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106039965/sk3060sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106039965/sk3060Isup2.hkl |
CCDC reference: 628507
A mixture of ZnI2 (0.16 g, 0.5 mmol), bipy (0.78 g, 0.5 mmol) and water (13 ml) was sealed in a 25 ml Teflon-lined stainless-steel reactor, heated to 443 K for 72 h, and then slowly cooled to room temperature. Block-shaped lightyellow crystals of (I), suitable for X-ray analysis, were obtained by filtration (yield 23.2%).
All H atoms were located theoretically and refined as riding atoms, with C—H distances in the range 0.93—0.97 Å and with Uiso(H) = 1.2Ueq(C).
Data collection: SMART (Siemens, 1996); cell refinement: SMART & SAINT (Siemens, 1996); data reduction: XPREP in SHELXTL (Siemens, 1996); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and ASP (Chen, 2002); software used to prepare material for publication: SHELXTL.
[ZnI2(C10H8N2)] | F(000) = 1744 |
Mr = 950.71 | Dx = 2.341 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9437 reflections |
a = 17.140 (3) Å | θ = 1.3–25.7° |
b = 13.930 (3) Å | µ = 6.37 mm−1 |
c = 11.950 (2) Å | T = 293 K |
β = 109.00 (3)° | Block, light yellow |
V = 2697.7 (10) Å3 | 0.5 × 0.45 × 0.2 mm |
Z = 4 |
Siemens SMART CCD area-detector diffractometer | 5080 independent reflections |
Radiation source: fine-focus sealed tube | 3979 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ϕ and ω scans | θmax = 25.7°, θmin = 1.3° |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | h = −17→20 |
Tmin = 0.632, Tmax = 1.000 | k = −16→16 |
14426 measured reflections | l = −14→11 |
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)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0581P)2 + 24.4231P] where P = (Fo2 + 2Fc2)/3 |
5080 reflections | (Δ/σ)max = 0.001 |
271 parameters | Δρmax = 1.08 e Å−3 |
0 restraints | Δρmin = −0.76 e Å−3 |
[ZnI2(C10H8N2)] | V = 2697.7 (10) Å3 |
Mr = 950.71 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 17.140 (3) Å | µ = 6.37 mm−1 |
b = 13.930 (3) Å | T = 293 K |
c = 11.950 (2) Å | 0.5 × 0.45 × 0.2 mm |
β = 109.00 (3)° |
Siemens SMART CCD area-detector diffractometer | 5080 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | 3979 reflections with I > 2σ(I) |
Tmin = 0.632, Tmax = 1.000 | Rint = 0.030 |
14426 measured reflections |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0581P)2 + 24.4231P] where P = (Fo2 + 2Fc2)/3 |
5080 reflections | Δρmax = 1.08 e Å−3 |
271 parameters | Δρmin = −0.76 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
Zn1 | −0.38009 (6) | 0.74595 (8) | 0.54523 (10) | 0.0431 (3) | |
Zn2 | 0.12596 (6) | 0.71552 (7) | 0.15077 (9) | 0.0409 (2) | |
I1 | −0.40061 (4) | 0.58708 (5) | 0.63828 (6) | 0.0564 (2) | |
I2 | −0.35877 (5) | 0.91385 (5) | 0.63893 (7) | 0.0621 (2) | |
I3 | 0.13013 (4) | 0.55375 (4) | 0.05331 (6) | 0.05166 (19) | |
I4 | 0.12093 (5) | 0.87511 (5) | 0.04460 (7) | 0.0642 (2) | |
N1 | −0.2812 (4) | 0.7312 (6) | 0.4830 (7) | 0.0471 (18) | |
N2 | 0.0255 (4) | 0.7154 (5) | 0.2104 (7) | 0.0423 (17) | |
N3 | 0.2259 (4) | 0.7257 (5) | 0.3070 (7) | 0.0454 (18) | |
N4 | 0.5204 (4) | 0.7473 (6) | 0.8864 (7) | 0.0452 (18) | |
C1 | −0.2335 (7) | 0.6530 (7) | 0.4936 (11) | 0.059 (3) | |
H1A | −0.2409 | 0.6014 | 0.5386 | 0.071* | |
C2 | −0.1743 (6) | 0.6471 (8) | 0.4401 (11) | 0.062 (3) | |
H2A | −0.1430 | 0.5915 | 0.4480 | 0.074* | |
C3 | −0.1605 (5) | 0.7221 (6) | 0.3748 (8) | 0.0410 (19) | |
C4 | −0.0966 (5) | 0.7185 (7) | 0.3161 (9) | 0.045 (2) | |
C5 | −0.0811 (6) | 0.6361 (7) | 0.2631 (10) | 0.054 (2) | |
H5A | −0.1116 | 0.5806 | 0.2615 | 0.065* | |
C6 | −0.0199 (6) | 0.6377 (7) | 0.2130 (10) | 0.055 (3) | |
H6A | −0.0091 | 0.5815 | 0.1787 | 0.067* | |
C7 | 0.0091 (6) | 0.7952 (7) | 0.2597 (10) | 0.056 (3) | |
H7A | 0.0389 | 0.8506 | 0.2578 | 0.068* | |
C8 | −0.0500 (6) | 0.7980 (7) | 0.3127 (10) | 0.053 (2) | |
H8A | −0.0591 | 0.8549 | 0.3474 | 0.063* | |
C9 | −0.2093 (6) | 0.8022 (7) | 0.3652 (9) | 0.049 (2) | |
H9A | −0.2024 | 0.8547 | 0.3213 | 0.059* | |
C10 | −0.2679 (6) | 0.8048 (7) | 0.4199 (9) | 0.053 (2) | |
H10A | −0.2998 | 0.8599 | 0.4130 | 0.063* | |
C11 | 0.2709 (6) | 0.6501 (7) | 0.3608 (9) | 0.056 (3) | |
H11A | 0.2620 | 0.5920 | 0.3201 | 0.067* | |
C12 | 0.3296 (6) | 0.6519 (7) | 0.4722 (9) | 0.057 (3) | |
H12A | 0.3594 | 0.5969 | 0.5039 | 0.069* | |
C13 | 0.3433 (5) | 0.7374 (7) | 0.5362 (8) | 0.042 (2) | |
C14 | 0.4025 (5) | 0.7436 (7) | 0.6586 (8) | 0.042 (2) | |
C15 | 0.4160 (6) | 0.6631 (7) | 0.7349 (9) | 0.056 (2) | |
H15A | 0.3857 | 0.6070 | 0.7108 | 0.067* | |
C16 | 0.4752 (6) | 0.6690 (7) | 0.8465 (9) | 0.053 (2) | |
H16A | 0.4836 | 0.6157 | 0.8958 | 0.063* | |
C17 | 0.5069 (6) | 0.8237 (8) | 0.8162 (9) | 0.056 (2) | |
H17A | 0.5370 | 0.8794 | 0.8434 | 0.068* | |
C18 | 0.4476 (6) | 0.8229 (8) | 0.7004 (9) | 0.056 (3) | |
H18A | 0.4400 | 0.8775 | 0.6533 | 0.067* | |
C19 | 0.2992 (6) | 0.8169 (7) | 0.4791 (9) | 0.050 (2) | |
H19A | 0.3086 | 0.8765 | 0.5162 | 0.060* | |
C20 | 0.2418 (6) | 0.8085 (7) | 0.3683 (9) | 0.051 (2) | |
H20A | 0.2124 | 0.8629 | 0.3337 | 0.061* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.0403 (5) | 0.0428 (6) | 0.0477 (6) | 0.0024 (4) | 0.0163 (5) | −0.0036 (5) |
Zn2 | 0.0401 (5) | 0.0364 (5) | 0.0475 (6) | −0.0006 (4) | 0.0161 (4) | −0.0029 (4) |
I1 | 0.0634 (4) | 0.0467 (4) | 0.0636 (4) | −0.0019 (3) | 0.0268 (3) | 0.0024 (3) |
I2 | 0.0712 (5) | 0.0476 (4) | 0.0700 (5) | 0.0013 (3) | 0.0263 (4) | −0.0151 (3) |
I3 | 0.0592 (4) | 0.0376 (3) | 0.0623 (4) | −0.0021 (3) | 0.0255 (3) | −0.0079 (3) |
I4 | 0.0890 (5) | 0.0403 (4) | 0.0651 (5) | −0.0033 (3) | 0.0274 (4) | 0.0059 (3) |
N1 | 0.042 (4) | 0.044 (4) | 0.059 (5) | 0.001 (3) | 0.022 (4) | −0.003 (4) |
N2 | 0.039 (4) | 0.040 (4) | 0.051 (4) | −0.003 (3) | 0.019 (3) | −0.007 (3) |
N3 | 0.040 (4) | 0.043 (4) | 0.053 (5) | 0.003 (3) | 0.015 (3) | −0.004 (4) |
N4 | 0.041 (4) | 0.047 (4) | 0.049 (5) | −0.001 (3) | 0.016 (4) | 0.002 (4) |
C1 | 0.066 (6) | 0.044 (6) | 0.084 (8) | 0.009 (5) | 0.046 (6) | 0.015 (5) |
C2 | 0.056 (6) | 0.044 (6) | 0.096 (8) | 0.008 (5) | 0.040 (6) | 0.003 (6) |
C3 | 0.035 (4) | 0.038 (5) | 0.052 (5) | −0.002 (4) | 0.015 (4) | −0.004 (4) |
C4 | 0.040 (5) | 0.042 (5) | 0.057 (6) | −0.007 (4) | 0.022 (4) | −0.013 (4) |
C5 | 0.056 (6) | 0.043 (5) | 0.075 (7) | −0.007 (4) | 0.037 (5) | −0.010 (5) |
C6 | 0.056 (6) | 0.045 (6) | 0.072 (7) | −0.004 (5) | 0.031 (5) | −0.015 (5) |
C7 | 0.051 (6) | 0.045 (6) | 0.077 (7) | −0.006 (4) | 0.027 (5) | −0.011 (5) |
C8 | 0.051 (5) | 0.039 (5) | 0.077 (7) | −0.006 (4) | 0.032 (5) | −0.006 (5) |
C9 | 0.051 (5) | 0.035 (5) | 0.067 (6) | 0.000 (4) | 0.028 (5) | 0.005 (4) |
C10 | 0.058 (6) | 0.036 (5) | 0.070 (7) | 0.017 (4) | 0.030 (5) | 0.009 (5) |
C11 | 0.062 (6) | 0.042 (5) | 0.056 (6) | 0.002 (5) | 0.009 (5) | −0.011 (5) |
C12 | 0.062 (6) | 0.043 (6) | 0.059 (6) | 0.016 (5) | 0.008 (5) | 0.001 (5) |
C13 | 0.036 (4) | 0.046 (5) | 0.045 (5) | 0.001 (4) | 0.015 (4) | −0.001 (4) |
C14 | 0.033 (4) | 0.048 (5) | 0.046 (5) | −0.003 (4) | 0.015 (4) | −0.002 (4) |
C15 | 0.051 (6) | 0.048 (6) | 0.067 (7) | −0.007 (4) | 0.017 (5) | 0.000 (5) |
C16 | 0.056 (6) | 0.049 (6) | 0.053 (6) | −0.011 (5) | 0.017 (5) | 0.002 (5) |
C17 | 0.058 (6) | 0.050 (6) | 0.057 (6) | −0.016 (5) | 0.013 (5) | −0.001 (5) |
C18 | 0.058 (6) | 0.054 (6) | 0.047 (6) | −0.001 (5) | 0.004 (5) | 0.006 (5) |
C19 | 0.043 (5) | 0.042 (5) | 0.059 (6) | 0.001 (4) | 0.009 (4) | −0.014 (4) |
C20 | 0.047 (5) | 0.039 (5) | 0.060 (6) | 0.009 (4) | 0.008 (5) | −0.002 (4) |
Zn1—N1 | 2.071 (7) | C5—H5A | 0.9300 |
Zn1—N4i | 2.101 (8) | C6—H6A | 0.9300 |
Zn1—I1 | 2.5520 (13) | C7—C8 | 1.360 (14) |
Zn1—I2 | 2.5673 (13) | C7—H7A | 0.9300 |
Zn2—N2 | 2.068 (7) | C8—H8A | 0.9300 |
Zn2—N3 | 2.088 (8) | C9—C10 | 1.365 (13) |
Zn2—I4 | 2.5471 (13) | C9—H9A | 0.9300 |
Zn2—I3 | 2.5483 (12) | C10—H10A | 0.9300 |
N1—C10 | 1.335 (12) | C11—C12 | 1.383 (14) |
N1—C1 | 1.343 (12) | C11—H11A | 0.9300 |
N2—C7 | 1.329 (12) | C12—C13 | 1.393 (14) |
N2—C6 | 1.338 (12) | C12—H12A | 0.9300 |
N3—C11 | 1.340 (12) | C13—C19 | 1.389 (13) |
N3—C20 | 1.344 (12) | C13—C14 | 1.486 (13) |
N4—C17 | 1.328 (13) | C14—C18 | 1.348 (13) |
N4—C16 | 1.333 (12) | C14—C15 | 1.416 (14) |
N4—Zn1ii | 2.101 (8) | C15—C16 | 1.390 (14) |
C1—C2 | 1.367 (14) | C15—H15A | 0.9300 |
C1—H1A | 0.9300 | C16—H16A | 0.9300 |
C2—C3 | 1.369 (14) | C17—C18 | 1.425 (14) |
C2—H2A | 0.9300 | C17—H17A | 0.9300 |
C3—C9 | 1.376 (12) | C18—H18A | 0.9300 |
C3—C4 | 1.481 (12) | C19—C20 | 1.373 (13) |
C4—C8 | 1.373 (13) | C19—H19A | 0.9300 |
C4—C5 | 1.379 (13) | C20—H20A | 0.9300 |
C5—C6 | 1.368 (13) | ||
N1—Zn1—N4i | 101.5 (3) | N2—C7—C8 | 121.8 (9) |
N1—Zn1—I1 | 108.4 (2) | N2—C7—H7A | 119.1 |
N4i—Zn1—I1 | 104.2 (2) | C8—C7—H7A | 119.1 |
N1—Zn1—I2 | 103.3 (2) | C7—C8—C4 | 121.3 (9) |
N4i—Zn1—I2 | 108.2 (2) | C7—C8—H8A | 119.4 |
I1—Zn1—I2 | 128.33 (5) | C4—C8—H8A | 119.4 |
N2—Zn2—N3 | 103.0 (3) | C10—C9—C3 | 120.3 (9) |
N2—Zn2—I4 | 106.0 (2) | C10—C9—H9A | 119.9 |
N3—Zn2—I4 | 105.7 (2) | C3—C9—H9A | 119.9 |
N2—Zn2—I3 | 107.9 (2) | N1—C10—C9 | 122.4 (8) |
N3—Zn2—I3 | 109.4 (2) | N1—C10—H10A | 118.8 |
I4—Zn2—I3 | 123.07 (5) | C9—C10—H10A | 118.8 |
C10—N1—C1 | 117.8 (8) | N3—C11—C12 | 124.9 (9) |
C10—N1—Zn1 | 115.9 (6) | N3—C11—H11A | 117.6 |
C1—N1—Zn1 | 126.2 (7) | C12—C11—H11A | 117.6 |
C7—N2—C6 | 117.3 (8) | C11—C12—C13 | 118.9 (9) |
C7—N2—Zn2 | 118.1 (6) | C11—C12—H12A | 120.5 |
C6—N2—Zn2 | 124.3 (6) | C13—C12—H12A | 120.5 |
C11—N3—C20 | 115.5 (8) | C19—C13—C12 | 116.4 (8) |
C11—N3—Zn2 | 123.5 (6) | C19—C13—C14 | 121.7 (8) |
C20—N3—Zn2 | 120.5 (6) | C12—C13—C14 | 121.9 (8) |
C17—N4—C16 | 117.9 (8) | C18—C14—C15 | 117.1 (9) |
C17—N4—Zn1ii | 117.3 (6) | C18—C14—C13 | 122.5 (9) |
C16—N4—Zn1ii | 124.5 (7) | C15—C14—C13 | 120.3 (8) |
N1—C1—C2 | 121.7 (9) | C16—C15—C14 | 119.1 (9) |
N1—C1—H1A | 119.1 | C16—C15—H15A | 120.5 |
C2—C1—H1A | 119.1 | C14—C15—H15A | 120.5 |
C1—C2—C3 | 120.9 (9) | N4—C16—C15 | 123.4 (9) |
C1—C2—H2A | 119.6 | N4—C16—H16A | 118.3 |
C3—C2—H2A | 119.6 | C15—C16—H16A | 118.3 |
C2—C3—C9 | 116.9 (8) | N4—C17—C18 | 122.0 (9) |
C2—C3—C4 | 122.3 (8) | N4—C17—H17A | 119.0 |
C9—C3—C4 | 120.8 (8) | C18—C17—H17A | 119.0 |
C8—C4—C5 | 117.2 (8) | C14—C18—C17 | 120.5 (10) |
C8—C4—C3 | 120.9 (8) | C14—C18—H18A | 119.7 |
C5—C4—C3 | 121.9 (8) | C17—C18—H18A | 119.7 |
C6—C5—C4 | 118.5 (9) | C20—C19—C13 | 120.6 (9) |
C6—C5—H5A | 120.7 | C20—C19—H19A | 119.7 |
C4—C5—H5A | 120.7 | C13—C19—H19A | 119.7 |
N2—C6—C5 | 123.9 (9) | N3—C20—C19 | 123.6 (9) |
N2—C6—H6A | 118.1 | N3—C20—H20A | 118.2 |
C5—C6—H6A | 118.1 | C19—C20—H20A | 118.2 |
Symmetry codes: (i) x−1, −y+3/2, z−1/2; (ii) x+1, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [ZnI2(C10H8N2)] |
Mr | 950.71 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 293 |
a, b, c (Å) | 17.140 (3), 13.930 (3), 11.950 (2) |
β (°) | 109.00 (3) |
V (Å3) | 2697.7 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 6.37 |
Crystal size (mm) | 0.5 × 0.45 × 0.2 |
Data collection | |
Diffractometer | Siemens SMART CCD area-detector diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.632, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14426, 5080, 3979 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.611 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.135, 1.04 |
No. of reflections | 5080 |
No. of parameters | 271 |
H-atom treatment | H-atom parameters constrained |
w = 1/[σ2(Fo2) + (0.0581P)2 + 24.4231P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.08, −0.76 |
Computer programs: SMART (Siemens, 1996), SMART & SAINT (Siemens, 1996), XPREP in SHELXTL (Siemens, 1996), SHELXTL and ASP (Chen, 2002).
Zn1—N1 | 2.071 (7) | Zn2—N2 | 2.068 (7) |
Zn1—N4i | 2.101 (8) | Zn2—N3 | 2.088 (8) |
Zn1—I1 | 2.5520 (13) | Zn2—I4 | 2.5471 (13) |
Zn1—I2 | 2.5673 (13) | Zn2—I3 | 2.5483 (12) |
N1—Zn1—N4i | 101.5 (3) | N2—Zn2—N3 | 103.0 (3) |
N1—Zn1—I1 | 108.4 (2) | N2—Zn2—I4 | 106.0 (2) |
N4i—Zn1—I1 | 104.2 (2) | N3—Zn2—I4 | 105.7 (2) |
N1—Zn1—I2 | 103.3 (2) | N2—Zn2—I3 | 107.9 (2) |
N4i—Zn1—I2 | 108.2 (2) | N3—Zn2—I3 | 109.4 (2) |
I1—Zn1—I2 | 128.33 (5) | I4—Zn2—I3 | 123.07 (5) |
Symmetry code: (i) x−1, −y+3/2, z−1/2. |
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Over the past few years considerable efforts have been devoted to the synthesis and structural characterization of coordination polymers. 4,4'-Bipyridine (bipy) as a bridging ligand has been used to construct supermolecular polymers (Hu & Englert, 2005; Nordell et al., 2004; Pedireddi & Varughese, 2004; Vittal et al., 2003; Yang et al., 2004). It is not unusual that the backbone of these polymers is subject to considerable modification due to the influence of the coligands and the difference in reaction parameters. For example, according to the literature, it is found that the structures of polymers of type [ZnX2(bipy)] (X = Cl or Br) are influenced by the reaction conditions and coligands (Hu & Englert, 2001, 2005; Liang et al., 2001; Fu et al., 2001). Two isomorphic phases of the one-dimensional coordination polymer [ZnCl2(bipy)] were prepared from hydrothermal reactions with different stoichiometry ratios of the reactants. It is interesting that when the temperature is decreased to 130 K both polymorphs can convert to a two-dimensional network and that the conversion is reversible (Hu & Englert, 2005). Polymeric [ZnBr2(bipy)] has a one-dimensional zigzag chain structure (Hu & Englert, 2001). However, based on the results of a search in the Cambridge Structural Database (Version 5.27; Allen, 2002), the structure and properties of polymeric [ZnI2(bipy)] have not been reported. We report here a new polymeric compound, [ZnI2(bipy)]n, (I), with a zigzag polymeric chain structure, obtained via hydrothermal synthesis.
In (I), there are two crystallographically independent Zn atoms in the asymmetric unit. Both are tetracoordinated in a distorted tetrahedral environment by two N atoms from two different bipy ligands and two I atoms. The differences are their Zn—N and Zn—I distances (Table 1). As a result of this coordination, the molecular structure shows a zigzag polymeric chain, which is similar to that in the polymers [ZnX2(bipy)] (X = Cl or Br), as shown in Fig. 1. In (I), an interesting phenomenon is that the two pyridine rings of the same bipy ligand are not coplanar [the dihedral angles of between the two planes are 32.22 (13) and 38.42 (16)°]. In constrast, the two pyridine rings of the same bipy ligand in the polymers ZnX2(bipy) (X = Cl or Br) are coplanar. Figs. 2 and 3 show that zigzag chains stack on top of each other. As shown in Fig. 2, there are two different π–π stacking interactions. One relates bipy ring R1 (N1/C1–C3/C9/C10) to bipy ring R2 (N2/C4–C8) of an adjacent bipy ligand, denoted R1i···R2 [symmetry code: (i) x, 3/2 − y, − 1/2 + z]. The second is formed between bipy ring R3 (N3/C11–C13/C19/C20) and bipy ring R4 (N4/C14–C18) of an adjacent bipy ligand, denoted R3···R4i [symmetry code: (i) x, −y + 3/2, z − 1/2]. The two bipy rings involved in each π–π stacking interaction are nearly parallel, with dihedral angles of 6.9 (3)° for R1i···R2 and 6.1 (4)° for R3···R4i, centroid-to-centroid distances of 4.282 (2) (R1i···R2) and 3.971 (2) Å (R3···R4i), and plane-to-plane distances of 3.61 (6) (R2···R1i) and 3.73 (6) Å (R3···R4i) which is smaller than that in both isomorphic polymers [ZnCl2(bipy)] [3.85 (7) Å; Fu et al., 2001] and [ZnBr2(bipy)] [4.17 (5) Å; Hu & Englert, 2001]. The face-to-face π–π stacking interactions between adjacent bipy ligands stabilize the structure.