To further investigate the relationship between the structures of benzotriazol-1-yl-based pyridyl ligands and their complexes, a new linear one-dimensional Hg
II coordination polymer, [HgCl
2(C
12H
10N
4)]
n, with the 1-(2-pyridylmethyl)-1
H-benzotriazole (
L) ligand was obtained through the reaction of
L with HgCl
2. In this complex, each Hg
II center within the one-dimensional chain is coordinated by two chloride anions as well as by one pyridine and one benzotriazole N-atom donor of two distinct
L ligands in a distorted tetrahedral geometry, forming a linear one-dimensional chain running along the [010] direction. Weak C—H
π and π–π stacking interactions link the one-dimensional motifs to generate an overall two-dimensional network parallel to the (100) plane. Comparison of the structural differences with previous findings suggests that the presence of different metal centers may plays an important role in the construction of such supramolecular frameworks.
Supporting information
CCDC reference: 718131
The ligand L was synthesized according to the method reported by Liu,
Sun et al. (2008). A solution of HgCl2 (0.1 mmol) in a mixture
of
CH3OH (15 ml) and CH3CN (5 ml) was added to L (0.1 mmol). The
yellow solid that formed was filtered off, and the resulting solution was kept
at room temperature. Yellow single crystals of complex (I) suitable for X-ray
analysis were obtained by slow evaporation of the solvent after several days
(yield ~40%). Elemental analysis calculated for C12H10Cl2HgN4: C
29.92, H 2.09, N 11.63%; found: C 29.81, H 2.17, N 11.51%.
H atoms were included in calculated positions and treated in the subsequent
refinement as riding atoms [C—H = 0.93 (aromatic) or 0.97 Å (methylene),
with Uiso(H) = 1.2Ueq(C)]. The position of the highest peak
is at (0.4051, 0.7210, 0.1189) (1.43 Å from H2). The position of the deepest
hole is at (0.3568, 0.5704, 0.7213) (0.92 Å from Hg1).
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).
catena-Poly[[dichloridomercury(II)]-µ-1-(2-pyridylmethyl)-
1
H-benzotriazole]
top
Crystal data top
[HgCl2(C12H10N4)] | Z = 2 |
Mr = 481.73 | F(000) = 448 |
Triclinic, P1 | Dx = 2.307 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.8769 (16) Å | Cell parameters from 2303 reflections |
b = 8.8723 (18) Å | θ = 1.9–28.0° |
c = 11.130 (2) Å | µ = 11.47 mm−1 |
α = 102.88 (3)° | T = 293 K |
β = 98.22 (3)° | Block, yellow |
γ = 109.70 (3)° | 0.19 × 0.17 × 0.12 mm |
V = 693.4 (3) Å3 | |
Data collection top
Bruker P4 diffractometer | 2444 independent reflections |
Radiation source: fine-focus sealed tube | 2190 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.081 |
ω scans | θmax = 25.0°, θmin = 2.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→9 |
Tmin = 0.131, Tmax = 0.257 | k = −10→10 |
6923 measured reflections | l = −13→13 |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.052 | H-atom parameters constrained |
wR(F2) = 0.120 | w = 1/[σ2(Fo2) + (0.0432P)2 + 5.424P] where P = (Fo2 + 2Fc2)/3 |
S = 1.11 | (Δ/σ)max = 0.001 |
2444 reflections | Δρmax = 2.13 e Å−3 |
173 parameters | Δρmin = −1.85 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0059 (9) |
Crystal data top
[HgCl2(C12H10N4)] | γ = 109.70 (3)° |
Mr = 481.73 | V = 693.4 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.8769 (16) Å | Mo Kα radiation |
b = 8.8723 (18) Å | µ = 11.47 mm−1 |
c = 11.130 (2) Å | T = 293 K |
α = 102.88 (3)° | 0.19 × 0.17 × 0.12 mm |
β = 98.22 (3)° | |
Data collection top
Bruker P4 diffractometer | 2444 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2190 reflections with I > 2σ(I) |
Tmin = 0.131, Tmax = 0.257 | Rint = 0.081 |
6923 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.11 | Δρmax = 2.13 e Å−3 |
2444 reflections | Δρmin = −1.85 e Å−3 |
173 parameters | |
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. |
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Hg1 | 0.53129 (6) | 0.42782 (5) | 0.29481 (4) | 0.0414 (2) | |
C1 | 0.718 (2) | 0.3400 (16) | 0.0518 (11) | 0.053 (3) | |
H1 | 0.7012 | 0.4385 | 0.0506 | 0.063* | |
C2 | 0.771 (2) | 0.2638 (18) | −0.0485 (13) | 0.062 (4) | |
H2 | 0.7853 | 0.3076 | −0.1166 | 0.074* | |
C3 | 0.8018 (18) | 0.1208 (17) | −0.0466 (11) | 0.051 (3) | |
H3 | 0.8425 | 0.0680 | −0.1117 | 0.061* | |
C4 | 0.7708 (16) | 0.0572 (14) | 0.0550 (10) | 0.039 (3) | |
H4 | 0.7854 | −0.0420 | 0.0571 | 0.047* | |
C5 | 0.7180 (13) | 0.1428 (12) | 0.1533 (9) | 0.030 (2) | |
C6 | 0.687 (2) | 0.0873 (15) | 0.2679 (12) | 0.052 (3) | |
H61 | 0.7502 | 0.1829 | 0.3426 | 0.063* | |
H62 | 0.5549 | 0.0495 | 0.2650 | 0.063* | |
C7 | 0.9273 (15) | −0.0380 (12) | 0.3215 (9) | 0.033 (2) | |
C8 | 1.0996 (16) | 0.0931 (14) | 0.3644 (11) | 0.041 (3) | |
H8 | 1.1147 | 0.2030 | 0.3691 | 0.049* | |
C9 | 1.2472 (18) | 0.0486 (16) | 0.3997 (11) | 0.049 (3) | |
H9 | 1.3655 | 0.1322 | 0.4295 | 0.059* | |
C10 | 1.2270 (17) | −0.1176 (15) | 0.3929 (10) | 0.044 (3) | |
H10 | 1.3308 | −0.1406 | 0.4187 | 0.052* | |
C11 | 1.0565 (17) | −0.2445 (15) | 0.3487 (10) | 0.042 (3) | |
H11 | 1.0420 | −0.3549 | 0.3412 | 0.050* | |
C12 | 0.9041 (15) | −0.2025 (12) | 0.3151 (10) | 0.033 (2) | |
N1 | 0.6897 (12) | 0.2840 (10) | 0.1506 (8) | 0.034 (2) | |
N2 | 0.7492 (13) | −0.0457 (11) | 0.2813 (8) | 0.037 (2) | |
N3 | 0.6292 (13) | −0.2019 (11) | 0.2552 (9) | 0.041 (2) | |
N4 | 0.7158 (13) | −0.2982 (11) | 0.2734 (9) | 0.042 (2) | |
Cl1 | 0.7113 (4) | 0.4535 (4) | 0.4912 (3) | 0.0465 (7) | |
Cl2 | 0.2573 (5) | 0.3545 (4) | 0.1442 (3) | 0.0580 (9) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Hg1 | 0.0473 (4) | 0.0295 (3) | 0.0469 (3) | 0.0154 (2) | 0.0012 (2) | 0.0153 (2) |
C1 | 0.082 (10) | 0.045 (7) | 0.044 (7) | 0.033 (7) | 0.023 (7) | 0.019 (6) |
C2 | 0.077 (10) | 0.070 (10) | 0.053 (8) | 0.031 (8) | 0.030 (7) | 0.033 (7) |
C3 | 0.057 (8) | 0.072 (9) | 0.030 (6) | 0.037 (7) | 0.004 (5) | 0.010 (6) |
C4 | 0.053 (7) | 0.037 (6) | 0.032 (5) | 0.028 (6) | 0.002 (5) | 0.008 (5) |
C5 | 0.025 (5) | 0.026 (5) | 0.037 (5) | 0.012 (4) | −0.005 (4) | 0.006 (4) |
C6 | 0.083 (10) | 0.040 (7) | 0.059 (8) | 0.039 (7) | 0.033 (7) | 0.029 (6) |
C7 | 0.040 (6) | 0.028 (5) | 0.024 (5) | 0.006 (5) | 0.007 (4) | 0.005 (4) |
C8 | 0.041 (7) | 0.026 (6) | 0.049 (6) | 0.006 (5) | 0.008 (5) | 0.014 (5) |
C9 | 0.047 (7) | 0.055 (8) | 0.037 (6) | 0.009 (6) | 0.004 (5) | 0.018 (6) |
C10 | 0.050 (7) | 0.052 (7) | 0.028 (5) | 0.017 (6) | 0.004 (5) | 0.016 (5) |
C11 | 0.055 (8) | 0.040 (6) | 0.044 (6) | 0.027 (6) | 0.010 (6) | 0.027 (5) |
C12 | 0.045 (6) | 0.027 (5) | 0.036 (5) | 0.019 (5) | 0.008 (5) | 0.018 (5) |
N1 | 0.042 (5) | 0.028 (5) | 0.037 (5) | 0.019 (4) | 0.007 (4) | 0.012 (4) |
N2 | 0.046 (6) | 0.030 (5) | 0.043 (5) | 0.018 (4) | 0.014 (4) | 0.018 (4) |
N3 | 0.045 (6) | 0.032 (5) | 0.050 (6) | 0.013 (5) | 0.007 (5) | 0.025 (4) |
N4 | 0.045 (6) | 0.026 (5) | 0.054 (6) | 0.014 (4) | −0.001 (5) | 0.017 (4) |
Cl1 | 0.0564 (19) | 0.0404 (16) | 0.0407 (15) | 0.0247 (14) | −0.0058 (13) | 0.0098 (12) |
Cl2 | 0.0479 (19) | 0.056 (2) | 0.0594 (19) | 0.0164 (16) | −0.0124 (15) | 0.0174 (16) |
Geometric parameters (Å, º) top
Hg1—Cl2 | 2.329 (3) | C6—H62 | 0.9700 |
Hg1—Cl1 | 2.348 (3) | C7—N2 | 1.384 (14) |
Hg1—N4i | 2.460 (9) | C7—C8 | 1.388 (15) |
Hg1—N1 | 2.548 (9) | C7—C12 | 1.392 (14) |
C1—N1 | 1.321 (15) | C8—C9 | 1.381 (17) |
C1—C2 | 1.364 (18) | C8—H8 | 0.9300 |
C1—H1 | 0.9300 | C9—C10 | 1.412 (17) |
C2—C3 | 1.374 (18) | C9—H9 | 0.9300 |
C2—H2 | 0.9300 | C10—C11 | 1.363 (16) |
C3—C4 | 1.388 (17) | C10—H10 | 0.9300 |
C3—H3 | 0.9300 | C11—C12 | 1.399 (15) |
C4—C5 | 1.385 (14) | C11—H11 | 0.9300 |
C4—H4 | 0.9300 | C12—N4 | 1.384 (14) |
C5—N1 | 1.351 (12) | N2—N3 | 1.325 (12) |
C5—C6 | 1.489 (15) | N3—N4 | 1.291 (12) |
C6—N2 | 1.452 (13) | N4—Hg1ii | 2.460 (9) |
C6—H61 | 0.9700 | | |
| | | |
Cl2—Hg1—Cl1 | 155.58 (13) | N2—C7—C12 | 104.4 (9) |
Cl2—Hg1—N4i | 100.9 (2) | C8—C7—C12 | 122.5 (11) |
Cl1—Hg1—N4i | 97.6 (2) | C9—C8—C7 | 115.2 (11) |
Cl2—Hg1—N1 | 97.1 (2) | C9—C8—H8 | 122.4 |
Cl1—Hg1—N1 | 98.4 (2) | C7—C8—H8 | 122.4 |
N4i—Hg1—N1 | 91.1 (3) | C8—C9—C10 | 123.2 (11) |
N1—C1—C2 | 124.7 (12) | C8—C9—H9 | 118.4 |
N1—C1—H1 | 117.7 | C10—C9—H9 | 118.4 |
C2—C1—H1 | 117.7 | C11—C10—C9 | 120.5 (12) |
C1—C2—C3 | 118.5 (12) | C11—C10—H10 | 119.8 |
C1—C2—H2 | 120.8 | C9—C10—H10 | 119.8 |
C3—C2—H2 | 120.8 | C10—C11—C12 | 117.5 (11) |
C2—C3—C4 | 118.3 (11) | C10—C11—H11 | 121.2 |
C2—C3—H3 | 120.8 | C12—C11—H11 | 121.2 |
C4—C3—H3 | 120.8 | N4—C12—C7 | 107.2 (9) |
C5—C4—C3 | 119.4 (10) | N4—C12—C11 | 131.8 (10) |
C5—C4—H4 | 120.3 | C7—C12—C11 | 121.0 (10) |
C3—C4—H4 | 120.3 | C1—N1—C5 | 117.5 (10) |
N1—C5—C4 | 121.5 (10) | C1—N1—Hg1 | 114.8 (7) |
N1—C5—C6 | 115.1 (9) | C5—N1—Hg1 | 126.7 (7) |
C4—C5—C6 | 123.5 (9) | N3—N2—C7 | 109.5 (8) |
N2—C6—C5 | 114.6 (9) | N3—N2—C6 | 121.0 (10) |
N2—C6—H61 | 108.6 | C7—N2—C6 | 129.5 (9) |
C5—C6—H61 | 108.6 | N4—N3—N2 | 110.2 (9) |
N2—C6—H62 | 108.6 | N3—N4—C12 | 108.7 (8) |
C5—C6—H62 | 108.6 | N3—N4—Hg1ii | 117.1 (7) |
H61—C6—H62 | 107.6 | C12—N4—Hg1ii | 130.8 (6) |
N2—C7—C8 | 133.1 (10) | | |
| | | |
N1—C1—C2—C3 | −2 (2) | C4—C5—N1—Hg1 | 166.6 (8) |
C1—C2—C3—C4 | 3 (2) | C6—C5—N1—Hg1 | −12.9 (13) |
C2—C3—C4—C5 | −2.8 (18) | Cl2—Hg1—N1—C1 | 60.9 (8) |
C3—C4—C5—N1 | 2.3 (16) | Cl1—Hg1—N1—C1 | −138.0 (8) |
C3—C4—C5—C6 | −178.3 (12) | N4i—Hg1—N1—C1 | −40.2 (9) |
N1—C5—C6—N2 | −169.3 (10) | Cl2—Hg1—N1—C5 | −107.4 (8) |
C4—C5—C6—N2 | 11.2 (17) | Cl1—Hg1—N1—C5 | 53.7 (8) |
N2—C7—C8—C9 | 178.1 (11) | N4i—Hg1—N1—C5 | 151.5 (8) |
C12—C7—C8—C9 | 0.5 (16) | C8—C7—N2—N3 | −177.0 (11) |
C7—C8—C9—C10 | 0.2 (17) | C12—C7—N2—N3 | 0.9 (11) |
C8—C9—C10—C11 | 0.7 (18) | C8—C7—N2—C6 | 2.2 (19) |
C9—C10—C11—C12 | −2.1 (16) | C12—C7—N2—C6 | −179.9 (10) |
N2—C7—C12—N4 | −0.6 (11) | C5—C6—N2—N3 | −104.0 (12) |
C8—C7—C12—N4 | 177.6 (10) | C5—C6—N2—C7 | 76.8 (15) |
N2—C7—C12—C11 | 179.8 (10) | C7—N2—N3—N4 | −1.0 (12) |
C8—C7—C12—C11 | −2.0 (16) | C6—N2—N3—N4 | 179.8 (10) |
C10—C11—C12—N4 | −176.8 (11) | N2—N3—N4—C12 | 0.6 (12) |
C10—C11—C12—C7 | 2.7 (16) | N2—N3—N4—Hg1ii | 162.2 (7) |
C2—C1—N1—C5 | 1.3 (19) | C7—C12—N4—N3 | 0.0 (12) |
C2—C1—N1—Hg1 | −168.2 (12) | C11—C12—N4—N3 | 179.6 (11) |
C4—C5—N1—C1 | −1.5 (15) | C7—C12—N4—Hg1ii | −158.2 (7) |
C6—C5—N1—C1 | 179.1 (11) | C11—C12—N4—Hg1ii | 21.3 (18) |
Symmetry codes: (i) x, y+1, z; (ii) x, y−1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···Cg1iii | 0.93 | 2.90 | 3.688 (3) | 143 |
Symmetry code: (iii) −x+2, −y, −z. |
Experimental details
Crystal data |
Chemical formula | [HgCl2(C12H10N4)] |
Mr | 481.73 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 7.8769 (16), 8.8723 (18), 11.130 (2) |
α, β, γ (°) | 102.88 (3), 98.22 (3), 109.70 (3) |
V (Å3) | 693.4 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 11.47 |
Crystal size (mm) | 0.19 × 0.17 × 0.12 |
|
Data collection |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.131, 0.257 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6923, 2444, 2190 |
Rint | 0.081 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.052, 0.120, 1.11 |
No. of reflections | 2444 |
No. of parameters | 173 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 2.13, −1.85 |
Selected geometric parameters (Å, º) topHg1—Cl2 | 2.329 (3) | Hg1—N4i | 2.460 (9) |
Hg1—Cl1 | 2.348 (3) | Hg1—N1 | 2.548 (9) |
| | | |
Cl2—Hg1—Cl1 | 155.58 (13) | Cl2—Hg1—N1 | 97.1 (2) |
Cl2—Hg1—N4i | 100.9 (2) | Cl1—Hg1—N1 | 98.4 (2) |
Cl1—Hg1—N4i | 97.6 (2) | N4i—Hg1—N1 | 91.1 (3) |
Symmetry code: (i) x, y+1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···Cg1ii | 0.93 | 2.90 | 3.688 (3) | 143 |
Symmetry code: (ii) −x+2, −y, −z. |
In recent years, increasing attention has been focused on the construction of coordination polymers, also known as metal-organic frameworks (Janiak, 2003; Robin & Fromm, 2006). The rational engineering and controlled preparation of such novel coordination polymers are currently of great interest in coordination and supramolecular chemistry because of their interesting topologies (Chen et al., 2006; Hill et al., 2005; Kitagawa et al., 2004; Liu, Chang et al., 2008; Steel, 2005; Wang et al., 2008; Yaghi et al., 2003) and potential uses as functional materials (Bu et al., 2004; Hou et al., 2005; Liu, Sañudo et al., 2008; Liu, Wang et al., 2007; Tao et al., 2008). One of the most successful strategies for constructing such complexes has been the assembly reaction of different metal ions (as nodes) with well designed organic ligands (as building blocks), which, so far, has been at an evolutionary stage with the current focus mainly laid on understanding the factors that determine the crystal packing, as well as on exploring relevant potential properties (Chen et al., 2006; Du et al., 2007; Liu, Shi et al., 2006; Zou et al., 2006). In addition, various intra- and/or inter-molecular weak interactions, such as π–π stacking (Janiak, 2000) and C—H···π (Sony & Ponnuswamy, 2006) and C—H···X (X = O, N, S, F, Cl, Br, I and so on) hydrogen-bonding (Desiraju & Steiner, 1999) interactions also affect the final structures of coordination complexes, especially in the aspect of linking the multi-nuclear discrete subunits or low-dimensional motifs into higher-dimensional frameworks.
Numerous related bis-heterocyclic chelating or bridging ligands have been synthesized and have been used extensively to construct functional coordination complexes that contain different hetero-aromatic ring systems, for example pyridine, pyrazine, quinoline, quinoxaline, pyrazole, imidazole, thiazoles and their benzo analogues (Constable, 1989; Constable & Steel, 1989; Steel, 2005). As such, we have found that Richardson & Steel (2003) have initially reported studies concerning five N-containing bis-heterocyclic ligands bearing 1-substituted benzotriazole subunits. In our previous work, we have also reported the preparation of a nonplanar flexible benzotriazol-1-yl-based pyridyl ligand, namely 1-(4-pyridylmethyl)-1H-benzotriazole (4pbt). Its reaction with AgNO3 led to a one-dimensional double-helical coordination polymer, {[Ag(4pbt)](NO3)}n, formed by C–H···π supramolecular interactions between adjacent single-helical chains (Liu, Sun et al., 2008). The results therein indicated that the N-donor spatial position of the pendant pyridyl group in such benzotriazol-1-yl-based pyridyl ligands, as compared with the previous finding (Richardson & Steel, 2003), played an important role on the final structures of relevant coordination complexes. As part of a study on the coordination possibilities of benzotriazole-based ligands with different metal centers in the self-assembly process of coordination complexes, we have chosen sequentially the ligand 1-(2-pyridylmethyl)-1H-benzotriazole (L) to construct a new one-dimensional HgII complex though its reaction with HgCl2 under a conventional solution method. We report here the crystal structure of [Hg(L)Cl2]n, (I), and briefly discuss the effect of the coordination geometry of different metal centers on the structures of the relevant coordination complexes.
The crystal structure of (I) consists of one-dimensional linear neutral chains, [Hg(L)Cl2]n(Fig. 1). In each one-dimensional chain, there exist only one kind of crystallographically independent HgII center, which is four-coordinated by two Cl- anions and two N-atom donors, one from the benzotriazole ring of one L ligand and the other from the pyridine ring of another distinct L ligand. The Hg—N and Hg—Cl bond distances as well as the bond angles around each HgII center (Table 1) are within the expected range for such complexes (Orpen et al., 1989; Wang et al., 2007). The coordination geometry around the HgII center can be described as a distorted tetrahedron. Each L ligand takes a µ2-bridging coordination mode to connect the HgII centers, generating a perfect linear chain along the [010] direction, with adjacent Hg atoms separated by a b-axis translation [Hg···Hg = b = 8.8723 (18) Å]. Moreover, adjacent one-dimensional chains are linked together to form an overall two-dimensional sheet running parallel to the (100) plane (Fig. 2) by the co-effects of inter-chain π–π stacking interactions between completely parallel benzotriazole rings of adjacent L ligands [the centroid–centroid separation is 3.706 (5) Å and the average interplanar separation 3.4494 Å] (Janiak, 2000)] and C—H···π supramolecular interactions involving the C7–C12 phenyl rings of the L ligand (centroid Cg1, see Table 2) (Sony & Ponnuswamy, 2006). Thus, the various intra- or intermolecular weak interactions mentioned above play an important role in the formation of (I), especially in the aspect of linking the low-dimensional motifs into higher-dimensional supramolecular networks.
To explore the coordination possibilities of relevant benzotriazol-1-yl-based pyridyl bis-heterocyclic ligands, Richardson & Steel (2003) synthesized L and selected four different types of metal centers with different coordination geometries as representative subjects for coordination with it. A mononuclear complex, [Ru(L)(bpy)2Cl]PF6 (bpy is 2,2'-bipyridine), and a dinuclear complex, [Pd2(L)2Cl4], with an intramolecular Pd—Pd separation of 6.739 (1) Å, were obtained, while RuII and PdII were chosen as examples of stereoregular octahedral and square-planar metals to react with L. In addition, CuII (Melnik et al., 2000) and AgI (Munakata, et al., 1998) centers have also been proved very popular in recent years and been widely employed as the components for the construction of diverse coordination architectures with various N-containing heterocyclic ligands. For example, the previously reported metal–organic coordination architectures constructed from ligand L also include two centrosymmetric dinuclear complexes, [Cu(L)]2Cl4 and [Ag(L)]2(NO3)2, where CuII and AgI were selected as examples of metals that have more flexible coordination numbers and geometries (Richardson & Steel, 2003). In this contribution, when we used HgCl2 to react with L under the conventional solution conditions, a perfect one-dimensional linear coordination polymer, [Hg(L)Cl2]n, (I), was produced, in which the coordination geometry around the HgII center can be described as a distorted tetrahedron. Thus, in comparision with the previous finding, the present work reveals that the coordination geometry of different metal centers could play an important role on the final structures of relevant coordination complexes. This fact may offer the means to construct coordination architectures with potentially useful properties just by variation of the metal center.