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The title complex, [PbBr2(bipy)]n (bipy is 4,4'-bi­pyridine, C10H8N2), was obtained by hydro­thermal reaction of Pb(O2CCH3), NaBr and bipy. The bipy group acts as a linear bifunctional bridge forming a planar {-[Pb(bipy)]-}n belt in the direction of the b axis. The remaining lead coordination sites are occupied by Br ions which link Pb centres in adjacent belts through double bridges to form extended two-dimensional layers.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100014992/qa0434sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100014992/qa0434Isup2.hkl
Contains datablock I

CCDC reference: 156194

Comment top

In recent years, an increasing interest has been given to low-dimensional organic–inorganic hybrid compounds owing to their special magnetic, electronic and optoelectronic properties (Lacroix et al., 1994; Chakravarthy & Guloy, 1997). Studies suggest that complex systems consisting of organic and inorganic components have great potential for the creation of functional materials utilizing the wide variety of properties associated with each component. Lead halide-based (PbX3, PbX4 and PbX5) molecules with ionic-type hybrid compounds have been extensively studied (Conadi et al., 1997; Chakravarthy & Guloy, 1997), because they form a stable exciton with a large binding energy of several hundred meV and exhibit attractive optical properties such as strong and sharp photoluminescence (Papavassiliou & Kontselas, 1995) and electroluminescence (Hattori et al., 1996), and highly efficient non-linear optical effects (Kondo et al., 1998). However, the lead halide adducts Pb(L)X2 (X = halide and L = ligand) with ligands coordinatively linked to the inorganic backbone have received little attention and structural information on this type of compounds is still rather scarce (Zhu et al., 1999). Herein, the hydrothermal growth and crystal structure of the two-dimensional lead coordination polymer [PbBr2(bpy)]n (bpy is 4,4'-bipyridine), (I), is reported. \scheme

Structural analysis of (I) reveals that the Pb centre has a distorted octahedral coordination with four µ2-Br and two bridging 4,4'-bpy at trans positions. The Pb—Br bond lengths of 2.999 (2) and 3.008 (2) Å are comparable with those in the reported lead bromides (Klapotke et al., 1999), while the Pb—N bond length of 2.659 (14) Å is significantly longer than those in [PbI2(L)]n [L is 2,2'-bipyridine; Pb—N = 2.516; L is 1,10-phenanthroline, Pb—N = 2.518 (8); Zhu et al., 1999]. The crystal structure of compound (I) consists of two-dimensional [PbBr2(bpy)] networks built upon PbBr4(bpy)2 building blocks. The two-dimensional layers are formed in the bc plane by connecting metal centres through bridging Br and 4,4'-bpy ligands. The adjacent bpy ligands are parallel to each other at a distance of 3.74 Å. These layers stack on top of each other along the c axis at a distance of c/2 to complete the three dimensional structure. Therefore, the present crystal structure is very similar to those observed for [MCl2(bpy)]n (M = Fe, Co; Lawandy et al., 1999) and [HgBr2(bpy)]n (Pan et al., 1999).

Experimental top

A solution of Pb(O2CCH3) (1 mmol), NaBr (2 mmol), bipy (1 mmol) and water (10 ml) was heated at 393 K for 3 d in a 23 ml acid digestion bomb. After cooling to room temperature, triangular prismatic crystals of (I) were isolated.

Refinement top

Data collection was curtailed after 93% completion, since the data at the end were very weak. The largest positive and negative features in the final difference synthesis are close to Pb.

Computing details top

Data collection: CAD-4 Software (Enraf-Noinus, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

(I) top
Crystal data top
[PbBr2(C10H8N2)]F(000) = 468
Mr = 523.19Dx = 2.715 Mg m3
Monoclinic, C2/mMo Kα radiation, λ = 0.71073 Å
a = 12.282 (3) ÅCell parameters from 25 reflections
b = 12.407 (3) Åθ = 2.3–27.5°
c = 4.2191 (8) ŵ = 19.40 mm1
β = 95.55 (3)°T = 293 K
V = 639.9 (2) Å3Triangular prism, colourless
Z = 20.10 × 0.10 × 0.08 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
709 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 27.5°, θmin = 2.3°
ω scansh = 1515
Absorption correction: ψ scan
(Fair, 1990)
k = 160
Tmin = 0.179, Tmax = 0.212l = 50
721 measured reflections3 standard reflections every 265 reflections
721 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128H-atom parameters constrained
S = 1.11 w = 1/[σ2(Fo2) + (0.0797P)2 + 7.2192P]
where P = (Fo2 + 2Fc2)/3
721 reflections(Δ/σ)max < 0.001
39 parametersΔρmax = 1.56 e Å3
0 restraintsΔρmin = 3.85 e Å3
Crystal data top
[PbBr2(C10H8N2)]V = 639.9 (2) Å3
Mr = 523.19Z = 2
Monoclinic, C2/mMo Kα radiation
a = 12.282 (3) ŵ = 19.40 mm1
b = 12.407 (3) ÅT = 293 K
c = 4.2191 (8) Å0.10 × 0.10 × 0.08 mm
β = 95.55 (3)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
709 reflections with I > 2σ(I)
Absorption correction: ψ scan
(Fair, 1990)
Rint = 0.000
Tmin = 0.179, Tmax = 0.2123 standard reflections every 265 reflections
721 measured reflections intensity decay: none
721 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.128H-atom parameters constrained
S = 1.11Δρmax = 1.56 e Å3
721 reflectionsΔρmin = 3.85 e Å3
39 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
xyzUiso*/Ueq
Pb0.50001.00000.50000.0364 (3)
Br0.67493 (13)1.00000.9492 (4)0.0541 (5)
C10.4173 (11)0.7290 (11)0.396 (5)0.066 (4)
H1A0.35970.76640.31950.079*
C20.4141 (10)0.6196 (10)0.397 (4)0.058 (3)
H2A0.35380.58450.32900.070*
C30.50000.5590 (12)0.50000.042 (3)
N0.50000.7857 (11)0.50000.060 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb0.0375 (4)0.0303 (4)0.0426 (5)0.0000.0105 (3)0.000
Br0.0389 (8)0.0713 (12)0.0536 (9)0.0000.0122 (6)0.000
C10.055 (7)0.035 (6)0.112 (11)0.004 (5)0.031 (7)0.014 (7)
C20.049 (7)0.041 (6)0.089 (9)0.006 (5)0.030 (6)0.011 (6)
C30.039 (7)0.033 (8)0.054 (8)0.0000.007 (6)0.000
N0.051 (8)0.033 (7)0.095 (12)0.0000.011 (7)0.000
Geometric parameters (Å, º) top
Pb—N2.659 (14)C1—N1.343 (15)
Pb—Ni2.659 (14)C1—C21.358 (18)
Pb—Br2.9992 (18)C2—C31.398 (14)
Pb—Bri2.9992 (18)C3—C2v1.398 (14)
Pb—Brii3.008 (2)C3—C3vi1.46 (3)
Pb—Briii3.008 (2)N—C1v1.343 (15)
Br—Pbiv3.008 (2)
N—Pb—Ni180.0Br—Pb—Briii89.22 (4)
N—Pb—Br90.0Bri—Pb—Briii90.78 (4)
Ni—Pb—Br90.0Brii—Pb—Briii180.0
N—Pb—Bri90.0Pb—Br—Pbiv89.22 (4)
Ni—Pb—Bri90.0N—C1—C2122.9 (13)
Br—Pb—Bri180.0C1—C2—C3121.2 (12)
N—Pb—Brii90.0C2v—C3—C2114.8 (14)
Ni—Pb—Brii90.0C2v—C3—C3vi122.6 (7)
Br—Pb—Brii90.78 (4)C2—C3—C3vi122.6 (7)
Bri—Pb—Brii89.22 (4)C1v—N—C1116.9 (15)
N—Pb—Briii90.0C1v—N—Pb121.5 (8)
Ni—Pb—Briii90.0C1—N—Pb121.5 (8)
Symmetry codes: (i) x1, y+2, z+1; (ii) x1, y+2, z+2; (iii) x, y, z1; (iv) x, y, z+1; (v) x1, y, z+1; (vi) x1, y+1, z+1.

Experimental details

Crystal data
Chemical formula[PbBr2(C10H8N2)]
Mr523.19
Crystal system, space groupMonoclinic, C2/m
Temperature (K)293
a, b, c (Å)12.282 (3), 12.407 (3), 4.2191 (8)
β (°) 95.55 (3)
V3)639.9 (2)
Z2
Radiation typeMo Kα
µ (mm1)19.40
Crystal size (mm)0.10 × 0.10 × 0.08
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionψ scan
(Fair, 1990)
Tmin, Tmax0.179, 0.212
No. of measured, independent and
observed [I > 2σ(I)] reflections
721, 721, 709
Rint0.000
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.128, 1.11
No. of reflections721
No. of parameters39
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.56, 3.85

Computer programs: CAD-4 Software (Enraf-Noinus, 1989), CAD-4 Software, MolEN (Fair, 1990), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997).

Selected geometric parameters (Å, º) top
Pb—N2.659 (14)Pb—Bri3.008 (2)
Pb—Br2.9992 (18)
N—Pb—Nii180.0Br—Pb—Brii180.0
N—Pb—Br90.0N—Pb—Briii90.0
N—Pb—Brii90.0Brii—Pb—Briii89.22 (4)
Symmetry codes: (i) x, y, z1; (ii) x1, y+2, z+1; (iii) x1, y+2, z+2.
 

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