Download citation
Download citation
link to html
In the title compound, {(C10H12N2)2[Pb2Br8]}n, the asymmetric unit consists of half a cation and one-quarter of a doubly-bridged dinuclear anionic unit. The planar cations lies on a twofold axis that runs lengthwise through both rings. The Pb and one Br atoms are located on twofold axes, whereas the second Br atom is located on a mirror plane and the third lies on a general position. The polymeric anion forms an infinite ladder structure running along the c axis with rungs consisting of Pb and bridging Br atoms, with two octa­hedra sharing edges as the rungs of the ladder and sharing vertices as the rails. There are N—H...Br hydrogen-bonding inter­actions, ca 3.21 Å, linking the PbBr ladders to the cations.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807021186/dn2167sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807021186/dn2167Isup2.hkl
Contains datablock I

CCDC reference: 650525

Key indicators

  • Single-crystal X-ray study
  • T = 295 K
  • Mean [sigma](C-C) = 0.019 Å
  • R factor = 0.054
  • wR factor = 0.123
  • Data-to-parameter ratio = 17.5

checkCIF/PLATON results

No syntax errors found



Alert level C GOODF01_ALERT_2_C The least squares goodness of fit parameter lies outside the range 0.80 <> 2.00 Goodness of fit given = 0.731 PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.98 PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT342_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ... 19 PLAT480_ALERT_4_C Long H...A H-Bond Reported H1C .. BR2 .. 3.06 Ang.
Alert level G FORMU01_ALERT_1_G There is a discrepancy between the atom counts in the _chemical_formula_sum and _chemical_formula_moiety. This is usually due to the moiety formula being in the wrong format. Atom count from _chemical_formula_sum: C10 H12 Br4 N2 Pb1 Atom count from _chemical_formula_moiety:C6 H12 Br4 N2 Pb1 ABSTM02_ALERT_3_G The ratio of expected to reported Tmax/Tmin(RR) is > 1.50 Tmin and Tmax reported: 0.102 0.228 Tmin and Tmax expected: 0.033 0.123 RR = 1.652 Please check that your absorption correction is appropriate. PLAT794_ALERT_5_G Check Predicted Bond Valency for Pb1 (2) 2.30
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check

Comment top

Research in the field of organic inorganic hybrid compounds is of great interest. This is because of the their special magnetic, electronic and optoelectronic properties (Cui et al., 2000; Lacroix et al.,1994; Chakravarthy & Guloy, 1997). Haloplumbates, have demonstrated a structural diversity in lead-halide based organic inorganic hybrids (Billing & Lemerrer, 2005) in particular, in terms of the nets formed by the inorganic components, which show many distinct topologies. Examples are layers of corner sharing octahedra, linear chains of face sharing octahedra as well as a number of mixed intermediates (Billing & Lemerrer, 2005). In the crystal structure of the title complex, (I). The use of 2,3-dimethylquinoxaline (henceforth dmqxH2) and its protonation were expected to create many important centers of interaction with the bromo-lead anion, e.g. NH···Br, CH···Br and possibly Br···aryl and aryl···aryl interactions.

In the title compound, (I), {C10H12Br4N2Pb}n, the asymmetric unit consists of half of the repeated extended structure of both cation and anion. The planar cations [C10H12N2]2+ with both nitrogen atoms protonated, lies on a 2-fold axis that runs lengthwise between the two halves (Fig. 1). The dinuclear unit [Pb2Br10]6- consists of two distorted octahedra bridged by Br3 and its symmetry related Br3i [Symmetry code: (iii) -x + 1, -y, -z + 1). These dinuclear units are further interconnected through bridging Br2 to form a polymeric chain structure developping parallel to the c axis (Fig. 2). This anion chain demonstrates a novel structural arrangement in metal halide extended anion networking.

The Pb—Br distances are similar, 3.0242 (6)–3.0448 (16) Å and fall within the range of Pb—Br distances reported previously for compounds containing lead-bromides (Reynolds et al., 2003; Cui et al., 2000; Klapotke et al., 1999). The bond angles for linear Br—Pb—Br are in the range 170.87 (9)– 174.84 (4)°, while those for perpendicular Br—Pb—Br are in the range 83.85 (5)–94.95 (6)°. In the dmqxH2 cation, the bond distances and angles are the same as those reported previously, within experimental error (Willett & Twamley, 2001).

The extra supramolecularity in the structure is represented by H-bonding (Table 1) leading to a layer arrangement in ac plane.

Related literature top

For related literature, see: Billing & Lemerrer (2005); Chakravarthy & Guloy (1997); Cui et al. (2000); Klapotke et al. (1999); Lacroix et al. (1994); Reynolds et al. (2003); Willett & Twamley (2001).

Experimental top

A solution of PbCl2 (1.0 mmol), in absolute ethanol (10 ml), was added to a stirred hot solution of 2,3-dimethylquinoxaline (1 mmol) in absolute ethanol (10 ml) containing 60% HBr (3 ml) and liquid Br2 (2 ml). After heating to reflux for ca 3 h, the mixture was filtered and the filtrate allowed to stand undisturbed at room temperature. Complex (I) crystallized out over 2 days as red blocks. Crystals were filtered off, washed with diethyl ether and dried under vacuum.

Refinement top

All H atoms were initially located in a difference Fourier map and were subsequently refined using a riding model, with C—H distances of 0.96 Å and Uiso(H) = 1.5eq(C) for methyl H atoms; C—H = 0.96 Å and Uiso(H) = 1.2eq(C) for aromatic H atoms, and N—H = 0.86 Å and Uiso(H) = 1.2eq(N).

Structure description top

Research in the field of organic inorganic hybrid compounds is of great interest. This is because of the their special magnetic, electronic and optoelectronic properties (Cui et al., 2000; Lacroix et al.,1994; Chakravarthy & Guloy, 1997). Haloplumbates, have demonstrated a structural diversity in lead-halide based organic inorganic hybrids (Billing & Lemerrer, 2005) in particular, in terms of the nets formed by the inorganic components, which show many distinct topologies. Examples are layers of corner sharing octahedra, linear chains of face sharing octahedra as well as a number of mixed intermediates (Billing & Lemerrer, 2005). In the crystal structure of the title complex, (I). The use of 2,3-dimethylquinoxaline (henceforth dmqxH2) and its protonation were expected to create many important centers of interaction with the bromo-lead anion, e.g. NH···Br, CH···Br and possibly Br···aryl and aryl···aryl interactions.

In the title compound, (I), {C10H12Br4N2Pb}n, the asymmetric unit consists of half of the repeated extended structure of both cation and anion. The planar cations [C10H12N2]2+ with both nitrogen atoms protonated, lies on a 2-fold axis that runs lengthwise between the two halves (Fig. 1). The dinuclear unit [Pb2Br10]6- consists of two distorted octahedra bridged by Br3 and its symmetry related Br3i [Symmetry code: (iii) -x + 1, -y, -z + 1). These dinuclear units are further interconnected through bridging Br2 to form a polymeric chain structure developping parallel to the c axis (Fig. 2). This anion chain demonstrates a novel structural arrangement in metal halide extended anion networking.

The Pb—Br distances are similar, 3.0242 (6)–3.0448 (16) Å and fall within the range of Pb—Br distances reported previously for compounds containing lead-bromides (Reynolds et al., 2003; Cui et al., 2000; Klapotke et al., 1999). The bond angles for linear Br—Pb—Br are in the range 170.87 (9)– 174.84 (4)°, while those for perpendicular Br—Pb—Br are in the range 83.85 (5)–94.95 (6)°. In the dmqxH2 cation, the bond distances and angles are the same as those reported previously, within experimental error (Willett & Twamley, 2001).

The extra supramolecularity in the structure is represented by H-bonding (Table 1) leading to a layer arrangement in ac plane.

For related literature, see: Billing & Lemerrer (2005); Chakravarthy & Guloy (1997); Cui et al. (2000); Klapotke et al. (1999); Lacroix et al. (1994); Reynolds et al. (2003); Willett & Twamley (2001).

Computing details top

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. Displacement ellpisoid (30%) plot of (I), showing the atom-numbering scheme. The complete coordination about Pb1 and cation have been included. [Symmetry codes: (i) 1 - x, -y, 1 - z; (ii) x, y, 1 + z; (iii) 1 - x, - y, 1 - z; (iv) x, 1 - y, z; (v) 1 - x, 1 - y, 1 - z; (vi) 2 - x, y, -z].
[Figure 2] Fig. 2. View of unit cell approximately down a axis showing H-bonding between Br1 and N3.
catena-poly[bis(2,3-dimethylquinoxalinium) [[di-µ2-bromido-bis[dibromoplumbate(II)]]-di-µ2-bromido]] top
Crystal data top
(C10H12N2)2[Pb2Br8]F(000) = 1232
Mr = 1374.04Dx = 2.918 Mg m3
Monoclinic, C2/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yCell parameters from 3034 reflections
a = 9.4180 (19) Åθ = 1.5–27.9°
b = 28.141 (6) ŵ = 20.99 mm1
c = 6.0290 (12) ÅT = 295 K
β = 101.83 (3)°Block, red
V = 1563.9 (6) Å30.20 × 0.15 × 0.10 mm
Z = 2
Data collection top
Rigaku Mercury CCD
diffractometer
1419 independent reflections
Radiation source: fine-focus sealed tube875 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.092
Detector resolution: 14.6306 pixels mm-1θmax = 25.2°, θmin = 3.1°
dtintegrate.ref scansh = 1111
Absorption correction: numerical
(SHAPE Tracing Software; Rigaku, 2000)
k = 3333
Tmin = 0.102, Tmax = 0.228l = 76
7780 measured reflections
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)] = 0.054Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123H-atom parameters constrained
S = 0.73 w = 1/[σ2(Fo2) + (0.0005P)2]
where P = (Fo2 + 2Fc2)/3
1419 reflections(Δ/σ)max < 0.001
81 parametersΔρmax = 2.30 e Å3
0 restraintsΔρmin = 1.46 e Å3
Crystal data top
(C10H12N2)2[Pb2Br8]V = 1563.9 (6) Å3
Mr = 1374.04Z = 2
Monoclinic, C2/mMo Kα radiation
a = 9.4180 (19) ŵ = 20.99 mm1
b = 28.141 (6) ÅT = 295 K
c = 6.0290 (12) Å0.20 × 0.15 × 0.10 mm
β = 101.83 (3)°
Data collection top
Rigaku Mercury CCD
diffractometer
1419 independent reflections
Absorption correction: numerical
(SHAPE Tracing Software; Rigaku, 2000)
875 reflections with I > 2σ(I)
Tmin = 0.102, Tmax = 0.228Rint = 0.092
7780 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0540 restraints
wR(F2) = 0.123H-atom parameters constrained
S = 0.73Δρmax = 2.30 e Å3
1419 reflectionsΔρmin = 1.46 e Å3
81 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
Pb10.50000.57831 (3)0.50000.0288 (3)
Br10.73667 (15)0.65358 (6)0.5497 (2)0.0386 (5)
Br20.50000.58691 (8)0.00000.0475 (7)
Br30.2733 (2)0.50000.4132 (4)0.0358 (6)
C10.9022 (16)0.5680 (5)0.167 (3)0.038 (4)
H1A0.97850.55510.28170.057*
H1B0.87620.54550.04610.057*
H1C0.81920.57460.23160.057*
C20.9527 (13)0.6126 (5)0.078 (2)0.027 (3)
C40.9533 (12)0.6952 (5)0.076 (2)0.027 (3)
C50.9127 (14)0.7363 (5)0.169 (2)0.034 (4)
H50.85980.73620.28290.040*
C60.9558 (15)0.7782 (6)0.080 (2)0.045 (4)
H60.92490.80710.12830.054*
N30.9122 (11)0.6516 (4)0.1469 (17)0.022 (2)
H3A0.85610.65100.24290.026*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pb10.0225 (4)0.0360 (6)0.0290 (5)0.0000.0080 (3)0.000
Br10.0285 (8)0.0535 (12)0.0373 (9)0.0104 (7)0.0145 (7)0.0096 (7)
Br20.0521 (15)0.0652 (18)0.0253 (13)0.0000.0083 (11)0.000
Br30.0244 (11)0.0332 (14)0.0494 (14)0.0000.0066 (9)0.000
C10.042 (9)0.042 (10)0.036 (9)0.002 (8)0.021 (8)0.004 (8)
C20.023 (7)0.033 (9)0.024 (8)0.001 (7)0.001 (6)0.001 (7)
C40.015 (6)0.040 (10)0.024 (8)0.003 (7)0.003 (5)0.002 (7)
C50.037 (8)0.036 (10)0.032 (9)0.002 (8)0.016 (7)0.003 (8)
C60.045 (10)0.055 (12)0.037 (10)0.011 (8)0.013 (7)0.012 (8)
N30.023 (6)0.018 (7)0.025 (6)0.000 (5)0.010 (5)0.003 (5)
Geometric parameters (Å, º) top
Pb1—Br23.0242 (6)C4—C51.372 (18)
Pb1—Br33.0380 (14)C4—N31.381 (16)
Pb1—Br13.0448 (16)C4—C4i1.40 (2)
C1—C21.481 (18)C5—C61.389 (19)
C1—H1A0.9600C5—H50.9300
C1—H1B0.9600C6—C6i1.40 (3)
C1—H1C0.9600C6—H60.9300
C2—N31.262 (15)N3—H3A0.8600
C2—C2i1.42 (2)
Br2ii—Pb1—Br2170.81 (9)H1B—C1—H1C109.5
Br2ii—Pb1—Br394.95 (6)N3—C2—C2i119.4 (8)
Br2—Pb1—Br391.71 (6)N3—C2—C1118.4 (12)
Br3—Pb1—Br3iii87.00 (6)C2i—C2—C1122.2 (8)
Br2ii—Pb1—Br189.76 (5)C5—C4—N3120.4 (12)
Br2—Pb1—Br183.85 (5)N3—C4—C4i117.2 (7)
Br3—Pb1—Br1174.84 (4)C4—C5—C6115.6 (13)
Br3iii—Pb1—Br190.76 (4)C4—C5—H5122.2
Br1—Pb1—Br1iv91.84 (6)C6—C5—H5122.2
Pb1—Br3—Pb1iii93.00 (6)C5—C6—C6i121.9 (8)
C2—C1—H1A109.5C5—C6—H6119.1
C2—C1—H1B109.5C2—N3—C4123.3 (12)
H1A—C1—H1B109.5C2—N3—H3A118.3
C2—C1—H1C109.5C4—N3—H3A118.3
H1A—C1—H1C109.5
Symmetry codes: (i) x+2, y, z; (ii) x, y, z+1; (iii) x+1, y+1, z+1; (iv) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3A···Br10.862.353.206 (10)171
C1—H1C···Br20.963.063.752 (14)130

Experimental details

Crystal data
Chemical formula(C10H12N2)2[Pb2Br8]
Mr1374.04
Crystal system, space groupMonoclinic, C2/m
Temperature (K)295
a, b, c (Å)9.4180 (19), 28.141 (6), 6.0290 (12)
β (°) 101.83 (3)
V3)1563.9 (6)
Z2
Radiation typeMo Kα
µ (mm1)20.99
Crystal size (mm)0.20 × 0.15 × 0.10
Data collection
DiffractometerRigaku Mercury CCD
Absorption correctionNumerical
(SHAPE Tracing Software; Rigaku, 2000)
Tmin, Tmax0.102, 0.228
No. of measured, independent and
observed [I > 2σ(I)] reflections
7780, 1419, 875
Rint0.092
(sin θ/λ)max1)0.600
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.054, 0.123, 0.73
No. of reflections1419
No. of parameters81
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)2.30, 1.46

Computer programs: CrystalClear (Rigaku, 2000), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1999), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3A···Br10.862.353.206 (10)171
C1—H1C···Br20.963.063.752 (14)130
 

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