catena-Poly­[[bis­(thio­cyanato-N)lead(II)]-[mu]-1,2-bis(4-pyridyl)ethane-N:N']

In the title coordination polymer, [Pb(NCS)₂(C₁₂H₁₂N₂)], the coordination geometry about the Pb^II atom is a distorted octahedron, composed of two N atoms from bpe ligands [bpe is 1,2-bis(4-pyridyl)ethane], two other N atoms from NCS^- groups and two neighbouring S atoms through short contacts. The trans-bpe ligands act as bridges between two Pb^II centres resulting in the formation of a linear chain. The terminal S atoms of the NCS^- ligands make short contacts with the Pb^II atom of neighbouring chains to form an infinite two-dimensional polymeric structure.

S1. Comment

The study of coordination polymers in modern supramolecular chemistry has spawned tremendous interest in the role of multifunctional bridging ligands in determining the final type or topology of the self-assembled product. Among these basic building blocks, 4,4'-bipyridine and its derivatives have been widely employed for their appropriate rigidity and capacity in the construction of solid-state architecture, mostly with linear chain structures (Fujita & Kwon, 1994; Witherly & Blake, 1997; Losier & Zaworotko, 1996; Hennigar et al., 1997; Lu et al., 1997). The main effort in this field have been devoted to their reactions with transition metals with different coordination numbers and preferences. However, there are few reports on bivalent main group metal polymers such as Pb^II polymers with these spacers. We report here the self assembly of a two-dimensional polymer with Pb^II, (I). \sch

The Pb^II adopts a distorted octahedral geometry. The bpe acts as a bridge between two Pb^II centers to result in the formation of a linear Pb-pbe-Pb chain. The terminal S atoms of the NCS^- ligands make short contacts with the Pb^II atom of the neighbouring polymeric chain to form an infinite two-dimensional polymeric structure (Fig. 2).

Its octahedral coordination is defined by four N atoms and two S atoms: two N atoms belong to NCS^- anions [Pb—N1 = 2.413 (9), Pb—N2 = 2.415 (9) Å], two other N atoms belong to the bpe units [Pb—N3 = 2.570 (7), Pb—N4ⁱ= 2.713 (8) Å] and two S atoms [Pb—S1ⁱⁱ = 3.226 (6), Pb—S2ⁱⁱ = 3.196 (6) Å]. The equatorial plane consists of N1, N2, S1ⁱⁱ and S2ⁱⁱ atoms whereas the axial atoms are N3 and N4ⁱ. [Symmetry codes: (i) 1 + x, 1 + y, 1 + z; (ii) x, -1 + y, z].

The N3—Pb—N4ⁱ angle is 160.7 (3)°, smaller than those found in the related transition metal assemblies exhibiting M-anti-bpe-M bridges (Hong & Do, 1998; Hernandez et al., 1999, 2000; Fujita et al., 1994). The chain exhibits slight zigzag characteristics. The terminal NCS^- groups is almost linear with N—C—S angles of 176.9 (1) and 179.2 (1)°, respectively. The connections between the Pb^II atom and two NCS^- groups are bent with the Pb—N—C angles of 145.7 (1) and 153.1 (9)°, respectively. It can be deduced that the bivalent main group metals exhibiting different coordination preferences influence the crystal packing and final structure of self-assembled product.

Related literature

For related literature, see: Fujita & Kwon (1994, 1994); Fujita, Kwon, Miyazawa & Ogura (1994); Hennigar et al. (1997); Hernandez et al. (1999, 2000); Hong & Do (1998); Lu et al. (1997); Witherly & Blake (1997).

S2. Experimental

The title compound was synthesized by mixing successively the methanol solution of Pb(NO₃)₂ (0.03 g, 0.1 mmol), bpe (0.02 g, 0.1 mmol), and KNCS (0.02 g, 0.2 mmol) at room temperature. Colorless crystals were obtained by slow evaporation of the solution.

S3. Refinement

T. The number of Friedel pairs used is 1644.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 1990).

Figures

	Fig. 1. The structure of (I) showing 50% probability displacement ellipsoids with numbering scheme.
	Fig. 2. Packing diagram viewed down the a axis.

Catena-[m-1,2-bis(4-pyridyl)ethane-bis-thiocyanato)Lead(II)]

Crystal data

[Pb(NCS)2(C12H12N2)]	F(000) = 476
Mr = 507.59	Dx = 2.023 Mg m^−3
Monoclinic, Pc	Mo Kα radiation, λ = 0.71073 Å
a = 11.6335 (1) Å	Cell parameters from 5094 reflections
b = 5.6309 (1) Å	θ = 2.0–28.2°
c = 14.8578 (2) Å	µ = 10.37 mm^−1
β = 121.091 (1)°	T = 293 K
V = 833.48 (2) Å^3	Prism, colourless
Z = 2	0.42 × 0.28 × 0.22 mm

Data collection

Siemens SMART CCD area detector diffractometer	3678 independent reflections
Radiation source: fine-focus sealed tube	3398 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
Detector resolution: 8.33 pixels mm^-1	θmax = 28.2°, θmin = 2.0°
ω scans	h = −15→15
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −7→3
Tmin = 0.042, Tmax = 0.102	l = −19→18
5572 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.038	w = 1/[σ^2(Fo^2)] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.089	(Δ/σ)max = 0.001
S = 0.92	Δρmax = 1.38 e Å^−3
3678 reflections	Δρmin = −1.64 e Å^−3
203 parameters	Extinction correction: SHELXTL (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.0199 (10)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack, H. D. (1983), Acta Cryst. A39, 876-881
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.006 (9)

Special details

Experimental. he data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal-to-detector distance was 4 cm and the detector swing angle was -35°. Coverage of the unique set is over 98.3% complete. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the duplicate reflections, and was found to be negligible

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 (Ų)

	x	y	z	Uiso*/Ueq
Pb	1.00026 (7)	0.59744 (4)	0.25149 (6)	0.03240 (12)
S1	0.7742 (4)	1.3377 (9)	0.2804 (4)	0.0528 (10)
S2	1.2239 (4)	1.3226 (10)	0.2282 (4)	0.0612 (12)
N1	0.8497 (9)	0.9230 (16)	0.2216 (9)	0.053 (2)
N2	1.0960 (12)	0.8898 (16)	0.1902 (10)	0.055 (2)
N3	0.8194 (7)	0.5060 (16)	0.0599 (5)	0.0358 (16)
N4	0.1747 (9)	−0.1568 (17)	−0.5732 (6)	0.048 (2)
C1	0.8185 (11)	1.0955 (16)	0.2469 (9)	0.033 (2)
C2	1.1533 (12)	1.070 (2)	0.2083 (10)	0.039 (3)
C3	0.8415 (11)	0.317 (2)	0.0169 (7)	0.049 (2)
H3A	0.9288	0.2603	0.0462	0.07 (4)*
C4	0.7387 (14)	0.200 (3)	−0.0699 (10)	0.045 (3)
H4B	0.7566	0.0631	−0.0955	0.10 (6)*
C5	0.6077 (9)	0.292 (2)	−0.1190 (7)	0.039 (2)
C6	0.5907 (10)	0.487 (2)	−0.0753 (8)	0.048 (2)
H6A	0.5054	0.5527	−0.1051	0.12 (7)*
C7	0.6965 (11)	0.5943 (19)	0.0126 (9)	0.047 (3)
H7A	0.6805	0.7321	0.0389	0.04 (3)*
C8	0.4961 (14)	0.170 (3)	−0.2150 (10)	0.053 (4)
H8A	0.4116	0.2036	−0.2194	0.05 (3)*
H8B	0.5105	0.0000	−0.2071	0.08 (5)*
C9	0.4861 (13)	0.246 (2)	−0.3148 (8)	0.049 (3)
H9A	0.4678	0.4151	−0.3245	0.09 (6)*
H9B	0.5716	0.2183	−0.3097	0.06 (4)*
C10	0.3775 (10)	0.115 (2)	−0.4089 (7)	0.044 (2)
C11	0.2417 (16)	0.174 (3)	−0.4558 (12)	0.052 (4)
H11A	0.2158	0.3087	−0.4343	0.06 (4)*
C12	0.1449 (11)	0.028 (3)	−0.5359 (9)	0.054 (3)
H12A	0.0548	0.0651	−0.5638	0.05 (4)*
C13	0.3028 (12)	−0.215 (2)	−0.5290 (9)	0.052 (3)
H13A	0.3254	−0.3482	−0.5536	0.04 (3)*
C14	0.4048 (12)	−0.085 (2)	−0.4478 (9)	0.056 (3)
H14A	0.4934	−0.1341	−0.4189	0.06 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pb	0.03174 (15)	0.02993 (15)	0.02920 (16)	−0.0068 (2)	0.01124 (11)	−0.0074 (2)
S1	0.063 (3)	0.0359 (17)	0.079 (3)	0.0086 (17)	0.050 (2)	−0.0003 (19)
S2	0.049 (2)	0.042 (2)	0.092 (3)	−0.0073 (18)	0.035 (2)	−0.008 (2)
N1	0.039 (5)	0.046 (5)	0.064 (6)	0.006 (3)	0.019 (5)	−0.015 (4)
N2	0.068 (6)	0.041 (5)	0.071 (7)	−0.005 (4)	0.047 (6)	0.002 (4)
N3	0.033 (4)	0.044 (4)	0.022 (3)	−0.005 (3)	0.008 (3)	−0.009 (3)
N4	0.048 (5)	0.052 (5)	0.029 (4)	−0.013 (4)	0.010 (4)	−0.017 (4)
C1	0.036 (5)	0.033 (5)	0.031 (6)	−0.004 (4)	0.019 (5)	−0.002 (4)
C2	0.039 (6)	0.046 (6)	0.032 (6)	0.007 (4)	0.017 (5)	0.001 (4)
C3	0.042 (5)	0.062 (6)	0.029 (4)	0.003 (5)	0.008 (4)	−0.007 (5)
C4	0.047 (6)	0.041 (7)	0.034 (6)	0.002 (5)	0.013 (5)	−0.004 (5)
C5	0.037 (5)	0.045 (5)	0.030 (4)	−0.011 (4)	0.012 (4)	0.002 (4)
C6	0.031 (4)	0.058 (6)	0.041 (5)	−0.006 (5)	0.008 (4)	−0.008 (5)
C7	0.038 (5)	0.050 (7)	0.039 (5)	0.002 (4)	0.010 (4)	−0.011 (4)
C8	0.055 (7)	0.059 (7)	0.038 (6)	−0.026 (6)	0.018 (6)	−0.010 (5)
C9	0.049 (7)	0.061 (8)	0.026 (5)	−0.028 (6)	0.012 (5)	−0.014 (5)
C10	0.036 (5)	0.062 (7)	0.023 (4)	−0.014 (4)	0.007 (4)	−0.008 (4)
C11	0.051 (7)	0.056 (7)	0.040 (7)	−0.010 (6)	0.016 (6)	−0.023 (6)
C12	0.034 (5)	0.070 (7)	0.041 (5)	−0.010 (5)	0.008 (4)	−0.007 (6)
C13	0.054 (6)	0.041 (6)	0.050 (6)	0.001 (5)	0.018 (5)	−0.014 (5)
C14	0.044 (6)	0.066 (8)	0.043 (6)	0.004 (5)	0.012 (5)	−0.013 (5)

Geometric parameters (Å, º)

Pb—N2	2.415 (9)	C5—C8	1.508 (14)
Pb—N1	2.413 (9)	C6—C7	1.387 (14)
Pb—N3	2.570 (7)	C6—H6A	0.9300
Pb—N4^i	2.713 (8)	C7—H7A	0.9300
S1—C1	1.625 (11)	C8—C9	1.488 (16)
S2—C2	1.591 (14)	C8—H8A	0.9700
N1—C1	1.165 (12)	C8—H8B	0.9701
N2—C2	1.167 (15)	C9—C10	1.508 (13)
N3—C3	1.336 (15)	C9—H9A	0.9701
N3—C7	1.322 (13)	C9—H9B	0.9699
N4—C12	1.308 (16)	C10—C14	1.375 (16)
N4—C13	1.323 (15)	C10—C11	1.40 (2)
N4—Pb^ii	2.713 (8)	C11—C12	1.406 (17)
C3—C4	1.389 (17)	C11—H11A	0.9300
C3—H3A	0.9300	C12—H12A	0.9300
C4—C5	1.404 (17)	C13—C14	1.386 (15)
C4—H4B	0.9300	C13—H13A	0.9300
C5—C6	1.343 (17)	C14—H14A	0.9301
N2—Pb—N1	81.1 (3)	N3—C7—H7A	119.1
N2—Pb—N3	89.6 (4)	C6—C7—H7A	119.1
N1—Pb—N3	81.2 (3)	C9—C8—C5	113.5 (10)
N2—Pb—N4^i	75.7 (4)	C9—C8—H8A	108.8
N1—Pb—N4^i	84.3 (3)	C5—C8—H8A	108.9
N3—Pb—N4^i	160.7 (3)	C9—C8—H8B	108.9
C1—N1—Pb	153.1 (9)	C5—C8—H8B	108.8
C2—N2—Pb	145.7 (10)	H8A—C8—H8B	107.7
C3—N3—C7	117.9 (8)	C8—C9—C10	112.4 (9)
C3—N3—Pb	116.1 (6)	C8—C9—H9A	109.1
C7—N3—Pb	123.8 (7)	C10—C9—H9A	109.2
C12—N4—C13	117.7 (9)	C8—C9—H9B	109.1
C12—N4—Pb^ii	125.6 (7)	C10—C9—H9B	109.1
C13—N4—Pb^ii	116.3 (7)	H9A—C9—H9B	107.9
N1—C1—S1	179.2 (11)	C14—C10—C11	115.7 (10)
N2—C2—S2	176.9 (12)	C14—C10—C9	121.7 (11)
N3—C3—C4	122.3 (11)	C11—C10—C9	122.3 (12)
N3—C3—H3A	118.8	C12—C11—C10	119.1 (14)
C4—C3—H3A	118.9	C12—C11—H11A	120.5
C5—C4—C3	119.5 (12)	C10—C11—H11A	120.4
C5—C4—H4B	120.2	N4—C12—C11	123.6 (12)
C3—C4—H4B	120.2	N4—C12—H12A	118.3
C4—C5—C6	116.1 (9)	C11—C12—H12A	118.2
C4—C5—C8	119.9 (12)	N4—C13—C14	122.7 (12)
C6—C5—C8	124.0 (10)	N4—C13—H13A	118.7
C5—C6—C7	122.1 (10)	C14—C13—H13A	118.6
C5—C6—H6A	118.9	C10—C14—C13	121.2 (11)
C7—C6—H6A	119.0	C10—C14—H14A	119.3
N3—C7—C6	121.8 (10)	C13—C14—H14A	119.5
N2—Pb—N1—C1	−86 (2)	C3—N3—C7—C6	4.1 (17)
N3—Pb—N1—C1	−177 (2)	Pb—N3—C7—C6	−158.6 (9)
N4^i—Pb—N1—C1	−10 (2)	C5—C6—C7—N3	−1.8 (19)
N1—Pb—N2—C2	67.1 (17)	C4—C5—C8—C9	−84.9 (15)
N3—Pb—N2—C2	148.2 (18)	C6—C5—C8—C9	95.1 (14)
N4^i—Pb—N2—C2	−19.3 (17)	C5—C8—C9—C10	177.7 (13)
N2—Pb—N3—C3	98.1 (8)	C8—C9—C10—C14	−94.9 (14)
N1—Pb—N3—C3	179.2 (8)	C8—C9—C10—C11	78.8 (17)
N4^i—Pb—N3—C3	137.4 (10)	C14—C10—C11—C12	1 (2)
N2—Pb—N3—C7	−99.0 (9)	C9—C10—C11—C12	−173.1 (13)
N1—Pb—N3—C7	−17.9 (9)	C13—N4—C12—C11	4 (2)
N4^i—Pb—N3—C7	−59.6 (13)	Pb^ii—N4—C12—C11	−168.7 (12)
C7—N3—C3—C4	−5.3 (18)	C10—C11—C12—N4	−3 (2)
Pb—N3—C3—C4	158.7 (10)	C12—N4—C13—C14	−1.7 (19)
N3—C3—C4—C5	4 (2)	Pb^ii—N4—C13—C14	171.3 (10)
C3—C4—C5—C6	−1.7 (18)	C11—C10—C14—C13	0.7 (19)
C3—C4—C5—C8	178.3 (12)	C9—C10—C14—C13	174.8 (12)
C4—C5—C6—C7	0.6 (18)	N4—C13—C14—C10	0 (2)
C8—C5—C6—C7	−179.4 (11)

Symmetry codes: (i) x+1, y+1, z+1; (ii) x−1, y−1, z−1.