4,7-Bis(4-pyridyl­ethynyl)-2,1,3-benzo­thia­diazo­le and its dipyridinium diperchlorate

The title compound, C₂₀H₁₀N₄S, and its dipyridinium salt, 4,4′-(2,1,3-benzo­diazol-4,7-diyl­diethynyl)­dipyridinium diperchlorate, C₂₀H₁₂N₄S²⁺·2ClO₄⁻, display bond alternation in the 2,1,3-benzo­thia­diazo­le rings, which suggests their quinonoid character. The dipyridinium dication mol­ecules stack along the a axis and form a dimer with short S...N interheteroatom contacts [3.146 (4) Å] between the two 1,2,5-thia­diazo­le rings. The dimer is surrounded by the perchlorate anions with which it forms a large number of intermolecular N—H...O and C—H...O hydrogen bonds.

S1. Comment

A long, rigid and conjugated bridging ligand has received much current interest for the construction of self-assembling macrocyclic architectures (Lehn, 1995; Fujita, 1999) and the development of molecular wires (Tour, 1996). Additionally, incorporation of redox-active and/or luminescent parts into the ligands is attractive in exploring functional supramolecular systems (Hock et al., 1996; Sun & Lees, 2000). With this in mind we have recently synthesized a novel ligand with a 2,1,3-benzothiadiazole ring and two terminal pyridine rings, 4,7-bis(4-pyridylethynyl)-2,1,3-benzothiadiazole, (I). The S and the N atoms in the 1,2,5-thiadiazole ring of (I) are expected to form short interheteroatom contacts which can bring unique molecular networks (Yamashita & Tomura, 1998). In the course of our studies on (I), we have also isolated its dipyridinium salt, 4,4'-(2,1,3-benzodiazol-4,7-diyldiethynyl)dipyridinium diperchlorate, (II), as single crystals. We report here the molecular structures and the unique crystal structures of (I) and (II). \sch

Compounds (I) and (II) crystallize in the P2₁/a and the P2₁/c space groups, respectively, with one molecule in the asymmetric unit. The molecular structures of (I) and (II) are shown in Figs. 1 and 2, and selected geometric parameters are listed in Tables 1 and 2, respectively. Compound (I) and the dipyridinium dication in (II) generally have similar molecular geometries. They are long and linear molecules with lengths of 16.557 (5) Å for (I) and 16.387 (6) Å for (II) (N3—N4 distance). The dipyridinium dication of (II) is more linear [C8—C7—C1 179.4 (6) and C15—C14—C4 178.7 (5)°], while (I) bends slightly [C8—C7—C1 176.2 (4) and C15—C14—C4 174.4 (5)°]. The 2,1,3-benzothiadiazole and two pyridine rings are planar within the deviation of 0.026 (3) for (I) and 0.038 (4) Å for (II). Compound (I) lies in a plane (r.m.s. deviation of fitted atoms; 0.1043 Å), and the angles between the 2,1,3-benzothiadiazole and two pyridine rings are 1.5 (2)° (C9—C10—C11—N3—C12—C13) and 11.6 (2)° (C16—C17—C18—N4—C19—C20). In the dipyridinium dication in (II), the 2,1,3-benzothiadiazole and one pyridine ring (C9—C10—C11—N3—C12—C13) are almost coplanar [r.m.s. deviation of fitted atoms; 0.0541 Å and the angle between the planes for the two rings; 5.4 (3)°], while the other pyridine ring tilts toward the 2,1,3-benzothiadiazole one with the angle of 44.5 (2)°. The C1—C7, C8—C9, C4—C14 and C15—C16 bonds [1.429 (4)–1.445 (4) for (I) and 1.428 (6)–1.438 (6) Å for (II)] are almost the same length as the typical C_aromatic—C_sp bond, 1.434 Å (Allen et al., 1987).

There is considerable shortening of the C1—C6 and C4—C5 bonds compared to the other bonds in the benzene rings of (I) and (II). Such double bond fixation suggests quinonoid character of the 2,1,3-benzothiadiazole ring in (I) and (II). The geometric parameters of the 1,2,5-thiadiazole rings in (I) and (II) are almost the same as those of 3,4-diphenyl-1,2,5-thiadiazole (Mellini & Merlino, 1976).

Fig. 3 shows the packing diagram of (II) viewed along the a axis. The dipyridinium dication molecules form unistacks along the a axis. The interstack distance (distance between the two 2,1,3-benzothiadiazole ring planes within the stack) is 3.40 (1) Å. The most remarkable feature of the crystal structure of (II) is the existence of short S···N interheteroatom contacts [3.146 (4) Å for S1···N2(-x, -y + 1, -z) and N2···S1(-x, -y + 1, -z)] between the two 1,2,5-thiadiazole rings. The S···N distance is 6.1% shorter, and the S1···S1(-x, -y + 1, -z) [3.960 (3) Å] and the N2···N2(-x, -y + 1, -z) [3.048 (8) Å] between the 1,2,5-thiadiazole rings are 6.5 and 1.6% longer than the sum of the corresponding van der Waals radii (Pauling, 1960), respectively. Thus the dipyridinium dication molecules form a dimer with the short S—N contacts, which is planar and lies in a plane within the deviation of 0.09 (1) Å. No short S—N interheteroatom contact within the sum of the van der Waals radii of the S and the N atoms was observed in the crystal structure of (I) [the shortest S···N interheteroatom contact; S1···N4(-x + 3/2, y + 1/2, -z + 1) 3.380 (3) Å]. Interestingly, the dimer is surrounded by the perchlorate anions, as shown in Fig. 3. A large number of intermolecular N—H···O and C—H···O hydrogen bonds (Taylor & Kennard, 1982; Biradha et al., 1993; Batchelor et al., 2000) are observed between the dipyridinium dication and the oxygen atoms of the perchlorate anions (see Table 3). The intermolecular O···O distances of the perchlorates are in the range of 3.044 (6) to 3.286 (6) Å.

Studies on the construction of new molecular architectures using compound (I) are now in progress.

S2. Experimental

Compound (I) was synthesized by the reaction of 4,7-dibromo-2,1,3-benzothiadiazole (Pilgram et al., 1970) with 4-ethynylpyridine (Ciana & Haim, 1984). To a solution of 4-ethynylpyridine (1.63 g, 15.9 mmol) and 4,7-dibromo-2,1,3-benzothiadiazole (2.00 g, 6.8 mmol) in triethylamine (150 ml), bis(triphenylphosphine)palladium(II) dichloride (0.115 g, 0.164 mmol) and copper(I) bromide (0.101 g, 0.702 mmol) was added. After stirring for 30 min at 333 K, the reaction mixture was stirred for 2 d at 363 K under argon. Triethylamine was removed in vacuo and the residue was dissolved in CH₂Cl₂. The solution was washed with aqueous K₂CO₃, and dried over Na₂SO₄. After the solvent was evaporated in vacuo, the crude product (yield 1.79 g, 78%) was purified by sublimation (453–473 K, 10^-2 torr) to give (I) as a yellow powder. Slow evaporation of a solution of (I) in CH₂Cl₂-ethyl acetate (5:1) afforded yellow crystals of (I) suitable for X-ray analysis. Physical data for (I): m.p. 523–525 K; ¹H NMR (CDCl₃, 270 MHz): δ 7.55 (d), 7.88 (s), 8.69 (d); MS (EI): m/z 338 (M⁺). Slow evaporation of a solution of (I) with copper(II) perchlorate in CH₂Cl₂-ethyl acetate (5:1) gave orange crystals of (II) suitable for X-ray analysis.

S3. Refinement

All H atoms of (I) were placed in geometrically calculated positions and refined by using a riding model. All H atoms of (II) were localized in the Fourier map and refined isotropically.

Computing details

For both compounds, data collection: CAD-4 EXPRESS Software (Enraf-Nonius, 1992); cell refinement: CAD-4 EXPRESS Software; data reduction: TEXSAN (Molecular Structure Corporation, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. Molecular structure of (I) with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Molecular structure of (II) with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 3. Packing diagram of (II) viewed along the a axis. Dotted lines show the short S···N interheteroatom contacts.

(I) 4,7-bis[(4-pyridyl)ethynyl]-2,1,3-benzothiadiazole

Crystal data

C20H10N4S	Dx = 1.411 Mg m^−3
Mr = 338.38	Melting point: 524 K
Monoclinic, P21/a	Cu Kα radiation, λ = 1.54178 Å
a = 12.487 (2) Å	Cell parameters from 25 reflections
b = 7.5477 (13) Å	θ = 18.7–42.4°
c = 17.513 (3) Å	µ = 1.88 mm^−1
β = 105.22 (2)°	T = 296 K
V = 1592.8 (5) Å^3	Prismatic, yellow
Z = 4	0.50 × 0.30 × 0.10 mm
F(000) = 696

Data collection

Enraf-Nonius CAD-4 diffractometer	1902 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.079
Graphite monochromator	θmax = 74.3°, θmin = 5.2°
ω–2θ scans	h = −15→0
Absorption correction: ψ scan (North et al., 1968)	k = −9→0
Tmin = 0.454, Tmax = 0.835	l = −21→21
3416 measured reflections	3 standard reflections every 120 min
3254 independent reflections	intensity decay: 2.4%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.068	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.209	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ^2(Fo^2) + (0.1016P)^2 + 0.5079P] where P = (Fo^2 + 2Fc^2)/3
3254 reflections	(Δ/σ)max < 0.001
226 parameters	Δρmax = 0.69 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

Special details

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

1.5818 (0.0221) x - 6.6462 (0.0067) y + 7.1354 (0.0259) z = 6.0990 (0.0289)

* 0.0042 (0.0028) N3 * 0.0090 (0.0028) C9 * -0.0040 (0.0029) C10 * -0.0028 (0.0030) C11 * 0.0011 (0.0030) C12 * -0.0076 (0.0030) C13

Rms deviation of fitted atoms = 0.0055

1.2657 (0.0098) x - 6.6518 (0.0049) y + 7.3340 (0.0198) z = 6.2092 (0.0135)

Angle to previous plane (with approximate e.s.d.) = 1.48 (0.18)

* -0.0020 (0.0019) S1 * -0.0044 (0.0026) N1 * 0.0160 (0.0026) N2 * -0.0087 (0.0028) C1 * -0.0016 (0.0032) C2 * 0.0049 (0.0033) C3 * -0.0263 (0.0030) C4 * 0.0078 (0.0031) C5 * 0.0143 (0.0030) C6

Rms deviation of fitted atoms = 0.0122

- 0.8891 (0.0247) x - 7.0043 (0.0055) y + 6.5072 (0.0274) z = 4.6045 (0.0155)

Angle to previous plane (with approximate e.s.d.) = 11.64 (0.15)

* -0.0071 (0.0029) N4 * -0.0028 (0.0030) C16 * -0.0084 (0.0034) C17 * 0.0137 (0.0034) C18 * -0.0046 (0.0030) C19 * 0.0092 (0.0030) C20

Rms deviation of fitted atoms = 0.0084

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
S1	0.73678 (9)	0.07406 (18)	0.78638 (6)	0.0666 (4)
N1	0.6460 (3)	0.1108 (5)	0.83501 (18)	0.0544 (8)
N2	0.6621 (3)	−0.0274 (5)	0.70975 (18)	0.0548 (8)
N3	0.3540 (3)	0.3989 (5)	1.14848 (17)	0.0537 (8)
N4	0.5864 (3)	−0.4239 (5)	0.33033 (18)	0.0606 (10)
C1	0.4457 (3)	0.0464 (5)	0.81057 (18)	0.0433 (8)
C2	0.5499 (3)	0.0443 (5)	0.79170 (18)	0.0430 (8)
C3	0.5594 (3)	−0.0351 (5)	0.71896 (19)	0.0437 (8)
C4	0.4642 (3)	−0.1088 (5)	0.66424 (19)	0.0465 (9)
C5	0.3667 (3)	−0.1089 (6)	0.6856 (2)	0.0527 (10)
H5	0.3044	−0.1609	0.6519	0.063*
C6	0.3570 (3)	−0.0321 (5)	0.7579 (2)	0.0486 (9)
H6	0.2886	−0.0351	0.7697	0.058*
C7	0.4348 (3)	0.1264 (5)	0.8830 (2)	0.0471 (9)
C8	0.4198 (3)	0.1887 (5)	0.94134 (19)	0.0499 (9)
C9	0.3987 (3)	0.2616 (5)	1.01131 (18)	0.0440 (8)
C10	0.4800 (3)	0.3453 (5)	1.0694 (2)	0.0505 (9)
H10	0.5515	0.3575	1.0636	0.061*
C11	0.4541 (3)	0.4102 (6)	1.1357 (2)	0.0549 (10)
H11	0.5101	0.4652	1.1740	0.066*
C12	0.2776 (4)	0.3207 (6)	1.0921 (2)	0.0570 (11)
H12	0.2069	0.3114	1.0997	0.068*
C13	0.2930 (3)	0.2518 (6)	1.0233 (2)	0.0546 (10)
H13	0.2346	0.2001	0.9857	0.065*
C14	0.4766 (3)	−0.1775 (5)	0.5900 (2)	0.0505 (9)
C15	0.4958 (4)	−0.2288 (6)	0.5320 (2)	0.0568 (10)
C16	0.5251 (4)	−0.2938 (5)	0.4627 (2)	0.0512 (10)
C17	0.6354 (4)	−0.3077 (7)	0.4619 (2)	0.0691 (13)
H17	0.6912	−0.2716	0.5056	0.083*
C18	0.6621 (4)	−0.3758 (7)	0.3957 (3)	0.0696 (13)
H18	0.7366	−0.3884	0.3970	0.084*
C19	0.4815 (4)	−0.4092 (6)	0.3322 (2)	0.0585 (11)
H19	0.4271	−0.4429	0.2872	0.070*
C20	0.4473 (4)	−0.3482 (6)	0.3954 (2)	0.0553 (10)
H20	0.3720	−0.3434	0.3930	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0588 (6)	0.0885 (9)	0.0556 (6)	−0.0093 (6)	0.0202 (5)	−0.0071 (6)
N1	0.060 (2)	0.062 (2)	0.0436 (16)	−0.0068 (17)	0.0174 (15)	−0.0061 (16)
N2	0.059 (2)	0.065 (2)	0.0465 (17)	0.0000 (17)	0.0244 (15)	−0.0019 (16)
N3	0.065 (2)	0.062 (2)	0.0410 (16)	−0.0010 (17)	0.0268 (15)	−0.0132 (15)
N4	0.088 (3)	0.063 (2)	0.0387 (16)	−0.008 (2)	0.0314 (17)	−0.0103 (16)
C1	0.059 (2)	0.045 (2)	0.0295 (15)	0.0048 (18)	0.0184 (15)	0.0021 (15)
C2	0.057 (2)	0.045 (2)	0.0288 (15)	0.0010 (17)	0.0154 (15)	−0.0001 (14)
C3	0.058 (2)	0.045 (2)	0.0334 (16)	0.0006 (17)	0.0196 (15)	0.0009 (15)
C4	0.064 (2)	0.048 (2)	0.0318 (16)	0.0004 (18)	0.0209 (16)	−0.0027 (15)
C5	0.064 (2)	0.059 (2)	0.0358 (18)	−0.008 (2)	0.0136 (17)	−0.0076 (17)
C6	0.054 (2)	0.058 (2)	0.0376 (18)	0.0000 (19)	0.0192 (16)	−0.0013 (17)
C7	0.059 (2)	0.051 (2)	0.0364 (17)	0.0083 (18)	0.0213 (16)	0.0000 (16)
C8	0.065 (2)	0.056 (2)	0.0314 (16)	0.009 (2)	0.0177 (16)	0.0023 (16)
C9	0.058 (2)	0.048 (2)	0.0283 (15)	0.0090 (18)	0.0161 (15)	−0.0022 (15)
C10	0.046 (2)	0.067 (3)	0.0414 (18)	0.0070 (19)	0.0171 (16)	−0.0042 (18)
C11	0.058 (2)	0.074 (3)	0.0323 (16)	−0.003 (2)	0.0111 (16)	−0.0126 (18)
C12	0.059 (2)	0.069 (3)	0.050 (2)	−0.004 (2)	0.0256 (19)	−0.012 (2)
C13	0.062 (2)	0.062 (3)	0.0407 (19)	−0.005 (2)	0.0153 (17)	−0.0148 (18)
C14	0.071 (3)	0.048 (2)	0.0402 (18)	−0.0020 (19)	0.0272 (18)	−0.0034 (16)
C15	0.082 (3)	0.052 (2)	0.0410 (19)	−0.003 (2)	0.0252 (19)	0.0011 (18)
C16	0.083 (3)	0.043 (2)	0.0341 (17)	0.000 (2)	0.0273 (18)	−0.0008 (16)
C17	0.082 (3)	0.089 (4)	0.040 (2)	−0.024 (3)	0.021 (2)	−0.017 (2)
C18	0.078 (3)	0.085 (4)	0.058 (3)	−0.016 (3)	0.040 (2)	−0.013 (2)
C19	0.087 (3)	0.057 (3)	0.0312 (17)	0.010 (2)	0.0151 (19)	−0.0051 (17)
C20	0.065 (2)	0.065 (3)	0.0363 (18)	0.014 (2)	0.0147 (17)	−0.0041 (18)

Geometric parameters (Å, º)

S1—N1	1.611 (3)	C8—C9	1.429 (4)
S1—N2	1.613 (4)	C9—C10	1.386 (5)
N1—C2	1.338 (5)	C9—C13	1.391 (5)
N2—C3	1.334 (5)	C10—C11	1.375 (5)
N3—C12	1.318 (5)	C10—H10	0.9300
N3—C11	1.329 (5)	C11—H11	0.9300
N4—C19	1.324 (5)	C12—C13	1.372 (5)
N4—C18	1.329 (5)	C12—H12	0.9300
C1—C6	1.376 (5)	C13—H13	0.9300
C1—C2	1.424 (5)	C14—C15	1.170 (5)
C1—C7	1.444 (4)	C15—C16	1.442 (5)
C2—C3	1.441 (4)	C16—C20	1.378 (5)
C3—C4	1.430 (5)	C16—C17	1.385 (6)
C4—C5	1.365 (5)	C17—C18	1.387 (5)
C4—C14	1.445 (4)	C17—H17	0.9300
C5—C6	1.426 (5)	C18—H18	0.9300
C5—H5	0.9300	C19—C20	1.367 (5)
C6—H6	0.9300	C19—H19	0.9300
C7—C8	1.183 (4)	C20—H20	0.9300
N1—S1—N2	100.83 (17)	C11—C10—H10	120.2
C2—N1—S1	106.7 (2)	C9—C10—H10	120.2
C3—N2—S1	106.5 (2)	N3—C11—C10	124.0 (4)
C12—N3—C11	115.5 (3)	N3—C11—H11	118.0
C19—N4—C18	116.1 (3)	C10—C11—H11	118.0
C6—C1—C2	117.6 (3)	N3—C12—C13	126.0 (4)
C6—C1—C7	121.7 (3)	N3—C12—H12	117.0
C2—C1—C7	120.7 (3)	C13—C12—H12	117.0
N1—C2—C1	127.1 (3)	C12—C13—C9	118.0 (4)
N1—C2—C3	112.8 (3)	C12—C13—H13	121.0
C1—C2—C3	120.2 (3)	C9—C13—H13	121.0
N2—C3—C4	126.3 (3)	C15—C14—C4	174.4 (5)
N2—C3—C2	113.2 (3)	C14—C15—C16	177.1 (5)
C4—C3—C2	120.5 (3)	C20—C16—C17	116.7 (3)
C5—C4—C3	117.5 (3)	C20—C16—C15	122.9 (4)
C5—C4—C14	124.1 (4)	C17—C16—C15	120.4 (4)
C3—C4—C14	118.4 (3)	C16—C17—C18	119.6 (4)
C4—C5—C6	122.2 (4)	C16—C17—H17	120.2
C4—C5—H5	118.9	C18—C17—H17	120.2
C6—C5—H5	118.9	N4—C18—C17	123.3 (4)
C1—C6—C5	122.0 (4)	N4—C18—H18	118.4
C1—C6—H6	119.0	C17—C18—H18	118.4
C5—C6—H6	119.0	N4—C19—C20	124.7 (4)
C8—C7—C1	176.2 (4)	N4—C19—H19	117.6
C7—C8—C9	178.5 (5)	C20—C19—H19	117.6
C10—C9—C13	117.0 (3)	C19—C20—C16	119.5 (4)
C10—C9—C8	122.8 (3)	C19—C20—H20	120.2
C13—C9—C8	120.2 (4)	C16—C20—H20	120.2
C11—C10—C9	119.6 (3)
N2—S1—N1—C2	−0.5 (3)	C1—C7—C8—C9	8 (21)
N1—S1—N2—C3	0.7 (3)	C7—C8—C9—C10	169 (16)
S1—N1—C2—C1	−179.7 (3)	C7—C8—C9—C13	−12 (16)
S1—N1—C2—C3	0.1 (4)	C13—C9—C10—C11	1.4 (6)
C6—C1—C2—N1	−179.1 (4)	C8—C9—C10—C11	−179.1 (4)
C7—C1—C2—N1	0.2 (6)	C12—N3—C11—C10	−0.4 (6)
C6—C1—C2—C3	1.1 (5)	C9—C10—C11—N3	−0.3 (7)
C7—C1—C2—C3	−179.6 (3)	C11—N3—C12—C13	0.0 (7)
S1—N2—C3—C4	178.0 (3)	N3—C12—C13—C9	1.1 (7)
S1—N2—C3—C2	−0.7 (4)	C10—C9—C13—C12	−1.7 (6)
N1—C2—C3—N2	0.4 (5)	C8—C9—C13—C12	178.8 (4)
C1—C2—C3—N2	−179.8 (3)	C5—C4—C14—C15	178 (4)
N1—C2—C3—C4	−178.4 (3)	C3—C4—C14—C15	−1 (5)
C1—C2—C3—C4	1.4 (5)	C4—C14—C15—C16	31 (12)
N2—C3—C4—C5	178.1 (4)	C14—C15—C16—C20	160 (9)
C2—C3—C4—C5	−3.3 (5)	C14—C15—C16—C17	−18 (9)
N2—C3—C4—C14	−2.2 (6)	C20—C16—C17—C18	−0.7 (7)
C2—C3—C4—C14	176.4 (3)	C15—C16—C17—C18	178.0 (4)
C3—C4—C5—C6	2.7 (6)	C19—N4—C18—C17	−2.2 (7)
C14—C4—C5—C6	−177.0 (4)	C16—C17—C18—N4	2.5 (8)
C2—C1—C6—C5	−1.7 (6)	C18—N4—C19—C20	0.4 (7)
C7—C1—C6—C5	179.0 (3)	N4—C19—C20—C16	1.2 (7)
C4—C5—C6—C1	−0.2 (6)	C17—C16—C20—C19	−0.9 (6)
C6—C1—C7—C8	4 (6)	C15—C16—C20—C19	−179.6 (4)
C2—C1—C7—C8	−175 (6)

(II) 4,7-bis[(4-pyridinium)ethynyl]-2,1,3-benzothiadiazole diperchlorate

Crystal data

C20H12N4S^2+·2ClO4^−	F(000) = 1096
Mr = 539.30	Dx = 1.608 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54178 Å
a = 5.1097 (3) Å	Cell parameters from 25 reflections
b = 24.4522 (16) Å	θ = 15.9–42.4°
c = 17.8489 (13) Å	µ = 4.02 mm^−1
β = 92.281 (5)°	T = 296 K
V = 2228.3 (3) Å^3	Plate, orange
Z = 4	0.35 × 0.15 × 0.05 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	2774 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.062
Graphite monochromator	θmax = 74.3°, θmin = 3.1°
ω–2θ scans	h = −6→6
Absorption correction: ψ scan (North et al., 1968)	k = 0→30
Tmin = 0.334, Tmax = 0.824	l = −22→0
4684 measured reflections	3 standard reflections every 120 min
4543 independent reflections	intensity decay: 0.4%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.061	Hydrogen site location: difference Fourier map
wR(F^2) = 0.205	All H-atom parameters refined
S = 1.00	w = 1/[σ^2(Fo^2) + (0.1212P)^2 + 0.9345P] where P = (Fo^2 + 2Fc^2)/3
4543 reflections	(Δ/σ)max < 0.001
364 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.37 e Å^−3

Special details

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

3.4016 (0.0073) x + 8.4890 (0.0485) y - 12.2532 (0.0277) z = 4.4493 (0.0309)

* 0.0029 (0.0034) N3 * 0.0067 (0.0032) C9 * -0.0050 (0.0037) C10 * 0.0003 (0.0038) C11 * -0.0011 (0.0035) C12 * -0.0037 (0.0035) C13

Rms deviation of fitted atoms = 0.0039

3.3987 (0.0053) x + 6.4008 (0.0261) y - 12.9448 (0.0142) z = 3.1741 (0.0130)

Angle to previous plane (with approximate e.s.d.) = 5.38 (1/4)

* -0.0324 (0.0024) S1 * -0.0075 (0.0032) N1 * 0.0010 (0.0032) N2 * 0.0132 (0.0036) C1 * 0.0289 (0.0040) C2 * 0.0283 (0.0039) C3 * 0.0190 (0.0036) C4 * -0.0377 (0.0041) C5 * -0.0128 (0.0040) C6

Rms deviation of fitted atoms = 0.0232

3.4307 (0.0078) x + 17.9292 (0.0352) y - 2.3964 (0.0406) z = 11.6039 (0.0294)

Angle to previous plane (with approximate e.s.d.) = 44.46 (0.17)

* 0.0004 (0.0035) N4 * -0.0078 (0.0035) C16 * -0.0024 (0.0040) C17 * 0.0062 (0.0042) C18 * -0.0108 (0.0035) C19 * 0.0144 (0.0037) C20

Rms deviation of fitted atoms = 0.0085

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
Cl1	0.0095 (2)	0.27338 (5)	0.26293 (6)	0.0502 (3)
Cl2	0.1575 (2)	0.38122 (4)	0.53621 (6)	0.0480 (3)
O1	0.2857 (7)	0.2713 (2)	0.2756 (2)	0.0826 (12)
O2	−0.1122 (8)	0.27617 (18)	0.3331 (2)	0.0737 (11)
O3	−0.0782 (8)	0.22629 (15)	0.2218 (2)	0.0738 (11)
O4	−0.0575 (9)	0.32089 (16)	0.2197 (2)	0.0773 (11)
O5	0.4337 (7)	0.38644 (16)	0.5441 (2)	0.0723 (11)
O6	0.0869 (7)	0.36157 (17)	0.4616 (2)	0.0712 (11)
O7	0.0369 (8)	0.43301 (17)	0.5439 (3)	0.0860 (13)
O8	0.0685 (9)	0.3431 (2)	0.5882 (3)	0.1015 (17)
S1	0.2860 (3)	0.46762 (5)	0.06362 (8)	0.0669 (4)
N1	0.5192 (8)	0.47523 (16)	0.1267 (2)	0.0572 (10)
N2	0.1687 (8)	0.52864 (16)	0.0604 (2)	0.0536 (10)
N3	1.6612 (8)	0.41586 (19)	0.3859 (2)	0.0563 (11)
H3	1.783 (13)	0.399 (2)	0.413 (4)	0.079 (19)*
N4	−0.6422 (8)	0.76057 (18)	−0.0713 (2)	0.0545 (10)
H4	−0.750 (12)	0.785 (3)	−0.097 (4)	0.09 (2)*
C1	0.6761 (8)	0.55280 (19)	0.2046 (2)	0.0458 (10)
C2	0.5133 (8)	0.52731 (18)	0.1481 (2)	0.0435 (9)
C3	0.3094 (8)	0.55849 (18)	0.1100 (2)	0.0429 (10)
C4	0.2712 (8)	0.61377 (18)	0.1280 (2)	0.0444 (10)
C5	0.4246 (10)	0.6368 (2)	0.1841 (3)	0.0546 (12)
H5	0.425 (10)	0.672 (2)	0.193 (3)	0.050 (14)*
C6	0.6303 (10)	0.6068 (2)	0.2213 (3)	0.0529 (11)
H6	0.743 (9)	0.6239 (18)	0.254 (2)	0.045 (12)*
C7	0.8839 (8)	0.5230 (2)	0.2425 (3)	0.0479 (10)
C8	1.0566 (9)	0.4987 (2)	0.2742 (3)	0.0485 (10)
C9	1.2644 (8)	0.47005 (17)	0.3130 (2)	0.0414 (9)
C10	1.3244 (10)	0.4170 (2)	0.2939 (3)	0.0525 (11)
H10	1.233 (10)	0.4023 (19)	0.260 (3)	0.050 (14)*
C11	1.5289 (11)	0.3904 (2)	0.3318 (3)	0.0579 (13)
H11	1.573 (10)	0.360 (2)	0.322 (3)	0.056 (15)*
C12	1.6093 (10)	0.4661 (2)	0.4067 (3)	0.0556 (12)
H12	1.710 (9)	0.4800 (19)	0.447 (3)	0.048 (13)*
C13	1.4108 (9)	0.4946 (2)	0.3715 (3)	0.0497 (11)
H13	1.384 (7)	0.5304 (16)	0.385 (2)	0.025 (9)*
C14	0.0728 (9)	0.64459 (19)	0.0872 (3)	0.0483 (10)
C15	−0.0881 (9)	0.67010 (19)	0.0523 (3)	0.0510 (11)
C16	−0.2799 (8)	0.70171 (18)	0.0103 (2)	0.0440 (10)
C17	−0.3046 (11)	0.6964 (2)	−0.0669 (3)	0.0595 (13)
H17	−0.210 (12)	0.669 (2)	−0.090 (3)	0.082 (19)*
C18	−0.4878 (11)	0.7266 (3)	−0.1068 (3)	0.0641 (15)
H18	−0.483 (11)	0.727 (2)	−0.154 (3)	0.072 (18)*
C19	−0.6266 (10)	0.7669 (2)	0.0029 (3)	0.0514 (11)
H19	−0.751 (11)	0.791 (2)	0.024 (3)	0.067 (16)*
C20	−0.4410 (10)	0.7384 (2)	0.0448 (3)	0.0518 (11)
H20	−0.429 (9)	0.7397 (19)	0.094 (3)	0.048 (13)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0471 (6)	0.0586 (7)	0.0444 (6)	0.0004 (5)	−0.0055 (4)	0.0005 (5)
Cl2	0.0413 (5)	0.0453 (5)	0.0566 (6)	−0.0052 (4)	−0.0095 (4)	0.0056 (5)
O1	0.046 (2)	0.129 (4)	0.072 (3)	0.002 (2)	−0.0047 (18)	0.001 (2)
O2	0.072 (2)	0.102 (3)	0.048 (2)	0.014 (2)	0.0081 (17)	−0.001 (2)
O3	0.092 (3)	0.059 (2)	0.069 (2)	0.004 (2)	−0.020 (2)	−0.0066 (18)
O4	0.090 (3)	0.061 (2)	0.079 (3)	−0.011 (2)	−0.014 (2)	0.011 (2)
O5	0.0388 (18)	0.080 (3)	0.097 (3)	−0.0069 (17)	−0.0122 (18)	0.000 (2)
O6	0.065 (2)	0.086 (3)	0.061 (2)	0.0151 (19)	−0.0187 (18)	−0.0068 (19)
O7	0.069 (3)	0.063 (2)	0.125 (4)	0.008 (2)	−0.014 (2)	−0.022 (2)
O8	0.094 (3)	0.124 (4)	0.084 (3)	−0.052 (3)	−0.027 (2)	0.047 (3)
S1	0.0742 (9)	0.0495 (7)	0.0752 (9)	0.0038 (6)	−0.0179 (7)	−0.0041 (6)
N1	0.059 (2)	0.047 (2)	0.065 (3)	0.0106 (18)	−0.003 (2)	0.0064 (19)
N2	0.051 (2)	0.053 (2)	0.055 (2)	0.0023 (18)	−0.0121 (18)	−0.0009 (18)
N3	0.043 (2)	0.063 (3)	0.063 (3)	0.0074 (19)	−0.0073 (19)	0.026 (2)
N4	0.049 (2)	0.058 (2)	0.055 (2)	0.0085 (19)	−0.0082 (18)	0.015 (2)
C1	0.035 (2)	0.058 (3)	0.044 (2)	0.0069 (19)	−0.0057 (17)	0.012 (2)
C2	0.038 (2)	0.048 (2)	0.045 (2)	0.0045 (18)	−0.0019 (17)	0.0093 (19)
C3	0.035 (2)	0.047 (2)	0.046 (2)	0.0033 (18)	−0.0049 (17)	0.0096 (18)
C4	0.041 (2)	0.046 (2)	0.046 (2)	0.0052 (18)	−0.0055 (18)	0.0093 (19)
C5	0.059 (3)	0.046 (3)	0.058 (3)	0.008 (2)	−0.008 (2)	0.002 (2)
C6	0.046 (2)	0.057 (3)	0.054 (3)	0.000 (2)	−0.014 (2)	0.002 (2)
C7	0.034 (2)	0.061 (3)	0.049 (2)	0.0032 (19)	−0.0019 (18)	0.010 (2)
C8	0.042 (2)	0.053 (3)	0.050 (2)	0.003 (2)	−0.0042 (19)	0.010 (2)
C9	0.036 (2)	0.044 (2)	0.044 (2)	0.0052 (17)	0.0015 (17)	0.0094 (18)
C10	0.057 (3)	0.048 (3)	0.052 (3)	−0.001 (2)	−0.014 (2)	−0.002 (2)
C11	0.064 (3)	0.040 (3)	0.069 (3)	0.017 (2)	−0.001 (3)	0.004 (2)
C12	0.048 (3)	0.064 (3)	0.053 (3)	−0.010 (2)	−0.014 (2)	0.012 (2)
C13	0.051 (3)	0.046 (3)	0.051 (3)	0.002 (2)	−0.004 (2)	0.003 (2)
C14	0.041 (2)	0.050 (3)	0.053 (3)	0.0049 (19)	−0.0048 (19)	0.007 (2)
C15	0.048 (2)	0.049 (3)	0.056 (3)	0.004 (2)	−0.009 (2)	0.004 (2)
C16	0.039 (2)	0.046 (2)	0.046 (2)	0.0015 (18)	−0.0074 (18)	0.0050 (19)
C17	0.060 (3)	0.067 (3)	0.051 (3)	0.021 (3)	−0.003 (2)	−0.003 (2)
C18	0.057 (3)	0.095 (4)	0.039 (3)	0.006 (3)	−0.014 (2)	0.003 (3)
C19	0.046 (2)	0.047 (3)	0.061 (3)	0.005 (2)	−0.002 (2)	0.002 (2)
C20	0.061 (3)	0.053 (3)	0.041 (2)	0.010 (2)	−0.006 (2)	−0.002 (2)

Geometric parameters (Å, º)

Cl1—O1	1.421 (4)	C4—C14	1.438 (6)
Cl1—O2	1.423 (4)	C5—C6	1.424 (7)
Cl1—O3	1.428 (4)	C5—H5	0.87 (5)
Cl1—O4	1.429 (4)	C6—H6	0.91 (5)
Cl2—O8	1.405 (4)	C7—C8	1.188 (6)
Cl2—O7	1.417 (4)	C8—C9	1.428 (6)
Cl2—O5	1.418 (3)	C9—C10	1.378 (6)
Cl2—O6	1.447 (4)	C9—C13	1.395 (6)
S1—N2	1.608 (4)	C10—C11	1.385 (7)
S1—N1	1.617 (4)	C10—H10	0.83 (5)
N1—C2	1.330 (6)	C11—H11	0.80 (5)
N2—C3	1.335 (6)	C12—C13	1.362 (7)
N3—C12	1.314 (7)	C12—H12	0.94 (5)
N3—C11	1.314 (7)	C13—H13	0.92 (4)
N3—H3	0.88 (7)	C14—C15	1.188 (6)
N4—C18	1.324 (7)	C15—C16	1.435 (6)
N4—C19	1.332 (6)	C16—C20	1.379 (6)
N4—H4	0.91 (6)	C16—C17	1.385 (7)
C1—C6	1.375 (7)	C17—C18	1.370 (7)
C1—C2	1.426 (6)	C17—H17	0.93 (6)
C1—C7	1.434 (6)	C18—H18	0.84 (6)
C2—C3	1.440 (5)	C19—C20	1.374 (7)
C3—C4	1.405 (6)	C19—H19	0.95 (6)
C4—C5	1.367 (7)	C20—H20	0.88 (5)
O1—Cl1—O2	109.2 (2)	C1—C6—H6	118 (3)
O1—Cl1—O3	110.0 (3)	C5—C6—H6	120 (3)
O2—Cl1—O3	110.6 (3)	C8—C7—C1	179.4 (6)
O1—Cl1—O4	109.2 (3)	C7—C8—C9	179.3 (6)
O2—Cl1—O4	109.5 (3)	C10—C9—C13	118.1 (4)
O3—Cl1—O4	108.3 (2)	C10—C9—C8	120.6 (4)
O8—Cl2—O7	112.1 (3)	C13—C9—C8	121.2 (4)
O8—Cl2—O5	110.0 (3)	C9—C10—C11	119.5 (5)
O7—Cl2—O5	110.2 (2)	C9—C10—H10	118 (3)
O8—Cl2—O6	108.2 (3)	C11—C10—H10	123 (3)
O7—Cl2—O6	107.0 (3)	N3—C11—C10	119.6 (5)
O5—Cl2—O6	109.4 (2)	N3—C11—H11	118 (4)
N2—S1—N1	100.4 (2)	C10—C11—H11	123 (4)
C2—N1—S1	106.6 (3)	N3—C12—C13	120.1 (5)
C3—N2—S1	107.1 (3)	N3—C12—H12	117 (3)
C12—N3—C11	123.1 (4)	C13—C12—H12	123 (3)
C12—N3—H3	115 (4)	C12—C13—C9	119.6 (5)
C11—N3—H3	121 (4)	C12—C13—H13	118 (2)
C18—N4—C19	122.4 (4)	C9—C13—H13	122 (2)
C18—N4—H4	121 (4)	C15—C14—C4	178.7 (5)
C19—N4—H4	116 (4)	C14—C15—C16	179.1 (5)
C6—C1—C2	118.2 (4)	C20—C16—C17	118.2 (4)
C6—C1—C7	121.0 (4)	C20—C16—C15	121.6 (4)
C2—C1—C7	120.7 (4)	C17—C16—C15	120.1 (4)
N1—C2—C1	127.1 (4)	C18—C17—C16	120.0 (5)
N1—C2—C3	113.3 (4)	C18—C17—H17	121 (4)
C1—C2—C3	119.6 (4)	C16—C17—H17	119 (4)
N2—C3—C4	127.0 (4)	N4—C18—C17	119.8 (5)
N2—C3—C2	112.6 (4)	N4—C18—H18	121 (4)
C4—C3—C2	120.4 (4)	C17—C18—H18	119 (4)
C5—C4—C3	118.9 (4)	N4—C19—C20	119.7 (5)
C5—C4—C14	121.8 (4)	N4—C19—H19	117 (3)
C3—C4—C14	119.3 (4)	C20—C19—H19	123 (3)
C4—C5—C6	121.4 (5)	C16—C20—C19	119.9 (5)
C4—C5—H5	123 (3)	C16—C20—H20	117 (3)
C6—C5—H5	115 (3)	C19—C20—H20	123 (3)
C1—C6—C5	121.5 (5)
N2—S1—N1—C2	0.0 (4)	C1—C7—C8—C9	19 (96)
N1—S1—N2—C3	−0.3 (4)	C7—C8—C9—C10	168 (100)
S1—N1—C2—C1	177.6 (4)	C7—C8—C9—C13	−11 (54)
S1—N1—C2—C3	0.3 (5)	C13—C9—C10—C11	−1.3 (7)
C6—C1—C2—N1	−176.7 (5)	C8—C9—C10—C11	179.2 (5)
C7—C1—C2—N1	4.0 (7)	C12—N3—C11—C10	0.1 (8)
C6—C1—C2—C3	0.5 (7)	C9—C10—C11—N3	0.7 (8)
C7—C1—C2—C3	−178.8 (4)	C11—N3—C12—C13	−0.2 (8)
S1—N2—C3—C4	−177.8 (4)	N3—C12—C13—C9	−0.4 (8)
S1—N2—C3—C2	0.4 (5)	C10—C9—C13—C12	1.2 (7)
N1—C2—C3—N2	−0.5 (6)	C8—C9—C13—C12	−179.3 (4)
C1—C2—C3—N2	−178.0 (4)	C5—C4—C14—C15	105 (24)
N1—C2—C3—C4	177.9 (4)	C3—C4—C14—C15	−75 (24)
C1—C2—C3—C4	0.3 (7)	C4—C14—C15—C16	−75 (48)
N2—C3—C4—C5	175.7 (5)	C14—C15—C16—C20	−72 (35)
C2—C3—C4—C5	−2.3 (7)	C14—C15—C16—C17	107 (35)
N2—C3—C4—C14	−4.3 (7)	C20—C16—C17—C18	−0.9 (8)
C2—C3—C4—C14	177.6 (4)	C15—C16—C17—C18	180.0 (5)
C3—C4—C5—C6	3.5 (8)	C19—N4—C18—C17	0.1 (9)
C14—C4—C5—C6	−176.4 (5)	C16—C17—C18—N4	−0.4 (9)
C2—C1—C6—C5	0.6 (7)	C18—N4—C19—C20	1.5 (8)
C7—C1—C6—C5	180.0 (5)	C17—C16—C20—C19	2.5 (7)
C4—C5—C6—C1	−2.7 (8)	C15—C16—C20—C19	−178.4 (5)
C6—C1—C7—C8	−3 (60)	N4—C19—C20—C16	−2.8 (8)
C2—C1—C7—C8	177 (100)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···O6^i	0.88 (7)	1.97 (7)	2.843 (5)	171 (4)
N4—H4···O8^ii	0.91 (6)	2.18 (6)	2.975 (6)	145 (5)
C5—H5···O3^iii	0.87 (5)	2.73 (5)	3.314 (7)	126 (3)
C10—H10···O4^iv	0.83 (5)	2.57 (5)	3.299 (7)	148 (3)
C11—H11···O1^iv	0.80 (5)	2.73 (5)	3.307 (7)	131 (4)
C11—H11···O2^i	0.80 (5)	2.61 (5)	3.341 (6)	153 (4)
C12—H12···O7^v	0.94 (5)	2.49 (5)	3.162 (7)	129 (3)
C12—H12···O7^i	0.94 (5)	2.62 (5)	3.317 (7)	132 (3)
C13—H13···O5^v	0.92 (4)	2.55 (4)	3.358 (6)	147 (2)
C13—H13···O7^vi	0.92 (4)	2.69 (4)	3.306 (7)	125 (2)
C17—H17···O4^vii	0.93 (6)	2.74 (6)	3.382 (7)	127 (4)
C18—H18···O1^vii	0.84 (6)	2.43 (6)	3.223 (7)	157 (4)
C18—H18···O3^viii	0.84 (6)	2.75 (6)	3.177 (6)	113 (4)
C18—H18···O4^viii	0.84 (6)	2.84 (6)	3.230 (7)	110 (4)
C19—H19···O2^ii	0.95 (6)	2.69 (5)	3.273 (6)	120 (3)
C19—H19···O6^ii	0.95 (6)	2.46 (6)	3.378 (7)	162 (3)
C19—H19···O8^ii	0.95 (6)	2.84 (5)	3.305 (6)	111 (3)
C20—H20···O1^iii	0.88 (5)	2.54 (5)	3.370 (7)	159 (3)
C20—H20···O2^ii	0.88 (5)	2.87 (5)	3.348 (6)	116 (3)

Symmetry codes: (i) x+2, y, z; (ii) −x−1, y+1/2, −z+1/2; (iii) −x, y+1/2, −z+1/2; (iv) x+1, y, z; (v) −x+2, −y+1, −z+1; (vi) −x+1, −y+1, −z+1; (vii) −x, −y+1, −z; (viii) −x−1, −y+1, −z.