3,6-Di-2-pyridinio-1,2,4,5-tetrazine diperchlorate

The structure of the title compound, C₁₂H₁₀N₆²⁺·2ClO₄⁻, has a crystallographic center of symmetry. The pyridinium ring makes a dihedal angle of 26.4 (3)° with the mean plane of the central 1,2,4,5-tetrazine plane. The perchlorate anions link the cations to form a chain structure through C—H...O close contacts and N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.037
• wR factor = 0.116
• Data-to-parameter ratio = 11.4

checkCIF results

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ADDSYM reports no extra symmetry


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          _diffrn_standards_interval_time are missing. Number of measurements
          between standards or time (min) between standards.


 1 Alert Level A = Potentially serious problem

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S1. Comment

3,6-Di-2-pyridyl-1,2,4,5-tetrazine (Dptz) has been applied as a coordinative π-acceptor moiety in the study of photophysical and redox properties of transition metal complexes, and a bridging building block for supramolecular assemblies (Campos-Fernandez et al., 1999; Bu et al., 2000). This type of aromatic compounds also exhibit proton-sponge properties (Staab et al., 1988; Robertson et al., 1998), which can act as external proton acceptors through formation of N—H···Y hydrogen bonds. In the present paper, we report the crystal structure of the diprotonated salt of Dptz, namely 3,6-di-2-pyridinio-1,2,4,5-tetrazine, (I).

There is half a molecule in the asymmetric unit and the other half is inversion related (Fig. 1). The bond distances and angles (Table 1) agree with those of the structure of Dptz (Klein et al., 1998). The structure shows the expected trans configuration for the two pyridine groups. The pyridine ring makes a dihedal angle of 26.4 (3)° with the mean plane of the central 1,2,4,5-tetrazine plane (the value in the structure of Dptz molecule is 19.1°).

The perchlorate anions act as bridges to link the cations through hydrogen bonds, forming a chain structure as shown in Fig. 2. The C(N)···O and H···O separations, and the bond angles are listed in Table 2, which are in the normal range of the weak interactions (Sasada, 1984; Desiraju, 1991). The cations are stacked in the a direction with the closest approach between the pyridine and tetrazine ring of ca 4.0 Å, indicating no significant π···π stacking interactions.

S2. Experimental

Dptz was prepared following the literature procedure of Kaim & Kohlmann (1987). Crystals of (I) were obtained by slow diffusion of diethyl ether into an acetonitrile solution of Dptz in the presence of HClO₄.

S3. Refinement

H atoms were located by geometry and constrained.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Bruker, 1997).

Figures

	Fig. 1. ORTEPII (Johnson, 1976) view of diprotonated Dptz shown with 30% probability ellipsoids.
	Fig. 2. View of the one-dimensional chain in the crystal (irrelative H atoms have been omitted for clarity).

Diprotonated 3,6-di-2-pyridyl-1,2,4,5-tetrazine diperchlorate

Crystal data

C12H10N6^2+·2ClO4^−	Z = 1
Mr = 437.16	F(000) = 222
Triclinic, P1	Dx = 1.736 Mg m^−3
a = 5.6592 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.5549 (13) Å	Cell parameters from 1718 reflections
c = 8.7070 (14) Å	θ = 2.4–25.0°
α = 87.454 (3)°	µ = 0.45 mm^−1
β = 85.360 (3)°	T = 293 K
γ = 85.004 (3)°	Prism, red
V = 418.27 (11) Å^3	0.30 × 0.20 × 0.10 mm

Data collection

Bruker SMART 1000 diffractometer	1339 reflections with I > 2σ(I)
ω scans	Rint = 0.015
Absorption correction: multi-scan [SAINT (Bruker 1998) and SADABS (Sheldrick, 1997)]	θmax = 25.0°
Tmin = 0.877, Tmax = 0.957	h = −5→6
1726 measured reflections	k = −7→10
1454 independent reflections	l = −9→10

Refinement

Refinement on F^2	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.037	w = 1/[σ^2(Fo^2) + (0.0934P)^2 + 0.2332P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.117	(Δ/σ)max < 0.001
S = 0.89	Δρmax = 0.36 e Å^−3
1454 reflections	Δρmin = −0.26 e Å^−3
127 parameters

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.

Refinement. Full-MATRIX

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.16265 (9)	0.71966 (6)	0.83431 (6)	0.0408 (2)
N1	1.2307 (3)	0.4536 (2)	0.4571 (2)	0.0370 (4)
N2	1.1008 (3)	0.3547 (2)	0.5387 (2)	0.0379 (4)
N3	0.5438 (3)	0.3597 (2)	0.7588 (2)	0.0362 (4)
H3A	0.5227	0.4603	0.7625	0.043*
C1	0.8753 (4)	0.4054 (2)	0.5783 (2)	0.0336 (5)
O1	0.1435 (5)	0.8201 (3)	0.7020 (2)	0.0810 (7)
O2	0.0313 (4)	0.5867 (2)	0.8221 (2)	0.0673 (6)
O3	0.0840 (4)	0.8022 (3)	0.9678 (2)	0.0700 (6)
O4	0.4109 (3)	0.6686 (2)	0.8442 (3)	0.0706 (6)
C2	0.7289 (4)	0.2961 (2)	0.6694 (2)	0.0352 (5)
C3	0.7679 (4)	0.1365 (3)	0.6654 (3)	0.0464 (6)
H3B	0.8989	0.0904	0.6076	0.056*
C4	0.6095 (5)	0.0439 (3)	0.7488 (3)	0.0517 (6)
H4A	0.6320	−0.0649	0.7457	0.062*
C5	0.4197 (4)	0.1136 (3)	0.8359 (3)	0.0463 (6)
H5A	0.3108	0.0526	0.8905	0.056*
C6	0.3921 (4)	0.2734 (3)	0.8416 (3)	0.0418 (5)
H6A	0.2675	0.3218	0.9032	0.050*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0446 (4)	0.0335 (3)	0.0438 (4)	−0.0009 (2)	−0.0018 (2)	−0.0042 (2)
N1	0.0339 (9)	0.0337 (9)	0.0433 (10)	−0.0048 (7)	−0.0016 (7)	0.0029 (7)
N2	0.0370 (9)	0.0339 (9)	0.0426 (10)	−0.0048 (7)	−0.0025 (7)	0.0052 (7)
N3	0.0358 (9)	0.0320 (9)	0.0403 (9)	−0.0023 (7)	−0.0035 (7)	0.0038 (7)
C1	0.0359 (10)	0.0324 (10)	0.0333 (10)	−0.0060 (8)	−0.0054 (8)	0.0002 (8)
O1	0.1176 (19)	0.0633 (13)	0.0634 (13)	−0.0117 (12)	−0.0225 (12)	0.0192 (10)
O2	0.0782 (13)	0.0485 (10)	0.0805 (14)	−0.0201 (9)	−0.0232 (10)	−0.0020 (9)
O3	0.0680 (13)	0.0760 (13)	0.0659 (12)	−0.0143 (10)	0.0190 (10)	−0.0287 (10)
O4	0.0500 (11)	0.0606 (12)	0.1014 (16)	0.0066 (9)	−0.0087 (10)	−0.0223 (11)
C2	0.0352 (11)	0.0366 (11)	0.0336 (10)	−0.0048 (8)	−0.0021 (8)	0.0018 (8)
C3	0.0505 (13)	0.0355 (11)	0.0510 (13)	−0.0039 (10)	0.0098 (10)	−0.0006 (9)
C4	0.0596 (15)	0.0343 (12)	0.0596 (14)	−0.0068 (10)	0.0044 (12)	0.0043 (10)
C5	0.0458 (12)	0.0436 (12)	0.0491 (13)	−0.0115 (10)	0.0004 (10)	0.0103 (10)
C6	0.0337 (11)	0.0480 (13)	0.0422 (12)	−0.0030 (9)	0.0006 (9)	0.0074 (9)

Geometric parameters (Å, º)

Cl1—O3	1.4078 (18)	N3—C2	1.344 (3)
Cl1—O1	1.412 (2)	C1—N1^i	1.334 (3)
Cl1—O2	1.4244 (19)	C1—C2	1.468 (3)
Cl1—O4	1.443 (2)	C2—C3	1.366 (3)
N1—N2	1.316 (2)	C3—C4	1.387 (3)
N1—C1^i	1.334 (3)	C4—C5	1.372 (4)
N2—C1	1.334 (3)	C5—C6	1.365 (3)
N3—C6	1.328 (3)
O3—Cl1—O1	110.13 (15)	N1^i—C1—C2	116.56 (18)
O3—Cl1—O2	111.22 (13)	N2—C1—C2	117.15 (18)
O1—Cl1—O2	110.23 (14)	N3—C2—C3	119.29 (19)
O3—Cl1—O4	107.81 (13)	N3—C2—C1	116.83 (18)
O1—Cl1—O4	107.82 (15)	C3—C2—C1	123.9 (2)
O2—Cl1—O4	109.54 (12)	C2—C3—C4	119.1 (2)
N2—N1—C1^i	117.02 (17)	C5—C4—C3	119.7 (2)
N1—N2—C1	116.69 (17)	C6—C5—C4	119.3 (2)
C6—N3—C2	122.60 (19)	N3—C6—C5	119.9 (2)
N1^i—C1—N2	126.29 (18)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3a···O4	0.86	1.98	2.800 (3)	159
C6—H6a···O3^ii	0.93	2.50	3.149 (4)	127

Symmetry code: (ii) −x, −y+1, −z+2.