Isophthalic acid–3,6-bis­(2-pyrazin­yl)-1,4-dihydro-1,2,4,5-tetra­zine (1/1)

The cocrystallization of isophthalic acid (H₂ip) with 3,6-bis­(2-pyrazin­yl)-1,4-dihydro-1,2,4,5-tetra­zine (H₂bpztz) yields the title binary mol­ecular cocrystal, C₈H₆O₄·C₁₀H₈N₈ or [(H₂ip)·(H₂bpztz)]. In the isophthalic acid molecule, a crystallographic twofold rotation axis passes between the carboxyl substituents. In the tricyclic molecule, a crystallographic twofold rotation axis is perpendicular to the central ring. Inter­molecular O—H...N and C—H...O inter­actions between the carboxyl and pyrazinyl groups of the two components produces a one-dimensional zigzag tape. Further N—H...N hydrogen bonds between adjacent H₂bpztz mol­ecules generate a three-dimensional supra­molecular network. The resulting diamond networks are of fivefold parallel inter­penetration and are consolidated by π–π stacking inter­actions (3.70 Å) between the aromatic rings.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.041
• wR factor = 0.106
• Data-to-parameter ratio = 10.8

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.764     1.000
            Tmin(prime) and Tmax expected:      0.962     0.993
            RR(prime) =      0.788
            Please check that your absorption correction is appropriate.
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.79
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.19 Ratio
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          2
              C8 H6 O4

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Crystal engineering for the design and assembly of crystalline supramolecular solids is of current interest (Desiraju, 1989). In this regard, it is well known that weak interactions such as hydrogen bonding play an important role in regulating the final crystal packing (Etter, 1990; Steiner, 2002). Aromatic dicarboxylic acids, as robust hydrogen bonding participators, are widely used in the range of cocrystallization with complementary basic organic components to produce binary cocrystals with intriguing network structures (Du et al., 2005, and references therein). As a result, the pyridyl ring prefers to create the familiar carboxyl-pyridyl heterosynthon [denoted as R₂²(7)] with the carboxylic acid moiety. In this work, for the sake of further understanding the direction of hydrogen-bonding in such supramolecular frameworks, a multifunctional building block, namely 1,4-dihydro-3,6-bis(2-pyrazinyl)-1,2,4,5-tetrazine (H₂bpztz), is introduced to assemble with isophthalic acid (H₂ip). The resultant 1:1 binary cocrystal [(H₂ip).(H₂bpztz)], (I), exhibits a novel 3-D hydrogen-bonding architecture of 5-fold interpenetrating (Batten, 2001) diamond networks.

X-ray structural analysis of (I) confirms the expected 1:1 stoichiometry, as depicted in Figure 1, and both H₂ip and H₂bpztz molecules are located at the 2-fold axes. As for isophthalic acid, two carboxyl groups are located in a cis-arrangement in order to self-adjust the generation of the favorite hydrogen-bonded patterns. Within each H₂bpztz molecule, two terminal pyrazinyl planes make the dihedral angle of 26.5 (1)° with the central 6-member distorted ring, and are inclined to each other by 53.0 (1)°. As anticipated, each pyrazinyl group of H₂bpztz is connected to the carboxyl of H₂ip via the O1—H1···N2 and C6—H6···O2 interactions [heterosynthon R₂²(7), see Table 1 for details], giving a 1-D zigzag hydrogen-bonded tape along [010]. Further, the adjacent H₂bpztz molecules are linked by a pair of N4—H4A···N1 bonds between the imido and pyrazinyl groups [R₂²(10), see Table 1 for details], featuring another 1-D ribbon array along the [100] direction. The detailed hydrogen-bonding surroundings are shown in Figure 2. Due to the nonplanar folded configuration of the H₂bpztz molecule, such hydrogen-bonding interactions interlink the two components to form a 3-D supramolecular structure. From the viewpoint of network topology, if each H₂bpztz building block is considered as a tetrahedral node, a familiar diamond network is realised (Wells, 1977). The scale of the molecular components suggests that the dimensions of the channels (along the [100] direction) in this network are as large as ca 19 × 19 Å. As a consequence, this hydrogen-bonding set in turn is entangled by other four parallel ones, which thus generates a novel 5-fold interpenetrating architecture (Figure 3). Further analysis of crystal packing reveals significant π···π stacking interactions between the pyrazinyl as well as phenyl rings and their counterparts at (x, y, z - 1), with the centroid-to-centroid distance of ca 3.70 Å.

Related literature

For related literature, see: Batten (2001); Desiraju (1989); Du et al. (2005, and references therein); Etter (1990); Sarkar et al. (2003); Steiner (2002); Wells (1977).

S2. Experimental

1,4-Dihydro-3,6-bis(2-pyrazinyl)-1,2,4,5-tetrazine (H₂bpztz) was synthesized according to the literature procedure (Sarkar et al., 2003). A C₂H₅OH (5 ml) solution of isophthalic acid (16.6 mg, 0.1 mmol) was carefully layered onto a CHCl₃ (10 ml) solution of H₂bpztz (23.8 mg, 0.1 mmol) in a test tube. Orange prism crystals suitable for X-ray diffraction were observed on the tube wall over a period of 3 weeks. Yield: 28.4 mg (70%). Anal. Calcd for C₁₈H₁₄N₈O₄: C, 53.20; H, 3.47; N, 27.58%. Found: C, 53.17; H, 3.44; N, 27.69%. IR (KBr pellet, cm^-1): 3338(m), 1705(s).

S3. Refinement

There was no evidence of crystal decay during data collection. The space group Pnna was uniquely assigned from the systematic absences. All H atoms were visible in difference maps. C– and N-bound H atoms were placed at the calculated positions, with C—H and N—H distances of 0.93 and 0.91 Å, and treated as riding. O-bound H atoms of carboxyl were refined as rigid groups, allowed to rotate but not tip with O—H = 0.82 Å. The U_iso(H) values were set to 1.2 (for C and N) or 1.5 (for O) U_eq with regard to their parent atoms.

Computing details

Data collection: APEX2 (Bruker, 2003); cell refinement: APEX2 and SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL (Bruker, 2001).

Figures

	Fig. 1. Molecular structure of (I) with atom labeling, shown with 30% probability displacement ellipsoids. Symmetry codes: (i) x, 0.5 - y, -0.5 - z; (ii) 1.5 - x, -y, z.
	Fig. 2. Portion view of (I) showing the hydrogen bonding interactions (indicated as broken lines). Irrelevant hydrogen atoms were omitted for clarity. Symmetry codes: (i) -1/2 + x, y, 2 - z; (ii) 1 - x, -y, 2 - z; (iii) 1.5 - x, -y, z; (iv) 2 - x, -y, 2 - z; (v) 1/2 + x, y, 2 - z.
	Fig. 3. Schematic illustration of the 5-fold interpenetrating hydrogen-bonding networks in (I).

Isophthalic acid–3,6-bis(2-pyrazinyl)-1,4-dihydro-1,2,4,5-tetrazine (1/1)

Crystal data

C8H6O4·C10H8N8	F(000) = 840
Mr = 406.37	Dx = 1.599 Mg m^−3
Orthorhombic, Pnna	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2a 2bc	Cell parameters from 650 reflections
a = 13.546 (4) Å	θ = 3.0–19.8°
b = 33.654 (11) Å	µ = 0.12 mm^−1
c = 3.7035 (12) Å	T = 294 K
V = 1688.3 (9) Å^3	Prism, orange
Z = 4	0.32 × 0.10 × 0.06 mm

Data collection

Bruker APEX II CCD area-detector diffractometer	1501 independent reflections
Radiation source: fine-focus sealed tube	937 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.080
φ and ω scans	θmax = 25.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→16
Tmin = 0.764, Tmax = 1.000	k = −39→33
8125 measured reflections	l = −4→4

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.041	H-atom parameters constrained
wR(F^2) = 0.106	w = 1/[σ^2(Fo^2) + (0.0447P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
1501 reflections	Δρmax = 0.21 e Å^−3
139 parameters	Δρmin = −0.22 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0076 (13)

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. 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
O1	0.67031 (11)	0.18838 (5)	0.0948 (5)	0.0422 (5)
H1	0.6458	0.1681	0.1792	0.063*
O2	0.80749 (12)	0.15240 (5)	0.1263 (5)	0.0483 (6)
N1	0.52754 (13)	0.05363 (6)	0.7689 (5)	0.0301 (5)
N2	0.59035 (13)	0.12361 (5)	0.4414 (5)	0.0319 (5)
N3	0.78628 (13)	0.03824 (6)	0.8292 (5)	0.0303 (5)
N4	0.84163 (13)	0.00538 (5)	0.9555 (5)	0.0309 (5)
H4A	0.9065	0.0088	0.9066	0.037*
C1	0.76590 (17)	0.18285 (7)	0.0449 (7)	0.0308 (6)
C2	0.81727 (16)	0.21766 (6)	−0.1118 (6)	0.0264 (6)
C3	0.91976 (16)	0.21782 (7)	−0.1134 (6)	0.0323 (6)
H3	0.9542	0.1961	−0.0221	0.039*
C4	0.9707 (2)	0.2500	−0.2500	0.0356 (9)
H4	1.0394	0.2500	−0.2500	0.043*
C5	0.7662 (2)	0.2500	−0.2500	0.0284 (8)
H5	0.6975	0.2500	−0.2500	0.034*
C6	0.65414 (17)	0.09648 (6)	0.5560 (7)	0.0300 (6)
H6	0.7214	0.1011	0.5274	0.036*
C7	0.49510 (17)	0.11597 (7)	0.4964 (7)	0.0327 (6)
H7	0.4482	0.1345	0.4224	0.039*
C8	0.46425 (17)	0.08145 (7)	0.6598 (7)	0.0326 (6)
H8	0.3970	0.0774	0.6953	0.039*
C9	0.62340 (16)	0.06147 (7)	0.7171 (6)	0.0246 (6)
C10	0.69377 (15)	0.03110 (7)	0.8372 (6)	0.0245 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0314 (10)	0.0310 (11)	0.0641 (13)	0.0014 (8)	0.0053 (9)	0.0152 (10)
O2	0.0419 (11)	0.0300 (11)	0.0729 (15)	0.0081 (9)	0.0023 (9)	0.0182 (10)
N1	0.0262 (10)	0.0273 (12)	0.0368 (12)	0.0003 (10)	0.0014 (9)	0.0023 (9)
N2	0.0321 (11)	0.0228 (11)	0.0407 (13)	0.0029 (9)	0.0036 (9)	0.0036 (10)
N3	0.0246 (10)	0.0220 (11)	0.0445 (13)	0.0036 (9)	−0.0009 (9)	−0.0016 (10)
N4	0.0225 (10)	0.0234 (11)	0.0467 (13)	0.0019 (9)	−0.0062 (9)	−0.0062 (10)
C1	0.0319 (14)	0.0288 (14)	0.0316 (15)	0.0006 (12)	−0.0031 (11)	−0.0005 (11)
C2	0.0319 (13)	0.0226 (13)	0.0247 (14)	0.0009 (10)	−0.0011 (10)	−0.0002 (11)
C3	0.0333 (14)	0.0299 (15)	0.0336 (16)	0.0046 (11)	−0.0021 (11)	−0.0005 (12)
C4	0.0298 (18)	0.034 (2)	0.043 (2)	0.000	0.000	−0.0006 (18)
C5	0.0267 (17)	0.030 (2)	0.0282 (19)	0.000	0.000	−0.0026 (15)
C6	0.0271 (13)	0.0244 (13)	0.0385 (15)	−0.0001 (11)	0.0033 (11)	0.0014 (12)
C7	0.0309 (14)	0.0299 (14)	0.0374 (15)	0.0067 (12)	0.0015 (11)	0.0041 (12)
C8	0.0252 (12)	0.0315 (15)	0.0411 (16)	0.0037 (12)	0.0014 (11)	0.0054 (13)
C9	0.0255 (12)	0.0210 (13)	0.0273 (13)	0.0010 (10)	0.0014 (10)	−0.0023 (10)
C10	0.0254 (12)	0.0220 (13)	0.0260 (14)	−0.0008 (11)	0.0026 (10)	−0.0017 (11)

Geometric parameters (Å, º)

O1—C1	1.321 (3)	C3—C4	1.380 (3)
O1—H1	0.8200	C3—H3	0.9300
O2—C1	1.208 (3)	C4—C3^ii	1.380 (3)
N1—C8	1.332 (3)	C4—H4	0.9300
N1—C9	1.339 (3)	C5—C2^ii	1.388 (3)
N2—C6	1.327 (3)	C5—H5	0.9300
N2—C7	1.331 (3)	C6—C9	1.385 (3)
N3—C10	1.276 (3)	C6—H6	0.9300
N3—N4	1.416 (2)	C7—C8	1.375 (3)
N4—C10^i	1.389 (3)	C7—H7	0.9300
N4—H4A	0.9051	C8—H8	0.9300
C1—C2	1.481 (3)	C9—C10	1.467 (3)
C2—C5	1.388 (3)	C10—N4^i	1.389 (3)
C2—C3	1.388 (3)
C1—O1—H1	109.5	C2^ii—C5—C2	120.2 (3)
C8—N1—C9	116.2 (2)	C2^ii—C5—H5	119.9
C6—N2—C7	116.7 (2)	C2—C5—H5	119.9
C10—N3—N4	111.42 (19)	N2—C6—C9	121.8 (2)
C10^i—N4—N3	113.79 (16)	N2—C6—H6	119.1
C10^i—N4—H4A	112.6	C9—C6—H6	119.1
N3—N4—H4A	110.4	N2—C7—C8	121.7 (2)
O2—C1—O1	122.8 (2)	N2—C7—H7	119.2
O2—C1—C2	123.4 (2)	C8—C7—H7	119.2
O1—C1—C2	113.8 (2)	N1—C8—C7	122.1 (2)
C5—C2—C3	119.6 (2)	N1—C8—H8	118.9
C5—C2—C1	122.1 (2)	C7—C8—H8	118.9
C3—C2—C1	118.3 (2)	N1—C9—C6	121.4 (2)
C4—C3—C2	120.3 (2)	N1—C9—C10	116.7 (2)
C4—C3—H3	119.8	C6—C9—C10	121.9 (2)
C2—C3—H3	119.8	N3—C10—N4^i	120.8 (2)
C3^ii—C4—C3	120.0 (3)	N3—C10—C9	120.0 (2)
C3^ii—C4—H4	120.0	N4^i—C10—C9	119.16 (18)
C3—C4—H4	120.0
C10—N3—N4—C10^i	40.7 (2)	C9—N1—C8—C7	1.3 (3)
O2—C1—C2—C5	170.6 (2)	N2—C7—C8—N1	−0.6 (4)
O1—C1—C2—C5	−10.7 (3)	C8—N1—C9—C6	−0.5 (3)
O2—C1—C2—C3	−10.4 (4)	C8—N1—C9—C10	179.81 (19)
O1—C1—C2—C3	168.3 (2)	N2—C6—C9—N1	−0.9 (4)
C5—C2—C3—C4	0.3 (3)	N2—C6—C9—C10	178.7 (2)
C1—C2—C3—C4	−178.67 (17)	N4—N3—C10—N4^i	−0.7 (3)
C2—C3—C4—C3^ii	−0.16 (16)	N4—N3—C10—C9	179.97 (18)
C3—C2—C5—C2^ii	−0.16 (16)	N1—C9—C10—N3	−173.1 (2)
C1—C2—C5—C2^ii	178.8 (2)	C6—C9—C10—N3	7.3 (3)
C7—N2—C6—C9	1.5 (4)	N1—C9—C10—N4^i	7.6 (3)
C6—N2—C7—C8	−0.8 (4)	C6—C9—C10—N4^i	−172.1 (2)

Symmetry codes: (i) −x+3/2, −y, z; (ii) x, −y+1/2, −z−1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N2	0.82	1.94	2.752 (3)	172
N4—H4A···N1^iii	0.90	2.53	3.166 (3)	128
C6—H6···O2	0.93	2.56	3.223 (3)	129

Symmetry code: (iii) x+1/2, y, −z+2.