An independent refinement of H-atom coordinates from laboratory X-ray powder data in tetra­formaltrisazine

The structure of centrosymmetric tetra­formaltrisazine (systematic name: 1,2,3,4,5,6,7,8-octa­hydro-1,2,4,5-tetra­zino[1,2-a][1,2,4,5]tetra­zine), C₄H₁₂N₆, has been solved by simulated annealing from X-ray laboratory powder data and refined by Rietveld refinement without any restraints for non-H atoms. The coordinates of H atoms forming hydrogen bonds were refined independently. Tetra­formaltrisazine can be used as a biologically active compound.

Key indicators

• Powder X-ray study
• Mean [sigma](N-N) = 0.009 Å
• R factor = 0.000
• wR factor = 0.000
• Data-to-parameter ratio = 0.0

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT374_ALERT_2_A Long   N - N         Bond  N3     -   N3_a   ...       1.48 Ang.

Author Response: I think this distance is not too bad, regarding powder data.

Alert level B
PLAT241_ALERT_2_B Check High      Ueq as Compared to Neighbors for         N1
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for         C4

Alert level C
RADNW01_ALERT_1_C  The radiation wavelength lies outside the expected range
            for the supplied radiation type. Expected range 1.54175-1.54180
            Wavelength given =    1.54059

Author Response: The focusing monochromator strips only K\a~1~

PLAT087_ALERT_2_C Unsatisfactory S value (Too High) ..............       2.87

Alert level G
RADNT01_ALERT_1_G  Extra text has been found in the _diffrn_radiation_type field.
            Radiation given as Cu K\a~1~
            Radiation identified as Cu K\a
RADNW01_ALERT_1_G  The radiation wavelength given implies that Cu Kalpha1 has
            been used. Please check that this is correct.
            Wavelength given =    1.54059

Author Response: The focusing monochromator strips only K\a~1~

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

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

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Computing details

Data collection: HUBER G670 (HUBER Diffraktionstechnik GmbH, v. 4.3); cell refinement: MRIA (Zlokazov & Chernyshev, 1992); program(s) used to solve structure: MRIA; program(s) used to refine structure: MRIA; molecular graphics: PLUTON96 (Spek, 1996); software used to prepare material for publication: MRIA.

1,2,3,4,5,6,7,8-Octahydro-1,2,4,5-tetrazino[1,2-a][1,2,4,5]tetrazine

Crystal data

C4H12N6	F(000) = 156.0
Mr = 144.20	Dx = 1.375 Mg m^−3
Monoclinic, P21/n	Melting point = 488–490 K
Hall symbol: -P 2yn	Cu Kα1 radiation, λ = 1.54059 Å
a = 6.3243 (4) Å	µ = 0.81 mm^−1
b = 4.8633 (3) Å	T = 295 K
c = 11.3322 (9) Å	Particle morphology: lump-like
β = 92.042 (14)°	colourless
V = 348.32 (4) Å^3	flat_sheet, 15 × 15 mm
Z = 2	Specimen preparation: Prepared at 298 K

Data collection

Huber Guinier camera G670 diffractometer	Data collection mode: transmission
Radiation source: Fine focus sealed X-ray tube, Crystalloflex	Scan method: step
Focusing Ge monochromator	2θmin = 14.00°, 2θmax = 65.00°, 2θstep = 0.01°
Specimen mounting: pressed as a thin layer in the specimen holder of the camera

Refinement

Refinement on Inet	68 parameters
Least-squares matrix: full with fixed elements per cycle	0 restraints
Rwp = 0.025	0 constraints
Rexp = 0.008	H atoms treated by a mixture of independent and constrained refinement
RBragg = 0.019	Weighting scheme based on measured s.u.'s
6201 data points	(Δ/σ)max = 0.01
Excluded region(s): 3.00–13.99	Background function: Chebyshev polynomial up to the 5th order
Profile function: split-type pseudo-Voigt	Preferred orientation correction: none

Special details

Experimental. The mass spectrum was recorded on a Finnegan MAT90 in EI mode at 70 eV at 473 K. MS: [M⁺] m/z = 144 (36), 113 (22), 101 (25), 100 (41), 89 (31), 87 (99), 84 (10), 71 (25), 70 (37), 69 (7), 59 (15), 58 (13), 57 (100), 56 (53), 55 (25), 53 (17), 45 (51), 43 (36), 41 (37).

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

	x	y	z	Uiso*/Ueq
N1	0.0077 (10)	−0.2040 (11)	0.2101 (6)	0.0830 (6)*
N2	0.1578 (11)	−0.3412 (10)	0.1379 (6)	0.0766 (5)*
N3	−0.0640 (10)	0.0960 (12)	0.0350 (6)	0.0654 (5)*
C4	−0.1457 (10)	−0.0801 (12)	0.1307 (5)	0.0263 (5)*
C5	0.2479 (11)	−0.1941 (11)	0.0377 (6)	0.0550 (6)*
H1	0.078 (6)	−0.072 (7)	0.241 (3)	0.050*
H2	0.112 (6)	−0.503 (4)	0.123 (3)	0.050*
H4A	−0.2400	0.0305	0.1768	0.031*
H4B	−0.2299	−0.2259	0.0942	0.031*
H5A	0.3349	−0.3165	−0.0076	0.066*
H5B	0.3340	−0.0404	0.0654	0.066*

Geometric parameters (Å, º)

N1—N2	1.440 (15)	C4—H4A	0.9700
N1—C4	1.432 (9)	C4—H4B	0.9700
N1—H1	0.85 (4)	C5—H5A	0.9700
N2—C5	1.474 (9)	C5—H5B	0.9700
N2—H2	0.855 (15)	N3—N3^i	1.484 (9)
N3—C4	1.489 (9)	C5—N3^i	1.480 (9)
N2—N1—C4	106.5 (5)	N3—C4—H4B	108.0
N2—N1—H1	104 (2)	H4A—C4—H4B	107.3
C4—N1—H1	106 (2)	N2—C5—H5A	110.6
N1—N2—C5	119.6 (4)	N3^i—C5—H5A	110.6
N1—N2—H2	108 (3)	N2—C5—H5B	110.6
C5—N2—H2	116 (2)	N3^i—C5—H5B	110.6
N1—C4—N3	117.1 (3)	H5A—C5—H5B	108.8
N1—C4—H4A	108.0	C4—N3—N3^i	103.7 (5)
N3—C4—H4A	108.0	C4—N3—C5^i	107.7 (5)
N1—C4—H4B	108.0	C5^i—N3—N3^i	109.8 (6)

Symmetry code: (i) −x, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N2^ii	0.85 (4)	2.40 (4)	3.209 (9)	159 (3)
N2—H2···N3^iii	0.85 (2)	2.44 (3)	3.271 (8)	165 (3)

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