Structural verification of a tetrahydrotetrazole compound

Article abstract of DOI:10.1107/S2053229619010210

Tetrahydrotetrazoles are five-membered-ring heterocycles containing four contiguous saturated nitrogen atoms. Very few examples of such compounds have been reported in the literature. Our previous attempt at the synthesis of a member of this class of compound suggested that the N - N bonds may be more labile than expected. This finding raised the question as to whether the structures of any of the previously reported tetrahydrotetrazoles had been properly assigned. We have reproduced the synthesis of a reported tetrahydrotetrazole, namely 1,2-di-tert-butyl 3-phenyl-1H,2H,3H,10bH-[1,2,3,4]tetrazolo[5,1-a]isoquinoline-1,2-dicarboxylate, C25H30N4O4, and have now confidently confirmed its structure via X-ray crystallography. However, while sufficiently stable in the crystal phase, we discovered that it remains very labile in solution (having a half-life of only 15min at 20°C in CDCl3). A tentative reaction pathway for its dissociation based on ¹H NMR spectral evidence is provided.

Full text of DOI:10.1107/S2053229619010210

research papers
Structural verification of a tetrahydrotetrazole
compound
ISSN 2053-2296
Gary W. Breton,* Lauren A. Hahn and Kenneth L. Martin
Department of Chemistry and Biochemistry, Berry College, Mount Berry, GA 30149-5036, USA. *Correspondence
e-mail: gbreton@berry.edu
Received 8 May 2019
Accepted 17 July 2019
Tetrahydrotetrazoles are five-membered-ring heterocycles containing four
contiguous saturated nitrogen atoms. Very few examples of such compounds
have been reported in the literature. Our previous attempt at the synthesis of a
member of this class of compound suggested that the N—N bonds may be more
labile than expected. This finding raised the question as to whether the structures
of any of the previously reported tetrahydrotetrazoles had been properly
assigned. We have reproduced the synthesis of a reported tetrahydrotetrazole,
namely 1,2-di-tert-butyl 3-phenyl-1H,2H,3H,10bH-[1,2,3,4]tetrazolo[5,1-a]iso-
quinoline-1,2-dicarboxylate, C H N O , and have now confidently confirmed
Edited by H. Uekusa, Tokyo Institute of Tech-
nology, Japan
Keywords: tetrahydrotetrazole; tetrazolidine;
azimine; azo imide; crystal structure; azome-
thine imide.
CCDC reference: 1941061
25
30
4
4
its structure via X-ray crystallography. However, while sufficiently stable in the
crystal phase, we discovered that it remains very labile in solution (having a half-
Supporting information: this article has
supporting information at journals.iucr.org/c
ꢀ
life of only 15 min at 20 C in CDCl ). A tentative reaction pathway for its
3
1
dissociation based on H NMR spectral evidence is provided.
1
. Introduction
We recently investigated and reported upon a potential
synthetic route towards a little-investigated class of com-
pounds known as the tetrahydrotetrazoles (1) (Breton &
Martin, 2018). These compounds are characterized by having
single bonds between four contiguous saturated nitrogen
atoms present within a five-membered ring. Unlike carbon, its
neighbor in the periodic table, catenation of N atoms is
disfavored (L e´ gar e´ et al., 2019; Tang et al., 2013; Zhang &
Shreeve, 2013). Thus, it is not surprising that very few exam-
ples of tetrahydrotetrazoles have been reported in the litera-
ture (see representative examples in Fig. 1) (Bast et al., 1998;
Exner et al., 2000; Krageloh et al., 1984; Ostrovskii et al., 2008;
Tokitoh et al., 1989).
In a previous report, we related our attempt to synthesize a
novel tetrahydrotetrazole by oxidization of the readily avail-
able 1,1-bisurazole 5 (see Scheme 1) (Breton & Martin, 2018).
We unexpectedly found that rather than yielding the desired
tetrahydrotetrazole 7, the proposed diradicaloid intermediate
6
instead favored formation of the larger ten-membered ring
system 8, the structure of which was confirmed by X-ray
crystallography. Theoretical calculations confirmed the
susceptibility of the central N—N bond of 7 (labelled a in
Scheme 1) towards cleavage and, therefore, its propensity to
favor formation of 8. This work put into question whether the
#
2019 International Union of Crystallography
1
208 https://doi.org/10.1107/S2053229619010210
Acta Cryst. (2019). C75, 1208–1212

research papers
previously reported tetrahydrotetrazole 2, whose structure
closely resembles that of 7, indeed had the structure as
assigned in the literature. In addition, because all of the
reported tetrahydrotetrazoles share a similar central N—N
bond, we wondered whether the structure of any tetrahydro-
tetrazole that had been reported in the literature was correct
since none of the structures had been corroborated via X-ray
crystallographic analysis. Unfortunately, tetrahydrotetrazole 2
was obtained in low yield as a by-product from a reaction
pathway that would have been difficult to reproduce. On the
other hand, tetrahydrotetrazole 3 appeared to be a readily
accessible synthetic target. Interestingly, the authors of the
original report were only comfortable assigning the structure
of 3 as being ‘highly probable’ (Bast et al., 1998). Given this
uncertainty, along with the fact that 3 was characterized as a
crystalline solid, and therefore likely amenable to X-ray
crystallographic analysis, we selected 3 as a viable candidate
for structural confirmation of the tetrahydrotetrazole frame-
work.
Figure 1
The structures of 2 (Tokitoh et al., 1989), 3 (Bast et al., 1998), and 4
Krageloh et al., 1984) as representative examples of tetrahydrotetrazoles
(
previously reported in the literature.
2.16 mmol, 1.1 equiv.) as a solution in H O (2 ml). The mixture
2
became dark immediately and thickened with a precipitate of
11. The mixture was stirred manually with a spatula for 10 min,
and then washed four times with CS (2 ml). The organic
2
solution was dried over Na SO and filtered. To the resulting
2
4
deep-red–brown solution was added solid di-tert-butyl azodi-
carboxylate (0.4 g, 0.9 equiv.) immediately. The solution
became pale-yellow–orange in color. A sample of the solution
1
was subjected to H NMR spectroscopic analysis (in CS as
2
solvent), which showed the expected product 3, along with
some unreacted azodicarboxylate compound. The CS solvent
2
was removed by blowing dry N over the solution until a
2
crystalline material was obtained. The solid was dissolved in
diethyl ether (20 ml), followed by the slow addition of
petroleum ether (20 ml). The resulting solution was placed in a
freezer until crystals formed. The solvent was removed using a
pipette, and the crystals rinsed with cold petroleum ether to
ꢀ
afford 3 as pale-yellow–orange blocks (stored at ꢁ10 C) (m.p.
ꢀ
ꢁ1
9
1
6 C). IR (solid, cm ): 763, 779, 803, 1154, 1291, 1320, 1488,
ꢀ
1
594, 1646, 1715, 1752; H NMR (CDCl , ꢁ20 C): ꢀ 7.87 (br d,
3
J = 6.2 Hz, 1H), 7.40 (d, J = 8.1 Hz, 2H), 7.32 (t, J = 7.4 Hz, 2H),
7
7
5
.29 (d, J = 7.4 Hz, 1H), 7.20 (t, J = 7.4 Hz, 1H), 7.11 (t, J =
.4 Hz, 1H), 7.05 (d, J = 7.4 Hz, 1H), 6.49 (d, J = 8.1 Hz, 1H),
1
3
.78 (s, 1H), 5.76 (d, J = 8.1 Hz, 1H), 1.43 (s, 18H); C NMR
2
. Experimental
ꢀ
(
1
2
CDCl , ꢁ30 C): ꢀ 156.3, 146.2, 134.0, 130.7, 129.4, 129.2,
3
Unless otherwise specified, all reagents and solvents were
purchased from commercial sources and used without further
1 13
treatment or purification. H and C NMR spectra were
29.0, 126.7, 126.5, 125.1, 124.8, 117.5, 107.6, 83.2, 81.9, 72.1,
8.0, 27.7. The NMR spectra are provided in the supporting
information. The crystals formed from this method were
suitable for X-ray crystallographic analysis.
collected at 400 and 100 MHz, respectively, in CDCl as
3
solvent. Compounds 9 (Barbier et al., 1996) and 10 (Bast et al.,
1998) were prepared as described previously. X-ray diffraction
data were collected at Emory University’s X-ray Crystal-
lography Center on a Rigaku XtaLAB Synergy-S diffrac-
tometer with a HyPix-6000HE Hybrid Photon Counting
detector.
2.2. Dissociation of compound 3 in CDCl
3
As illustrated in Scheme 3, compound 3 (30 mg, 0.07 mmol)
was dissolved in CDCl (0.5 ml) at room temperature and
quickly inserted into the temperature-controlled probe of the
3
ꢀ
1
NMR spectrometer maintained at 20 C. A H NMR spectrum
was obtained every 5 min until loss of the signals for 3 was
observed (approximately 1 h). Signals for isoquinoline were
2.1. Synthesis of 3
As illustrated in Scheme 2, to compound 10 (0.5 g,
.95 mmol) in distilled H O (5 ml) was added Na CO (0.23 g,
1
1
observed along with signals attributed to azo imide 13. H
2
2
3
ꢂ
Acta Cryst. (2019). C75, 1208–1212
Breton et al.
Structural verification of a tetrahydrotetrazole 1209

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Table 1
Experimental details of 3.
Bast et al., 1998). Heating isoquinoline with 1-chloro-2,4-di-
nitrobenzene led to the formation of the N-(2,4-dinitrophen-
yl)isoquinolinium chloride salt, 9. Treatment of 9 with phenyl
hydrazine followed by acid-catalyzed hydrolysis afforded
2-anilinoisoquinolinium salt 10, as reported. Salt 10 serves as
the immediate precursor to azomethine imide 11 via depro-
Crystal data
Chemical formula
25 30 4 4
C H N O
450.53
Monoclinic, P2 /c
1
90
9.2613 (19), 10.882 (2), 23.583 (5)
95.54 (3)
2365.7 (8)
4
Mo Kꢂ
0.09
0.54 ꢃ 0.33 ꢃ 0.28
M
r
Crystal system, space group
Temperature (K)
˚
a, b, c (A)
tonation with Na CO in water. We extracted the deep-red–
2
ꢀ
3
ꢁ
V (A )
( )
˚
3
brown zwitterion 11 into carbon disulfide, which formed the
1
CS adduct 12 (this was confirmed by H NMR analysis rela-
Z
Radiation type
2
tive to the spectrum reported in the literature). The solution
remained deeply colored, however, suggesting that at least
some free 11 remains available for further reaction (see
Scheme 2). Therefore, instead of isolating adduct 12 as
described in the literature, we instead simply added 0.9
equivalents of di-tert-butyl azodicarboxylate directly to the
ꢁ
1
ꢃ (mm
)
Crystal size (mm)
Data collection
Diffractometer
Absorption correction
XtaLAB Synergy Dualflex HyPix
Gaussian (CrysAlis PRO; Rigaku
OD, 2018)
0.372, 1.000
183544, 24326, 19422
Tmin, Tmax
CS solution, which quickly quenched the characteristic color
2
No. of measured, independent and
observed [I > 2ꢄ(I)] reflections
of the imide to form an adduct, presumably that of compound
3. The CS was removed with a gentle stream of dry nitrogen
R
int
0.036
1.075
2
˚
ꢁ1
)
(sin ꢅ/ꢆ)max (A
gas and the resulting solid taken up in a 1:1 (v/v) mixture of
ether and petroleum ether. This solution was placed in a
freezer until the adduct crystallized as pale-yellow blocks. The
Refinement
2
2
2
R[F > 2ꢄ(F )], wR(F ), S
No. of reflections
No. of parameters
0.042, 0.116, 1.04
24326
418
All H-atom parameters refined
1
melting point, IR spectrum, and H NMR spectrum (see below
for further discussion) agreed with the literature data,
confirming the synthesis of the previously reported adduct.
H-atom treatment
˚
ꢁ3
)
Áꢇmax, Áꢇmin (e A
0.71, ꢁ0.25
Computer programs: CrysAlis PRO (Rigaku OD, 2018), SHELXT (Sheldrick, 2015a),
SHELXL2017 (Sheldrick, 2015b) and OLEX2 (Dolomanov et al., 2009).
NMR (CDCl ): ꢀ 7.94 (br m, 2H), 7.44 (t, J = 7.3 Hz, 2H), 7.31
3
(
t, J = 7.3 Hz, 1H), 1.64 (s, 9H), 1.51 (br s, 9H). The NMR
spectrum is provided in the supporting information. Allowing
the above solution to stand at room temperature overnight led
to loss of the signals attributed to 13.
2.3. Computational methods
Geometry optimization and energy calculations were
performed using GAUSSIAN16 software (Frisch et al., 2016)
employing the M062X functional and 6-311G(d,p) basis set.
Analysis of the vibrational frequencies for the optimized
structures confirmed the absence of imaginary frequencies for
the ground-state structures. Natural bond orbital (NBO)
calculations were carried out with the NBO6 program at the
B3LYP/6-31G(d) level of theory (Glendening et al., 2013).
Additional details for the optimized structures are provided in
the supporting information.
2.4. Refinement
Crystal data, data collection and structure refinement
details are summarized in Table 1. H atoms were refined as
unconstrained atoms with individual isotropic displacement
parameters.
3
.2. X-ray crystallographic analysis
3
. Results and discussion
Crystals of 3 grown from a mixture of ether and petroleum
3.1. Synthesis
ꢀ
ether at ꢁ10 C as described in the Experimental section (x2)
were suitable for X-ray crystallographic analysis. A displace-
ment ellipsoid diagram is provided in Fig. 2(a). The X-ray
The synthesis of compound 3 generally followed previous
reports from the literature (see Scheme 2) (Barbier et al., 1996;
ꢂ
1
210 Breton et al.
Structural verification of a tetrahydrotetrazole
Acta Cryst. (2019). C75, 1208–1212

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Figure 2
a) Displacement ellipsoid diagram for compound 3, with non-H atoms drawn at the 50% probability level. (b) Spatial placement of the N-atom lone
pairs (colored blue) of 3, as predicted by NBO calculations.
(
˚
structure confirmed the presence of the tetrahydrotetrazole
ring within the structure of 3. Note that as far as we know, this
is the first published crystal structure of a tetrahydrotetrazole
ring system. Four singly-bonded N atoms are clearly evident in
the structure. The N atoms adopt a conformation relative to
one another so as to minimize destabilizing repulsive inter-
actions from neighboring lone pairs. This is readily visualized
from the results of a natural bond orbital (NBO) calculation
on the crystal structure geometry carried out at the B3LYP/6-
the two sets of data (ꢄ0.01 A), and the same trend in relative
bond lengths is observed. In particular, the long C9—N4 bond
is retained in the computationally obtained in vacuo geometry.
Long bonds are often indicative of strain within a molecule
(Liebman & Greenberg, 1976). For compound 3, the long
bond could conceivably act to relieve some of the steric
interaction between the tert-butyl carboxylate group on atom
N3 and the isoquinoline ring system.
31G(d) level of theory (see Fig. 2b). Of particular interest are
3
.3. Studies on the stability of tetrahydrotetrazole 3
the lengths of the five bonds defining the tetrahydrotetrazole
ring embedded within the structure of 3 (see Fig. 3).
According to the National Institute of Standards and Tech-
nology (Johnson, 2018), hydrazine has an N—N bond length
Compound 3 was stable in crystalline form even at room
temperature (at least for short periods of time), but it was
observed to be much less stable in solution. Dissolution of the
pale-yellow crystals of 3 in CDCl at room temperature
resulted in rapid formation of the deep-red–brown color
characteristic of azomethine imide 11, suggesting some retro-
cycloaddition of adduct 3. Indeed, in the original report on 3, it
was indicated that formation of a deeply colored solution
upon warming an originally colorless solution of 3 was
reversible upon cooling (Bast et al., 1998). In agreement with
˚
of 1.446 A. The N1—N2 and N2—N3 bonds in tetrahydro-
tetrazole 3 are similar in length, but somewhat shorter than
3
that of hydrazine. The N3—N4 bond is the shortest of the
three N—N bonds, but all three are relatively close in value
˚
(differences of 0.0136 and 0.0131 A from the N1—N2 and
N2—N3 bonds, respectively). In particular, the central N2—
N3 bond shows no indication of being particularly strained or
prone to rupture. According to the same source, a C—N bond
the authors, we found that if a CDCl solution of the product is
3
˚
has an average length of 1.421 A and generally ranges from
prepared at room temperature, the deep-red color that
immediately formed was lost upon cooling the solution to
˚
.35 to 1.49 A. Thus, the C9—N1 bond of 3 is somewhat long
1
relative to the average, but falls within the typical bond-length
range. Notably, however, the C9—N4 bond is not only
˚
considerably longer (Á = 0.09 A) than the average C—N bond
length, but also significantly exceeds the sum of the atomic
˚
radii (1.47 A). To ensure that the long bond was not an arte-
fact of crystal packing forces, we optimized the geometry of
compound 3 computationally at the M062X/6-311G(d) level of
theory using the coordinates from the crystal structure
geometry as initial input. The computationally derived bond
lengths are compared to the experimentally derived bond
lengths in Fig. 3. Generally, there is good agreement between
Figure 3
Relevant experimentally and computationally [M062X/6-311G(d)]
˚
derived bond lengths (A) for the tetrahydrotetrazole ring of compound 3.
ꢂ
Acta Cryst. (2019). C75, 1208–1212
Breton et al.
Structural verification of a tetrahydrotetrazole 1211

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ꢀ
ꢁ
10 C. There were not significant amounts of di-tert-butyl
1
4. Conclusions
azodicarboxylate present in the H NMR spectrum, however,
so the extent of retro-cycloaddition must be very limited. We
learned that if a solution of 3 was prepared and maintained at
The structure of compound 3, as proposed earlier in the
literature, has been confirmed by X-ray crystallography to be
that of a tetrahydrotetrazole. We believe this is the first crys-
tallographic verification of this unique heterocyclic ring
system. A particularly interesting revelation from the X-ray
analysis was the observation of an unusually long C—N bond
ꢀ
ꢁ
10 C, the color attributed to 11 did not form. When this cold
ꢀ
solution was transferred directly to the pre-cooled (ꢁ20 C)
1
probe of the magnet for NMR analysis, a clean H NMR
spectrum corresponding to that previously reported for 3
could be collected.
1
in the structure. H NMR spectroscopy studies confirm that
compound 3 undergoes dissociation in solution to form iso-
quinoline and a secondary compound. NMR data and theo-
retical calculations support the assignment of the secondary
compound as azo imide 13.
Acknowledgements
GWB and KLM thank Berry College for providing financial
support for this project, and thank Dr John Bacsa, Facilities
Director of Emory University’s X-ray Crystallography Center
(supported by the National Science Foundation under CHE-
1626172), for collecting the X-ray crystal data on compound 3.
References
Barbier, D., Marazano, C., Das, B. C. & Potier, P. (1996). J. Org. Chem.
6
1, 9596–9598.
Bast, K., Behrens, M., Durst, T., Grashey, R., Huisgen, R., Schiffer, R.
Temme, R. (1998). Eur. J. Org. Chem. 1998, 379–385.
&
If a cold solution of 3 was warmed and then maintained at
ꢀ
Breton, G. W. & Martin, K. L. (2018). Acta Cryst. C74, 558–563.
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. &
Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.
20 C, however, loss of signals attributed to 3 was observed in
1
the H NMR spectrum. Concurrently, the growth of signals
attributed to isoquinoline and a new compound were
observed. The half-life for this reaction was estimated to be a
Egger, N., Hoesch, L. & Dreiding, A. S. (1983). Helv. Chim. Acta, 66,
1599–1607.
Exner, K., Fischer, G., Bahr, N., Beckmann, E., Lugan, M., Yang, F.,
Rihs, G., Keller, M., Hunkler, D., Knothe, L. & Prinzbach, H.
(2000). Eur. J. Org. Chem. 2000, 763–785.
1
relatively fast 15 minutes, as determined by H NMR spec-
troscopy. The new compound that forms is apparently not
stable, and undergoes further decomposition upon standing in
solution at room temperature to ultimately afford a complex
mixture of products. This interesting solution-phase behavior
was not reported in the initial report (Bast et al., 1998).
Provided the clue that isoquinoline was formed from decom-
position of 3 in solution, we speculated that the new
Frisch, M. J., et al. (2016). GAUSSIAN16. Revision B.01. Gaussian
Inc., Wallingford CT, USA. http://www.gaussian.com.
Glendening, E. D., Badenhoop, J. K., Reed, A. E., Carpenter, J. E.,
Bohmann, J. A., Morales, C. M., Landis, C. R. & Weinhold, F.
(2013). NBO6.0. Theoretical Chemistry Institute, University of
Wisconsin, Madison, USA. http://nbo6.chem.wisc.edu/.
Johnson, R. D. III (2018). Editor. NIST Computational Chemistry
Comparison and Benchmark Database, NIST Standard Reference
Database Number 101, Release 19, April 2018. http://cccbdb.
NIST.gov/.
1
compound formed is the azo imide 13 (Scheme 3). The H
NMR signals for the secondary compound were consistent
with proposed structure 13: aromatic protons consisting of a
broad downfield multiplet at 7.94 ppm (2H), a triplet at
Krageloh, K., Anderson, G. H. & Stang, P. J. (1984). J. Am. Chem.
Soc. 106, 6015–6021.
L e´ gar e´ , M. A., Rang, M., B e´ langer-Chabot, G., Schweizer, J. I.,
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Ostrovskii, V. A., Koldobskii, G. I. & Trifonov, R. E. (2008).
Comprehensive Heterocyclic Chemistry III, edited by A. R.
Katrizky, C. A. Ramsden, E. F. V. Scriven & R. J. K. Taylor,
Vol. 6, p. 261. New York: Elsevier.
7
.41 ppm (2H) and a triplet at 7.31 ppm (1H), and inequi-
valent tert-butyl signals at 1.64 and 1.51 ppm (broadened). The
broadening of some signals is likely due to the hindered
rotation of the phenyl and tert-butyl groups in the sterically-
congested environment. An azo imide similar to 13 has been
reported previously (14; see Scheme 3), and its susceptibility
to decomposition upon standing at room temperature, similar
to the decomposition of the proposed azo imide 14, was noted
Rigaku OD (2018). CrysAlis PRO. Rigaku Corporation, Yarnton,
Oxfordshire, England.
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.
(Egger et al., 1983). The dissociation process is likely favored
by relief of the internal molecular strain that resulted in the
formation of the long C—N bond observed in the structure of
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.
Tang, Y., Yang, H. & Cheng, G. (2013). Synlett, 24, 2183–2187.
Tokitoh, N., Suzuki, T., Itami, A., Goto, M. & Ando, W. (1989).
Tetrahedron Lett. 30, 1249–1252.
Zhang, Q. & Shreeve, J. M. (2013). Angew. Chem. Int. Ed. 52, 8792–
8794.
3. Calculations at the M062X/6-311G(d,p) level of theory on 3,
isoquinoline, and 13 predict a favorable change in free energy
ꢁ
1
(
ÁG = ꢁ17.9 kcal mol ) for the decomposition process.
ꢂ
1
212 Breton et al.
Structural verification of a tetrahydrotetrazole
Acta Cryst. (2019). C75, 1208–1212

supporting information
supporting information
Acta Cryst. (2019). C75, 1208-1212 [https://doi.org/10.1107/S2053229619010210]
Structural verification of a tetrahydrotetrazole compound
Gary W. Breton, Lauren A. Hahn and Kenneth L. Martin
Computing details
Data collection: CrysAlis PRO (Rigaku OD, 2018); cell refinement: CrysAlis PRO (Rigaku OD, 2018); data reduction:
CrysAlis PRO (Rigaku OD, 2018); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to
refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used
to prepare material for publication: OLEX2 (Dolomanov et al., 2009).
1
,2-Di-tert-butyl 3-phenyl-1H,2H,3H,10bH-[1,2,3,4]tetrazolo[5,1-a]isoquinoline-1,2-dicarboxylate
Crystal data
−3
C
25
H
30
N O
4 4
x
D = 1.265 Mg m
M
r
= 450.53
Melting point: 369 K
Monoclinic, P2
1
/c
Mo Kα radiation, λ = 0.71073 Å
Cell parameters from 79687 reflections
θ = 1.7–49.2°
µ = 0.09 mm
T = 90 K
a = 9.2613 (19) Å
b = 10.882 (2) Å
c = 23.583 (5) Å
β = 95.54 (3)°
−1
3
V = 2365.7 (8) Å
Block, colourless
Z = 4
0.54 × 0.33 × 0.28 mm
F(000) = 960
Data collection
XtaLAB Synergy Dualflex HyPix
diffractometer
Radiation source: micro-focus sealed X-ray
tube, PhotonJet (Mo) X-ray Source
Mirror monochromator
183544 measured reflections
24326 independent reflections
19422 reflections with I > 2σ(I)
R
int = 0.036
θ
max = 49.8°, θmin = 1.7°
ω scans
h = −19→19
k = −21→23
l = −45→50
Absorption correction: gaussian
(CrysAlis PRO; Rigaku OD, 2018)
T
min = 0.372, Tmax = 1.000
Refinement
2
Refinement on F
Primary atom site location: dual
Least-squares matrix: full
Hydrogen site location: difference Fourier map
All H-atom parameters refined
2
2
R[F > 2σ(F )] = 0.042
2
2
2
2
wR(F ) = 0.116
w = 1/[σ (F
o
) + (0.0602P) + 0.2083P]
2
2
S = 1.03
where P = (F
o
+ 2F )/3
c
2
4
0
4326 reflections
18 parameters
restraints
(Δ/σ)max = 0.003
Δρmax = 0.71 e Å
Δρmin = −0.25 e Å
−
3
−
3
Acta Cryst. (2019). C75, 1208-1212
sup-1

supporting information
Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance
matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles;
correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate
(isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
2
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å )
x
y
z
Uiso*/Ueq
O1
O2
O3
O4
N1
N2
N3
N4
C1
H1
C2
H2
C3
C4
H4
C5
H5
C6
H6
C7
H7
C8
C9
H9
C10
C11
H11
C12
H12
C13
H13
C14
H14
C15
H15
C16
C17
C18
H18A
0.27581 (3)
0.42718 (3)
0.31619 (3)
0.20284 (4)
0.02413 (3)
0.05946 (3)
0.20532 (3)
0.21584 (3)
0.06390 (4)
0.0390 (9)
0.12033 (4)
0.1349 (10)
0.15273 (4)
0.20068 (5)
0.2127 (11)
0.22737 (5)
0.2610 (11)
0.20595 (5)
0.2238 (11)
0.15994 (4)
0.1493 (10)
0.13412 (4)
0.09017 (4)
0.0233 (8)
−0.03570 (4)
−0.17551 (4)
−0.2052 (10)
−0.27025 (5)
−0.3665 (11)
−0.22630 (5)
−0.2939 (11)
−0.08583 (5)
−0.0504 (12)
0.00991 (5)
0.1076 (11)
0.31477 (4)
0.37557 (4)
0.29049 (5)
0.2746 (11)
0.73921 (3)
0.60049 (3)
0.67435 (3)
0.49959 (3)
0.52644 (3)
0.65338 (3)
0.65133 (3)
0.54738 (3)
0.48733 (4)
0.5467 (8)
0.37654 (4)
0.3516 (8)
0.29276 (3)
0.17264 (4)
0.1439 (9)
0.09330 (4)
0.0096 (9)
0.13303 (4)
0.0772 (10)
0.25292 (3)
0.2814 (8)
0.33298 (3)
0.46394 (3)
0.4678 (7)
0.71725 (3)
0.67480 (4)
0.5941 (9)
0.74630 (4)
0.7162 (9)
0.85958 (4)
0.9094 (9)
0.90087 (4)
0.9823 (10)
0.82997 (4)
0.8593 (9)
0.65636 (3)
0.77151 (3)
0.86999 (4)
0.9417 (10)
0.78541 (2)
0.83311 (2)
0.96733 (2)
0.99317 (2)
0.82967 (2)
0.83777 (2)
0.86364 (2)
0.89982 (2)
0.77611 (2)
0.7462 (4)
0.76764 (2)
0.7285 (4)
0.81520 (2)
0.80703 (2)
0.7668 (4)
0.85290 (2)
0.8470 (4)
0.90772 (2)
0.9406 (4)
0.91666 (2)
0.9553 (4)
0.87069 (2)
0.88103 (2)
0.9109 (3)
0.87237 (2)
0.87762 (2)
0.8611 (4)
0.90630 (2)
0.9081 (4)
0.92885 (2)
0.9488 (4)
0.92372 (2)
0.9386 (5)
0.89583 (2)
0.8916 (4)
0.82525 (2)
0.74242 (2)
0.70787 (2)
0.7332 (4)
0.01366 (4)
0.01571 (5)
0.01277 (4)
0.01693 (5)
0.01196 (4)
0.01109 (4)
0.01050 (4)
0.01086 (4)
0.01436 (5)
0.0192 (18)*
0.01607 (6)
0.024 (2)*
0.01501 (5)
0.01941 (7)
0.030 (2)*
0.02194 (7)
0.032 (2)*
0.02048 (7)
0.033 (2)*
0.01655 (6)
0.0203 (18)*
0.01338 (5)
0.01160 (4)
0.0129 (15)*
0.01151 (4)
0.01539 (5)
0.025 (2)*
0.01872 (6)
0.029 (2)*
0.02054 (7)
0.030 (2)*
0.02242 (8)
0.042 (3)*
0.01805 (6)
0.028 (2)*
0.01128 (4)
0.01410 (5)
0.02097 (7)
0.034 (2)*
Acta Cryst. (2019). C75, 1208-1212
sup-2

supporting information
H18B
H18C
C19
H19A
H19B
H19C
C20
H20A
H20B
H20C
C21
0.3474 (11)
0.2004 (10)
0.51594 (5)
0.5774 (10)
0.4928 (11)
0.5667 (12)
0.40079 (6)
0.4617 (11)
0.4554 (10)
0.3125 (10)
0.24080 (4)
0.35314 (4)
0.21485 (5)
0.2402 (11)
0.1726 (12)
0.1452 (10)
0.42713 (5)
0.4558 (11)
0.5160 (12)
0.3600 (12)
0.45844 (5)
0.4965 (10)
0.4113 (11)
0.5397 (11)
0.9002 (10)
0.8343 (9)
0.82367 (5)
0.7599 (9)
0.8866 (9)
0.8615 (9)
0.65914 (4)
0.6004 (9)
0.6840 (9)
0.6246 (9)
0.57102 (3)
0.71857 (3)
0.73970 (5)
0.7858 (9)
0.6633 (10)
0.7857 (9)
0.84033 (4)
0.8803 (9)
0.8251 (10)
0.8944 (10)
0.62985 (4)
0.6665 (9)
0.5510 (9)
0.6167 (9)
0.6766 (4)
0.6905 (4)
0.77147 (2)
0.7902 (4)
0.8007 (4)
0.7433 (4)
0.70642 (2)
0.7289 (4)
0.6749 (4)
0.6886 (4)
0.95807 (2)
1.02605 (2)
1.05462 (2)
1.0910 (4)
1.0646 (5)
1.0287 (4)
1.01594 (2)
1.0528 (4)
0.9961 (4)
0.9927 (5)
1.05809 (2)
1.0944 (4)
1.0645 (4)
1.0358 (4)
0.035 (2)*
0.027 (2)*
0.02137 (7)
0.028 (2)*
0.033 (2)*
0.034 (2)*
0.02022 (7)
0.032 (2)*
0.026 (2)*
0.026 (2)*
0.01159 (4)
0.01257 (5)
0.02044 (7)
0.031 (2)*
0.037 (3)*
0.028 (2)*
0.01948 (6)
0.030 (2)*
0.035 (2)*
0.036 (2)*
0.01855 (6)
0.028 (2)*
0.028 (2)*
0.031 (2)*
C22
C23
H23A
H23B
H23C
C24
H24A
H24B
H24C
C25
H25A
H25B
H25C
2
Atomic displacement parameters (Å )
11
22
33
12
13
23
U
U
U
U
U
U
O1
O2
O3
O4
N1
N2
N3
N4
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
0.01323 (9)
0.01207 (9)
0.01592 (10)
0.02262 (12)
0.01166 (9)
0.01000 (9)
0.01013 (9)
0.01248 (9)
0.01354 (12)
0.01536 (13)
0.01249 (11)
0.01706 (14)
0.01895 (15)
0.01834 (15)
0.01558 (13)
0.01170 (11)
0.01114 (10)
0.01197 (10)
0.01255 (11)
0.01477 (13)
0.01518 (10)
0.01753 (11)
0.01261 (9)
0.01558 (11)
0.01191 (10)
0.01155 (9)
0.01134 (9)
0.01003 (9)
0.01697 (13)
0.01701 (13)
0.01263 (12)
0.01319 (13)
0.01170 (13)
0.01174 (13)
0.01189 (12)
0.01050 (11)
0.01069 (10)
0.01124 (10)
0.01596 (13)
0.02046 (16)
0.01316 (9)
0.00325 (7)
0.00354 (8)
−0.00433 (7)
−0.00587 (9)
0.00010 (7)
0.00428 (7)
0.00256 (8)
0.00040 (7)
0.00139 (8)
−0.00027 (7)
0.00063 (7)
0.00076 (7)
−0.00029 (7)
−0.00055 (9)
0.00109 (10)
0.00180 (10)
0.00533 (13)
0.00599 (15)
0.00164 (13)
0.00032 (11)
0.00054 (9)
0.00041 (8)
0.00191 (8)
0.00365 (9)
0.00680 (11)
0.00513 (7)
0.00487 (8)
0.01774 (10)
0.00963 (8)
0.01255 (9)
0.01202 (9)
0.01165 (9)
0.00999 (8)
0.00980 (8)
0.01221 (11)
0.01575 (12)
0.01995 (13)
0.02859 (18)
0.0358 (2)
−0.00066 (7)
0.00363 (8)
−0.00217 (7)
−0.00086 (7)
0.00175 (7)
0.00056 (7)
−0.00032 (7)
−0.00225 (7)
0.00117 (10)
0.00058 (10)
−0.00107 (9)
−0.00098 (10)
−0.00012 (11)
−0.00076 (11)
−0.00184 (10)
−0.00152 (8)
−0.00145 (8)
0.00070 (8)
0.00090 (7)
−0.00345 (9)
−0.00531 (10)
−0.00415 (10)
−0.00574 (12)
−0.00189 (13)
0.00242 (12)
0.00124 (10)
−0.00148 (9)
−0.00070 (8)
0.00019 (8)
0.0312 (2)
0.02187 (15)
0.01775 (12)
0.01283 (10)
0.01148 (10)
0.01807 (13)
0.02190 (15)
−0.00103 (9)
−0.00054 (11)
−0.00334 (10)
−0.00420 (12)
Acta Cryst. (2019). C75, 1208-1212
sup-3

supporting information
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C23
C24
C25
0.01936 (15)
0.02111 (17)
0.01639 (13)
0.01117 (10)
0.01572 (12)
0.02573 (18)
0.01873 (15)
0.02767 (19)
0.01299 (11)
0.01253 (11)
0.01573 (14)
0.02259 (16)
0.01928 (15)
0.01922 (16)
0.01592 (15)
0.01323 (13)
0.01158 (10)
0.01339 (12)
0.02020 (16)
0.02050 (16)
0.01729 (15)
0.01130 (10)
0.01427 (12)
0.02806 (19)
0.01579 (14)
0.02031 (16)
0.02430 (17)
0.0315 (2)
0.00141 (12)
−0.00126 (12)
−0.00203 (10)
0.00015 (8)
0.00862 (13)
0.00915 (15)
0.00671 (12)
0.00149 (8)
0.00582 (9)
0.00849 (13)
0.00518 (13)
0.00709 (13)
0.00034 (8)
0.00060 (8)
0.00463 (11)
0.00075 (12)
−0.00306 (11)
−0.00541 (13)
−0.00849 (14)
−0.00486 (11)
0.00151 (8)
0.02544 (16)
0.01117 (10)
0.01403 (11)
0.01822 (14)
0.02546 (18)
0.01667 (14)
0.01033 (9)
0.01080 (10)
0.01812 (14)
0.01981 (15)
0.01514 (13)
0.00324 (9)
0.00371 (9)
0.01002 (14)
−0.00404 (12)
0.00551 (13)
−0.00198 (8)
−0.00043 (9)
0.00095 (13)
−0.00553 (12)
0.00355 (12)
0.00857 (12)
0.00382 (13)
0.00060 (11)
0.00086 (8)
−0.00206 (8)
−0.00534 (13)
−0.00359 (11)
−0.00109 (11)
Geometric parameters (Å, º)
O1—C16
O1—C17
O2—C16
O3—C21
O3—C22
O4—C21
N1—N2
N1—C1
N1—C9
N2—N3
N2—C10
N3—N4
N3—C16
N4—C9
N4—C21
C1—C2
C2—C3
C3—C4
1.3268 (5)
C3—C8
C4—C5
C5—C6
C6—C7
C7—C8
C8—C9
C10—C11
C10—C15
C11—C12
C12—C13
C13—C14
C14—C15
C17—C18
C17—C19
C17—C20
C22—C23
C22—C24
C22—C25
1.4062 (6)
1.4784 (6)
1.2044 (5)
1.3305 (5)
1.4748 (5)
1.2120 (5)
1.4282 (5)
1.4148 (6)
1.4700 (6)
1.4277 (6)
1.4369 (5)
1.4146 (4)
1.4237 (6)
1.5086 (5)
1.3949 (5)
1.3367 (6)
1.4541 (6)
1.3998 (6)
1.3875 (8)
1.3953 (8)
1.3948 (6)
1.3933 (6)
1.5085 (6)
1.3915 (6)
1.3943 (6)
1.3955 (6)
1.3879 (7)
1.3926 (7)
1.3880 (6)
1.5196 (6)
1.5197 (7)
1.5195 (6)
1.5211 (7)
1.5210 (6)
1.5204 (6)
C16—O1—C17
C21—O3—C22
N2—N1—C9
C1—N1—N2
C1—N1—C9
N1—N2—C10
N3—N2—N1
N3—N2—C10
N4—N3—N2
N4—N3—C16
C16—N3—N2
N3—N4—C9
C21—N4—N3
120.13 (3)
120.02 (3)
105.40 (3)
109.53 (3)
118.23 (3)
113.49 (3)
103.72 (3)
111.82 (3)
106.11 (3)
113.73 (3)
115.47 (3)
107.33 (3)
116.22 (3)
C8—C9—N4
113.80 (3)
121.12 (4)
120.38 (3)
118.16 (3)
119.47 (4)
120.41 (4)
119.68 (4)
120.44 (4)
119.61 (4)
108.34 (3)
128.61 (4)
122.73 (3)
102.08 (3)
C11—C10—N2
C11—C10—C15
C15—C10—N2
C10—C11—C12
C13—C12—C11
C12—C13—C14
C15—C14—C13
C14—C15—C10
O1—C16—N3
O2—C16—O1
O2—C16—N3
O1—C17—C18
Acta Cryst. (2019). C75, 1208-1212
sup-4

supporting information
C21—N4—C9
C2—C1—N1
C1—C2—C3
C4—C3—C2
C4—C3—C8
C8—C3—C2
C5—C4—C3
C4—C5—C6
C7—C6—C5
C8—C7—C6
C3—C8—C9
C7—C8—C3
C7—C8—C9
N1—C9—N4
N1—C9—C8
116.75 (3)
122.96 (4)
120.32 (4)
121.60 (4)
119.19 (4)
119.21 (4)
120.59 (4)
119.92 (4)
120.18 (4)
119.95 (4)
120.25 (3)
120.14 (4)
119.59 (4)
102.20 (3)
113.65 (3)
O1—C17—C19
O1—C17—C20
C18—C17—C19
C20—C17—C18
C20—C17—C19
O3—C21—N4
O4—C21—O3
O4—C21—N4
O3—C22—C23
O3—C22—C24
O3—C22—C25
C24—C22—C23
C25—C22—C23
C25—C22—C24
110.10 (4)
109.37 (4)
110.80 (4)
111.58 (4)
112.42 (4)
110.60 (3)
127.75 (3)
121.53 (3)
109.65 (4)
101.79 (3)
109.81 (4)
110.43 (4)
113.77 (4)
110.73 (4)
N1—N2—N3—N4
N1—N2—N3—C16
N1—N2—C10—C11
N1—N2—C10—C15
N1—C1—C2—C3
N2—N1—C1—C2
N2—N1—C9—N4
N2—N1—C9—C8
N2—N3—N4—C9
N2—N3—N4—C21
N2—N3—C16—O1
N2—N3—C16—O2
N2—C10—C11—C12
N2—C10—C15—C14
N3—N2—C10—C11
N3—N2—C10—C15
N3—N4—C9—N1
N3—N4—C9—C8
N3—N4—C21—O3
N3—N4—C21—O4
N4—N3—C16—O1
N4—N3—C16—O2
C1—N1—N2—N3
C1—N1—N2—C10
C1—N1—C9—N4
C1—N1—C9—C8
C1—C2—C3—C4
C1—C2—C3—C8
C2—C3—C4—C5
C2—C3—C8—C7
C2—C3—C8—C9
C3—C4—C5—C6
−35.80 (3)
91.19 (3)
−23.78 (5)
162.85 (3)
−4.16 (6)
141.94 (4)
−27.23 (3)
−150.29 (3)
18.43 (3)
−114.35 (4)
42.68 (4)
−143.34 (4)
−172.86 (4)
172.36 (4)
−140.69 (3)
45.94 (4)
C4—C3—C8—C9
C4—C5—C6—C7
C5—C6—C7—C8
C6—C7—C8—C3
C6—C7—C8—C9
C7—C8—C9—N1
C7—C8—C9—N4
C8—C3—C4—C5
C9—N1—N2—N3
C9—N1—N2—C10
C9—N1—C1—C2
C9—N4—C21—O3
C9—N4—C21—O4
C10—N2—N3—N4
C10—N2—N3—C16
C10—C11—C12—C13
C11—C10—C15—C14
C11—C12—C13—C14
C12—C13—C14—C15
C13—C14—C15—C10
C15—C10—C11—C12
C16—O1—C17—C18
C16—O1—C17—C19
C16—O1—C17—C20
C16—N3—N4—C9
176.78 (3)
−1.01 (7)
0.53 (6)
0.73 (6)
−177.57 (3)
−162.30 (3)
81.25 (5)
1.04 (6)
39.42 (4)
−82.14 (4)
21.26 (5)
−158.24 (3)
25.47 (5)
86.87 (4)
−146.14 (3)
0.80 (7)
5.38 (3)
−1.06 (7)
−1.24 (8)
0.53 (8)
0.62 (8)
0.36 (6)
−178.18 (4)
−60.47 (5)
63.53 (5)
−109.59 (3)
117.63 (4)
1.27 (6)
174.78 (3)
−59.09 (5)
−176.04 (3)
66.61 (4)
137.87 (3)
128.33 (3)
−29.91 (4)
153.80 (4)
165.71 (3)
−20.31 (5)
−88.77 (4)
149.67 (3)
95.55 (4)
−27.50 (4)
174.71 (4)
−4.67 (6)
−178.34 (4)
177.88 (3)
−3.83 (5)
0.21 (7)
C16—N3—N4—C21
C17—O1—C16—O2
C17—O1—C16—N3
C21—O3—C22—C23
C21—O3—C22—C24
C21—O3—C22—C25
C21—N4—C9—N1
Acta Cryst. (2019). C75, 1208-1212
sup-5

supporting information
C3—C8—C9—N1
C3—C8—C9—N4
C4—C3—C8—C7
19.40 (5)
−97.05 (5)
−1.51 (5)
C21—N4—C9—C8
C22—O3—C21—O4
C22—O3—C21—N4
−99.17 (4)
−5.01 (6)
178.99 (3)
Acta Cryst. (2019). C75, 1208-1212
sup-6