Synthesis and crystal structure of 2,9-di­amino-5,6,11,12-tetra­hydro­dibenzo[a,e]cyclo­octene

Valdez, N.; Nagel, E.; Redline, E.; Rodriguez, M.; Staiger, C.; Dugger, J.; Foster, J.

doi:10.1107/S2056989024004468

research communications

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 80| Part 6| June 2024| Pages 645-648

https://doi.org/10.1107/S2056989024004468

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Synthesis and crystal structure of 2,9-diamino-5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene

Nichole Valdez,^a ^* Eric Nagel,^a Erica Redline,^a Mark Rodriguez,^a Chad Staiger,^a Jason Dugger ^a and Jeffrey Foster ^b

^aSandia National Laboratories, 1515 Eubank Blvd. SE, Albuquerque, NM 87123, USA, and ^bOak Ridge National Laboratory, 5200 1 Bethel Valley Rd., Oak Ridge, Tennessee 37831, USA
^*Correspondence e-mail: nrvalde@sandia.gov

Edited by L. Van Meervelt, Katholieke Universiteit Leuven, Belgium (Received 30 April 2024; accepted 13 May 2024; online 21 May 2024)

The cis- form of diaminodibenzocyclooctane (DADBCO, C₁₆H₁₈N₂) is of interest as a negative coefficient of thermal expansion (CTE) material. The crystal structure was determined through single-crystal X-ray diffraction at 100 K and is presented herein.

Keywords: crystal structure; thermoset polymer; polymers; CTE; characterization.

CCDC reference: 2355133

1. Chemical context

Thermoset polymers are high performance materials that demonstrate excellent chemical, thermal, and mechanical stability at low weight and cost, making them ubiquitous in a wide range of applications such as insulating layers, encapsulants, adhesives, barriers, and composites (Biron, 2013 ; Brostow et al., 2014 ; Dickie et al., 1988 ; Pascault et al., 2002 ; Guo, 2018 ). Because these applications involve an interface between different materials, the thermal expansion behaviors of each constituent must be considered to achieve suitable performance. Most solid materials exhibit a positive coefficient of thermal expansion (CTE), the rate at which thermal expansion occurs during positive temperature change. Large differences in CTE between the various materials in composites and devices results in internal thermomechanical stress at interfaces, which in turn reduces service life and may initiate device failure (Okura et al., 2000 ; de Vreugd et al., 2010 ).

One strategy to mitigate CTE incompatibilities is the covalent incorporation of thermally activated contractile units into the polymer (Shen et al., 2013 ). These units counteract the thermal expansion during heating, reducing the CTE below that of the parent material. Materials capable of zero or even negative CTE are achievable with this method. Dibenzocyclooctane (DBCO) is one such unit, which achieves a thermally activated volume decrease by undergoing a reversible twist-boat to chair conformational change (Shen et al., 2013; Wang et al., 2018 ; Fu et al., 2020 ). Diaminodibenzocyclooctane (DADBCO), an aminated derivative, is also able to undergo this CTE modifying conformational change. However, it was found that epoxy resins incorporating 2,2′-DADBCO (cis) demonstrated negative CTE behavior while those utilizing 2,3′-DADBCO (trans) did not (Foster et al., 2021 ). These two materials are not differentiable by most characterization methods including IR, MS, and NMR. In addition, melting points are unreliable due to the difficulty of separation of these two isomers.

2. Structural Commentary

The cis-DADBCO molecules (point group C2) crystallizes in the chair conformation in space group Pna2₁. The structure was determined at 100 K and is illustrated in Fig. 1. The carbon rings are labeled as Ring 1: C11–C16 with nitrogen N1 connected to Ring 1 at C16, Ring 2: C21–C26 with N2 connected to Ring 2 at C26. The center cyclooctane contains carbon atoms: C12, C13, C31–C34, C22, C23. The plane of Ring 1 (C11–C16) makes a 59.9 (1)° angle with the plane that contains the four central atoms of the chair cyclooctane, C31–34. Nitrogen N1 is essentially planar with Ring 1 with a deviation from the plane of −0.025 (4) Å. The plane of Ring 2 (C21–26) makes a 56.7 (1)° angle with the aforementioned cyclooctane plane. Nitrogen N2 is essentially planar with Ring 2 with a deviation from the plane of 0.026 (4)°. The puckering parameters (Cremer & Pople, 1975 ) of the center cyclooctane are: total puckering amplitude Q = 0.906 (4) Å, q₂ = 0.024 (4) Å φ₂ = 146 (9)°, q₃ = 0.906 (4) Å φ₃ = 111.6 (2)°, q₄ = −0.005 (4) Å.

Figure 1
Displacement ellipsoid plot of cis-DADBCO with atom labels. Ellipsoids are drawn at the 50% probability level.

3. Supramolecular Features

Hydrogen bonding appears to be possible between the two amine groups from one independent molecule to the next through hydrogen H1B on nitrogen N2 to nitrogen N1 (bond length 2.452 Å) and through hydrogen H2A on nitrogen N2 to nitrogen N1 (bond length 2.458 Å). This information is summarized in Table 1 and illustrated in Fig. 2. N—H..π and C—H..π interactions are also included in Table 1.

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of rings C11–C16 and C21–C26, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯N2ⁱ	0.86 (4)	2.46 (4)	3.295 (5)	165 (4)
N2—H2A⋯N1ⁱⁱ	0.88	2.46	3.295 (5)	159
N2—H2B⋯Cg2ⁱⁱⁱ	0.88	2.96	3.742 (4)	149
C14—H14⋯Cg1^iv	0.95	2.84	3.572 (4)	135
C32—H32A⋯Cg1ⁱⁱ	0.99	2.78	3.640 (4)	145
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (ii) $[-x+1, -y+1, z-{\script{1\over 2}}]$ ; (iii) $[-x-{\script{1\over 2}}, y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iv) $[-x+2, -y+1, z+{\script{1\over 2}}]$ .

Figure 2
Hydrogen bonding in the crystal packing of the title compound. Incomplete molecules in the range are omitted for clarity. Displacement ellipsoids are drawn at 50% probability.

4. Database survey

A search was performed on the Cambridge Structural Database (CSD Version 5.45, March 2024; Groom et al., 2016 ) using ConQuest (Version 2024.1.0), and this aminated structure was not found. At time of submission there were eight 6,8,6 ring system entries in the CSD, with cyclooctane as the central ring, no additional rings linked, and no chemical substitutions in the core 6,8,6 carbon rings. A search of the chemical formula also yielded no results. An overview of 6,8,6 ring systems can be found in Domiano et al. (1992 ). The 6,8,6 motif also appears in circulene systems, see Miyoshi et al. (2022 ).

5. Synthesis and crystallization

Synthesis of dibenzocyclooctane (DBCO)

The synthesis of DBCO was carried out according to a literature procedure (Franck et al., 2012 ). An oven-dried three-necked round-bottom flask equipped with a stir bar was charged with lithium metal (3.30 g, 478 mmol, 2.5 equiv) and 100 mL of anhydrous THF in an Ar-filled glovebox. The flask was sealed with two rubber septa and vacuum adapter with a stopcock. The flask was removed from the glovebox and connected to a Schlenk line. The flask was fitted with a reflux condenser and pressure-equalizing addition funnel under N₂ flow. A solution of α,α′-dibromo-o-xylene (50.2 g, 190 mmol, 1 equiv) in 100 mL of anhydrous THF was prepared and transferred to the addition funnel. This solution was added dropwise to the Li suspension with vigorous stirring under an N₂ atmosphere. After ∼1/4 of this solution had been added, the reaction mixture began to reflux, and the addition was paused to allow the exotherm to subside. After 5 min, the dropwise addition was resumed, taking 1 h to add the remaining solution. The addition funnel was replaced with a glass stopper and the reaction mixture was heated at reflux overnight under N₂. Complete consumption of the starting material was confirmed by TLC in petroleum ether. The reaction flask was cooled in an ice bath and the reaction mixture was then carefully filtered over a glass frit to remove unreacted Li. The filtrate was concentrated in vacuo and was re-suspended in 200 mL of CH₂Cl₂. The resulting suspension was filtered over a pad of silica gel and the silica gel pad was washed with an additional 200 mL of CH₂Cl₂. The combined filtrates were dried over Na₂SO₄ and concentrated in vacuo, yielding 20.7 g of viscous yellow oil that solidified upon standing. The crude product was further purified via Kugelrohr distillation at 463 K under vacuum to afford the pure product as a white crystalline solid.

Synthesis of dinitro dibenzocyclooctane (DNDBCO)

DBCO (4.55 g, 21.9 mmol, 1 equiv) was dissolved in 200 mL of CH₂Cl₂ in a round-bottom flask equipped with a stir bar. The flask was fitted with a pressure-equalizing addition funnel and was placed in an ice bath. To the flask was added 25 mL HNO₃ (∼20 equiv) dropwise via the addition funnel at 273 K. During the addition, the reaction mixture developed a deep red color. The flask was removed from the ice bath and allowed to warm to room temperature. The reaction mixture was stirred at room temperature for 2 h, during which time the color of the reaction mixture changed from deep red to yellow–orange. The reaction mixture was poured into a beaker containing 300 mL of cold deionized (DI) H₂O to quench the reaction, and this biphasic mixture was transferred to a separatory funnel. The aqueous layer was discarded, and the organic layer was washed subsequently with DI H₂O, saturated NaHCO₃ solution (2×), and brine, dried over Na₂SO₄, filtered, and concentrated in vacuo. Upon further drying under vacuum, a yellow solid was obtained that was used in the next step without further purification.

Synthesis of diamino dibenzocyclooctane (DADBCO)

A three-necked round-bottom flask equipped with a stir bar was charged with 10% Pd/C (0.89 g, 5 mol% Pd relative to DNDBCO). The flask was fitted with two rubber septa and a vacuum adapter and was placed under an N₂ atmosphere. To the flask was added 150 mL of MeOH followed by DNDBCO (5.05 g, 16.9 mmol, 1 equiv) under N₂ flow. The rubber septa were replaced with vacuum adapters attached to H₂-filled balloons, and the N₂ atmosphere was exchanged for H₂ via five vacuum/H₂-back-fill cycles. The reaction mixture was then stirred overnight at room temperature under H₂, over which time the solid DNDBCO slowly dissolved. The complete consumption of the starting material was confirmed by TLC in 2:1 hexane/ethyl acetate. The reaction mixture was filtered over a pad of celite to remove the Pd/C and the filtrate was concentrated in vacuo. The resulting dark-red oil was re-dissolved in 1M HCl solution and was washed with CH₂Cl₂ (3×). The pH of the solution was then adjusted to pH >10 using ∼4M NaOH solution, and the precipitated product was extracted with EtOAc (2×). The combined EtOAc solutions were washed with DI H₂O and brine, dried over Na₂SO₄, filtered, and concentrated in vacuo. Further drying under vacuum afforded the product as a light-pink solid (3.05 g, 76% yield). Note: DADBCO was obtained as a mixture of isomers, where the ratio of ortho/meta anilines was ∼2:3. The various isomers could be isolated via exhaustive silica gel chromatography, eluting with a gradient from 0–50% EtOAc in hexane. In particular, the 2,2′ and 2,3′ isomers were suspected as the last and second to last compounds that eluted from the column, respectively. A suitable crystal of the 2,2′ material was grown for XRD analysis by allowing a saturated hot toluene solution to cool to room temperature over several hours followed by further cooling to 273 K.

6. Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 2. The hydrogen atoms on N2 were placed with a riding-bond model, whereas the hydrogen atoms on N1 were placed manually to match observed electron density. The distance of the manually placed atoms was constrained with DFIX and for the hydrogen atoms on N1 the isotropic thermal parameters were refined without constraints. All other H atoms were generated via the riding-bond model and refined with U(H) = 1.2U_eq(C/N). The absolute structure was not determined due to the absence of heavy atoms (Flack parameter = 0.3), and the inversion twin law was used for refinement.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₆H₁₈N₂
M_r	238.32
Crystal system, space group	Orthorhombic, Pna2₁
Temperature (K)	100
a, b, c (Å)	8.8641 (3), 22.0075 (6), 6.2771 (2)
V (Å³)	1224.52 (7)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	0.59
Crystal size (mm)	0.1 × 0.1 × 0.01

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.459, 0.754
No. of measured, independent and observed [I > 2σ(I)] reflections	39813, 2060, 1781
R_int	0.118
(sin θ/λ)_max (Å⁻¹)	0.588

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.106, 1.08
No. of reflections	2060
No. of parameters	173
No. of restraints	172
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.22
Absolute structure	Refined as an inversion twin
Absolute structure parameter	0.3 (12)
Computer programs: APEX2 and SAINT (Bruker, 2019 ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC reference: 2355133

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989024004468/vm2301sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989024004468/vm2301Isup2.hkl

PLATON outputs and SHELX plane calculations. DOI: https://doi.org/10.1107/S2056989024004468/vm2301sup3.docx

Supporting information file. DOI: https://doi.org/10.1107/S2056989024004468/vm2301Isup4.cml

checkCIF report

Computing details top

2,9-Diamino-5,6,11,12-tetrahydrodibenzo[a,e][8]annulene top

Crystal data top

C₁₆H₁₈N₂	D_x = 1.293 Mg m⁻³
M_r = 238.32	Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, Pna2₁	Cell parameters from 8510 reflections
a = 8.8641 (3) Å	θ = 4.0–73.6°
b = 22.0075 (6) Å	µ = 0.59 mm⁻¹
c = 6.2771 (2) Å	T = 100 K
V = 1224.52 (7) Å³	Needle, clear light green
Z = 4	0.1 × 0.1 × 0.01 mm
F(000) = 512

Data collection top

Bruker APEXII CCD diffractometer	1781 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.118
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 65.0°, θ_min = 4.0°
T_min = 0.459, T_max = 0.754	h = −10→10
39813 measured reflections	k = −25→25
2060 independent reflections	l = −6→7

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.046	w = 1/[σ²(F_o²) + (0.0353P)² + 0.9951P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.106	(Δ/σ)_max < 0.001
S = 1.08	Δρ_max = 0.18 e Å⁻³
2060 reflections	Δρ_min = −0.22 e Å⁻³
173 parameters	Absolute structure: Refined as an inversion twin
172 restraints	Absolute structure parameter: 0.3 (12)
Primary atom site location: shelXT

Special details top

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.

Refinement. Refined as a 2-component inversion twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.8644 (4)	0.33304 (16)	0.4674 (6)	0.0276 (8)
H1A	0.855 (5)	0.325 (2)	0.332 (4)	0.058 (18)*
H1B	0.950 (4)	0.321 (2)	0.516 (7)	0.052 (16)*
N2	0.3459 (4)	0.76938 (14)	0.2091 (6)	0.0295 (9)
H2A	0.293746	0.748604	0.114219	0.035*
H2B	0.284518	0.793724	0.279538	0.035*
C11	0.7832 (4)	0.43707 (17)	0.3906 (6)	0.0205 (9)
H11	0.750058	0.424326	0.253757	0.025*
C12	0.7645 (4)	0.49766 (16)	0.4496 (6)	0.0181 (8)
C13	0.8118 (4)	0.51680 (17)	0.6518 (6)	0.0186 (8)
C14	0.8763 (4)	0.47369 (16)	0.7896 (7)	0.0211 (8)
H14	0.908901	0.485974	0.927203	0.025*
C15	0.8932 (4)	0.41367 (17)	0.7284 (7)	0.0228 (9)
H15	0.935284	0.385279	0.825644	0.027*
C16	0.8497 (4)	0.39431 (17)	0.5276 (7)	0.0217 (9)
C31	0.6953 (4)	0.54170 (17)	0.2940 (6)	0.0195 (8)
H31A	0.692418	0.522457	0.151541	0.023*
H31B	0.760925	0.577985	0.284019	0.023*
C32	0.5330 (4)	0.56256 (16)	0.3539 (6)	0.0192 (8)
H32A	0.467057	0.556422	0.228475	0.023*
H32B	0.495208	0.535789	0.468896	0.023*
C33	0.7993 (4)	0.58216 (16)	0.7233 (7)	0.0214 (8)
H33A	0.836432	0.608605	0.606980	0.026*
H33B	0.866689	0.588157	0.847236	0.026*
C34	0.6377 (4)	0.60340 (17)	0.7861 (6)	0.0217 (8)
H34A	0.572848	0.567063	0.802213	0.026*
H34B	0.642990	0.623702	0.926614	0.026*
C21	0.4468 (4)	0.66922 (16)	0.2906 (7)	0.0205 (8)
H21	0.418445	0.656557	0.151499	0.025*
C22	0.5171 (4)	0.62758 (17)	0.4262 (6)	0.0182 (8)
C23	0.5629 (4)	0.64650 (17)	0.6289 (6)	0.0213 (8)
C24	0.5334 (5)	0.70611 (17)	0.6907 (7)	0.0269 (9)
H24	0.564002	0.719258	0.828207	0.032*
C25	0.4600 (5)	0.74720 (19)	0.5557 (7)	0.0287 (10)
H25	0.439745	0.787438	0.602401	0.034*
C26	0.4170 (4)	0.72879 (17)	0.3533 (7)	0.0235 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0259 (19)	0.0224 (18)	0.034 (2)	0.0023 (15)	0.0022 (17)	−0.0011 (16)
N2	0.0270 (18)	0.0243 (18)	0.037 (2)	0.0035 (14)	−0.0119 (16)	0.0037 (15)
C11	0.0109 (18)	0.026 (2)	0.025 (2)	−0.0010 (15)	−0.0004 (15)	0.0018 (16)
C12	0.0108 (17)	0.0217 (19)	0.022 (2)	0.0020 (15)	0.0000 (16)	0.0021 (16)
C13	0.0106 (17)	0.0234 (18)	0.022 (2)	0.0013 (15)	0.0018 (16)	−0.0004 (16)
C14	0.0129 (17)	0.027 (2)	0.023 (2)	−0.0011 (15)	0.0004 (16)	0.0019 (17)
C15	0.0153 (18)	0.027 (2)	0.026 (2)	0.0022 (16)	0.0008 (17)	0.0042 (18)
C16	0.0179 (19)	0.0185 (19)	0.029 (2)	0.0003 (15)	0.0041 (17)	0.0010 (17)
C31	0.0152 (18)	0.0242 (19)	0.019 (2)	0.0001 (15)	−0.0003 (16)	−0.0019 (16)
C32	0.0140 (17)	0.0197 (19)	0.024 (2)	−0.0009 (14)	−0.0024 (16)	−0.0010 (15)
C33	0.0175 (18)	0.0240 (19)	0.023 (2)	−0.0017 (15)	0.0000 (17)	−0.0019 (16)
C34	0.0232 (19)	0.0210 (18)	0.021 (2)	0.0029 (16)	−0.0043 (17)	−0.0023 (16)
C21	0.0157 (18)	0.0207 (18)	0.025 (2)	−0.0007 (15)	−0.0031 (17)	0.0004 (16)
C22	0.0141 (18)	0.0189 (19)	0.022 (2)	−0.0010 (14)	0.0011 (16)	0.0018 (15)
C23	0.0186 (19)	0.0215 (19)	0.024 (2)	0.0000 (15)	−0.0030 (17)	−0.0006 (16)
C24	0.031 (2)	0.023 (2)	0.027 (2)	0.0030 (18)	−0.0071 (17)	−0.0039 (18)
C25	0.032 (2)	0.022 (2)	0.032 (3)	0.0022 (18)	−0.0055 (19)	−0.0045 (18)
C26	0.0185 (19)	0.0217 (19)	0.030 (2)	−0.0010 (16)	−0.0073 (17)	0.0034 (17)

Geometric parameters (Å, º) top

N1—H1A	0.87 (2)	C31—C32	1.556 (5)
N1—H1B	0.86 (2)	C32—H32A	0.9900
N1—C16	1.406 (5)	C32—H32B	0.9900
N2—H2A	0.8817	C32—C22	1.508 (5)
N2—H2B	0.8824	C33—H33A	0.9900
N2—C26	1.419 (5)	C33—H33B	0.9900
C11—H11	0.9500	C33—C34	1.557 (5)
C11—C12	1.394 (5)	C34—H34A	0.9900
C11—C16	1.404 (5)	C34—H34B	0.9900
C12—C13	1.401 (5)	C34—C23	1.520 (5)
C12—C31	1.506 (5)	C21—H21	0.9500
C13—C14	1.406 (5)	C21—C22	1.398 (5)
C13—C33	1.511 (5)	C21—C26	1.394 (5)
C14—H14	0.9500	C22—C23	1.399 (6)
C14—C15	1.384 (5)	C23—C24	1.393 (5)
C15—H15	0.9500	C24—H24	0.9500
C15—C16	1.385 (6)	C24—C25	1.400 (6)
C31—H31A	0.9900	C25—H25	0.9500
C31—H31B	0.9900	C25—C26	1.387 (6)

H1A—N1—H1B	111 (4)	C22—C32—C31	116.1 (3)
C16—N1—H1A	116 (3)	C22—C32—H32A	108.3
C16—N1—H1B	107 (3)	C22—C32—H32B	108.3
H2A—N2—H2B	109.3	C13—C33—H33A	108.4
C26—N2—H2A	109.7	C13—C33—H33B	108.4
C26—N2—H2B	109.6	C13—C33—C34	115.4 (3)
C12—C11—H11	119.1	H33A—C33—H33B	107.5
C12—C11—C16	121.9 (4)	C34—C33—H33A	108.4
C16—C11—H11	119.1	C34—C33—H33B	108.4
C11—C12—C13	119.5 (4)	C33—C34—H34A	108.5
C11—C12—C31	119.5 (4)	C33—C34—H34B	108.5
C13—C12—C31	121.0 (3)	H34A—C34—H34B	107.5
C12—C13—C14	118.4 (4)	C23—C34—C33	115.1 (3)
C12—C13—C33	122.2 (3)	C23—C34—H34A	108.5
C14—C13—C33	119.3 (3)	C23—C34—H34B	108.5
C13—C14—H14	119.4	C22—C21—H21	119.0
C15—C14—C13	121.1 (4)	C26—C21—H21	119.0
C15—C14—H14	119.4	C26—C21—C22	121.9 (4)
C14—C15—H15	119.5	C21—C22—C32	118.7 (3)
C14—C15—C16	121.1 (4)	C21—C22—C23	119.2 (3)
C16—C15—H15	119.5	C23—C22—C32	121.9 (3)
C11—C16—N1	121.1 (4)	C22—C23—C34	122.1 (3)
C15—C16—N1	120.9 (4)	C24—C23—C34	119.3 (4)
C15—C16—C11	117.9 (3)	C24—C23—C22	118.6 (4)
C12—C31—H31A	108.7	C23—C24—H24	119.1
C12—C31—H31B	108.7	C23—C24—C25	121.8 (4)
C12—C31—C32	114.2 (3)	C25—C24—H24	119.1
H31A—C31—H31B	107.6	C24—C25—H25	120.2
C32—C31—H31A	108.7	C26—C25—C24	119.6 (4)
C32—C31—H31B	108.7	C26—C25—H25	120.2
C31—C32—H32A	108.3	C21—C26—N2	119.7 (4)
C31—C32—H32B	108.3	C25—C26—N2	121.5 (4)
H32A—C32—H32B	107.4	C25—C26—C21	118.8 (4)

C11—C12—C13—C14	−0.3 (5)	C31—C32—C22—C21	108.3 (4)
C11—C12—C13—C33	178.1 (3)	C31—C32—C22—C23	−75.3 (4)
C11—C12—C31—C32	108.7 (4)	C32—C22—C23—C34	2.6 (5)
C12—C11—C16—N1	178.4 (3)	C32—C22—C23—C24	−174.8 (4)
C12—C11—C16—C15	1.8 (5)	C33—C13—C14—C15	−178.4 (3)
C12—C13—C14—C15	0.0 (5)	C33—C34—C23—C22	68.8 (5)
C12—C13—C33—C34	76.1 (5)	C33—C34—C23—C24	−113.8 (4)
C12—C31—C32—C22	109.5 (4)	C34—C23—C24—C25	−177.7 (4)
C13—C12—C31—C32	−71.9 (4)	C21—C22—C23—C34	179.0 (3)
C13—C14—C15—C16	1.3 (5)	C21—C22—C23—C24	1.6 (5)
C13—C33—C34—C23	−107.9 (4)	C22—C21—C26—N2	179.7 (3)
C14—C13—C33—C34	−105.6 (4)	C22—C21—C26—C25	0.7 (6)
C14—C15—C16—N1	−178.8 (3)	C22—C23—C24—C25	−0.2 (6)
C14—C15—C16—C11	−2.1 (5)	C23—C24—C25—C26	−1.0 (6)
C16—C11—C12—C13	−0.6 (5)	C24—C25—C26—N2	−178.3 (4)
C16—C11—C12—C31	178.8 (3)	C24—C25—C26—C21	0.7 (6)
C31—C12—C13—C14	−179.7 (3)	C26—C21—C22—C32	174.7 (3)
C31—C12—C13—C33	−1.3 (5)	C26—C21—C22—C23	−1.9 (5)

Hydrogen-bond geometry (Å, º) top

Cg1 and Cg2 are the centroids of rings C11–C16 and C21–C26, respectively.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···N2ⁱ	0.86 (4)	2.46 (4)	3.295 (5)	165 (4)
N2—H2A···N1ⁱⁱ	0.88	2.46	3.295 (5)	159
N2—H2B···Cg2ⁱⁱⁱ	0.88	2.96	3.742 (4)	149
C14—H14···Cg1^iv	0.95	2.84	3.572 (4)	135
C32—H32A···Cg1ⁱⁱ	0.99	2.78	3.640 (4)	145

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

Acknowledgements

This research was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the US Department of Energy's National Nuclear Security Administration under Contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the US Department of Energy or the United States Government.

References

Biron, M. (2013). Editor. Thermosets and Composites, 2nd ed., ch. 6 Composites, pp 299–243. Oxford: William Andrew Publishing. https://doi.org/10.1016/B978-1-4557-3124-4.00006-7 Google Scholar
Brostow, W., Goodman, S. & Wahrmund, J. (2014). Handbook of Thermoset Plastics, 3^rd ed., edited by H. Dodiuk & S. Goodman, ch. 8 Epoxies, pp 191–252. Boston: William Andrew Publishing. https://doi.org/10.1016/B978-1-4557-3107-7.00008-7 Google Scholar
Bruker (2019). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
Dickie, R., Labana, S. & Bauer, R. (1988). Editors. Cross-Linked Polymers: Chemistry, Properties, and Applications, vol 367. Washington, D. C.: American Chemical Society. https://doi.org/10.1021/bk-1988-0367.fw001 Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Domiano, P., Cozzini, P., Claramunt, R. M., Lavandera, J. L., Sanz, D. & Elguero, J. (1992). J. Chem. Soc. Perkin Trans. 2, pp. 1609–1620. CSD CrossRef Google Scholar
Foster, J., Staiger, C., Dugger, J. & Redline, E. (2021). ACS Macro Lett. 10, 940–944. CrossRef CAS PubMed Google Scholar
Franck, G., Brill, M. & Helmchen, G. (2012). Org. Syn. 89, 55–65. CAS Google Scholar
Fu, W., Alam, T., Li, J., Bustamante, J., Lien, T., Adams, R. W., Teat, S. J., Stokes, B., Yang, W., Liu, Y. & Lu, J. (2020). J. Am. Chem. Soc. 142, 16651–16660. CSD CrossRef CAS PubMed Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Guo, Q. (2018). Editor.Thermosets, 2nd ed., ch. 8–13. Amsterdam: Elsevier. ISBN: 978-0081010211 Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Miyoshi, H., Sugiura, R., Kishi, R., Spisak, S. N., Wei, Z., Muranaka, A., Uchiyama, M., Kobayashi, N., Chatterjee, S., Ie, Y., Hisaki, I., Petrukhina, M. A., Nishinaga, T., Nakano, M. & Tobe, Y. (2022). Angew. Chem. Int. Ed. 61, e202115316. CSD CrossRef Google Scholar
Okura, J., Shetty, S., Ramakrishnan, B., Dasgupta, A., Caers, J. F. J. M. & Reinikainen, T. (2000). Microelectron. Reliab. 40, 1173–1180. CrossRef Google Scholar
Pascault, J., Sautereau, H., Verdu, J. & Williams, R. (2002). Thermosetting Polymers. New York: CRC Press. ISBN: 978-0429208072 Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Shen, X., Viney, C., Johnson, E., Wang, C. & Lu, J. (2013). Nat. Chem. 5, 1035–1041. CrossRef CAS PubMed Google Scholar
Vreugd, J. de, Jansen, K., Ernst, L. & Bohm, C. (2010). Microelectron. Reliab. 50, 910–916. Google Scholar
Wang, Z., Huang, Y., Guo, J., Li, Z., Xu, J., Lu, J. & Wang, C. (2018). Macromolecules, 51, 1377–1385. CrossRef CAS Google Scholar

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research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Synthesis and crystal structure of 2,9-di­amino-5,6,11,12-tetra­hydro­dibenzo[a,e]cyclo­octene

1. Chemical context

2. Structural Commentary

3. Supra­molecular Features

4. Database survey

5. Synthesis and crystallization

6. Refinement

Supporting information

Acknowledgements

References

research communications

Synthesis and crystal structure of 2,9-diamino-5,6,11,12-tetrahydrodibenzo[a,e]cyclooctene

3. Supramolecular Features