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

IUCrJ
Volume 9| Part 5| September 2022| Pages 544-550
ISSN: 2052-2525

Metal-free enantiomorphic perovskite [dabcoH2]2+[H3O]+Br3 and its one-dimensional polar polymorph

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aNational Centre for Nuclear Research, Andrzeja Sołtana 7, Otwock, Świerk 05-400, Poland, bInstitute of Physics; Department of Structure Analysis, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Prague 6 16253, Czech Republic, and cFaculty of Chemistry, Adam Mickiewicz University in Poznań, Umultowska 89 b, Poznań 61-614, Poland
*Correspondence e-mail: armand.budzianowski@ncbj.gov.pl, katran@amu.edu.pl

Edited by A. N. Cormack, Alfred University, USA (Received 3 February 2022; accepted 20 June 2022; online 16 July 2022)

The structure and stoichiometry of a new metal-free and ammonium-free compound [dabcoH2]2+H3O+Br3 (where [dabcoH2]2+ = 1,4-di­aza­bicyclo­[2.2.2]octane dication) correspond to the general formula ABX3 characteristic of perovskites. In enantiomorphic trigonal polymorph α of [dabcoH2]2+H3O+Br3, the corner-sharing [H3O]Br6 octahedra combine into a 3D framework embedding [dabcoH2]2+ dications in pseudo-cubic cages. In the more dense polymorph β, the face-sharing [H3O]Br6 octahedra form 1D polyanionic columns separated by [dabcoH2]2+ dications. These different topologies correlate with different crystal fields around the cations and their different disorder types: orientational disorders of [dabcoH2]2+ dications and H3O+ cations in polymorph α and positional disorder of [H3O]+ cations in polymorph β. The orientational disorder increases the lengths of OH⋯Br hydrogen bonds in polymorph α, but NH⋯Br distances of ordered dabcoH2 dications are longer in polymorph β. The presence of polar [H3O]+ cations in [dabcoH2]2+H3O+Br3 polymorphs offers additional polarizability of the centres compared with analogous metal-free [dabcoH2]2+[NH4]+Br3 perovskite.

1. Introduction

Perovskites constitute a wide group of crystalline materials with the characteristic formula ABX3 and structures built from corner-sharing BX6 octahedra and A cations in the cubic voids. The importance of perovskites is connected with their properties such as ferroelectric and relaxor properties (Strukov & Levanyuk, 1998[Strukov, B. A. & Levanyuk, A. P. (1998). Ferroelectric Phenomena in Crystals, Physical Foundations. Berlin, Heidelberg: Springer Verlag.]), and numerous applications, for example as digital memories (Scott, 2000[Scott, J. F. (2000). Ferroelectric Memories. Berlin, Heidelberg: Springer-Verlag.]), sensors or photovoltaics (Szafrański & Katrusiak, 2017[Szafrański, M. & Katrusiak, A. (2017). J. Phys. Chem. Lett. 8, 2496-2506.], 2016[Szafrański, M. & Katrusiak, A. (2016). J. Phys. Chem. Lett. 7, 3458-3466.]). The mineral CaTiO3, discovered in 1839 by Gustav Rose in the Ural mountains was named perovskite, after mineralogist Lev Alekseyevich von Perovski. Later, the name perovskite was used to describe a wider group of minerals with analogous structures and the general formula ABO3, then extended to ABX3, where X was a halide anion. Finally, organic–inorganic hybrid perovskites were designed, with large complex unit cells, and which still correspond to the networks built of corner-sharing octahedra or the octahedra corners connected through organic linkers, sometimes of considerable size (Boström & Goodwin, 2021[Boström, H. L. B. & Goodwin, A. L. (2021). Acc. Chem. Res. 54, 1288-1297.]). Also, 2D and 1D perovskite analogues differentiated in the composition (e.g. ABO4, CsPb2Br5), ionicity and topologies (e.g. corner/edge/face-sharing octahedra) are also often described as perovskite analogues. Properties and applications of perovskite materials are often connected with their phase transitions and symmetry changes at phase transitions, involving ionic displacements or tilts of the BX6 octahedra (Glazer, 1972[Glazer, A. M. (1972). Acta Cryst. B28, 3384-3392.]; Howard & Carpenter, 2010[Howard, C. J. & Carpenter, M. A. (2010). Acta Cryst. B66, 40-50.]; Carpenter & Howard, 2009[Carpenter, M. A. & Howard, C. J. (2009). Acta Cryst. B65, 134-146.]). They can induce spontaneous polarization and ferroelectricity of crystals, such as for example in BaTiO3 and PbTiO3 (Megaw, 1946[Megaw, H. D. (1946). Nature, 157, 20-21.], 1952[Megaw, H. D. (1952). Acta Cryst. 5, 739-749.]; Shirane et al., 1950[Shirane, G., Hoshino, S. & Suzuki, K. (1950). J. Phys. Soc. Jpn, 5, 453-455.]; Shirane & Takeda, 1952[Shirane, G. & Takeda, A. (1952). J. Phys. Soc. Jpn, 7, 1-4.]; Shirane & Pepinsky, 1953[Shirane, G. & Pepinsky, R. (1953). Phys. Rev. 91, 812-815.]; Nelmes & Kuhs, 1985[Nelmes, R. J. & Kuhs, W. F. (1985). Solid State Commun. 54, 721-723.]). In some structures, the symmetry and properties are connected with the disorder of the ions. In recent years, metal-free perovskites are sought for their applications in sensors, detectors, light-emitting diodes (LEDs), photovoltaics and, generally, optoelectronics (Song et al., 2020[Song, X., Cui, Q., Liu, Y., Xu, Z., Cohen, H., Ma, C., Fan, Y., Zhang, Y., Ye, H., Peng, Z., Li, R., Chen, Y., Wang, J., Sun, H., Yang, Z., Liu, Z., Yang, Z., Huang, W., Hodes, G., Liu, S. & Zhao, K. (2020). Adv. Mater. 32, 2003353.]; 2021a[Song, X., Hodes, G., Zhao, K. & Liu, S. Z. (2021a). Adv. Energy Mater. 11, 2003331.]; 2021b[Song, X., Li, Q., Han, J., Ma, C., Xu, Z., Li, H., Wang, P., Yang, Z., Cui, Q., Gao, L., Quan, Z., Liu, S. & Zhao, K. (2021b). Adv. Mater. 33, 2102190.]). The main advantages of organic and hybrid organic–inorganic substitutes of ceramic perovskites are their reduced toxicity, owing to the absence of heavy metals, lower cost of production and processing (formation of thin layers, also in the flexible form) and their easier environment-friendly disposal and recycling. Owing to weaker cohesion forces, bio-friendly metal-free perovskites can exhibit increased sensitivity to external stimuli (Cui et al., 2021[Cui, Q., Song, X., Liu, Y., Xu, Z., Ye, H., Yang, Z., Zhao, K. & Liu, S. (2021). Matter, 4, 2490-2507.]).

Recently, metal-free perovskites involving piperazine, dabco and ammonium cations (NH4+) were discovered (Bremner et al., 2002[Bremner, C. A., Simpson, M. & Harrison, W. T. A. (2002). J. Am. Chem. Soc. 124, 10960-10961.]), and later their analogues [dabcoH]2+[NH4]+Br3 and [MdabcoH]2+[NH4]+Br3 (Mdabco stands for N-methyl­ated dabco, i.e. 1,4-di­aza­bicyclo­[2.2.2]octane, C6H12N2) were thoroughly investigated (Ye et al., 2018[Ye, H. Y., Tang, Y. Y., Li, P. F., Liao, W. Q., Gao, J. X., Hua, X. N., Cai, H., Shi, P. P., You, Y. M. & Xiong, R. G. (2018). Science, 361, 151-155.]; Morita et al., 2020[Morita, H., Tsunashima, R., Nishihara, S. & Akutagawa, T. (2020). CrystEngComm, 22, 2279-2282.]). These are considered environment-friendly and cheap alternatives to mineral perovskites (Li & Ji, 2018[Li, W. & Ji, L.-J. (2018). Science, 361, 132.]; Gao et al., 2021[Gao, Y., Meshkat, S., Johnston, A., Zheng, C., Walters, G., Feng, Q., Wang, X., Sun, M.-J., Najarian, A. M., Xue, D., Wang, Y.-K., Saidaminov, M. I., Voznyy, O., Hoogland, S. & Sargent, E. H. (2021). Appl. Mater. Interfaces, 13, 19042-19047.]). At present, we report another metal-free perovskite compound [dabcoH2]2+[H3O]+Br3 obtained in the form of two polymorphs, α and β. Polymorph α has the structure of the analogous metal-free 3D perovskite [dabcoH2]2+[NH4]+Br3, where the [H3O]Br6 octahedra share vertices (Ye et al., 2018[Ye, H. Y., Tang, Y. Y., Li, P. F., Liao, W. Q., Gao, J. X., Hua, X. N., Cai, H., Shi, P. P., You, Y. M. & Xiong, R. G. (2018). Science, 361, 151-155.]). In the structure of polymorph β, [H3O]Br6 octahedra share faces in 1D columns (Bremner et al., 2002[Bremner, C. A., Simpson, M. & Harrison, W. T. A. (2002). J. Am. Chem. Soc. 124, 10960-10961.]; Ye et al., 2018[Ye, H. Y., Tang, Y. Y., Li, P. F., Liao, W. Q., Gao, J. X., Hua, X. N., Cai, H., Shi, P. P., You, Y. M. & Xiong, R. G. (2018). Science, 361, 151-155.]). Both polymorphs α and β of [dabcoH2]2+[H3O]+Br3 are disordered, but in a different manner. It is characteristic that disorder effects are essential for the properties of many types of crystals, including perovskites and dabco monosalts, where the disorder is connected to the ferroelectric and relaxor properties (Szafrański & Katrusiak, 2004[Szafrański, M. & Katrusiak, A. (2004). J. Phys. Chem. B, 108, 15709-15713.]). Our present study is primarily aimed at identifying the structural features of the [dabcoH2]2+H3O+Br3 polymorphs.

2. Experimental

Single crystals of [dabcoH2]2+[H3O]+Br3, where [dabcoH2]2+ of the formula [C6H14N2]2+ stands for diprotonated 1,4-di­aza­bicyclo­[2.2.2]octane, were found as a small fraction of crystallizations aimed at growing relaxor ferroelectric dabcoH+ bromide (dabcoHBr) from the aqueous solution of dabco and HBr in a 1:1 equimolar ratio (Budzianowski & Katrusiak, 2006[Budzianowski, A. & Katrusiak, A. (2006). J. Phys. Chem. B, 110, 9755-9758.]; Szafrański & Katrusiak, 2004[Szafrański, M. & Katrusiak, A. (2004). J. Phys. Chem. B, 108, 15709-15713.]). The X-ray diffraction studies of selected single crystals revealed the presence of a tri-component salt [dabcoH2]2+ hydro­nium tribromide, [dabcoH2]2+[H3O]+Br3 (polymorph α). Later, this compound (polymorph β) was obtained close to 100% yield by cooling and slowly evaporating the aqueous solution of dabco with the hydro­bromic acid at a 1:3 molar ratio (the initial crystallization of the equimolar dabco:HBr aqueous solution revealed polymorph α only). The single-crystal X-ray diffraction data (Table 1[link]) were measured with a KUMA KM4-CCD diffractometer with a graphite-monochromated fine-focus Mo Kα tube and an Oxford Diffraction XCalibur R diffractometer with a fine-focus X-ray source from a Cu Kα tube and Ruby CCD detector; using the latest version of CrysAlis and CrysAlis PRO software (Rigaku OD, 2003[Rigaku OD (2003). CrysAlis, version 1.171.13 beta. Yarnton, Oxfordshire, England.], 2019a[Rigaku OD (2019a). CrysAlis PRO, version 1.171.40.57a. Yarnton, Oxfordshire, England.]). The crystal structure of polymorph α-[dabcoH2]2+[H3O]+Br3 was partly solved by direct methods in ShelxS-97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and then JANA (Petříček et al., 2014[Petříček, V., Dušek, M. & Palatinus, L. (2014). Z. Kristallogr. 229, 345-352.]) produced the model. Because of the disorder in the structure, we attempted structural refinements in the lower-symmetry space groups with ShelxL (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. A71, 3-8.]; Barbour, 2020[Barbour, L. J. (2020). J. Appl. Cryst. 53, 1141-1146.]; Hübschle et al., 2011[Hübschle, C. B., Sheldrick, G. M. & Dittrich, B. (2011). J. Appl. Cryst. 44, 1281-1284.]) and JANA (Petříček et al., 2014[Petříček, V., Dušek, M. & Palatinus, L. (2014). Z. Kristallogr. 229, 345-352.]). Finally, we established that polymorph α-[dabcoH2]2+[H3O]+Br3 crystallizes in the enantiomorphic trigonal space group P3221 (no indication of racemic twinning was detected); the refinement of its structure revealed disorder of the dabcoH2 dications in two orientations with nearly equal site-occupation factors of 0.53:0.47(2) (Table 1[link]). Similar procedures were applied for solving and refining polymorph β-[dabcoH2]2+[H3O]+Br3 in the trigonal space group P3c1, where positional disorder was found for two of three symmetry-independent H3O+ cations; they are disordered at different rates, each in two sites located on a threefold axis (Table 1[link]). The structure of polymorph β approximates the structure with a 3× smaller unit cell and the symmetry of the space group P62c (cf. Table S1, Model 4 of the supporting information). The drawings of crystal structures were prepared with the programs Mercury (Macrae et al., 2020[Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226-235.]), POV-Ray (Barbour, 2020[Barbour, L. J. (2020). J. Appl. Cryst. 53, 1141-1146.]; Cason, 2004[Cason, C. J. (2004). POV-RAY for Windows. Persistence of Vision, Raytracer Pty. Ltd, Victoria, Australia. http://www.povray.org.]) and Vesta (Momma & Izumi, 2011[Momma, K. & Izumi, F. (2011). J. Appl. Cryst. 44, 1272-1276.]). Selected structures were presented as autostereograms to facilitate their 3D perception (Katrusiak, 2001[Katrusiak, A. (2001). J. Mol. Graphics Modell. 19, 363-367.]).

Table 1
Crystal data and experimental details for [dabcoH2]2+[H3O]+Br3 polymorphs α and β determined at 297 K and 0.1 MPa

Note the different rates of disorder of independent hydro­nium cations in polymorph β.

  α-polymorph β-polymorph
Chemical formula moiety [C6H14N2]·3Br+·HO+ [C6H14N2]·3Br+·HO+
Disordered cation/ratio dabcoH2+ 0.53:0.47(2) orientation, H3O+ disordered in 2 half-occupied orientations 2H3O+ cations positionally disordered, each in 2 sites, 0.51:0.49(3), 0.84:0.16(1)
Empirical formula C6H17Br3N2O C6H17Br3N2O
Formula weight 372.94 372.94
Crystal system Trigonal Trigonal
Space group (No.) P3221 (154) P3c1 (158)
a, b, c (Å) 9.5838(3), 9.5838(3), 23.2270(8) 16.0425(1), 16.0425(1), 7.9666(7)
α, β, γ (°) 90, 90, 120 90, 90, 120
Volume (Å3) 1847.56(13) 1775.61(16)
Z/Z 6/1 6/(3 × 1/3)
V/Z 307.93(2) 295.94(3)
Dx (g cm−3) 2.011 2.093
Wavelength (Å) 0.71073 1.54184
θ range (°) 2.454–29.253 3.181–71.234
Min/max indices h, k, l −13/12, −9/12, −31/30 −19/19, −19/19, −9/9
F(000) 1080 1080
Reflections (all) 14765 37462
Independent reflections/Rint 3159/0.0526 2269/0.0573
θ to 100% completeness (°) 25.242 67.684
Max/min transmission 0.985/0.956 0.334/0.060
Data/restraints/parameters 3159/84/201 2269/13/131
GooF on F2 1.077 1.053
Final R1/wR2 Σ[I > 2σI] 0.0415/0.652 0.0287/0.0782
R1/wR2 (all data) 0.0705/0.740 0.0319/0.0814
Extinction coefficient 0.00143(13)
Absorption coefficient (mm−1) 9.792 12.368
Absolute structure parameter 0.005(15) −0.02(2)
Max diff. peak/hole [eÅ−3] 0.548/−0.607 0.443/−0.468

The final crystal and structural data and experimental details for both polymorphs are summarized in CIF format in the Cambridge Crystallographic Database Centre as supplementary publications 2132130 and 2132131. They can be obtained free of charge from the Cambridge Structural Database at https://www.ccdc.cam.ac.uk/structures/.

3. Discussion

The structure of polymorph α-[dabcoH2]2+[H3O]+Br3, where the corner-sharing [H3O]Br6 octahedra are connected in a 3D framework occluding dabcoH2 dications (Fig. 1[link]) clearly corresponds to the classical perovskite structures of the formula ABBr3 (Glazer, 1972[Glazer, A. M. (1972). Acta Cryst. B28, 3384-3392.]; Megaw, 1946[Megaw, H. D. (1946). Nature, 157, 20-21.]). Moreover, the symmetry of the polymorph α-[dabcoH2]2+[H3O]+Br3 can be connected to the tilts of the [H3O]Br6 octahedra, consistent with Glazer's code a-a-a- for mineral perovskites. However, due to the non-spherical symmetry of H3O+ and [dabcoH2]2+ cations, the unit-cell volume is increased and the crystal symmetry of α-[dabcoH2]2+[H3O]+Br3 is lowered to one of the enantiomeric space groups P3221 or P3121. The trigonal unit cell (Z = 6) of α-[dabcoH2]2+[H3O]+Br3 comprises six prototypic perovskite pseudo-rhombohedral sub-units (Z′ = 1). An average prototypic pseudo-rhombohedral unit (pR) can be represented in terms of the trigonal (Tr) unit vectors according to the matrix (cf. Figs. 1[link] and 2[link]):

[({\bf r}{\rm pR}) = \left ({\matrix{2/3 & 1/3 & 1/6 \cr -1/3 & 1/3 & 1/6 \cr -1/3 & -2/3 & 1/6}}\right )({\bf r}{\rm Tr}),\eqno (1)]

where the vector indices refer to lattices Tr and pR. This transformation yields the idealized prototypic rhombohedral unit cell, of the dimensions apR = 6.753 Å and αpR = 90.40°, close to the average of the true dimensions of the pseudo-rhombohedral cell: apR = 6.720, bpR = 6.784, cpR = 6.755 Å, αpR = 90.12°, βpR = 90.67° and αpR = 90.42° (cf. Figs. 1[link] and 2[link]). The reverse transformation, from the prototypic rhombohedral sub-unit pR to the trigonal unit cell Tr, is

[({\bf r}{\rm Tr}) = \left( {\matrix{ 1 & { - 1} & {0} \cr 0 & {1} & { - 1} \cr 2 & {2} & {2} \cr } } \right)({\bf r}{\rm pRr}).\eqno (2)]

In ABX3 perovskite structures the interactions between cations (B) and anions (X) forming the 3D polyanionic framework [BX3]n are mainly electrostatic, like those between the framework and cations A contained in the cages. The shortest contacts in the structure of α-[dabcoH2]2+[H3O]+Br3 confirm that the H3O+ cations are OH⋯Br bonded into the 3D framework (Table 2[link]). The shortest distances C—H⋯Br are listed in Table 3[link]. Also, the [dabcoH2]2+ cations are NH⋯Br bonded to the linker anions, and these hydrogen bonds are somewhat shorter than those assigned to the framework. Such short contacts between the central cation and the atoms that form the cages are often present in perovskite structures and are considered a significant contribution to the stability and stiffness of the crystals (Ciupa-Litwa et al., 2020[Ciupa-Litwa, A., Ptak, M., Kucharska, E., Hanuza, J. & Mączka, M. (2020). Molecules, 25, 5215.]; Collings et al., 2016[Collings, I. E., Hill, J. A., Cairns, A. B., Cooper, R. I., Thompson, A. L., Parker, J. E., Tang, C. C. & Goodwin, A. L. (2016). Dalton Trans. 45, 4169-4178.]; Scatena et al., 2021[Scatena, R., Andrzejewski, M., Johnson, R. D. & Macchi, P. (2021). J. Mater. Chem. C. 9, 8051-8056.]; Adjogri & Meyer, 2020[Adjogri, S. J. & Meyer, E. L. (2020). Molecules, 25, 5039.]; Hou et al., 2020[Hou, Y., Wu, C., Yang, D., Ye, T., Honavar, V. G., van Duin, A. C. T., Wang, K. & Priya, S. (2020). J. Appl. Phys. 128, 060906.]).

Table 2
Hydrogen-bond contacts in α-[dabcoH2]2+[H3O]+Br3, with the donor–acceptor (DA) distances shorter than the sum of their van der Waals radii (Bondi, 1964[Bondi, A. (1964). J. Phys. Chem. 68, 441-451.]) and angle D—H⋯A larger than 110°

D—H⋯A D—H (Å) H⋯A (Å) DA (Å) D—H⋯A (°)
O(2w)—H(21w)⋯Br(1A)i 0.8201(14) 2.564(16) 3.370(5) 168(6)
O(2w)—H(22w)⋯Br(2A)ii 0.8201(14) 2.62(2) 3.394(4) 158(6)
O(2w)—H(23w)⋯Br(3A)iii 0.8201(15) 2.625(16) 3.4303(12) 167(6)
O(1w)—H(11w)⋯Br(3A)iv 0.8201(14) 2.62(2) 3.411(5) 162(6)
O(1w)—H(12w)⋯Br(1A) 0.8201(14) 2.59(2) 3.3591(9) 156(5)
O(1w)—H(13w)⋯Br(2A)v 0.8201(15) 2.639(19) 3.439(5) 166(6)
N(1A)—H(1A)⋯Br(2A) 0.98 2.39 3.244(13) 145.0
N(2A)—H(2A)⋯Br(3A) 0.98 2.37 3.240(14) 148.1
N(1B)—H(1B)⋯Br(2A) 0.98 2.36 3.249(15) 150.1
N(2B)—H(2B)⋯Br(3A) 0.98 2.36 3.243(16) 149.0
Symmetry codes: (i) 1 − x, yx, 2/3 − z; (ii) xy + 1, −y + 1, 1/3 − z; (iii) 2 − x, 1 − x + y, 2/3 − z; (iv) y, x, 1 − z; (v) −x, yx, 2/3 − z.

Table 3
Shortest interionic contacts corresponding to hydrogen bonds NH⋯Br and OH⋯Br in β-[dabcoH2]2+[H3O]+Br3; cf. Table 2[link]

D—H⋯A D—H (Å) H⋯A (Å) DA (Å) D—H⋯A (°)
O(1w)—H(1w)⋯Br(1) 0.82(2) 2.31(3) 3.121(4) 169(12)
O(2w)—H(2w)⋯Br(2) 0.83(2) 2.6(2) 3.102(8) 119(18)
O(1wA)—H(1wA)⋯Br(1) 0.83(2) 2.23(11) 3.037(15) 165(40)
O(2wA)—H(2wA)⋯Br(2) 0.83(2) 2.33(4) 3.148(6) 171(17)
O(3w)—H(3w)⋯Br(3) 0.84(3) 2.30(5) 3.079(4) 154(9)
N(1)—H(1)⋯Br(1) 0.98 2.82 3.541(6) 130.7
N(1)—H(1)⋯Br(2) 0.98 2.96 3.602(7) 124.2
N(1)—H(1)⋯Br(3) 0.98 3.22 3.837(5) 122.2
N(2)—H(2)⋯Br(1)i 0.98 3.18 3.787(6) 121.6
N(2)—H(2)⋯Br(2)i 0.98 3.06 3.734(7) 126.8
N(2)—H(2)⋯Br(3)i 0.98 2.79 3.497(5) 129.5
C(1)—H(1A)⋯Br(2) 0.97 2.97 3.598(6) 123.4
C(1)—H(1B)⋯Br(1)ii 0.97 2.95 3.738(7) 139.4
C(2)—H(2A)⋯Br(1) 0.97 3.00 3.521(7) 115.4
C(2)—H(2B)⋯Br(3)iii 0.97 3.08 3.817(7) 133.9
C(3)—H(3A)⋯Br(3) 0.97 2.96 3.635(6) 127.5
C(3)—H(3B)⋯Br(2)iv 0.97 3.12 3.840(7) 132.0
C(4)—H(4A)⋯Br(1)ii 0.97 3.12 3.838(7) 131.8
C(4)—H(4B)⋯Br(2)i 0.97 3.00 3.593(6) 120.9
C(5)—H(5A)⋯Br(3)iii 0.97 3.01 3.781(7) 137.1
C(5)—H(5B)⋯Br(1)i 0.97 2.98 3.665(6) 129.0
C(6)—H(6A)⋯Br(2)iv 0.97 2.97 3.751(6) 138.8
C(6)—H(6B)⋯Br(3)i 0.97 3.00 3.553(6) 117.2
Symmetry codes: (i) y, x, z − 1; (ii) x, xy + 1, z − 1/2; (iii) 1 − y, 1 − x, z − 1/2; (iv) 1 − x + y, y, z − 1/2.
[Figure 1]
Figure 1
One pseudo-cubic subunit of the trigonal polymorph α-[dabcoH2]2+[H3O]+Br3, extracted from the 3D network of corner-sharing [H3O]Br6 octahedra (cf. Figs. S4, S5 and S6–S9). Colour and size code: large brown spheres Br, medium blue N, red O, medium brown C, small white H; two colours indicate the partial occupation of disordered N and C atoms.
[Figure 2]
Figure 2
Autostereographic view (Katrusiak, 2001[Katrusiak, A. (2001). J. Mol. Graphics Modell. 19, 363-367.]) of the structure of α-[dabcoH2]2+H3O+Br3. Hydrogen bonds are indicated by cyan lines. Colour code: brown Br, red O; for disordered cations their different positions are distinguished by two colours: light and dark blue N, light and dark grey C; light-grey and black H.

All hydrogen donors in the structure of α-[dabcoH2]2+[H3O]+Br3 are disordered. The hydro­nium H3O+ cations are orientationally disordered in two positions around the oxygen atom. The three hydrogen atoms are located in six half-occupied sites, consistent with the H3O+ dimensions (Lundren & Olovsson, 1976[Lundren, J.-O. & Olovsson, I. (1976). In The Hydrogen Bond. Structure and spectroscopy, Vol. 2, edited by P. Schuster, G. Zundel and C. Sandorfy, pp. 471-526. Amsterdam: North-Holland Publishing Company.]), as shown in Figs. 1[link], 2[link] and S1–S8 (Table S2). Each of the six half-occupied hydrogen sites is involved in one OH⋯Br hydrogen bond [Figs. S3(a) and S3(b)]. Dication [dabcoH2]2+ is disordered in two orientations. The dication is involved in two OH⋯Br hydrogen bonds. Each of these hydrogen bonds is split between two half-occupied hydrogen sites (Fig. 2[link]). There are also short distances (∼2.8 to ∼3 Å) between Br ions and methyl­ene hydrogen atoms. All hydrogen bonds listed in Table 2[link] can be classified as weak interactions, which are consistent with the considerable disorder of this structure. Like for the mineral perovskites, the symmetry of the crystal field around the cations plays a crucial role in their disorder.

In addition to the trigonal polymorph α-[dabcoH2]2+[H3O]+Br3, we found another concomitant trigonal polymorph β-[dabcoH2]2+[H3O]+Br3 (Table 1[link], Fig. 3[link]). In its structure, the octahedra of hydro­nium cations and bromine anions ([H3O]Br6) are face-to-face arranged into columns and the [dabcoH2]2+ dications are located between these columns. However, in contrast to polymorph α, in polymorph β-[dabcoH2]2+[H3O]+Br3 the [dabcoH2]2+ dications are ordered in general positions, while out of three independent hydro­nium cations [H3O]+ two are disordered. Each of these two [H3O]+ cations is disordered between a pair of sites along the same column along z, as illustrated in Fig. 4[link]. The distance between the pairs of partially occupied oxygen sites (Table 1[link]) is approximately equal to 1/4 of the unit-cell parameter c, i.e. about 2 Å. It is intriguing that the oxygen sites disordered along the threefold axes lie off the centre of the [H3O]+Br6 octahedra, while the centres of the octahedra are at the midpoints between the oxygen sites; the disordered [H3O]+ cation is also located off its octahedron centre (Fig. 4[link]). These off-centre sites of the oxygen atoms result in O⋯Br distances (Table 3[link]) significantly shorter compared with those in α-[dabcoH2]2+[H3O]+Br3 (Table 2[link]). The off-centre positional disorder of hydro­nium cations in β-[dabcoH2]2+[H3O]+Br3 suggests that the OH⋯Br hydrogen bonds favour shorter distances than those between the bromine anion and the octahedron centre. The longer O⋯Br distances in α-[dabcoH2]2+[H3O]+Br3 can be attributed to the orientational dynamic disorder of the H3O+ cation; its hydrogen atoms share the tetrahedrally located sites with the lone-electron pair: the tetrahedral sites do not match the octahedral locations of the bromine anions around, while the lone-electron pair does not contribute to the attraction of the hydrogen bonds, but it can be associated with some repulsion. On the other hand, the [dabcoH2]2+ dications in β-[dabcoH2]2+[H3O]+Br3 are stabilized in the ordered position by their trigonal environment and form NH⋯Br contacts that are significantly longer than those of disordered [dabcoH2]2+ dications in the pseudo-cubic crystal environment of α-[dabcoH2]2+[H3O]+Br3 (Tables 2[link] and 3[link]).

[Figure 3]
Figure 3
Polymorph β-[dabcoH2]2+[H3O]+Br3 with chains of face-sharing octahedra: (a) parallel view along the [001] direction; and (b) autostereographic view (Katrusiak, 2001[Katrusiak, A. (2001). J. Mol. Graphics Modell. 19, 363-367.]) comparing the columns of face-sharing octahedra – the full translational symmetry along the unit-cell diagonal across the page is indicated by two grey circles below the drawing. The colour code for atoms is the same as in Fig. 1[link].
[Figure 4]
Figure 4
Crystal structure of polymorph β-[dabcoH2]2+[H3O]+Br3 projected along (a) the [001] direction and (b) the [010] direction. Partially occupied sites of the disordered hydro­nium cations are indicated. Colour code: brown Br; blue N, red O; dark grey C; light grey H.

The crystallographic information about polymorphs explains the origin of different disorder types in their structure. The [dabcoH2]2+ dications can assume either the D3 twisted left or right propeller conformation, or the averaged D3h symmetry (Olejniczak et al., 2013[Olejniczak, A., Anioła, M., Szafrański, M., Budzianowski, A. & Katrusiak, A. (2013). Cryst. Growth Des. 13, 2872-2879.]). However, in polymorph α the dications are located in the pseudo-cubic cages, approximating the Oh symmetry. Consequently, the crystal environment of polymorph α does not stabilize one specific orientation of the cation. On the other hand, the trigonal symmetry of polymorph β results in the trigonal surrounding of the dications, matching their symmetry well. Indeed, the shape of pseudo-D3h-symmetric dications is consistent with the trigonal crystal environment. In polymorph α, the hydro­nium cations are located at the vertices of the pseudo-cubic cages, which does not favour any of their displacements. In polymorph β, the [H3O]+ cations are located in the channel-like surrounding of the threefold axes, which does not appear to strongly favour any site along z and results in the disorder of the cations. Interestingly, the structure of polymorph β approximates the higher symmetry of space group P62c, with the unit cell 3× smaller (Figs. S9–S16, Tables S1 and S2). This high symmetry is broken by small tilts of the dications and displacements of the Br anions, as well as by the differences between the hydro­nium cations, ordered and disordered to different extents (Table 1[link]), as shown in the structure projections in Fig. 4[link].

4. Conclusions

Polymorphs of [dabcoH2]2+[H3O]+Br3 illustrate the universality of perovskite structures and their characteristic features. The general formula ABX3 of perovskites, initially associated with minerals and ionic crystals, can clearly be extended to various hybrid organic–inorganic compounds, where organic central A cations interact with (in)organic X linkers, binding the B metal centres in the systems with much weaker cohesion forces, such as hydrogen bonds and electrostatic interactions between molecular ions. Even the metal-free compounds still display the characteristic structural properties of perovskites, controlled by the tilts of BX6 octahedra and disorder of the cations: the size and orientation of the molecular ions are additional factors responsible for the crystal symmetry and macroscopic properties of the hybrid and metal-free perovskites. The structures of both polymorphs of [dabcoH2]2+[H3O]+Br3 are disordered under normal conditions, which is an indication of possible temperature and pressure-induced phase transitions of properties. Both orientational and positional disorder are present and they interplay with the crystal field around the cations and their hydrogen bond capabilities. Polymorph α-[dabcoH2]2+[H3O]+Br3, like its close analogue [dabcoH2]2+[NH4]+Br3, is one of very few enantiomorphic and polar perovskites reported so far. With the exception of C4H14N2RbCl3 (Paton & Harrison, 2010[Paton, L. A. & Harrison, W. T. A. (2010). Angew. Chem. Int. Ed. 49, 7684-7687.]), the previously reported enantiomorphic perovskites employed chiral cations, for example in (R)-, (S)-3-(fluoro­pyrrolidinium)MnBr3 and in (R)-, (S)-N,N-di­methyl-3-fluoro­pyrrolidinium CdCl3 (Gao et al., 2020[Gao, J.-X., Zhang, W.-Y., Wu, Z.-G., Zheng, Y.-X. & Fu, D.-W. (2020). J. Am. Chem. Soc. 142, 4756-4761.]; Peng et al., 2021[Peng, H., Cheng, H., Liu, Y.-H., Yang, M.-J., Liao, W.-Q. & Ai, Y. (2021). J. Mater. Chem. C. 9, 1918-1922.]), where the enantiomorphic form of the crystal was permanently connected with the chiral cation used for the synthesis. To our knowledge, the polymorphs [dabcoH2]2+[NH4]+Br3 and α-[dabcoH2]2+[H3O]+Br3 are the first metal-free enantiomorphic and polar 3D perovskite structures where no permanent chiral cations are present and therefore this structure can be switched between two enantiomorphs. The structure of polymorph β-[dabcoH2]2+[H3O]+Br3 is polar, which can also potentially result in ferroelectric properties. Thus, in both polymorphs, the substitution of the non-polar [NH4]+ cation with the polar [H3O]+ cation can result in increased polarizability of the system and advantageous switchable properties desired for practical applications in optoelectronic devices.

5. Related literature

The following references are cited in the supporting information: Rigaku OD (2019b[Rigaku OD (2019b). CrysAlis PRO, version 1.171.39.25a. Yarnton, Oxfordshire, England.], 2020[Rigaku OD (2020). CrysAlis PRO, version 1.171.40.79a. Yarnton, Oxfordshire, England.], 2021[Rigaku OD (2021). CrysAlis PRO, version 1.171.41.122a. Yarnton, Oxfordshire, England.]); Clark & Reid (1995[Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897.]); Laetsch & Downs (2006[Laetsch, T. A. & Downs, R. T. (2006). Program and Abstracts of the 19th General Meeting of the International Mineralogical Association, 23-28 July 2006, Kobe, Japan. P08-25.]).

Supporting information


Computing details top

Data collection: CrysAlis Version 1.171.13 beta (release 14.11.2003 CrysAlis171 VC++) for dhbr1af_41001; CrysAlis PRO 1.171.39.25a (Rigaku OD, 2015) for dabco1_h168b6_abs2. For both structures, cell refinement: CrysAlis PRO 1.171.40.57a (Rigaku OD, 2019); data reduction: CrysAlis PRO 1.171.40.57a (Rigaku OD, 2019). Program(s) used to solve structure: SHELXS2013/1 (Sheldrick, 1990) JANA2006 for dhbr1af_41001; SHELXL2018/1 (Sheldrick, 2018) for dabco1_h168b6_abs2. Program(s) used to refine structure: SHELXL2016/6 (Sheldrick, 2016) JANA2006 for dhbr1af_41001; SHELXL2016/6 (Sheldrick, 2016) for dabco1_h168b6_abs2. Molecular graphics: X-SEED (Barbour, 2001) ShelXle (Hubschle et al., 2011) VESTA ( Momma & Izumi, 2011) for dhbr1af_41001; X-SEED (Barbour, 2020) ShelXle (Hubschle et al., 2011) Persistence of Vision Pty. Ltd. (2004). for dabco1_h168b6_abs2.

(dhbr1af_41001) top
Crystal data top
C6H14N2·3(Br)·H3ODx = 2.011 Mg m3
Mr = 372.94Mo Kα radiation, λ = 0.71073 Å
Trigonal, P3221Cell parameters from 3200 reflections
a = 9.5838 (3) Åθ = 3.0–25.3°
c = 23.2270 (8) ŵ = 9.79 mm1
V = 1847.56 (13) Å3T = 296 K
Z = 6Block, clear colourless
F(000) = 10800.10 × 0.10 × 0.10 mm
Data collection top
Xcalibur, Sapphire2, large Be window
diffractometer
3159 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source2323 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.053
Detector resolution: 8.1929 pixels mm-1θmax = 29.3°, θmin = 2.5°
Absorption correction: analytical
CrysAlisPro 1.171.40.57a (Rigaku Oxford Diffraction, 2019) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R.C. Clark & J.S. Reid. (Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
h = 1312
Tmin = 0.956, Tmax = 0.985k = 912
14765 measured reflectionsl = 3130
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F > 3σ(F)] = 0.042 w = 1/[σ2(Fo2) + (0.020P)2 + 0.7694P]
where P = (Fo2 + 2Fc2)/3
wR(F) = 0.074(Δ/σ)max = 0.001
S = 1.08Δρmax = 0.55 e Å3
3159 reflectionsΔρmin = 0.61 e Å3
201 parametersAbsolute structure: Flack x determined using 737 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
84 restraintsAbsolute structure parameter: 0.005 (15)
Primary atom site location: structure-invariant direct methods
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Br1A0.14646 (8)0.47635 (9)0.41669 (3)0.04436 (19)
Br2A0.03007 (9)0.20114 (9)0.09569 (3)0.0434 (2)
Br3A0.64491 (9)0.53260 (9)0.40619 (3)0.0431 (2)
O2W1.0000000.6615 (7)0.3333330.069 (3)
H21W0.961 (10)0.573 (4)0.318 (3)0.083*0.5
H22W0.953 (5)0.704 (5)0.319 (2)0.083*0.5
H23W1.092 (3)0.715 (8)0.321 (3)0.083*0.5
O1W0.3328 (7)0.3328 (7)0.5000000.072 (3)
H11W0.398 (6)0.404 (4)0.5211 (18)0.086*0.5
H12W0.313 (5)0.376 (5)0.4734 (17)0.086*0.5
H13W0.250 (3)0.280 (7)0.5184 (19)0.086*0.5
N1A0.2147 (19)0.292 (2)0.2188 (7)0.047 (4)0.54 (2)
H1A0.1203260.2492510.1935110.056*0.54 (2)
N2A0.4474 (19)0.4055 (19)0.2864 (7)0.041 (4)0.54 (2)
H2A0.5407950.4491200.3122180.050*0.54 (2)
C1A0.1656 (19)0.213 (2)0.2777 (11)0.060 (7)0.54 (2)
H11A0.0979580.2474090.2969990.072*0.54 (2)
H12A0.1046910.0969140.2735750.072*0.54 (2)
C2A0.315 (3)0.262 (3)0.3126 (7)0.056 (5)0.54 (2)
H21A0.2986660.2840100.3519930.067*0.54 (2)
H22A0.3395900.1749430.3130100.067*0.54 (2)
C3A0.339 (3)0.258 (3)0.1933 (7)0.069 (7)0.54 (2)
H31A0.3590830.2906420.1532110.083*0.54 (2)
H32A0.3054040.1447160.1960760.083*0.54 (2)
C4A0.4919 (19)0.361 (2)0.2301 (11)0.053 (6)0.54 (2)
H41A0.5462630.3000170.2372620.063*0.54 (2)
H42A0.5653590.4577340.2091880.063*0.54 (2)
C5A0.289 (3)0.475 (2)0.2254 (12)0.065 (9)0.54 (2)
H51A0.3479410.5296020.1908920.077*0.54 (2)
H51B0.2044930.5016720.2313450.077*0.54 (2)
C6A0.401 (4)0.529 (3)0.2769 (13)0.045 (7)0.54 (2)
H61A0.4962600.6325260.2693250.054*0.54 (2)
H62A0.3475650.5389120.3106940.054*0.54 (2)
N1B0.290 (2)0.3273 (18)0.2004 (6)0.036 (4)0.46 (2)
H1B0.2484560.3049120.1608880.043*0.46 (2)
N2B0.386 (2)0.383 (2)0.3020 (7)0.032 (4)0.46 (2)
H2B0.4253690.4059040.3417680.039*0.46 (2)
C1B0.177 (2)0.188 (2)0.2390 (10)0.046 (6)0.46 (2)
H11B0.1843090.0933760.2300030.056*0.46 (2)
H12B0.0662540.1625800.2326980.056*0.46 (2)
C2B0.224 (3)0.237 (3)0.3014 (9)0.044 (6)0.46 (2)
H21B0.1465750.2593850.3198270.053*0.46 (2)
H22B0.2264350.1505160.3222560.053*0.46 (2)
C3B0.450 (3)0.341 (3)0.2019 (8)0.048 (6)0.46 (2)
H31B0.5278070.4384030.1821040.058*0.46 (2)
H32B0.4462560.2492010.1833650.058*0.46 (2)
C4B0.496 (2)0.349 (3)0.2669 (9)0.041 (5)0.46 (2)
H41B0.4856260.2469080.2785650.049*0.46 (2)
H42B0.6066620.4329090.2727610.049*0.46 (2)
C5B0.287 (2)0.477 (2)0.2227 (10)0.026 (5)0.46 (2)
H10.3383180.5646420.1951960.031*0.46 (2)
H52B0.1771530.4531270.2287040.031*0.46 (2)
C6B0.379 (4)0.523 (3)0.2789 (11)0.031 (6)0.46 (2)
H61B0.4870040.6119570.2727420.037*0.46 (2)
H62B0.3253710.5570110.3063480.037*0.46 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br1A0.0381 (4)0.0417 (4)0.0497 (4)0.0173 (4)0.0012 (3)0.0058 (3)
Br2A0.0477 (5)0.0446 (4)0.0371 (4)0.0225 (4)0.0084 (3)0.0032 (3)
Br3A0.0438 (5)0.0476 (4)0.0374 (4)0.0224 (4)0.0079 (4)0.0047 (3)
O2W0.064 (6)0.061 (4)0.083 (7)0.032 (3)0.002 (5)0.001 (2)
O1W0.072 (5)0.072 (5)0.072 (6)0.037 (5)0.007 (2)0.007 (2)
N1A0.032 (8)0.065 (11)0.050 (9)0.029 (9)0.023 (7)0.014 (9)
N2A0.036 (9)0.043 (8)0.044 (10)0.019 (7)0.014 (7)0.006 (7)
C1A0.031 (9)0.037 (10)0.091 (18)0.001 (8)0.021 (10)0.021 (14)
C2A0.079 (16)0.044 (10)0.042 (9)0.028 (12)0.003 (8)0.010 (8)
C3A0.088 (18)0.112 (19)0.048 (10)0.080 (16)0.017 (9)0.033 (9)
C4A0.031 (8)0.042 (11)0.089 (17)0.021 (8)0.022 (10)0.004 (14)
C5A0.08 (2)0.054 (13)0.08 (2)0.053 (15)0.005 (14)0.019 (12)
C6A0.036 (12)0.023 (10)0.072 (17)0.011 (9)0.017 (9)0.001 (9)
N1B0.037 (9)0.032 (8)0.023 (7)0.006 (8)0.008 (6)0.002 (6)
N2B0.037 (10)0.044 (11)0.026 (8)0.028 (10)0.008 (7)0.009 (7)
C1B0.035 (9)0.031 (9)0.055 (14)0.003 (8)0.014 (9)0.019 (9)
C2B0.051 (15)0.038 (12)0.039 (11)0.019 (13)0.020 (11)0.018 (10)
C3B0.052 (13)0.064 (16)0.034 (10)0.033 (13)0.012 (10)0.012 (12)
C4B0.040 (10)0.047 (11)0.044 (12)0.029 (9)0.012 (8)0.021 (11)
C5B0.009 (11)0.030 (10)0.025 (13)0.001 (9)0.000 (8)0.007 (9)
C6B0.034 (14)0.034 (12)0.028 (13)0.020 (11)0.012 (10)0.004 (9)
Geometric parameters (Å, º) top
O2W—H21W0.8201 (14)C4A—H42A0.9700
O2W—H22W0.8201 (14)C5A—C6A1.519 (17)
O2W—H23W0.8201 (15)C5A—H51A0.9700
O2W—H21Wi0.8201 (14)C5A—H51B0.9700
O2W—H22Wi0.8201 (14)C6A—H61A0.9700
O2W—H23Wi0.8201 (14)C6A—H62A0.9700
O1W—H11W0.8201 (14)N1B—C3B1.47 (2)
O1W—H12W0.8201 (14)N1B—C1B1.519 (18)
O1W—H13W0.8201 (15)N1B—C5B1.537 (17)
O1W—H11Wii0.8201 (14)N1B—H1B0.9800
O1W—H12Wii0.8201 (14)N2B—C6B1.477 (17)
O1W—H13Wii0.8201 (14)N2B—C2B1.48 (2)
N1A—C3A1.507 (19)N2B—C4B1.494 (19)
N1A—C1A1.519 (19)N2B—H2B0.9800
N1A—C5A1.537 (17)C1B—C2B1.52 (2)
N1A—H1A0.9800C1B—H11B0.9700
N2A—C2A1.461 (19)C1B—H12B0.9700
N2A—C6A1.470 (16)C2B—H21B0.9700
N2A—C4A1.504 (19)C2B—H22B0.9700
N2A—H2A0.9800C3B—C4B1.56 (2)
C1A—C2A1.502 (19)C3B—H31B0.9700
C1A—H11A0.9700C3B—H32B0.9700
C1A—H12A0.9700C4B—H41B0.9700
C2A—H21A0.9700C4B—H42B0.9700
C2A—H22A0.9700C5B—C6B1.511 (16)
C3A—C4A1.55 (2)C5B—H10.9700
C3A—H31A0.9700C5B—H52B0.9700
C3A—H32A0.9700C6B—H61B0.9700
C4A—H41A0.9700C6B—H62B0.9700
H21W—O2W—H22W105 (4)N2A—C4A—H42A109.6
H21W—O2W—H23W107 (4)C3A—C4A—H42A109.6
H22W—O2W—H23W104 (4)H41A—C4A—H42A108.1
H21W—O2W—H21Wi72 (10)C6A—C5A—N1A108.0 (13)
H22W—O2W—H21Wi175 (8)C6A—C5A—H51A110.1
H23W—O2W—H21Wi81 (9)N1A—C5A—H51A110.1
H21W—O2W—H22Wi175 (8)C6A—C5A—H51B110.1
H22W—O2W—H22Wi78 (7)N1A—C5A—H51B110.1
H23W—O2W—H22Wi68 (8)H51A—C5A—H51B108.4
H21Wi—O2W—H22Wi105 (4)N2A—C6A—C5A107.1 (13)
H21W—O2W—H23Wi81 (9)N2A—C6A—H61A110.3
H22W—O2W—H23Wi68 (8)C5A—C6A—H61A110.3
H23W—O2W—H23Wi170 (10)N2A—C6A—H62A110.3
H21Wi—O2W—H23Wi107 (4)C5A—C6A—H62A110.3
H22Wi—O2W—H23Wi104 (4)H61A—C6A—H62A108.6
H11W—O1W—H12W108 (2)C3B—N1B—C1B108.6 (14)
H11W—O1W—H13W108 (2)C3B—N1B—C5B114.1 (15)
H12W—O1W—H13W108 (2)C1B—N1B—C5B106.6 (14)
H11W—O1W—H11Wii74 (8)C3B—N1B—H1B109.2
H12W—O1W—H11Wii58 (6)C1B—N1B—H1B109.2
H13W—O1W—H11Wii165 (7)C5B—N1B—H1B109.2
H11W—O1W—H12Wii58 (6)C6B—N2B—C2B110.7 (18)
H12W—O1W—H12Wii164 (6)C6B—N2B—C4B111.0 (18)
H13W—O1W—H12Wii85 (5)C2B—N2B—C4B107.9 (14)
H11Wii—O1W—H12Wii108 (2)C6B—N2B—H2B109.1
H11W—O1W—H13Wii165 (7)C2B—N2B—H2B109.1
H12W—O1W—H13Wii85 (5)C4B—N2B—H2B109.1
H13W—O1W—H13Wii75 (9)N1B—C1B—C2B108.6 (14)
H11Wii—O1W—H13Wii108 (2)N1B—C1B—H11B110.0
H12Wii—O1W—H13Wii108 (2)C2B—C1B—H11B110.0
C3A—N1A—C1A109.2 (13)N1B—C1B—H12B110.0
C3A—N1A—C5A108.7 (17)C2B—C1B—H12B110.0
C1A—N1A—C5A109.2 (15)H11B—C1B—H12B108.4
C3A—N1A—H1A109.9N2B—C2B—C1B108.1 (13)
C1A—N1A—H1A109.9N2B—C2B—H21B110.1
C5A—N1A—H1A109.9C1B—C2B—H21B110.1
C2A—N2A—C6A110.7 (18)N2B—C2B—H22B110.1
C2A—N2A—C4A109.2 (13)C1B—C2B—H22B110.1
C6A—N2A—C4A109.9 (16)H21B—C2B—H22B108.4
C2A—N2A—H2A109.0N1B—C3B—C4B106.6 (13)
C6A—N2A—H2A109.0N1B—C3B—H31B110.4
C4A—N2A—H2A109.0C4B—C3B—H31B110.4
C2A—C1A—N1A108.8 (12)N1B—C3B—H32B110.4
C2A—C1A—H11A109.9C4B—C3B—H32B110.4
N1A—C1A—H11A109.9H31B—C3B—H32B108.6
C2A—C1A—H12A109.9N2B—C4B—C3B108.8 (15)
N1A—C1A—H12A109.9N2B—C4B—H41B109.9
H11A—C1A—H12A108.3C3B—C4B—H41B109.9
N2A—C2A—C1A108.1 (14)N2B—C4B—H42B109.9
N2A—C2A—H21A110.1C3B—C4B—H42B109.9
C1A—C2A—H21A110.1H41B—C4B—H42B108.3
N2A—C2A—H22A110.1C6B—C5B—N1B106.5 (13)
C1A—C2A—H22A110.1C6B—C5B—H1110.4
H21A—C2A—H22A108.4N1B—C5B—H1110.4
N1A—C3A—C4A104.3 (12)C6B—C5B—H52B110.4
N1A—C3A—H31A110.9N1B—C5B—H52B110.4
C4A—C3A—H31A110.9H1—C5B—H52B108.6
N1A—C3A—H32A110.9N2B—C6B—C5B109.5 (14)
C4A—C3A—H32A110.9N2B—C6B—H61B109.8
H31A—C3A—H32A108.9C5B—C6B—H61B109.8
N2A—C4A—C3A110.4 (12)N2B—C6B—H62B109.8
N2A—C4A—H41A109.6C5B—C6B—H62B109.8
C3A—C4A—H41A109.6H61B—C6B—H62B108.2
C3A—N1A—C1A—C2A51 (2)C3B—N1B—C1B—C2B71 (2)
C5A—N1A—C1A—C2A68 (2)C5B—N1B—C1B—C2B52 (2)
C6A—N2A—C2A—C1A51 (2)C6B—N2B—C2B—C1B69 (2)
C4A—N2A—C2A—C1A71 (2)C4B—N2B—C2B—C1B53 (2)
N1A—C1A—C2A—N2A19 (3)N1B—C1B—C2B—N2B14 (3)
C1A—N1A—C3A—C4A71 (2)C1B—N1B—C3B—C4B52 (2)
C5A—N1A—C3A—C4A48 (2)C5B—N1B—C3B—C4B67 (2)
C2A—N2A—C4A—C3A49 (2)C6B—N2B—C4B—C3B50 (2)
C6A—N2A—C4A—C3A73 (2)C2B—N2B—C4B—C3B71 (2)
N1A—C3A—C4A—N2A19 (2)N1B—C3B—C4B—N2B15 (3)
C3A—N1A—C5A—C6A76 (3)C3B—N1B—C5B—C6B48 (2)
C1A—N1A—C5A—C6A43 (3)C1B—N1B—C5B—C6B72 (2)
C2A—N2A—C6A—C5A75 (3)C2B—N2B—C6B—C5B49 (3)
C4A—N2A—C6A—C5A46 (3)C4B—N2B—C6B—C5B71 (3)
N1A—C5A—C6A—N2A22 (3)N1B—C5B—C6B—N2B20 (3)
Symmetry codes: (i) x+2, x+y+1, z+2/3; (ii) y, x, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2W—H21W···Br1Aiii0.82 (1)2.56 (2)3.370 (5)168 (6)
O2W—H22W···Br2Aiv0.82 (1)2.62 (2)3.394 (4)158 (6)
O2W—H23W···Br3Ai0.82 (1)2.63 (2)3.4303 (12)167 (6)
O1W—H11W···Br3Aii0.82 (1)2.62 (2)3.411 (5)162 (6)
O1W—H12W···Br1A0.82 (1)2.59 (2)3.3591 (9)156 (5)
O1W—H13W···Br2Av0.82 (1)2.64 (2)3.439 (5)166 (6)
N1Aa—H1Aa···Br2A0.982.393.244 (13)145
N2Aa—H2Aa···Br3A0.982.373.240 (14)148
C1Aa—H11Aa···Br1Av0.973.033.74 (2)131
C1Aa—H12Aa···Br2Avi0.972.883.77 (2)154
C2Aa—H22Aa···Br3Aiii0.973.083.98 (2)154
C3Aa—H31Aa···Br3Avii0.973.043.606 (15)118
C3Aa—H32Aa···Br3Aiii0.973.123.95 (2)145
C4Aa—H41Aa···Br1Aiii0.972.833.652 (18)143
C4Aa—H42Aa···Br2Aiv0.973.043.812 (18)137
C5Aa—H51Aa···Br1Aviii0.972.943.90 (3)176
C5Aa—H51Ba···Br1Av0.972.953.72 (3)138
C6Aa—H61Aa···Br2Aiv0.972.863.70 (3)146
C6Aa—H62Aa···Br1A0.973.003.94 (3)165
N1Bb—H1Bb···Br2A0.982.363.249 (15)150
N2Bb—H2Bb···Br3A0.982.363.243 (16)149
C1Bb—H12Bb···Br2Avi0.973.073.549 (16)112
C2Bb—H21Bb···Br1A0.973.063.83 (2)137
C2Bb—H22Bb···Br2Aix0.972.923.78 (2)149
C3Bb—H32Bb···Br3Avii0.972.943.770 (19)145
C4Bb—H41Bb···Br3Aiii0.973.053.93 (2)151
C4Bb—H42Bb···Br1Aiii0.973.033.544 (18)114
C5Bb—H1b···Br1Aviii0.973.023.85 (2)145
C5Bb—H52Bb···Br1Av0.972.763.71 (2)170
C6Bb—H61Bb···Br2Aiv0.972.963.89 (4)162
C6Bb—H62Bb···Br1A0.972.963.79 (4)145
Symmetry codes: (i) x+2, x+y+1, z+2/3; (ii) y, x, z+1; (iii) x+1, x+y, z+2/3; (iv) xy+1, y+1, z+1/3; (v) x, x+y, z+2/3; (vi) xy, y, z+1/3; (vii) y+1, xy, z1/3; (viii) y+1, xy+1, z1/3; (ix) x+y, x, z+1/3.
(1,4-diazabicyclo[2.2.2]octane) hydronium tri-bromide (dabco1_h168b6_abs2) top
Crystal data top
C6H14N2·3Br·H3Dx = 2.093 Mg m3
Mr = 372.94Cu Kα radiation, λ = 1.54184 Å
Trigonal, P3c1Cell parameters from 15432 reflections
a = 16.0425 (1) Åθ = 5.5–71.2°
c = 7.9666 (7) ŵ = 12.37 mm1
V = 1775.61 (16) Å3T = 299 K
Z = 6Plate, clear colourless
F(000) = 10800.48 × 0.28 × 0.14 mm
Data collection top
Xcalibur, Ruby
diffractometer
2269 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source2033 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.057
Detector resolution: 10.4922 pixels mm-1θmax = 71.2°, θmin = 3.2°
Absorption correction: analytical
CrysAlisPro 1.171.40.57a (Rigaku Oxford Diffraction, 2019) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R.C. Clark & J.S. Reid. (Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.
h = 1919
Tmin = 0.060, Tmax = 0.334k = 1919
37462 measured reflectionsl = 99
Refinement top
Refinement on F2H atoms treated by a mixture of independent and constrained refinement
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0539P)2 + 0.2214P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.029(Δ/σ)max = 0.001
wR(F2) = 0.081Δρmax = 0.44 e Å3
S = 1.05Δρmin = 0.47 e Å3
2269 reflectionsExtinction correction: SHELXL-2016/6 (Sheldrick 2016), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
131 parametersExtinction coefficient: 0.00143 (13)
13 restraintsAbsolute structure: Flack x determined using 934 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.02 (2)
Hydrogen site location: mixed
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O1W0.3333330.6666670.6967 (16)0.066 (3)0.834 (14)
H1W0.381 (5)0.664 (9)0.727 (9)0.079*0.834 (14)
O2W1.0000001.0000000.942 (3)0.086 (7)0.51 (2)
H2W0.946 (5)0.985 (16)0.906 (12)0.103*0.51 (2)
O1WA0.3333330.6666670.910 (8)0.066 (3)0.166 (14)
H1WA0.380 (19)0.66 (3)0.879 (17)0.079*0.166 (14)
O2WA1.0000001.0000000.687 (2)0.060 (5)0.49 (2)
H2WA0.951 (7)0.951 (7)0.719 (12)0.072*0.49 (2)
Br10.52723 (5)0.68784 (4)0.8224 (5)0.0517 (5)
Br20.82726 (5)0.80611 (5)0.8231 (5)0.0522 (5)
Br30.64555 (4)0.50584 (4)0.85219 (2)0.0452 (3)
O3W0.6666670.3333330.9623 (16)0.078 (3)
H3W0.644 (7)0.366 (6)0.917 (8)0.094*
N10.6640 (3)0.6712 (3)0.4887 (8)0.0378 (11)
H10.6615360.6747320.6113110.045*
N20.6690 (3)0.6620 (3)0.1785 (8)0.0385 (11)
H20.6712660.6585070.0559290.046*
C10.7133 (5)0.7713 (4)0.4200 (9)0.0480 (13)
H1A0.7783490.8073370.4636990.058*
H1B0.6787560.8039580.4527570.058*
C20.5636 (5)0.6166 (5)0.4237 (10)0.0527 (14)
H2A0.5286460.6491290.4549400.063*
H2B0.5307250.5525240.4720080.063*
C30.7188 (5)0.6220 (5)0.4445 (7)0.0432 (11)
H3A0.6878360.5580060.4931040.052*
H3B0.7837150.6580360.4886390.052*
C40.7155 (5)0.7647 (4)0.2288 (9)0.0489 (13)
H4A0.6814980.7943060.1785870.059*
H4B0.7815250.7988060.1893980.059*
C50.5668 (4)0.6100 (5)0.2326 (9)0.0471 (12)
H5A0.5363790.5431270.1981980.057*
H5B0.5323360.6387390.1810340.057*
C60.7217 (5)0.6154 (5)0.2529 (7)0.0435 (12)
H6A0.7879200.6479920.2142200.052*
H6B0.6913850.5484870.2185070.052*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O1W0.043 (4)0.043 (4)0.111 (9)0.0214 (19)0.0000.000
O2W0.066 (9)0.066 (9)0.12 (2)0.033 (4)0.0000.000
O1WA0.043 (4)0.043 (4)0.111 (9)0.0214 (19)0.0000.000
O2WA0.054 (7)0.054 (7)0.071 (11)0.027 (3)0.0000.000
Br10.0500 (4)0.0368 (4)0.0632 (11)0.0179 (2)0.0049 (3)0.0009 (2)
Br20.0507 (4)0.0500 (4)0.0650 (11)0.0320 (3)0.0031 (3)0.0045 (3)
Br30.0369 (4)0.0508 (4)0.0440 (7)0.0190 (2)0.0000 (2)0.0049 (2)
O3W0.053 (4)0.053 (4)0.129 (10)0.0264 (18)0.0000.000
N10.045 (2)0.038 (2)0.033 (3)0.0228 (18)0.0001 (13)0.0007 (14)
N20.046 (2)0.045 (2)0.032 (2)0.0276 (19)0.0003 (13)0.0017 (15)
C10.053 (3)0.031 (2)0.056 (4)0.018 (2)0.014 (3)0.011 (2)
C20.034 (3)0.055 (3)0.060 (4)0.016 (2)0.016 (2)0.002 (3)
C30.057 (3)0.050 (3)0.037 (3)0.038 (3)0.002 (2)0.003 (2)
C40.057 (3)0.036 (3)0.048 (3)0.019 (2)0.016 (2)0.017 (2)
C50.035 (2)0.053 (3)0.052 (3)0.021 (2)0.015 (2)0.009 (2)
C60.051 (3)0.055 (3)0.039 (3)0.037 (3)0.003 (2)0.011 (2)
Geometric parameters (Å, º) top
O1W—H1W0.82 (2)N2—C51.484 (7)
O1W—H1Wi0.82 (2)N2—C41.485 (7)
O1W—H1Wii0.83 (2)N2—C61.503 (7)
O2W—H2W0.83 (2)N2—H20.9800
O2W—H2Wiii0.83 (2)C1—C41.529 (8)
O2W—H2Wiv0.83 (2)C1—H1A0.9700
O1WA—H1WA0.83 (2)C1—H1B0.9700
O1WA—H1WAi0.83 (2)C2—C51.529 (8)
O1WA—H1WAii0.83 (2)C2—H2A0.9700
O2WA—H2WA0.83 (2)C2—H2B0.9700
O2WA—H2WAiii0.83 (2)C3—C61.532 (7)
O2WA—H2WAiv0.83 (2)C3—H3A0.9700
O3W—H3W0.84 (3)C3—H3B0.9700
O3W—H3Wv0.84 (3)C4—H4A0.9700
O3W—H3Wvi0.84 (3)C4—H4B0.9700
N1—C31.488 (7)C5—H5A0.9700
N1—C21.489 (8)C5—H5B0.9700
N1—C11.494 (7)C6—H6A0.9700
N1—H10.9800C6—H6B0.9700
H1W—O1W—H1Wi112 (5)N1—C2—C5108.9 (5)
H1W—O1W—H1Wii112 (5)N1—C2—H2A109.9
H1Wi—O1W—H1Wii112 (5)C5—C2—H2A109.9
H2W—O2W—H2Wiii109 (7)N1—C2—H2B109.9
H2W—O2W—H2Wiv109 (7)C5—C2—H2B109.9
H2Wiii—O2W—H2Wiv109 (7)H2A—C2—H2B108.3
H1WA—O1WA—H1WAi111 (9)N1—C3—C6108.7 (5)
H2WA—O2WA—H2WAiv111 (7)N1—C3—H3A110.0
H2WAiii—O2WA—H2WAiv111 (7)C6—C3—H3A110.0
H3W—O3W—H3Wv103 (5)N1—C3—H3B110.0
H3W—O3W—H3Wvi103 (5)C6—C3—H3B110.0
H3Wv—O3W—H3Wvi103 (5)H3A—C3—H3B108.3
C3—N1—C2111.0 (4)N2—C4—C1109.2 (5)
C3—N1—C1110.3 (4)N2—C4—H4A109.8
C2—N1—C1109.9 (4)C1—C4—H4A109.8
C3—N1—H1108.5N2—C4—H4B109.8
C2—N1—H1108.5C1—C4—H4B109.8
C1—N1—H1108.5H4A—C4—H4B108.3
C5—N2—C4110.2 (4)N2—C5—C2108.4 (5)
C5—N2—C6110.2 (4)N2—C5—H5A110.0
C4—N2—C6110.6 (4)C2—C5—H5A110.0
C5—N2—H2108.6N2—C5—H5B110.0
C4—N2—H2108.6C2—C5—H5B110.0
C6—N2—H2108.6H5A—C5—H5B108.4
N1—C1—C4108.0 (5)N2—C6—C3108.3 (5)
N1—C1—H1A110.1N2—C6—H6A110.0
C4—C1—H1A110.1C3—C6—H6A110.0
N1—C1—H1B110.1N2—C6—H6B110.0
C4—C1—H1B110.1C3—C6—H6B110.0
H1A—C1—H1B108.4H6A—C6—H6B108.4
Symmetry codes: (i) x+y, x+1, z; (ii) y+1, xy+1, z; (iii) x+y+1, x+2, z; (iv) y+2, xy+1, z; (v) y+1, xy, z; (vi) x+y+1, x+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···Br10.82 (2)2.31 (3)3.121 (4)169 (12)
O2W—H2W···Br20.83 (2)2.6 (2)3.102 (8)119 (18)
O1WA—H1WA···Br10.83 (2)2.23 (11)3.037 (15)165 (40)
O2WA—H2WA···Br20.83 (2)2.33 (4)3.148 (6)171 (17)
O3W—H3W···Br30.84 (3)2.30 (5)3.079 (4)154 (9)
N1—H1···Br10.982.823.541 (6)131
N1—H1···Br20.982.963.602 (7)124
N1—H1···Br30.983.223.837 (5)122
N2—H2···Br1vii0.983.183.787 (6)122
N2—H2···Br2vii0.983.063.734 (7)127
N2—H2···Br3vii0.982.793.497 (5)130
C1—H1A···Br20.972.973.598 (6)123
C1—H1B···Br1viii0.972.953.738 (7)139
C2—H2A···Br10.973.003.521 (7)115
C2—H2B···Br3ix0.973.083.817 (7)134
C3—H3A···Br30.972.963.635 (6)128
C3—H3B···Br2x0.973.123.840 (7)132
C4—H4A···Br1viii0.973.123.838 (7)132
C4—H4B···Br2vii0.973.003.593 (6)121
C5—H5A···Br3ix0.973.013.781 (7)137
C5—H5B···Br1vii0.972.983.665 (6)129
C6—H6A···Br2x0.972.973.751 (6)139
C6—H6B···Br3vii0.973.003.553 (6)117
Symmetry codes: (vii) x, y, z1; (viii) x, xy+1, z1/2; (ix) y+1, x+1, z1/2; (x) x+y+1, y, z1/2.
 

Funding information

This research was supported by the statutory funds of our institutions.

References

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IUCrJ
Volume 9| Part 5| September 2022| Pages 544-550
ISSN: 2052-2525