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Crystal structure of N-butyl-2,3-bis­­(di­cyclo­hexyl­amino)­cyclo­propeniminium chloride benzene monosolvate

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aDepartment of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, PA 19122, USA
*Correspondence e-mail: mzdilla@temple.edu

Edited by V. Jancik, Universidad Nacional Autónoma de México, México (Received 25 December 2021; accepted 11 August 2022; online 23 August 2022)

N-Butyl-2,3-bis­(di­cyclo­hexyl­amino)­cyclo­propenimine (1) crystallizes from benzene and hexa­nes in the presence of HCl as a mono­benzene solvate of the hydro­chloride salt, [1H]Cl·C6H6 or C31H54N3+·Cl·C6H6, in the P21/n space group. The protonation of 1 results in the generation of an aromatic structure based upon the delocalization of the cyclo­propene double bond around the cyclo­propene ring, giving three inter­mediate C—C bond lengths of ∼1.41 Å, and the delocalization of the imine-type C—N double bond, giving three inter­mediate C—N bond lengths of ∼1.32 Å. Ion–ion and ion–benzene packing inter­actions are described and illustrated.

1. Chemical context

Penta­substituted di­amino­propenimines are a relatively new class of superbases that operate via the establishment of a stable aromatic electronic delocalization upon protonation. Originally reported as four-electron Lewis donors (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]), a more recently exploited application for the use of penta­substituion is that of a superbase, with one of the six nitro­gen coordination sites available for protonation, making these mol­ecules facile initiators of stereoselective Michael (Bandar & Lambert, 2012[Bandar, J. S. & Lambert, T. H. (2012). J. Am. Chem. Soc. 134, 5552-5555.]) and Mannich reactions (Bandar & Lambert, 2013[Bandar, J. S. & Lambert, T. H. (2013). J. Am. Chem. Soc. 135, 11799-11802.]), hydro­aminations (Mirabdolbaghi & Dudding, 2015[Mirabdolbaghi, R. & Dudding, T. (2015). Org. Lett. 17, 1930-1933.]), and ring-opening polymerization (Stukenbroeker et al., 2015[Stukenbroeker, T. S., Bandar, J. S., Zhang, X., Lambert, T. H. & Waymouth, R. M. (2015). ACS Macro Lett. 4, 853-856.]; Xu et al., 2018[Xu, J., Liu, J., Li, Z., Xu, S., Wang, H., Guo, T., Gao, Y., Zhang, L., Zhang, C. & Guo, K. (2018). Polym. Chem. 9, 2183-2192.]). A number of examples of acid salts of these species have been structurally characterized, permitting direct observation of the aromatized cyclo­propeniminium structures (Stukenbroeker et al., 2015[Stukenbroeker, T. S., Bandar, J. S., Zhang, X., Lambert, T. H. & Waymouth, R. M. (2015). ACS Macro Lett. 4, 853-856.]; Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]; Bandar et al., 2015[Bandar, J. S., Barthelme, A., Mazori, A. Y. & Lambert, T. H. (2015). Chem. Sci. 6, 1537-1547.]; Belding & Dudding, 2014[Belding, L. & Dudding, T. (2014). Chem. Eur. J. 20, 1032-1037.]; Guest et al., 2020[Guest, M., Le Sueur, R., Pilkington, M. & Dudding, T. (2020). Chem. Eur. J. 26, 8608-8620.]; Kozma et al., 2015[Kozma, Á., Rust, J. & Alcarazo, M. (2015). Chem. Eur. J. 21, 10829-10834.]; Belding et al., 2016[Belding, L., Stoyanov, P. & Dudding, T. (2016). J. Org. Chem. 81, 6-13.]; Bandar & Lambert, 2012[Bandar, J. S. & Lambert, T. H. (2012). J. Am. Chem. Soc. 134, 5552-5555.], 2013[Bandar, J. S. & Lambert, T. H. (2013). J. Am. Chem. Soc. 135, 11799-11802.]; Mirabdolbaghi & Dudding, 2015[Mirabdolbaghi, R. & Dudding, T. (2015). Org. Lett. 17, 1930-1933.]). Examples of free-base penta­substituted di­amino­propenimines are uncommon, and these are typically only obtained with aromatic substituents at the imine position, which decreases the basicity of the imine by the delocalization of the nitro­gen lone pair p-orbital into the aromatic group, facilitating isolation (Guest et al., 2020[Guest, M., Le Sueur, R., Pilkington, M. & Dudding, T. (2020). Chem. Eur. J. 26, 8608-8620.]; Kozma et al., 2015[Kozma, Á., Rust, J. & Alcarazo, M. (2015). Chem. Eur. J. 21, 10829-10834.]; Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]). Some of these (Guest et al., 2020[Guest, M., Le Sueur, R., Pilkington, M. & Dudding, T. (2020). Chem. Eur. J. 26, 8608-8620.]; Kozma et al., 2015[Kozma, Á., Rust, J. & Alcarazo, M. (2015). Chem. Eur. J. 21, 10829-10834.]; Belding & Dudding, 2014[Belding, L. & Dudding, T. (2014). Chem. Eur. J. 20, 1032-1037.]) are bis­(cylopropenimine) variants of the famous `proton sponge', 1,8-bis­(di­methyl­amino)­naphthalene and related classes of bifunctional Lewis superbases (Alder et al., 1968[Alder, R. W., Bowman, P. S., Steele, W. R. S. & Winterman, D. R. (1968). Chem. Commun. pp. 723-724.]). The only other example, to our knowledge, is an N-amino­substituted example, which also decreases the basicity of the nitro­gen lone pair by induction, a minor resonance structure delocalizing the double bond into the N—N contact, and, in the crystal structure, a nearby hydrogen bond with a water proton (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]).

[Scheme 1]

N-Butyl-2,3-bis­(di­cyclo­hexyl­amino)­cyclo­propenimine (1) is a newer version of superbase with improved basicity, which has been explored as a catalyst for ring-opening polymerization. Cyclo­propenimines have a conjugate acid pKa of about 27, an improvement over that of the superbase 2-tert-butyl-1,1,3,3-tetra­methyl­guanidine (BTMG), which has a pKa of 23.56 (Bandar & Lambert, 2012[Bandar, J. S. & Lambert, T. H. (2012). J. Am. Chem. Soc. 134, 5552-5555.]). This allows 1[link] to deprotonate a lactide and initiate polymerization in the synthesis of polylactic acid, as shown in Fig. 1[link] (Stukenbroeker et al., 2015[Stukenbroeker, T. S., Bandar, J. S., Zhang, X., Lambert, T. H. & Waymouth, R. M. (2015). ACS Macro Lett. 4, 853-856.]). Compound 1 can mediate the polymerization of lactic acid to 99% completion in 10 minutes or less. However, no X-ray crystal structure of the free base, nor an acid salt of this superbase has been reported. In this report we provide the first X-ray crystallographic structure of a benzene solvate of the hydro­chloride salt [1H]Cl·C6H6.

[Figure 1]
Figure 1
Catalytic ring-opening polymerization mediated by 1.

2. Structural commentary

[1H]Cl crystallizes in the P21/n space group on a general position as a closely associated ion pair, with the protonation site at the n-butyl imine as expected, and one formula unit in the asymmetric unit, as well as one benzene molecule, also on a general position (Fig. 2[link]). The organic salt and the benzene molecule are generally well ordered, except for the δ methyl carbon of the n-butyl group, which shows a mild wagging disorder. This disorder was treated with a two-site disorder model.

[Figure 2]
Figure 2
Displacement ellipsoid plot of the asymmetric unit of [1H]Cl·C6H6 with ellipsoids set at the 50% probability level. Hydrogen atoms shown as small spheres.

Free-base 1 would be expected to have localized double bonds at the n-butyl­imine C=N position, and at the opposing cyclo­propene position (see scheme[link]). In the isolated free base of 1-mesityl-2,3-bis­(diiso­propyl­amino)­cyclo­propenimine (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]), the unprotonated C=N imine bond is 1.2951 (14) Å in length, while the C—N bonds to the tertiary amines are longer, at an average of 1.3494 (10) Å. The localized cyclo­propene double bond is shorter, at 1.3712 (14) Å, than the single bonded C—C cyclo­propene contacts at an average of 1.4155 (10) Å. Protonation of the n-butyl­imine position during crystal growth results in all nitro­gen atoms being three-coordinate, leading to delocalization of the imine double-bond character across all three C—N contacts. Correspondingly, the cyclo­propene double bond is delocalized around the ring, giving a three-membered aromatic system. In [1H]Cl, the central C3N3 triangle is thus highly planar, with the six atoms exhibiting an r.m.s. deviation of only 0.0052 Å from the best-fit plane of the six atoms. The three C—N bonds are approximately equal in length, with the two tertiary cyclo­hexyl­amine positions having C—N lengths of 1.3279 (13) Å on average. The C—N bond to the protonated butyl nitro­gen is only slightly shorter at 1.319 (2) Å. The three cyclo­propene C—C bonds exhibit lengths consistent with aromaticity; the unique C—C bond opposite the n-butyl group is 1.388 (2) Å, while the other two C—C bonds are similar or slightly shorter at 1.377 (2) and 1.383 (2) Å. Though these latter two bonds are equivalent under mol­ecular point symmetry, their differences are attributed to the asymmetric crystal packing environment of the P21/n space group. The comparable nature of the bond metrics of the three C—N bonds and the three cyclo­propenyl C—C bonds is consistent with aromatization, and an analogous aromatization of the C3N3 core of 1-mesityl-2,3-bis­(diiso­propyl­amino)­cyclo­propeniminium tetra­fluoro­borate was observed in the crystal structure of this salt (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]). See Table 1[link] for C3N3 bond metrics.

Table 1
Comparative bond lengths (Å) for 1-mesityl-2,3-bis­(diiso­propyl­amino)­cyclo­propenimine, 1-mesityl-2,3-bis­(diiso­propyl­amino)­cyclo­propeniminium (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]), and N-n-butyl-2,3-bis­(di­cyclo­hex­yl)cyclo­propeniminium

Divided entries refer to separate, related pairs of atoms and their associated metrics, e.g., 1.3450 (14)/1.3539 (14) denotes two distances for the two C—N(amine) contacts.

  Mes(C3N3)iPr4 [Mes(C3N3H)iPr4]BF4 [Bu(C3N3H)Cy4]Cl([1H]Cl)
C—N(imine) 1.2951 (14) 1.3342 (16) 1.319 (2)
C—N(amine) 1.3450 (14)/1.3539 (14) 1.3205 (15)/1.3286 (16) 1.3248 (17)/1.331 (2)
C—C(para) 1.3712 (14) 1.3984 (17) 1.388 (2)
C—C(meta) 1.4202 (14)/1.4108 (14) 1.3792 (16)/1.3827 (16) 1.377 (2)/1.3831 (19)

The comparison between free-base forms of cyclo­propenimine (Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]) and the protonated forms demonstrate aromatization upon protonation, and explain the behavior of 1 as a superbase. While alkyl­imines are typically weak bases (pKa of conjugate acid ranges from about 2–5 (Fraser et al., 1983[Fraser, R. R., Bresse, M., Chuaqui-Offermanns, N., Houk, K. N. & Rondan, N. G. (1983). Can. J. Chem. 61, 2729-2734.]), the pKa of 1H+ is a staggering 27 (Bandar & Lambert, 2012[Bandar, J. S. & Lambert, T. H. (2012). J. Am. Chem. Soc. 134, 5552-5555.]), more on the scale of a C—H bond. The drastic difference in basicity between typical alkyl­imines and 1 can be explained by the observed aromatization upon proton­ation. As a result, the 1H resonance of the N—H hydrogen in [1H]Cl is a sharp singlet at 7.4 ppm in deuterated chloro­form, suggesting little to no exchange like that typically observed for broad N—H resonances. The stabilization of a mol­ecule by aromatization is qu­anti­fied by the Dewar Resonance Energy (DRE), which ranges from about 6–25 kJ mol−1 per π electron (Slayden & Liebman, 2001[Slayden, S. W. & Liebman, J. F. (2001). Chem. Rev. 101, 1541-1566.]). Thus in the case of 1, aromatic stabilization between 12 and 50 kJ mol−1 upon protonation explains the large reported basicity.

3. Supra­molecular features

Inter­ionic/mol­ecular inter­actions were examined using packing diagrams, and by the determination of partial atomic charge from Hirshfeld analysis. In the following discussion Hirshfeld charges are presented in parenthesis. The proton of the butyl­imine group (+0.121) inter­acts strongly with the chloride ion (−0.666) at a short H⋯Cl distance of 2.26 (2) Å. The chloride is positioned in a pocket surrounded by hydrogen atoms. In addition to the strong inter­action with the acidic N—H proton, the chloride resides 2.8152 (7) Å from a benzene proton, H6AA (+0.046), and 2.7169 (6) Å from an intra­molecular axial cyclo­hexyl proton, H29A (+0.050). The crystal packing demonstrates that the C3N3 planes of all mol­ecules pack parallel to each other (as required by the space-group symmetry), with a normal slightly oblique to the (101) plane (see Fig. 3[link]). The mol­ecular planes stack in a staggered fashion via inter­vening inversion centers at the origin (Fig. 3[link], red) and at the center of the a edge (Fig. 3[link], teal). One face of the benzene solvent molecule inter­acts distally with the cyclo­hexyl group of one 1H+ ion [closest atomic C⋯C distance: 3.829 (3) Å, Fig. 3[link], green line], while the other face inter­acts distally with the disordered methyl group of the n-butyl chain [closest atomic C⋯C distance: 4.29 (3) Å, Fig. 3[link], orange line]. The benzene inter­acts weakly with two chloride ions approximately along its equatorial plane (Fig. 3[link], blue lines), one via H6S (+0.069) with H⋯Cl = 2.8152 (7) Å, also shown in Fig. 2[link], and the other via H3S (+0.062) with H⋯Cl = 2.8365 (7) Å. These benzene–chlorine inter­actions form a channel along the (101) plane, each channel situated 1/4 of the way along the b axis (Fig. 4[link], top). Viewed from 90° along the [101] direction, the benzene solvent molecules sit along a second channel, with the chloride ions sitting at the inter­sections of both channels, providing ionic bonds to the surrounding 1H+ cations (Fig. 4[link], bottom). In this latter view, it is apparent that along the [101] direction, the chloride ions are positioned between the axial protons H26 (+0.058) and H29B (+0.059) of the flanking cyclo­hexyl groups. In summary, the 1H+ cations inter­act with each other and through the benzene solvent molecule via their alkyl groups, and the chloride counter-ion is situated in a pocket of cyclo­hexyl and benzene C—H contacts, with the proximal N—H inter­action on one side.

[Figure 3]
Figure 3
Partially packed thermal ellipsoid plot of [1H]Cl·C6H6 showing neighboring inter­molecular/inter­ionic nearest neighbor inter­actions.
[Figure 4]
Figure 4
Top: Packed unit cell viewed along the 101 plane. Bottom: Packed unit cell viewed along the [101] direction.

4. Database survey

In addition to the penta­substituted examples discussed above, a survey of the Cambridge Structural Database (CSD, Version 5.34, November 2021; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for cyclo­propenimines reveals a number of other relevant structures. The parent (unsubstituted) di­amino­propeniminium cation has been structurally characterized with chloride and iodide counter-cations (UJAVEI and UJAVIM; Mishiro et al., 2016[Mishiro, K., Hu, F., Paley, D. W., Min, W. & Lambert, T. H. (2016). Eur. J. Org. Chem. pp. 1655-1659.]). Aprotic hexa­substituted examples are reported, and represent planar polyatomic cations (AHUVEH, Holthoff et al., 2020[Holthoff, J. M., Engelage, E., Weiss, R. & Huber, S. M. (2020). Angew. Chem. Int. Ed. 59, 11150-11157.]; DOSRUB, Abdelbassit et al., 2019[Abdelbassit, M. S., Curnow, O. J., Dixon, M. K. & Waterland, M. R. (2019). Chem. Eur. J. 25, 11650-11658.]; FURCIH, Clark et al., 1995[Clark, G. R., Surman, P. W. J. & Taylor, M. J. (1995). Faraday Trans. 91, 1523-1528.]; GAXYEJ, Radhakrishnan et al., 1987b[Radhakrishnan, T. P., Van Engen, D. & Soos, Z. G. (1987b). Mol. Cryst. Liq. Cryst. 150b, 473-492.]; GERXUX02, Butchard et al., 2012[Butchard, J. R., Curnow, O. J., Garrett, D. J., Maclagan, R. G. A. R., Libowitzky, E., Piccoli, P. M. B. & Schultz, A. J. (2012). Dalton Trans. 41, 11765-11775.]; GUNDUR, Curnow & Senthooran, 2020[Curnow, O. J. & Senthooran, R. (2020). Dalton Trans. 49, 9579-9582.]; IFAGUU, Curnow et al., 2018[Curnow, O. J., Polson, M. I. J., Walst, K. J. & Yunis, R. (2018). RSC Adv. 8, 28313-28322.]; LAYYOC01, Jin et al., 2018[Jin, Y., Wang, B., Zhang, W., Huang, S., Wang, K., Qi, X. & Zhang, Q. (2018). Chem. Eur. J. 24, 4620-4627.]; NUYBOB, Guest et al., 2020[Guest, M., Le Sueur, R., Pilkington, M. & Dudding, T. (2020). Chem. Eur. J. 26, 8608-8620.]; SERVIW, Kniep et al., 2013[Kniep, F., Jungbauer, S. H., Zhang, Q., Walter, S. M., Schindler, S., Schnapperelle, I., Herdtweck, E. & Huber, S. M. (2013). Angew. Chem. Int. Ed. 52, 7028-7032.]; TUSDOD, Radhakrishnan et al., 1987a[Radhakrishnan, T. P., Van Engen, D. & Soos, Z. G. (1987a). J. Phys. Chem. 91, 3273-3277.]; UGITIQ, Barthes et al., 2020[Barthes, C., Duhayon, C., Canac, Y. & César, V. (2020). Chem. Commun. 56, 3305-3308.], XIKYAT01, ZABFUG, Wallace et al., 2015[Wallace, A. J., Jayasinghe, C. D., Polson, M. I. J., Curnow, O. J. & Crittenden, D. L. (2015). J. Am. Chem. Soc. 137, 15528-15532.], XOSTIL, XOSTOR, XOSTUX, XOSVAF, XOSVEJ, Abdelbassit & Curnow, 2019[Abdelbassit, M. S. & Curnow, O. J. (2019). Chem. Eur. J. 25, 13294-13298.], YUVRAK, YUWJOR, Jungbauer et al., 2015[Jungbauer, S. H., Schindler, S., Herdtweck, E., Keller, S. & Huber, S. M. (2015). Chem. Eur. J. 21, 13625-13636.]). Another class of variants includes cyclo­propenemines tethered to ferrocene nuclei (TURNUQ, Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]; BEBPIK, BEBRAE, BEBREI, BEBRIM, BEBROS, Jess et al., 2017[Jess, K., Baabe, D., Freytag, M., Jones, P. G. & Tamm, M. (2017). Eur. J. Inorg. Chem. pp. 412-423.]). There are a few structural studies of Lewis complexes with metal ions (BEBRIM, Jess et al., 2017[Jess, K., Baabe, D., Freytag, M., Jones, P. G. & Tamm, M. (2017). Eur. J. Inorg. Chem. pp. 412-423.]; UGITOW, UGITUC, Barthes et al., 2020[Barthes, C., Duhayon, C., Canac, Y. & César, V. (2020). Chem. Commun. 56, 3305-3308.]; YOQPOM, Chen et al., 2019[Chen, W., Zhao, Y., Xu, W., Su, J.-H., Shen, L., Liu, L., Wu, B. & Yang, X.-J. (2019). Chem. Commun. 55, 9452-9455.]; TURNOK, Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]) or other boron-based Lewis acids (NUYBOB, Guest et al., 2020[Guest, M., Le Sueur, R., Pilkington, M. & Dudding, T. (2020). Chem. Eur. J. 26, 8608-8620.]; TURPOM, Bruns et al., 2010[Bruns, H., Patil, M., Carreras, J., Vázquez, A., Thiel, W., Goddard, R. & Alcarazo, M. (2010). Angew. Chem. Int. Ed. 49, 3680-3683.]). One structural report of a tris­ubstituted cyclo­propenimine is noted (XEXGEP; Xu et al., 2018[Xu, J., Liu, J., Li, Z., Xu, S., Wang, H., Guo, T., Gao, Y., Zhang, L., Zhang, C. & Guo, K. (2018). Polym. Chem. 9, 2183-2192.]), as well as several types of oligomeric versions (OGOLUT, OGORAF, OGOWOY, OGOWUE, OGOXAL, OGOXEP, OGOXIT, OGOXOZ, OGOXUF, OGOYAM, Kozma et al., 2015[Kozma, Á., Rust, J. & Alcarazo, M. (2015). Chem. Eur. J. 21, 10829-10834.]; SUSWAG, SUSWOU, Nacsa & Lambert, 2015[Nacsa, E. D. & Lambert, T. H. (2015). J. Am. Chem. Soc. 137, 10246-10253.]).

5. Synthesis and crystallization

Initially, crystals of [1H]Cl·C6H6 were obtained from the commercial sample of 1 via a double-vial apparatus by dissolution of N-butyl-2,3-bis­(di­cyclo­hexyl­amino)­cyclo­prop­enimine (1) in benzene in an inner vial, and charging the outer vial with hexa­nes. After diffusion for a few days at room temperature, powdery solid and a few colorless crystals of [1H]Cl·C6H6 were observed inside. The yield of crystalline [1H]Cl·C6H6 was significantly improved by the addition of HCl. To a glass shell vial containing 7.2 mg of N-butyl-2,3-bis­(di­cyclo­hexyl­amino)­cyclo­propenimine, 2 mL of benzene were added. A drop of dilute HCl (0.730 M) was added. This was diffused with 3 mL of hexa­nes in the outer vial for 2–3 days. Crystallization works best when the drop is not in contact with the walls of the vial where the crystals grow. Crystals were isolated by deca­nting the liquid from the inner vial using a disposable pipette, and taking care to remove the visible aqueous HCl droplet with the first pipette draw. After removing the mother liquor, the crystals were rinsed with hexa­nes. Yield 6.3 mg (70%). Yields in this small-scale preparation ranged from 22% to 70% across multiple attempts. 1H NMR (ppm) 400 MHz, CDCl3): δ(ppm): 0.97 (t, 3H, Me), 1.62–1.82 (m, 14H, Cy and Bu), 1.62–1.76 (m, 14H, Cy and Bu), 1.80 (d, 8H, Cy-β-H), 1.96 (d, 8H, Cy-β-H), 3.34 (tt, 4H, Cy-α-H), 3.56 (t, 2H, Bu-α-H), 7.4 (s, 1H, NH). 13C NMR (ppm) (400 MHz, CDCl3): δ(ppm): 13.97, 19.94, 24.58, 25.84, 32.34, 33.79, 46.15, 59.55, 114.01, 128.35. FTIR (cm−1): 2926 (m), 2851 (m), 1503 (s), 1445 (m), 1383 (w), 1374 (w), 1345 (w), 1324 (w), 1253 (w), 1188 (w), 1180 (w), 1102 (w), 1092 (w), 1004 (w), 895 (w), 696 (m). Analysis calculated for C31H53N3·0.5 C6H6 (%): C, 76.31; H, 10.38; N, 7.22. Found: C, 75.873; H, 10.83; N, 7.24. M.p. 353–356 K (decomposes).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. A disordered methyl group was treated with a two-site disorder model, with atom positions freely refined, and relative occupancies refined using Free Variable 2 with a final ratio of 0.71 (3): 0.29 (3). RIGU/SIMU restraints were applied to the wagging methyl group. C—H hydrogen atoms were treated using a standard riding model. The imine proton was located as a peak in the Fourier difference map and was freely refined.

Table 2
Experimental details

Crystal data
Chemical formula C31H54N3+·Cl·C6H6
Mr 582.33
Crystal system, space group Monoclinic, P21/n
Temperature (K) 100
a, b, c (Å) 12.253 (3), 22.699 (7), 12.884 (3)
β (°) 104.164 (7)
V3) 3474.6 (16)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.14
Crystal size (mm) 0.55 × 0.53 × 0.16
 
Data collection
Diffractometer Bruker D8 Quest Photon 100
Absorption correction Multi-scan (SADABS; Krause et al., 2015[Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3-10.])
Tmin, Tmax 0.662, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 48756, 8072, 6516
Rint 0.044
(sin θ/λ)max−1) 0.658
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.055, 0.136, 1.02
No. of reflections 8072
No. of parameters 385
No. of restraints 6
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.55, −0.40
Computer programs: COSMO, XPREP, and SAINT (Bruker, 2008[Bruker (2008). COSMO, SAINT, and XPREP. Bruker AXS Inc, Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. C71, 3-8.]), SHELXL (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. A71, 3-8.]), and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Hirshfeld charge was determined at the 3-21G/B3LYP level of theory by iterative computation of electronic structure of [1H]Cl·C6H6 using ORCA (Neese, 2018[Neese, F. (2018). WIREs Comput. Mol. Sci. 8, e1327.]) followed by rerefinement of the structure using non-spherical form factors computed using NoSpherA2 (Kleemiss et al., 2021[Kleemiss, F., Dolomanov, O. V., Bodensteiner, M., Peyerimhoff, N., Midgley, L., Bourhis, L. J., Genoni, A., Malaspina, L. A., Jayatilaka, D., Spencer, J. L., White, F., Grundkötter-Stock, B., Steinhauer, S., Lentz, D., Puschmann, H. & Grabowsky, S. (2021). Chem. Sci. 12, 1675-1692.]), and repeating the process until the structure converged. Hirshfeld charges resulting from this approach are given in Table 3[link].

Table 3
Hirshfeld charges of atoms in [1H]Cl·C6H6.

Cl1 −0.666 N1 −0.048 N2 −0.027
N3 −0.018 C1 0.026 C2 0.014
C3 0.024 C4 −0.036 C5 −0.102
C6 −0.095 C7 −0.133 C8 −0.011
C9 −0.103 C10 −0.093 C11 −0.097
C12 −0.088 C13 −0.093 C14 −0.008
C15 −0.097 C16 −0.094 C17 −0.098
C18 −0.098 C19 −0.101 C20 −0.005
C21 −0.094 C22 −0.093 C23 −0.093
C24 −0.091 C25 −0.093 C26 −0.002
C27 −0.096 C28 −0.094 C29 −0.099
C30 −0.093 C31 −0.097 C1S −0.058
C2S −0.071 C3S −0.078 C4S −0.084
C5S −0.082 C6S −0.064 H1S 0.071
H6S 0.069 H5S 0.065 H4S 0.062
H3S 0.062 H2S 0.056 H4A 0.051
H4B 0.075 H5A 0.061 H5b 0.042
H6AA 0.046 H6AB 0.055 H7A 0.050
H7B 0.039 H7C 0.051 H8 0.072
H9A 0.050 H9B 0.060 H10A 0.061
H10B 0.061 H11A 0.061 H11B 0.049
H12A 0.057 H12B 0.053 H13A 0.059
H13B 0.049 H14 0.066 H15A 0.057
H15B 0.062 H16A 0.051 H16B 0.052
H17A 0.055 H17B 0.051 H18A 0.056
H18B 0.062 H19A 0.055 H19B 0.065
H20 0.060 H21A 0.055 H21B 0.055
H22A 0.050 H22B 0.056 H23A 0.056
H23B 0.052 H24A 0.051 H24B 0.056
H25A 0.057 H25B 0.057 H26 0.058
H27A 0.049 H27B 0.062 H28A 0.044
H28B 0.057 H29A 0.050 H29B 0.059
H30A 0.061 H30B 0.039 H31A 0.047
H31B 0.064 H1 0.121    

Supporting information


Computing details top

Data collection: COSMO and XPREP (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

N-Butyl-2,3-bis(dicyclohexylamino)cyclopropeniminium chloride benzene monosolvate top
Crystal data top
C31H54N3+·Cl·C6H6Dx = 1.113 Mg m3
Mr = 582.33Melting point: 356 K
Monoclinic, P21/nMo Kα radiation, λ = 0.71076 Å
a = 12.253 (3) ÅCell parameters from 9959 reflections
b = 22.699 (7) Åθ = 2.6–29.6°
c = 12.884 (3) ŵ = 0.14 mm1
β = 104.164 (7)°T = 100 K
V = 3474.6 (16) Å3Chunk, colourless
Z = 40.55 × 0.53 × 0.16 mm
F(000) = 1280
Data collection top
Bruker D8 Quest Photon 100
diffractometer
8072 independent reflections
Radiation source: sealed tube6516 reflections with I > 2σ(I)
Detector resolution: 10.417 pixels mm-1Rint = 0.044
φ and ω scansθmax = 27.9°, θmin = 2.6°
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)
h = 1614
Tmin = 0.662, Tmax = 0.746k = 2929
48756 measured reflectionsl = 1616
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.055H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.136 w = 1/[σ2(Fo2) + (0.0605P)2 + 2.3777P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max = 0.001
8072 reflectionsΔρmax = 0.55 e Å3
385 parametersΔρmin = 0.40 e Å3
6 restraintsExtinction correction: SHELXL2018/3 (Sheldrick 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: dualExtinction coefficient: 0.0081 (7)
Special details top

Experimental. Single-crystal X-ray crystallographic data were obtained on a Bruker D8 Quest PHOTON 100 diffractometer with an Oxford Cryostream 700 low-temperature device. The radiation was from a sealed-tube molybdenum Kα source with a TRIUMPH monochromator. Crystals were typically multiple, and a single piece was cut away with a razor blade, mounted on a MiTeGen loop with paratone-N oil, and collected at 100K in ω/φ scansets. Integration was performed using SAINT, and data were reduced and absorption-corrected using SADABS (Bruker, 2008). Space group determination was performed using XPREP (Sheldrick, 2008), and the structure was solved using intrinsic phasing using SHELXT (Sheldrick,The structural model of [1H]Cl·C6H6 was refined using the least-squares approach with the ShelX package (Sheldrick, 2015a) with Olex2 as a GUI (Dolomanov et al., 2009). 2015b).

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)
Cl10.44296 (4)0.74552 (2)0.69373 (3)0.03152 (13)
N10.36809 (13)0.61997 (7)0.64021 (11)0.0287 (3)
N20.28059 (11)0.47671 (6)0.52228 (11)0.0214 (3)
N30.16710 (10)0.61804 (5)0.38294 (10)0.0153 (3)
C10.30625 (12)0.58844 (7)0.56140 (12)0.0187 (3)
C20.27226 (12)0.53505 (7)0.51360 (11)0.0161 (3)
C30.23000 (12)0.58703 (6)0.46257 (11)0.0152 (3)
C40.42658 (14)0.59655 (8)0.74386 (13)0.0258 (4)
H4A0.4821940.6258470.7814880.031*
H4B0.4680200.5604970.7332560.031*
C50.34533 (15)0.58187 (9)0.81298 (14)0.0297 (4)
H5A0.2996910.6171930.8185080.036*
H5B0.2933740.5504540.7775510.036*
C60.40470 (18)0.56176 (11)0.92421 (15)0.0417 (5)
H6AA0.4536900.5280010.9175690.050*0.71 (3)
H6AB0.4541390.5941030.9597930.050*0.71 (3)
H6BC0.4637450.5899930.9595470.050*0.29 (3)
H6BD0.4384140.5221860.9233340.050*0.29 (3)
C70.3303 (10)0.5437 (7)0.9956 (7)0.053 (2)0.71 (3)
H7A0.3769460.5315041.0653970.079*0.71 (3)
H7B0.2828710.5770331.0051810.079*0.71 (3)
H7C0.2824200.5107330.9628310.079*0.71 (3)
C7A0.302 (2)0.5607 (13)0.980 (2)0.052 (3)0.29 (3)
H7AA0.3291640.5481131.0550490.079*0.29 (3)
H7AB0.2695380.6002920.9782880.079*0.29 (3)
H7AC0.2444560.5331500.9424300.079*0.29 (3)
C80.36221 (13)0.45256 (7)0.61774 (12)0.0217 (3)
H80.3813820.4854890.6706310.026*
C90.47084 (15)0.43290 (10)0.59447 (16)0.0353 (4)
H9A0.5028620.4653280.5598800.042*
H9B0.4566790.3989840.5446530.042*
C100.55473 (15)0.41505 (11)0.69901 (17)0.0402 (5)
H10A0.6241440.3996940.6823820.048*
H10B0.5752680.4502690.7449650.048*
C110.50711 (16)0.36903 (8)0.75884 (15)0.0304 (4)
H11A0.5601590.3622420.8292200.036*
H11B0.4990930.3315620.7183470.036*
C120.39465 (16)0.38660 (12)0.77577 (17)0.0443 (6)
H12A0.4046910.4200500.8265420.053*
H12B0.3626320.3532190.8079930.053*
C130.31273 (15)0.40433 (13)0.67130 (17)0.0502 (7)
H13A0.2959390.3697770.6231350.060*
H13B0.2413070.4180200.6860610.060*
C140.22900 (14)0.43733 (7)0.43423 (12)0.0228 (3)
H140.2510600.3964030.4596150.027*
C150.10137 (15)0.43961 (8)0.40904 (14)0.0294 (4)
H15A0.0756630.4804020.3896870.035*
H15B0.0757360.4281550.4733450.035*
C160.04928 (19)0.39800 (10)0.31628 (16)0.0421 (5)
H16A0.0650280.3566900.3398590.051*
H16B0.0333950.4034390.2961430.051*
C170.09633 (19)0.40960 (8)0.21891 (15)0.0388 (5)
H17A0.0644230.3805500.1623110.047*
H17B0.0730380.4493740.1903860.047*
C180.2230 (2)0.40551 (9)0.24633 (15)0.0404 (5)
H18A0.2504160.4150610.1821580.048*
H18B0.2461210.3646570.2680720.048*
C190.27602 (15)0.44745 (8)0.33640 (13)0.0281 (4)
H19A0.2610600.4885900.3114590.034*
H19B0.3585670.4414980.3564040.034*
C200.10054 (12)0.59000 (6)0.28437 (11)0.0154 (3)
H200.1219320.5474040.2873670.018*
C210.02557 (12)0.59316 (7)0.27777 (12)0.0208 (3)
H21A0.0489400.6349100.2779060.025*
H21B0.0414750.5737040.3412560.025*
C220.09312 (14)0.56299 (8)0.17598 (14)0.0270 (4)
H22A0.0760430.5203000.1797940.032*
H22B0.1745550.5678250.1708900.032*
C230.06516 (14)0.58893 (8)0.07659 (13)0.0273 (4)
H23A0.1068680.5672040.0124910.033*
H23B0.0894790.6306300.0686750.033*
C240.06045 (14)0.58532 (8)0.08384 (12)0.0232 (3)
H24A0.0767850.6040270.0198780.028*
H24B0.0835350.5434800.0850980.028*
C250.12775 (12)0.61616 (7)0.18448 (12)0.0188 (3)
H25A0.1096340.6587340.1802550.023*
H25B0.2092170.6117980.1892370.023*
C260.15551 (12)0.68225 (6)0.39646 (12)0.0155 (3)
H260.0993980.6966440.3314000.019*
C270.10861 (13)0.69733 (7)0.49275 (12)0.0198 (3)
H27A0.0371980.6758210.4876070.024*
H27B0.1627710.6849870.5595410.024*
C280.08784 (14)0.76347 (7)0.49579 (14)0.0235 (3)
H28A0.0284440.7749890.4320410.028*
H28B0.0609700.7731610.5602350.028*
C290.19481 (14)0.79815 (7)0.49779 (14)0.0258 (3)
H29A0.2510740.7903340.5658570.031*
H29B0.1776270.8408250.4943570.031*
C300.24396 (14)0.78122 (7)0.40405 (14)0.0236 (3)
H30A0.3158160.8024690.4102040.028*
H30B0.1913590.7934860.3362720.028*
C310.26484 (12)0.71506 (7)0.40078 (12)0.0190 (3)
H31A0.2927220.7052340.3369570.023*
H31B0.3227220.7030200.4652930.023*
C1S0.68908 (19)0.74647 (9)0.54411 (18)0.0396 (5)
H1S0.6962250.7384750.6178440.048*
C2S0.78338 (18)0.74472 (10)0.5024 (2)0.0445 (5)
H2S0.8550700.7356440.5475610.053*
C3S0.77266 (19)0.75618 (10)0.3953 (2)0.0430 (5)
H3S0.8366970.7547210.3661550.052*
C4S0.6681 (2)0.76980 (9)0.33078 (18)0.0414 (5)
H4S0.6603780.7778320.2569660.050*
C5S0.57486 (18)0.77183 (9)0.37275 (18)0.0390 (5)
H5S0.5033600.7816120.3279550.047*
C6S0.58513 (17)0.75981 (8)0.47859 (18)0.0367 (4)
H6S0.5205820.7606380.5070680.044*
H10.3710 (18)0.6567 (11)0.6337 (18)0.035 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0369 (2)0.0277 (2)0.0232 (2)0.01656 (17)0.00559 (16)0.00049 (16)
N10.0371 (8)0.0193 (7)0.0193 (7)0.0048 (6)0.0128 (6)0.0002 (6)
N20.0270 (7)0.0164 (6)0.0174 (6)0.0060 (5)0.0013 (5)0.0020 (5)
N30.0169 (6)0.0138 (6)0.0123 (6)0.0014 (5)0.0021 (5)0.0010 (5)
C10.0179 (7)0.0185 (7)0.0166 (7)0.0012 (6)0.0017 (6)0.0013 (6)
C20.0153 (6)0.0185 (7)0.0129 (6)0.0028 (5)0.0003 (5)0.0009 (5)
C30.0142 (6)0.0168 (7)0.0138 (7)0.0005 (5)0.0017 (5)0.0023 (5)
C40.0286 (8)0.0260 (8)0.0159 (7)0.0020 (7)0.0081 (6)0.0003 (6)
C50.0251 (8)0.0343 (10)0.0262 (9)0.0035 (7)0.0007 (7)0.0116 (7)
C60.0414 (11)0.0616 (14)0.0217 (9)0.0093 (10)0.0068 (8)0.0050 (9)
C70.044 (4)0.091 (6)0.026 (3)0.019 (3)0.012 (2)0.012 (3)
C7A0.047 (7)0.085 (8)0.029 (5)0.024 (5)0.016 (5)0.017 (5)
C80.0245 (8)0.0200 (7)0.0167 (7)0.0071 (6)0.0023 (6)0.0010 (6)
C90.0238 (8)0.0507 (12)0.0337 (10)0.0075 (8)0.0112 (7)0.0191 (9)
C100.0218 (8)0.0586 (13)0.0395 (11)0.0113 (8)0.0063 (8)0.0230 (10)
C110.0353 (9)0.0249 (9)0.0254 (9)0.0039 (7)0.0033 (7)0.0046 (7)
C120.0296 (9)0.0728 (16)0.0298 (10)0.0027 (10)0.0060 (8)0.0271 (10)
C130.0189 (8)0.102 (2)0.0284 (10)0.0030 (10)0.0027 (7)0.0339 (12)
C140.0334 (8)0.0158 (7)0.0166 (7)0.0001 (6)0.0011 (6)0.0021 (6)
C150.0323 (9)0.0330 (9)0.0198 (8)0.0072 (7)0.0003 (7)0.0049 (7)
C160.0522 (12)0.0348 (10)0.0292 (10)0.0185 (9)0.0096 (9)0.0069 (8)
C170.0635 (13)0.0220 (9)0.0205 (8)0.0053 (9)0.0096 (8)0.0035 (7)
C180.0667 (14)0.0304 (10)0.0201 (8)0.0127 (9)0.0030 (9)0.0075 (7)
C190.0349 (9)0.0287 (9)0.0205 (8)0.0107 (7)0.0063 (7)0.0022 (7)
C200.0157 (6)0.0151 (7)0.0127 (6)0.0023 (5)0.0013 (5)0.0021 (5)
C210.0162 (7)0.0268 (8)0.0178 (7)0.0023 (6)0.0007 (6)0.0062 (6)
C220.0175 (7)0.0349 (9)0.0251 (8)0.0024 (7)0.0015 (6)0.0099 (7)
C230.0243 (8)0.0332 (9)0.0182 (8)0.0062 (7)0.0069 (6)0.0058 (7)
C240.0270 (8)0.0277 (8)0.0129 (7)0.0058 (7)0.0010 (6)0.0021 (6)
C250.0172 (7)0.0231 (8)0.0151 (7)0.0043 (6)0.0019 (6)0.0003 (6)
C260.0170 (6)0.0125 (7)0.0152 (7)0.0013 (5)0.0005 (5)0.0006 (5)
C270.0213 (7)0.0195 (7)0.0185 (7)0.0010 (6)0.0046 (6)0.0036 (6)
C280.0232 (8)0.0216 (8)0.0248 (8)0.0012 (6)0.0042 (6)0.0067 (6)
C290.0271 (8)0.0170 (7)0.0295 (9)0.0017 (6)0.0001 (7)0.0053 (6)
C300.0243 (8)0.0164 (7)0.0281 (8)0.0035 (6)0.0024 (6)0.0031 (6)
C310.0188 (7)0.0183 (7)0.0191 (7)0.0014 (6)0.0032 (6)0.0014 (6)
C1S0.0548 (12)0.0281 (10)0.0371 (11)0.0012 (9)0.0135 (9)0.0017 (8)
C2S0.0348 (10)0.0405 (12)0.0554 (14)0.0020 (9)0.0056 (10)0.0035 (10)
C3S0.0394 (11)0.0378 (11)0.0574 (14)0.0094 (9)0.0229 (10)0.0042 (10)
C4S0.0584 (13)0.0277 (10)0.0389 (11)0.0127 (9)0.0137 (10)0.0011 (8)
C5S0.0381 (10)0.0241 (9)0.0500 (12)0.0007 (8)0.0010 (9)0.0026 (9)
C6S0.0341 (10)0.0261 (9)0.0532 (13)0.0018 (7)0.0171 (9)0.0077 (8)
Geometric parameters (Å, º) top
N1—C11.319 (2)C16—C171.526 (3)
N1—C41.453 (2)C17—H17A0.9900
N1—H10.84 (2)C17—H17B0.9900
N2—C21.331 (2)C17—C181.507 (3)
N2—C81.4872 (19)C18—H18A0.9900
N2—C141.461 (2)C18—H18B0.9900
N3—C31.3247 (19)C18—C191.519 (3)
N3—C201.4752 (18)C19—H19A0.9900
N3—C261.4789 (19)C19—H19B0.9900
C1—C21.377 (2)C20—H201.0000
C1—C31.383 (2)C20—C211.528 (2)
C2—C31.388 (2)C20—C251.527 (2)
C4—H4A0.9900C21—H21A0.9900
C4—H4B0.9900C21—H21B0.9900
C4—C51.526 (3)C21—C221.531 (2)
C5—H5A0.9900C22—H22A0.9900
C5—H5B0.9900C22—H22B0.9900
C5—C61.510 (3)C22—C231.523 (3)
C6—H6AA0.9900C23—H23A0.9900
C6—H6AB0.9900C23—H23B0.9900
C6—H6BC0.9900C23—C241.521 (2)
C6—H6BD0.9900C24—H24A0.9900
C6—C71.502 (9)C24—H24B0.9900
C6—C7A1.60 (2)C24—C251.526 (2)
C7—H7A0.9800C25—H25A0.9900
C7—H7B0.9800C25—H25B0.9900
C7—H7C0.9800C26—H261.0000
C7A—H7AA0.9800C26—C271.528 (2)
C7A—H7AB0.9800C26—C311.522 (2)
C7A—H7AC0.9800C27—H27A0.9900
C8—H81.0000C27—H27B0.9900
C8—C91.502 (2)C27—C281.525 (2)
C8—C131.499 (3)C28—H28A0.9900
C9—H9A0.9900C28—H28B0.9900
C9—H9B0.9900C28—C291.524 (2)
C9—C101.535 (3)C29—H29A0.9900
C10—H10A0.9900C29—H29B0.9900
C10—H10B0.9900C29—C301.525 (2)
C10—C111.499 (3)C30—H30A0.9900
C11—H11A0.9900C30—H30B0.9900
C11—H11B0.9900C30—C311.526 (2)
C11—C121.501 (3)C31—H31A0.9900
C12—H12A0.9900C31—H31B0.9900
C12—H12B0.9900C1S—H1S0.9500
C12—C131.523 (3)C1S—C2S1.389 (3)
C13—H13A0.9900C1S—C6S1.379 (3)
C13—H13B0.9900C2S—H2S0.9500
C14—H141.0000C2S—C3S1.378 (4)
C14—C151.518 (2)C3S—H3S0.9500
C14—C191.526 (2)C3S—C4S1.381 (3)
C15—H15A0.9900C4S—H4S0.9500
C15—H15B0.9900C4S—C5S1.379 (3)
C15—C161.535 (3)C5S—H5S0.9500
C16—H16A0.9900C5S—C6S1.366 (3)
C16—H16B0.9900C6S—H6S0.9500
C1—N1—C4124.75 (15)C16—C17—H17A109.3
C1—N1—H1119.5 (16)C16—C17—H17B109.3
C4—N1—H1115.5 (16)H17A—C17—H17B107.9
C2—N2—C8117.30 (13)C18—C17—C16111.77 (16)
C2—N2—C14122.26 (13)C18—C17—H17A109.3
C14—N2—C8119.49 (13)C18—C17—H17B109.3
C3—N3—C20122.13 (12)C17—C18—H18A109.4
C3—N3—C26119.14 (12)C17—C18—H18B109.4
C20—N3—C26118.54 (11)C17—C18—C19111.36 (16)
N1—C1—C2151.11 (15)H18A—C18—H18B108.0
N1—C1—C3148.47 (15)C19—C18—H18A109.4
C2—C1—C360.37 (11)C19—C18—H18B109.4
N2—C2—C1146.06 (14)C14—C19—H19A109.4
N2—C2—C3153.88 (14)C14—C19—H19B109.4
C1—C2—C360.04 (11)C18—C19—C14111.05 (16)
N3—C3—C1146.57 (14)C18—C19—H19A109.4
N3—C3—C2153.84 (14)C18—C19—H19B109.4
C1—C3—C259.59 (11)H19A—C19—H19B108.0
N1—C4—H4A109.3N3—C20—H20107.4
N1—C4—H4B109.3N3—C20—C21111.47 (12)
N1—C4—C5111.76 (15)N3—C20—C25111.67 (12)
H4A—C4—H4B107.9C21—C20—H20107.4
C5—C4—H4A109.3C25—C20—H20107.4
C5—C4—H4B109.3C25—C20—C21111.18 (12)
C4—C5—H5A109.0C20—C21—H21A109.5
C4—C5—H5B109.0C20—C21—H21B109.5
H5A—C5—H5B107.8C20—C21—C22110.73 (13)
C6—C5—C4112.84 (15)H21A—C21—H21B108.1
C6—C5—H5A109.0C22—C21—H21A109.5
C6—C5—H5B109.0C22—C21—H21B109.5
C5—C6—H6AA108.3C21—C22—H22A109.4
C5—C6—H6AB108.3C21—C22—H22B109.4
C5—C6—H6BC111.6H22A—C22—H22B108.0
C5—C6—H6BD111.6C23—C22—C21111.21 (14)
C5—C6—C7A100.6 (11)C23—C22—H22A109.4
H6AA—C6—H6AB107.4C23—C22—H22B109.4
H6BC—C6—H6BD109.4C22—C23—H23A109.4
C7—C6—C5116.1 (5)C22—C23—H23B109.4
C7—C6—H6AA108.3H23A—C23—H23B108.0
C7—C6—H6AB108.3C24—C23—C22111.10 (13)
C7A—C6—H6BC111.6C24—C23—H23A109.4
C7A—C6—H6BD111.6C24—C23—H23B109.4
C6—C7—H7A109.5C23—C24—H24A109.5
C6—C7—H7B109.5C23—C24—H24B109.5
C6—C7—H7C109.5C23—C24—C25110.84 (13)
H7A—C7—H7B109.5H24A—C24—H24B108.1
H7A—C7—H7C109.5C25—C24—H24A109.5
H7B—C7—H7C109.5C25—C24—H24B109.5
C6—C7A—H7AA109.5C20—C25—H25A109.5
C6—C7A—H7AB109.5C20—C25—H25B109.5
C6—C7A—H7AC109.5C24—C25—C20110.73 (13)
H7AA—C7A—H7AB109.5C24—C25—H25A109.5
H7AA—C7A—H7AC109.5C24—C25—H25B109.5
H7AB—C7A—H7AC109.5H25A—C25—H25B108.1
N2—C8—H8106.6N3—C26—H26106.8
N2—C8—C9113.20 (14)N3—C26—C27112.48 (12)
N2—C8—C13112.58 (14)N3—C26—C31112.18 (12)
C9—C8—H8106.6C27—C26—H26106.8
C13—C8—H8106.6C31—C26—H26106.8
C13—C8—C9110.67 (16)C31—C26—C27111.30 (12)
C8—C9—H9A109.7C26—C27—H27A109.7
C8—C9—H9B109.7C26—C27—H27B109.7
C8—C9—C10109.82 (15)H27A—C27—H27B108.2
H9A—C9—H9B108.2C28—C27—C26109.86 (13)
C10—C9—H9A109.7C28—C27—H27A109.7
C10—C9—H9B109.7C28—C27—H27B109.7
C9—C10—H10A109.2C27—C28—H28A109.4
C9—C10—H10B109.2C27—C28—H28B109.4
H10A—C10—H10B107.9H28A—C28—H28B108.0
C11—C10—C9111.95 (16)C29—C28—C27111.15 (13)
C11—C10—H10A109.2C29—C28—H28A109.4
C11—C10—H10B109.2C29—C28—H28B109.4
C10—C11—H11A109.2C28—C29—H29A109.4
C10—C11—H11B109.2C28—C29—H29B109.4
C10—C11—C12112.11 (16)C28—C29—C30111.18 (13)
H11A—C11—H11B107.9H29A—C29—H29B108.0
C12—C11—H11A109.2C30—C29—H29A109.4
C12—C11—H11B109.2C30—C29—H29B109.4
C11—C12—H12A109.3C29—C30—H30A109.3
C11—C12—H12B109.3C29—C30—H30B109.3
C11—C12—C13111.82 (17)C29—C30—C31111.80 (13)
H12A—C12—H12B107.9H30A—C30—H30B107.9
C13—C12—H12A109.3C31—C30—H30A109.3
C13—C12—H12B109.3C31—C30—H30B109.3
C8—C13—C12110.27 (17)C26—C31—C30109.30 (12)
C8—C13—H13A109.6C26—C31—H31A109.8
C8—C13—H13B109.6C26—C31—H31B109.8
C12—C13—H13A109.6C30—C31—H31A109.8
C12—C13—H13B109.6C30—C31—H31B109.8
H13A—C13—H13B108.1H31A—C31—H31B108.3
N2—C14—H14106.5C2S—C1S—H1S120.0
N2—C14—C15111.86 (14)C6S—C1S—H1S120.0
N2—C14—C19111.73 (14)C6S—C1S—C2S120.1 (2)
C15—C14—H14106.5C1S—C2S—H2S120.1
C15—C14—C19113.31 (14)C3S—C2S—C1S119.8 (2)
C19—C14—H14106.5C3S—C2S—H2S120.1
C14—C15—H15A109.5C2S—C3S—H3S120.3
C14—C15—H15B109.5C2S—C3S—C4S119.5 (2)
C14—C15—C16110.85 (17)C4S—C3S—H3S120.3
H15A—C15—H15B108.1C3S—C4S—H4S119.8
C16—C15—H15A109.5C5S—C4S—C3S120.4 (2)
C16—C15—H15B109.5C5S—C4S—H4S119.8
C15—C16—H16A109.3C4S—C5S—H5S119.9
C15—C16—H16B109.3C6S—C5S—C4S120.1 (2)
H16A—C16—H16B108.0C6S—C5S—H5S119.9
C17—C16—C15111.41 (16)C1S—C6S—H6S120.0
C17—C16—H16A109.3C5S—C6S—C1S120.05 (19)
C17—C16—H16B109.3C5S—C6S—H6S120.0
N1—C1—C2—N24.0 (5)C11—C12—C13—C855.7 (3)
N1—C1—C2—C3177.3 (3)C13—C8—C9—C1058.7 (2)
N1—C1—C3—N32.2 (5)C14—N2—C2—C1173.4 (2)
N1—C1—C3—C2177.5 (3)C14—N2—C2—C39.2 (4)
N1—C4—C5—C6175.67 (16)C14—N2—C8—C968.4 (2)
N2—C2—C3—N32.0 (6)C14—N2—C8—C1358.1 (2)
N2—C2—C3—C1178.3 (4)C14—C15—C16—C1752.9 (2)
N2—C8—C9—C10173.80 (16)C15—C14—C19—C1853.5 (2)
N2—C8—C13—C12172.96 (18)C15—C16—C17—C1855.6 (2)
N2—C14—C15—C16179.90 (14)C16—C17—C18—C1956.5 (2)
N2—C14—C19—C18179.06 (14)C17—C18—C19—C1454.6 (2)
N3—C20—C21—C22179.07 (13)C19—C14—C15—C1652.51 (19)
N3—C20—C25—C24178.39 (12)C20—N3—C3—C1175.9 (2)
N3—C26—C27—C28174.43 (12)C20—N3—C3—C23.7 (4)
N3—C26—C31—C30174.66 (12)C20—N3—C26—C27117.46 (14)
C1—N1—C4—C573.7 (2)C20—N3—C26—C31116.15 (14)
C1—C2—C3—N3179.7 (3)C20—C21—C22—C2355.36 (18)
C2—N2—C8—C9100.70 (18)C21—C20—C25—C2456.42 (16)
C2—N2—C8—C13132.84 (18)C21—C22—C23—C2456.07 (19)
C2—N2—C14—C1567.2 (2)C22—C23—C24—C2556.65 (19)
C2—N2—C14—C1961.1 (2)C23—C24—C25—C2056.72 (17)
C2—C1—C3—N3179.8 (3)C25—C20—C21—C2255.63 (18)
C3—N3—C20—C21109.43 (15)C26—N3—C3—C19.3 (3)
C3—N3—C20—C25125.54 (14)C26—N3—C3—C2171.2 (3)
C3—N3—C26—C2757.58 (17)C26—N3—C20—C2165.46 (17)
C3—N3—C26—C3168.81 (17)C26—N3—C20—C2559.57 (16)
C3—C1—C2—N2178.7 (3)C26—C27—C28—C2956.36 (17)
C4—N1—C1—C215.3 (4)C27—C26—C31—C3058.31 (16)
C4—N1—C1—C3169.1 (2)C27—C28—C29—C3054.94 (18)
C4—C5—C6—C7177.2 (6)C28—C29—C30—C3155.23 (18)
C4—C5—C6—C7A170.9 (10)C29—C30—C31—C2656.37 (17)
C8—N2—C2—C14.6 (3)C31—C26—C27—C2858.71 (16)
C8—N2—C2—C3178.0 (3)C1S—C2S—C3S—C4S0.5 (3)
C8—N2—C14—C15124.29 (15)C2S—C1S—C6S—C5S0.6 (3)
C8—N2—C14—C19107.48 (16)C2S—C3S—C4S—C5S0.2 (3)
C8—C9—C10—C1155.2 (2)C3S—C4S—C5S—C6S0.6 (3)
C9—C8—C13—C1259.2 (3)C4S—C5S—C6S—C1S1.0 (3)
C9—C10—C11—C1252.4 (3)C6S—C1S—C2S—C3S0.2 (3)
C10—C11—C12—C1352.5 (3)
Comparative bond lengths (Å) for 1-mesityl-2,3-bis(diisopropylamino)cyclopropenimine, 1-mesityl-2,3-bis(diisopropylamino)cyclopropeniminium (Bruns et al., 2010), and 1-n-butyl-2,3-bis(dicyclohexyl)cyclopropeniminium top
Divided entries refer to separate, related pairs of atoms and their associated metrics, e.g., 1.3450 (14)/1.3539 (14) denotes two distances for the two C—N(amine) contacts.
Mes(C3N3)iPr4[Mes(C3N3H)iPr4]BF4[Bu(C3N3H)Cy4]Cl([1H]Cl)
C—N(imine)1.2951 (14)1.3342 (16)1.319 (2)
C—N(amine)1.3450 (14)/1.3539 (14)1.3205 (15)/1.3286 (16)1.3248 (17)/1.331 (2)
C—C(para)1.3712 (14)1.3984 (17)1.388 (2)
C—C(meta)1.4202 (14)/1.4108 (14)1.3792 (16)/1.3827 (16)1.377 (2)/1.3831 (19)
Hirshfeld charges of atoms in [1H]Cl·C6H6. top
Cl1-0.666N1-0.048N2-0.027
N3-0.018C10.026C20.014
C30.024C4-0.036C5-0.102
C6-0.095C7-0.133C8-0.011
C9-0.103C10-0.093C11-0.097
C12-0.088C13-0.093C14-0.008
C15-0.097C16-0.094C17-0.098
C18-0.098C19-0.101C20-0.005
C21-0.094C22-0.093C23-0.093
C24-0.091C25-0.093C26-0.002
C27-0.096C28-0.094C29-0.099
C30-0.093C31-0.097C1S-0.058
C2S-0.071C3S-0.078C4S-0.084
C5S-0.082C6S-0.064H1S0.071
H6S0.069H5S0.065H4S0.062
H3S0.062H2S0.056H4A0.051
H4B0.075H5A0.061H5b0.042
H6AA0.046H6AB0.055H7A0.050
H7B0.039H7C0.051H80.072
H9A0.050H9B0.060H10A0.061
H10B0.061H11A0.061H11B0.049
H12A0.057H12B0.053H13A0.059
H13B0.049H140.066H15A0.057
H15B0.062H16A0.051H16B0.052
H17A0.055H17B0.051H18A0.056
H18B0.062H19A0.055H19B0.065
H200.060H21A0.055H21B0.055
H22A0.050H22B0.056H23A0.056
H23B0.052H24A0.051H24B0.056
H25A0.057H25B0.057H260.058
H27A0.049H27B0.062H28A0.044
H28B0.057H29A0.050H29B0.059
H30A0.061H30B0.039H31A0.047
H31B0.064H10.121
 

Acknowledgements

The National Science Foundation under award 1800105, is gratefully acknowledged for support of this work. GMS acknowledges the Temple University Minority Access to Research Careers (MARC) program and its support from the National Institutes of Health under NIH/NIGMS award 5 T34 GM136494 for an undergraduate research fellowship.

Funding information

Funding for this research was provided by: National Science Foundation (grant No. 1800105 to Michael J. Zdilla); National Institutes of Health, National Institute of General Medical Sciences (grant No. 5T34 GM136494 to Gaby Muñoz Sanchez).

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