Synthesis, crystal structure, Hirshfeld surface analysis and energy framework calculations of trans-3,7,9,9-tetra­methyl-10-(prop-2-yn-1-yl)-1,2,3,4,4a,9,9a,10-octa­hydro­acridine

In the crystal of the new title octa­hydro­acridine, the mol­ecules are connected by C—H...π inter­actions, forming chains propagating along the b-axis direction that stack in a sandwich–herringbone arrangement.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.039
• wR factor = 0.107
• Data-to-parameter ratio = 16.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT410_ALERT_2_C Short Intra H...H Contact  H4A      ..H18B     .       1.97 Ang.
                                                      x,y,z  =      1_555 Check
PLAT911_ALERT_3_C Missing FCF Refl Between Thmin & STh/L=    0.600         18 Report
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....         10 Note
PLAT918_ALERT_3_C Reflection(s) with I(obs) much Smaller I(calc) .          7 Check
PLAT939_ALERT_3_C Large Value of Not (SHELXL) Weight Optimized S .      34.49 Check

Alert level G
PLAT199_ALERT_1_G Reported _cell_measurement_temperature ..... (K)        293 Check
PLAT200_ALERT_1_G Reported   _diffrn_ambient_temperature ..... (K)        293 Check
PLAT791_ALERT_4_G Model has Chirality at C3          (Sohnke SpGr)          S Verify
PLAT791_ALERT_4_G Model has Chirality at C5          (Sohnke SpGr)          S Verify
PLAT791_ALERT_4_G Model has Chirality at C6          (Sohnke SpGr)          R Verify
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Theta(Min).          2 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         26 Note
PLAT933_ALERT_2_G Number of OMIT Records in Embedded .res File ...          5 Note
PLAT961_ALERT_5_G Dataset Contains no Negative Intensities .......     Please Check
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density.          2 Info

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   5 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  10 ALERT level G = General information/check it is not something unexpected

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   5 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
              Please specify the role of each of the co-authors
              for your paper.

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

---

Computing details

Data collection: CrystalClear-SM Expert (Rigaku/MSC, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2019); data reduction: CrysAlis PRO (Rigaku OD, 2019); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

trans-3,7,9,9-Tetramethyl-10-(prop-2-yn-1-yl)-1,2,3,4,4a,9,9a,10-octahydroacridine

Crystal data

C20H27N	Dx = 1.118 Mg m^−3
Mr = 281.42	Melting point: 367 K
Orthorhombic, P212121	Cu Kα radiation, λ = 1.54184 Å
a = 10.05103 (9) Å	Cell parameters from 6301 reflections
b = 10.62943 (11) Å	θ = 2.8–74.2°
c = 15.64759 (16) Å	µ = 0.48 mm^−1
V = 1671.74 (3) Å^3	T = 293 K
Z = 4	Block, colorless
F(000) = 616	0.48 × 0.33 × 0.29 mm

Data collection

Rigaku Pilatus 200K diffractometer	3181 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source	3160 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.013
Detector resolution: 5.8140 pixels mm^-1	θmax = 74.2°, θmin = 5.7°
profile data from ω–scans	h = −9→11
Absorption correction: multi-scan (CrysAlisPRO; Rigaku OD, 2019)	k = −11→13
Tmin = 0.573, Tmax = 1.000	l = −19→19
6660 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.039	w = 1/[σ^2(Fo^2) + (0.0679P)^2 + 0.0783P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.107	(Δ/σ)max < 0.001
S = 1.11	Δρmax = 0.15 e Å^−3
3181 reflections	Δρmin = −0.19 e Å^−3
195 parameters	Extinction correction: SHELXL2018/3 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.037 (4)
Primary atom site location: dual	Absolute structure: Flack x determined using 1267 quotients [(I^+)-(I^-)]/[(I^+)+(I^-)] (Parsons et al., 2013)
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.3 (2)

Special details

Experimental. Characterization by X-ray powder diffraction

A small portion of the synthesized material, previously grounded in an agate mortar, was dusted on top of a flat plate low-background Si single crystal specimen holder. The powder diffraction pattern was registered at room temperature on a Bruker D8 ADVANCE diffractometer working in the Bragg-Brentano geometry using Cu Ka radiation, operating at 40 kV and 30 mA, and equipped with a LynxEye position-sensitive detector. The pattern was recorded from 6.00 to 70.00° (2θ) in steps of 0.01526°, at 1 sec/step. The standard instrument settings (Ni filter of 0.02 mm, Soller slits of 2.5°, Divergence slit of 0.2 mm, scatter screen height of 3 mm) were employed.

Characterization by ATR-FTIR, mass spectrometry, elemental analysis, and ¹H- and ¹³C-NMR

The IR spectrum was recorded in the region from 4000 to 500 cm^-1 on a Bruker Tensor 27 FTIR spectrophotometer coupled to a Bruker platinum ATR cell. Vibrational frequencies were calculated by the B3LYP method with a 6-31G basis set, as a strategy to correlate the experimental bands with their corresponding vibrational modes (Matsuura and Yoshida, 2006). The mass spectrum was recorded on a Hewlett Packard 5890a Series II Gas Chromatograph interfaced to an HP MS ChemStation Data System at 70 eV using a 60 m capillary column coated with HP-5 [5% phenylpoly(dimethylsiloxane)]. Elemental analysis was performed on a Thermo Scientific CHNS-O analyzer (Model Flash 2000) and the experimental values were within ± 0.4 of the theoretical values. NMR spectra (¹H and ¹³C) were measured on a Bruker Ultrashield-400 spectrometer (400 MHz ¹H NMR and 100 MHz ¹³C NMR), using CDCl₃ as solvent and reference. J values are reported in Hz; chemical shifts are reported in ppm (δ) relative to the solvent peak (residual CHCl₃ in CDCl₃ at 7.26 ppm for protons). Signals were designated as: s, singlet; d, doublet; dd, doublet of doublets; ddd, doublet of doublets of doublets; t, triplet; td, triplet of doublets; q, quartet; m, multiplet; br., broad.

Geometry and energy optimization

Semi-empirical quantum chemistry calculations were performed to evaluate the crystalline structure determined using single crystal X-ray diffraction techniques. The calculations were carried out using the treatment of periodic boundary conditions (Stewart, 2008) implemented in the MOPAC2016 package (Stewart, 2016). A laptop equipped with 1.60GHz Intel(R) Core(TM) i5-8250U CPU, 8Gb memory, and a Windows 10 operating system was used. To minimize border effects and obtain a full structure representation of the compound under study, the crystallographic unit cell was replicated l, m, and n times along the corresponding Cartesian axes. In each case, the keyword MERS = (l,m,n) was used, where l, m, and n could be either 1 or 2. Using the experimental crystal structure parameters, an input cluster of molecules for the compound was created using Mercury (Macrae et al., 2020) and MAKPOL (Stewart, 2018). The studied clusters consisted of 768 and 384 atoms. The geometry was energy minimized using the L-BFGS-B function minimizer with the PM6 (Stewart, 2007), PM7 (Stewart, 2013) and PM6-DH2 (Korth et al., 2010) methods, allowing the unit cell parameters and the atomic coordinates of all 768 and 384 atoms to vary in every case. The calculation was set to terminate when the gradient norm reached a value <10 Kcal mol-1 Å^-1. The optimized atomic positions were visualized and compared to the experimental atomic coordinates using the Crystal Packing Similarity capability of Mercury.

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.38131 (16)	0.67573 (14)	0.32881 (9)	0.0587 (4)
C1	0.5388 (2)	0.6967 (2)	0.54905 (12)	0.0651 (5)
H1A	0.522689	0.649842	0.601246	0.078*
H1B	0.631139	0.684239	0.533165	0.078*
C2	0.5154 (2)	0.8351 (2)	0.56596 (13)	0.0698 (5)
H2A	0.425363	0.847263	0.586694	0.084*
H2B	0.576286	0.863906	0.609906	0.084*
C3	0.53583 (17)	0.91189 (18)	0.48576 (13)	0.0620 (4)
H3	0.628642	0.900743	0.468121	0.074*
C4	0.44845 (17)	0.86058 (16)	0.41413 (12)	0.0566 (4)
H4A	0.466096	0.907853	0.362330	0.068*
H4B	0.355835	0.873562	0.429161	0.068*
C5	0.47082 (15)	0.72069 (16)	0.39624 (10)	0.0508 (4)
H5	0.562872	0.708887	0.377202	0.061*
C6	0.44943 (15)	0.64426 (16)	0.47810 (9)	0.0484 (4)
H6	0.357383	0.659273	0.496077	0.058*
C7	0.34579 (16)	0.54953 (16)	0.32338 (9)	0.0517 (4)
C8	0.38003 (15)	0.46188 (15)	0.38711 (9)	0.0492 (4)
C9	0.46345 (16)	0.50046 (17)	0.46439 (9)	0.0513 (4)
C10	0.27175 (19)	0.50620 (18)	0.25324 (11)	0.0621 (4)
H10	0.246012	0.563166	0.211266	0.075*
C11	0.23606 (19)	0.38138 (19)	0.24481 (12)	0.0648 (5)
H11	0.188546	0.355866	0.196845	0.078*
C12	0.26960 (18)	0.29373 (18)	0.30627 (12)	0.0620 (4)
C13	0.34035 (17)	0.33742 (17)	0.37640 (11)	0.0579 (4)
H13	0.362622	0.279976	0.418889	0.069*
C14	0.5139 (2)	1.0515 (2)	0.49995 (16)	0.0780 (6)
H14A	0.423655	1.065695	0.517634	0.117*
H14B	0.530617	1.096137	0.447712	0.117*
H14C	0.573460	1.081061	0.543498	0.117*
C15	0.2335 (3)	0.1564 (2)	0.29657 (17)	0.0872 (7)
H15A	0.222116	0.119406	0.352062	0.131*
H15B	0.303458	0.113374	0.266677	0.131*
H15C	0.152176	0.149164	0.264824	0.131*
C16	0.60856 (18)	0.4612 (2)	0.44781 (13)	0.0689 (5)
H16A	0.662066	0.482466	0.496540	0.103*
H16B	0.641587	0.504656	0.398371	0.103*
H16C	0.612541	0.372124	0.438170	0.103*
C17	0.4133 (2)	0.43261 (19)	0.54534 (11)	0.0659 (5)
H17A	0.463342	0.460816	0.593947	0.099*
H17B	0.424506	0.343467	0.538626	0.099*
H17C	0.320781	0.451316	0.553822	0.099*
C18	0.37514 (19)	0.74991 (18)	0.24998 (11)	0.0614 (4)
H18A	0.400066	0.696834	0.202166	0.074*
H18B	0.439266	0.817919	0.253479	0.074*
C19	0.2427 (2)	0.80308 (18)	0.23385 (11)	0.0646 (5)
C20	0.1372 (3)	0.8443 (2)	0.21983 (15)	0.0835 (6)
H20	0.053201	0.877163	0.208666	0.100*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0707 (9)	0.0631 (8)	0.0422 (7)	−0.0078 (7)	−0.0101 (6)	0.0074 (6)
C1	0.0652 (10)	0.0769 (11)	0.0531 (9)	−0.0001 (9)	−0.0168 (8)	0.0011 (8)
C2	0.0722 (11)	0.0804 (12)	0.0567 (10)	−0.0046 (9)	−0.0130 (8)	−0.0101 (9)
C3	0.0471 (8)	0.0699 (11)	0.0689 (10)	−0.0042 (8)	−0.0036 (8)	−0.0074 (9)
C4	0.0517 (8)	0.0632 (9)	0.0548 (8)	−0.0022 (7)	−0.0015 (7)	0.0025 (7)
C5	0.0431 (7)	0.0651 (9)	0.0443 (8)	−0.0003 (6)	0.0012 (6)	0.0006 (7)
C6	0.0403 (7)	0.0641 (9)	0.0407 (7)	0.0037 (6)	−0.0012 (5)	0.0012 (6)
C7	0.0500 (8)	0.0644 (9)	0.0405 (7)	0.0018 (7)	0.0005 (6)	0.0004 (6)
C8	0.0438 (7)	0.0622 (8)	0.0415 (7)	0.0039 (6)	0.0034 (6)	0.0000 (6)
C9	0.0485 (8)	0.0647 (9)	0.0406 (7)	0.0083 (7)	−0.0011 (6)	0.0022 (6)
C10	0.0706 (11)	0.0699 (10)	0.0458 (8)	−0.0005 (9)	−0.0104 (8)	0.0001 (7)
C11	0.0635 (10)	0.0775 (11)	0.0535 (9)	−0.0047 (8)	−0.0080 (8)	−0.0071 (8)
C12	0.0598 (9)	0.0662 (10)	0.0600 (9)	−0.0047 (8)	0.0047 (8)	−0.0057 (8)
C13	0.0581 (9)	0.0640 (9)	0.0515 (8)	0.0032 (7)	0.0038 (7)	0.0035 (7)
C14	0.0715 (12)	0.0732 (12)	0.0892 (15)	−0.0048 (10)	−0.0069 (10)	−0.0125 (11)
C15	0.1057 (17)	0.0729 (13)	0.0830 (14)	−0.0185 (12)	−0.0037 (13)	−0.0044 (11)
C16	0.0535 (9)	0.0854 (12)	0.0676 (10)	0.0171 (9)	−0.0066 (8)	−0.0088 (9)
C17	0.0826 (12)	0.0698 (10)	0.0454 (8)	0.0057 (9)	−0.0007 (8)	0.0085 (7)
C18	0.0699 (10)	0.0729 (10)	0.0415 (8)	−0.0074 (8)	0.0004 (7)	0.0087 (7)
C19	0.0803 (13)	0.0706 (10)	0.0429 (8)	−0.0053 (9)	−0.0014 (8)	0.0107 (7)
C20	0.0827 (15)	0.0995 (15)	0.0682 (13)	0.0113 (12)	−0.0027 (11)	0.0173 (12)

Geometric parameters (Å, º)

N1—C7	1.391 (2)	C9—C17	1.542 (2)
N1—C18	1.465 (2)	C10—C11	1.381 (3)
N1—C5	1.467 (2)	C10—H10	0.9300
C1—C2	1.514 (3)	C11—C12	1.381 (3)
C1—C6	1.533 (2)	C11—H11	0.9300
C1—H1A	0.9700	C12—C13	1.388 (3)
C1—H1B	0.9700	C12—C15	1.512 (3)
C2—C3	1.511 (3)	C13—H13	0.9300
C2—H2A	0.9700	C14—H14A	0.9600
C2—H2B	0.9700	C14—H14B	0.9600
C3—C14	1.517 (3)	C14—H14C	0.9600
C3—C4	1.525 (2)	C15—H15A	0.9600
C3—H3	0.9800	C15—H15B	0.9600
C4—C5	1.530 (2)	C15—H15C	0.9600
C4—H4A	0.9700	C16—H16A	0.9600
C4—H4B	0.9700	C16—H16B	0.9600
C5—C6	1.532 (2)	C16—H16C	0.9600
C5—H5	0.9800	C17—H17A	0.9600
C6—C9	1.550 (2)	C17—H17B	0.9600
C6—H6	0.9800	C17—H17C	0.9600
C7—C10	1.404 (2)	C18—C19	1.469 (3)
C7—C8	1.407 (2)	C18—H18A	0.9700
C8—C13	1.392 (2)	C18—H18B	0.9700
C8—C9	1.528 (2)	C19—C20	1.168 (3)
C9—C16	1.539 (2)	C20—H20	0.9300
C7—N1—C18	117.18 (14)	C8—C9—C6	108.94 (13)
C7—N1—C5	121.04 (13)	C16—C9—C6	112.13 (14)
C18—N1—C5	117.14 (14)	C17—C9—C6	108.53 (13)
C2—C1—C6	112.89 (15)	C11—C10—C7	121.85 (16)
C2—C1—H1A	109.0	C11—C10—H10	119.1
C6—C1—H1A	109.0	C7—C10—H10	119.1
C2—C1—H1B	109.0	C10—C11—C12	121.23 (17)
C6—C1—H1B	109.0	C10—C11—H11	119.4
H1A—C1—H1B	107.8	C12—C11—H11	119.4
C3—C2—C1	111.02 (17)	C11—C12—C13	116.75 (17)
C3—C2—H2A	109.4	C11—C12—C15	121.55 (18)
C1—C2—H2A	109.4	C13—C12—C15	121.69 (18)
C3—C2—H2B	109.4	C12—C13—C8	124.06 (16)
C1—C2—H2B	109.4	C12—C13—H13	118.0
H2A—C2—H2B	108.0	C8—C13—H13	118.0
C2—C3—C14	112.77 (19)	C3—C14—H14A	109.5
C2—C3—C4	109.82 (15)	C3—C14—H14B	109.5
C14—C3—C4	111.95 (16)	H14A—C14—H14B	109.5
C2—C3—H3	107.3	C3—C14—H14C	109.5
C14—C3—H3	107.3	H14A—C14—H14C	109.5
C4—C3—H3	107.3	H14B—C14—H14C	109.5
C3—C4—C5	113.42 (14)	C12—C15—H15A	109.5
C3—C4—H4A	108.9	C12—C15—H15B	109.5
C5—C4—H4A	108.9	H15A—C15—H15B	109.5
C3—C4—H4B	108.9	C12—C15—H15C	109.5
C5—C4—H4B	108.9	H15A—C15—H15C	109.5
H4A—C4—H4B	107.7	H15B—C15—H15C	109.5
N1—C5—C4	110.99 (13)	C9—C16—H16A	109.5
N1—C5—C6	110.04 (13)	C9—C16—H16B	109.5
C4—C5—C6	109.98 (13)	H16A—C16—H16B	109.5
N1—C5—H5	108.6	C9—C16—H16C	109.5
C4—C5—H5	108.6	H16A—C16—H16C	109.5
C6—C5—H5	108.6	H16B—C16—H16C	109.5
C5—C6—C1	109.31 (14)	C9—C17—H17A	109.5
C5—C6—C9	113.23 (13)	C9—C17—H17B	109.5
C1—C6—C9	113.91 (13)	H17A—C17—H17B	109.5
C5—C6—H6	106.6	C9—C17—H17C	109.5
C1—C6—H6	106.6	H17A—C17—H17C	109.5
C9—C6—H6	106.6	H17B—C17—H17C	109.5
N1—C7—C10	120.02 (14)	N1—C18—C19	112.97 (15)
N1—C7—C8	122.17 (14)	N1—C18—H18A	109.0
C10—C7—C8	117.80 (15)	C19—C18—H18A	109.0
C13—C8—C7	118.29 (15)	N1—C18—H18B	109.0
C13—C8—C9	120.52 (14)	C19—C18—H18B	109.0
C7—C8—C9	121.15 (15)	H18A—C18—H18B	107.8
C8—C9—C16	108.30 (13)	C20—C19—C18	178.9 (2)
C8—C9—C17	110.19 (14)	C19—C20—H20	180.0
C16—C9—C17	108.76 (15)
C6—C1—C2—C3	−57.2 (2)	C10—C7—C8—C9	178.42 (14)
C1—C2—C3—C14	−179.78 (16)	C13—C8—C9—C16	78.32 (19)
C1—C2—C3—C4	54.6 (2)	C7—C8—C9—C16	−99.15 (18)
C2—C3—C4—C5	−55.6 (2)	C13—C8—C9—C17	−40.5 (2)
C14—C3—C4—C5	178.33 (16)	C7—C8—C9—C17	142.00 (16)
C7—N1—C5—C4	−155.23 (15)	C13—C8—C9—C6	−159.48 (14)
C18—N1—C5—C4	49.6 (2)	C7—C8—C9—C6	23.05 (19)
C7—N1—C5—C6	−33.3 (2)	C5—C6—C9—C8	−48.98 (16)
C18—N1—C5—C6	171.56 (14)	C1—C6—C9—C8	−174.71 (13)
C3—C4—C5—N1	178.18 (14)	C5—C6—C9—C16	70.87 (17)
C3—C4—C5—C6	56.18 (18)	C1—C6—C9—C16	−54.85 (19)
N1—C5—C6—C1	−177.26 (14)	C5—C6—C9—C17	−168.97 (13)
C4—C5—C6—C1	−54.69 (17)	C1—C6—C9—C17	65.30 (18)
N1—C5—C6—C9	54.59 (17)	N1—C7—C10—C11	179.08 (18)
C4—C5—C6—C9	177.16 (12)	C8—C7—C10—C11	−1.8 (3)
C2—C1—C6—C5	56.8 (2)	C7—C10—C11—C12	1.3 (3)
C2—C1—C6—C9	−175.44 (15)	C10—C11—C12—C13	0.1 (3)
C18—N1—C7—C10	−18.0 (2)	C10—C11—C12—C15	−178.6 (2)
C5—N1—C7—C10	−173.17 (15)	C11—C12—C13—C8	−1.0 (3)
C18—N1—C7—C8	162.92 (16)	C15—C12—C13—C8	177.72 (19)
C5—N1—C7—C8	7.7 (2)	C7—C8—C13—C12	0.5 (3)
N1—C7—C8—C13	180.00 (15)	C9—C8—C13—C12	−177.06 (15)
C10—C7—C8—C13	0.9 (2)	C7—N1—C18—C19	86.5 (2)
N1—C7—C8—C9	−2.5 (2)	C5—N1—C18—C19	−117.36 (18)