organic compounds
4-[Bis(4-fluorophenyl)methyl]piperazin-1-ium picrate
aNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth, 6031, South Africa, bUniversity of Mysore, Department of Studies in Chemistry, Manasagangotri, Mysore 570 006, India, and cMangalore University, Department of Studies in Chemistry, Mangalagangotri 574 199, India
*Correspondence e-mail: richard.betz@webmail.co.za
The title compound {systematic name: 4-[bis(4-fluorophenyl)methyl]piperazin-1-ium 2,4,6-trinitrophenolate}, C17H19F2N2+·C6H2N3O7−, is the picrate salt of a piperazine-supported amine bearing a benzhydryl substituent on one of its N atoms. During co-crystallisation, protonation took place on the N atom of the secondary amine functionality. The non-aromatic six-membered heterocycle adopts a chair conformation. In the crystal, N—H⋯O hydrogen bonds as well as C—H⋯O contacts connect the components into a three-dimensional network.
Related literature
For background to the biological activity of piperazines, see: Brockunier et al. (2004); Bogatcheva et al. (2006). For related structures, see: Jasinski et al. (2010, 2011); Dutkiewicz et al. (2011). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For puckering analysis, see: Cremer & Pople (1975).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2010); cell SAINT (Bruker, 2010); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S160053681103580X/hg5090sup1.cif
contains datablocks I, global. DOI:Supporting information file. DOI: https://doi.org/10.1107/S160053681103580X/hg5090Isup2.cdx
Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681103580X/hg5090Isup3.hkl
Supporting information file. DOI: https://doi.org/10.1107/S160053681103580X/hg5090Isup4.cml
4,4'-Difluorobenzhydryl piperazine was obtained from R. L. Fine Chem., Bengaluru, India. 4,4'-Difluorobenzhydryl piperazine (2.88 g, 0.01 mol) was dissolved in 10 ml of methanol and picric acid (2.29 g, 0.01 mol) was also dissolved in 10 ml of methanol. Both the solutions were mixed and stirred in a beaker at 333 K for 30 minutes. The mixture was kept aside for a day at room temperature. The salt formed was filtered & dried in vaccum desiccator over phosphorous pentoxide. The compound was recrystallized from a mixture of (1:1) acetone and acetonitrile by slow evaporation (m.p: 513–516 K).
Carbon-bound H atoms were placed in calculated positions (C—H 0.95 Å for aromatic carbon atoms, C—H 0.99 Å for methylene groups) and were included in the
in the riding model approximation, with U(H) set to 1.2Ueq(C). Both nitrogen-bound H atoms were located on a difference Fourier map and refined freely.4,4'-Difluorobenzhydryl piperazine is an intermediate for the preparation of flunarizine which is a calcium channel blocker. Piperazines are among the most important building blocks in today's drug discovery. They are found in biologically active compounds across a number of different therapeutic areas such as antifungal, antibacterial, antimalarial, antipsychotic, antidepressant and antitumour activity against colon, prostate, breast, lung and leukemia tumors (Brockunier et al., 2004; Bogatcheva et al., 2006). The crystal structures of some related salts viz., levocetirizinium dipicrate (Jasinski et al., 2010), cinnarizinium dipicrate (Jasinski et al., 2011), 1-methylpiperazine-1,4-diium dipicrate (Dutkiewicz et al., 2011), have been reported. In the course of our studies on
of simple organic cations and in view of the importance of piperazines, we have determined the crystal and molecular structure of the title salt.Protonation occurred at the nitrogen atom that is part of the secondary amine functionality. The non-aromatic heterocycle adopts a chair conformation (1C4, N1CN2) according to a conformation analysis (Cremer & Pople, 1975). The least-squares planes defined by the carbon atoms of the two fluorophenyl moieties intersect at an angle of 73.71 (4) °. The planes defined by the atoms of the nitro groups on the picrate anion enclose angles of 7.62 (14) °, 33.52 (18) ° and 37.08 (17) °, respectively with the aromatic system they are bonded to (Fig. 1).
In the crystal, hydrogen bonds of the N–H···O type as well as C–H···O contacts are present. Both classical hydrogen bonds show bifurcation between the phenolic O atom as well as one of the nitro group's O atoms. The C–H···O contacts are supported by one of the hydrogen atoms of the non-aromatic heterocycle as well as one of the hydrogen atoms in ortho position to F atom in each of the fluorophenyl moieties. Apart from one O atom of a nitro group that forms a N–O···Cg contact with a neighbouring picrate anion, all O atoms act as acceptors for hydrogen atoms. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the classical hydrogen bonds is DDDD on the unitary level while the C–H···O contacts require a DD descriptor on the same level. In total, the entities of the title compound are connected to a three-dimensional network in the crystal. The shortest intercentroid distance between two centers of gravity was found at 4.0808 (7) Å and is apparent between one of the fluorophenyl moieties and the picrate anion (Fig. 2).
The packing of the title compound in the
is shown in Figure 3.For background to the biological activity of piperazines, see: Brockunier et al. (2004); Bogatcheva et al. (2006). For related structures, see: Jasinski et al. (2010, 2011); Dutkiewicz et al. (2011). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For puckering analysis, see: Cremer & Pople (1975).
Data collection: APEX2 (Bruker, 2010); cell
SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).Fig. 1. The molecular structure of the title compound, with atom labels and anisotropic displacement ellipsoids (drawn at 50% probability level). | |
Fig. 2. Selected intermolecular contacts, viewed along [0 0 - 1]. For clarity, the aromatic substituents on the tertiary nitrogen atom are omitted. Green dashed lines indicate C–H···O contacts, blue dashed lines indicate classical hydrogen bonds. Symmetry operators: i -x + 1, y + 1/2, -z + 1/2; ii x + 1, -y + 1/2, z + 1/2. | |
Fig. 3. Molecular packing of the title compound, viewed along [0 1 0] (anisotropic displacement ellipsoids drawn at 50% probability level). |
C17H19F2N2+·C6H2N3O7− | F(000) = 1072 |
Mr = 517.45 | Dx = 1.462 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9984 reflections |
a = 8.9425 (2) Å | θ = 2.5–28.3° |
b = 11.8286 (2) Å | µ = 0.12 mm−1 |
c = 23.0922 (4) Å | T = 200 K |
β = 105.720 (1)° | Block, yellow |
V = 2351.27 (8) Å3 | 0.52 × 0.49 × 0.41 mm |
Z = 4 |
Bruker APEXII CCD diffractometer | 5842 independent reflections |
Radiation source: fine-focus sealed tube | 5041 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.013 |
φ and ω scans | θmax = 28.3°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS: Bruker, 2008) | h = −10→11 |
Tmin = 0.928, Tmax = 1.000 | k = −15→13 |
20823 measured reflections | l = −30→30 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.039 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.111 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.058P)2 + 0.8015P] where P = (Fo2 + 2Fc2)/3 |
5842 reflections | (Δ/σ)max < 0.001 |
342 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.31 e Å−3 |
C17H19F2N2+·C6H2N3O7− | V = 2351.27 (8) Å3 |
Mr = 517.45 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.9425 (2) Å | µ = 0.12 mm−1 |
b = 11.8286 (2) Å | T = 200 K |
c = 23.0922 (4) Å | 0.52 × 0.49 × 0.41 mm |
β = 105.720 (1)° |
Bruker APEXII CCD diffractometer | 5842 independent reflections |
Absorption correction: multi-scan (SADABS: Bruker, 2008) | 5041 reflections with I > 2σ(I) |
Tmin = 0.928, Tmax = 1.000 | Rint = 0.013 |
20823 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.111 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.32 e Å−3 |
5842 reflections | Δρmin = −0.31 e Å−3 |
342 parameters |
x | y | z | Uiso*/Ueq | ||
F1 | 0.59114 (13) | 0.42083 (9) | 0.07691 (4) | 0.0571 (3) | |
F2 | −0.17242 (8) | 0.30044 (8) | 0.27076 (4) | 0.0414 (2) | |
N1 | 0.53229 (10) | 0.45389 (8) | 0.34157 (4) | 0.02357 (19) | |
N2 | 0.77494 (11) | 0.44880 (8) | 0.45221 (4) | 0.02322 (19) | |
H721 | 0.8435 (19) | 0.4073 (14) | 0.4805 (7) | 0.036 (4)* | |
H722 | 0.7972 (18) | 0.5235 (14) | 0.4633 (7) | 0.035 (4)* | |
C1 | 0.41152 (13) | 0.49894 (9) | 0.28976 (5) | 0.0243 (2) | |
H1 | 0.4030 | 0.5824 | 0.2952 | 0.029* | |
C2 | 0.49947 (13) | 0.48107 (10) | 0.39896 (5) | 0.0256 (2) | |
H2A | 0.3914 | 0.4593 | 0.3972 | 0.031* | |
H2B | 0.5104 | 0.5635 | 0.4064 | 0.031* | |
C3 | 0.61166 (12) | 0.41795 (10) | 0.44964 (5) | 0.0252 (2) | |
H3A | 0.5902 | 0.4370 | 0.4884 | 0.030* | |
H3B | 0.5970 | 0.3355 | 0.4431 | 0.030* | |
C4 | 0.80775 (12) | 0.43290 (10) | 0.39261 (5) | 0.0259 (2) | |
H4A | 0.8047 | 0.3514 | 0.3826 | 0.031* | |
H4B | 0.9129 | 0.4618 | 0.3945 | 0.031* | |
C5 | 0.68813 (12) | 0.49562 (10) | 0.34431 (5) | 0.0254 (2) | |
H5A | 0.6942 | 0.5776 | 0.3534 | 0.030* | |
H5B | 0.7098 | 0.4844 | 0.3049 | 0.030* | |
C11 | 0.45589 (13) | 0.47782 (10) | 0.23136 (5) | 0.0255 (2) | |
C12 | 0.48205 (16) | 0.56737 (11) | 0.19670 (6) | 0.0357 (3) | |
H12 | 0.4681 | 0.6426 | 0.2087 | 0.043* | |
C13 | 0.52840 (18) | 0.54931 (12) | 0.14453 (6) | 0.0423 (3) | |
H13 | 0.5465 | 0.6111 | 0.1210 | 0.051* | |
C14 | 0.54715 (16) | 0.44020 (13) | 0.12803 (5) | 0.0369 (3) | |
C15 | 0.51902 (18) | 0.34899 (12) | 0.16014 (6) | 0.0417 (3) | |
H15 | 0.5313 | 0.2741 | 0.1473 | 0.050* | |
C16 | 0.47223 (17) | 0.36882 (11) | 0.21181 (6) | 0.0372 (3) | |
H16 | 0.4509 | 0.3065 | 0.2343 | 0.045* | |
C21 | 0.25510 (12) | 0.44523 (9) | 0.28664 (5) | 0.0241 (2) | |
C22 | 0.24318 (14) | 0.33552 (10) | 0.30656 (6) | 0.0303 (2) | |
H22 | 0.3351 | 0.2936 | 0.3238 | 0.036* | |
C23 | 0.09940 (14) | 0.28616 (11) | 0.30173 (6) | 0.0321 (3) | |
H23 | 0.0917 | 0.2115 | 0.3158 | 0.039* | |
C24 | −0.03126 (13) | 0.34853 (11) | 0.27601 (5) | 0.0304 (2) | |
C25 | −0.02518 (14) | 0.45697 (12) | 0.25579 (6) | 0.0335 (3) | |
H25 | −0.1178 | 0.4978 | 0.2381 | 0.040* | |
C26 | 0.11954 (14) | 0.50573 (11) | 0.26174 (5) | 0.0298 (2) | |
H26 | 0.1260 | 0.5813 | 0.2487 | 0.036* | |
O1 | 0.04838 (9) | 0.14124 (7) | 0.02412 (4) | 0.02909 (18) | |
O31 | 0.31391 (13) | 0.16472 (9) | −0.00959 (5) | 0.0496 (3) | |
O32 | 0.30392 (17) | 0.32242 (10) | −0.05643 (6) | 0.0588 (3) | |
O41 | 0.22278 (14) | 0.65139 (8) | 0.05559 (5) | 0.0485 (3) | |
O42 | 0.08126 (16) | 0.63785 (9) | 0.11771 (6) | 0.0578 (3) | |
O51 | −0.12687 (16) | 0.26580 (12) | 0.15001 (5) | 0.0641 (4) | |
O52 | −0.20063 (15) | 0.17435 (12) | 0.06807 (5) | 0.0598 (4) | |
N3 | 0.27271 (13) | 0.26325 (9) | −0.01814 (5) | 0.0323 (2) | |
N4 | 0.14537 (14) | 0.59644 (9) | 0.08192 (5) | 0.0380 (3) | |
N5 | −0.11622 (13) | 0.24272 (10) | 0.10035 (5) | 0.0349 (2) | |
C31 | 0.07480 (12) | 0.24316 (9) | 0.03909 (5) | 0.0233 (2) | |
C32 | 0.18288 (13) | 0.31337 (10) | 0.01940 (5) | 0.0258 (2) | |
C33 | 0.20463 (14) | 0.42683 (10) | 0.03198 (5) | 0.0284 (2) | |
H33 | 0.2723 | 0.4702 | 0.0154 | 0.034* | |
C34 | 0.12583 (14) | 0.47641 (10) | 0.06937 (5) | 0.0299 (2) | |
C35 | 0.02432 (14) | 0.41477 (10) | 0.09322 (5) | 0.0307 (2) | |
H35 | −0.0260 | 0.4491 | 0.1201 | 0.037* | |
C36 | −0.00186 (13) | 0.30330 (10) | 0.07723 (5) | 0.0270 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
F1 | 0.0726 (6) | 0.0721 (7) | 0.0364 (4) | 0.0016 (5) | 0.0315 (4) | −0.0020 (4) |
F2 | 0.0245 (4) | 0.0574 (5) | 0.0434 (4) | −0.0087 (3) | 0.0112 (3) | −0.0072 (4) |
N1 | 0.0199 (4) | 0.0306 (5) | 0.0207 (4) | −0.0002 (3) | 0.0064 (3) | 0.0021 (3) |
N2 | 0.0215 (4) | 0.0250 (5) | 0.0227 (4) | 0.0005 (3) | 0.0052 (3) | 0.0024 (3) |
C1 | 0.0248 (5) | 0.0242 (5) | 0.0238 (5) | 0.0009 (4) | 0.0064 (4) | 0.0029 (4) |
C2 | 0.0218 (5) | 0.0334 (6) | 0.0230 (5) | 0.0022 (4) | 0.0081 (4) | 0.0020 (4) |
C3 | 0.0226 (5) | 0.0306 (5) | 0.0238 (5) | −0.0013 (4) | 0.0086 (4) | 0.0034 (4) |
C4 | 0.0219 (5) | 0.0315 (6) | 0.0258 (5) | 0.0015 (4) | 0.0090 (4) | −0.0003 (4) |
C5 | 0.0224 (5) | 0.0311 (6) | 0.0241 (5) | −0.0019 (4) | 0.0089 (4) | 0.0024 (4) |
C11 | 0.0241 (5) | 0.0297 (5) | 0.0219 (5) | −0.0011 (4) | 0.0045 (4) | 0.0023 (4) |
C12 | 0.0472 (7) | 0.0301 (6) | 0.0318 (6) | −0.0115 (5) | 0.0144 (5) | −0.0011 (5) |
C13 | 0.0555 (8) | 0.0427 (7) | 0.0331 (6) | −0.0150 (6) | 0.0195 (6) | 0.0033 (5) |
C14 | 0.0366 (6) | 0.0519 (8) | 0.0244 (5) | −0.0009 (6) | 0.0118 (5) | −0.0008 (5) |
C15 | 0.0556 (8) | 0.0374 (7) | 0.0349 (7) | 0.0105 (6) | 0.0171 (6) | 0.0008 (5) |
C16 | 0.0530 (8) | 0.0298 (6) | 0.0321 (6) | 0.0081 (6) | 0.0173 (6) | 0.0077 (5) |
C21 | 0.0227 (5) | 0.0270 (5) | 0.0222 (5) | 0.0013 (4) | 0.0054 (4) | 0.0008 (4) |
C22 | 0.0242 (5) | 0.0278 (6) | 0.0371 (6) | 0.0017 (4) | 0.0053 (4) | 0.0045 (5) |
C23 | 0.0303 (6) | 0.0304 (6) | 0.0359 (6) | −0.0034 (5) | 0.0091 (5) | 0.0006 (5) |
C24 | 0.0230 (5) | 0.0428 (7) | 0.0267 (5) | −0.0046 (5) | 0.0091 (4) | −0.0067 (5) |
C25 | 0.0243 (5) | 0.0453 (7) | 0.0308 (6) | 0.0085 (5) | 0.0076 (4) | 0.0042 (5) |
C26 | 0.0292 (6) | 0.0319 (6) | 0.0292 (5) | 0.0064 (5) | 0.0094 (4) | 0.0058 (4) |
O1 | 0.0264 (4) | 0.0238 (4) | 0.0361 (4) | −0.0003 (3) | 0.0067 (3) | −0.0050 (3) |
O31 | 0.0572 (7) | 0.0395 (5) | 0.0658 (7) | 0.0152 (5) | 0.0400 (6) | 0.0056 (5) |
O32 | 0.0885 (9) | 0.0463 (6) | 0.0618 (7) | −0.0101 (6) | 0.0547 (7) | 0.0002 (5) |
O41 | 0.0624 (7) | 0.0266 (5) | 0.0541 (6) | −0.0054 (4) | 0.0115 (5) | 0.0024 (4) |
O42 | 0.0807 (9) | 0.0339 (5) | 0.0635 (7) | 0.0032 (5) | 0.0279 (6) | −0.0179 (5) |
O51 | 0.0808 (9) | 0.0832 (9) | 0.0408 (6) | −0.0316 (7) | 0.0379 (6) | −0.0244 (6) |
O52 | 0.0595 (7) | 0.0789 (8) | 0.0511 (6) | −0.0385 (6) | 0.0324 (5) | −0.0295 (6) |
N3 | 0.0350 (5) | 0.0328 (5) | 0.0340 (5) | −0.0041 (4) | 0.0176 (4) | −0.0032 (4) |
N4 | 0.0454 (6) | 0.0256 (5) | 0.0375 (6) | 0.0030 (4) | 0.0016 (5) | −0.0041 (4) |
N5 | 0.0383 (6) | 0.0413 (6) | 0.0293 (5) | −0.0061 (5) | 0.0162 (4) | −0.0088 (4) |
C31 | 0.0234 (5) | 0.0244 (5) | 0.0208 (5) | 0.0014 (4) | 0.0038 (4) | −0.0010 (4) |
C32 | 0.0263 (5) | 0.0277 (5) | 0.0239 (5) | 0.0007 (4) | 0.0078 (4) | −0.0014 (4) |
C33 | 0.0295 (5) | 0.0268 (5) | 0.0272 (5) | −0.0020 (4) | 0.0045 (4) | 0.0011 (4) |
C34 | 0.0345 (6) | 0.0227 (5) | 0.0287 (5) | 0.0015 (4) | 0.0019 (4) | −0.0036 (4) |
C35 | 0.0335 (6) | 0.0321 (6) | 0.0255 (5) | 0.0033 (5) | 0.0064 (4) | −0.0067 (4) |
C36 | 0.0277 (5) | 0.0315 (6) | 0.0223 (5) | −0.0015 (4) | 0.0078 (4) | −0.0036 (4) |
F1—C14 | 1.3610 (14) | C15—H15 | 0.9500 |
F2—C24 | 1.3597 (13) | C16—H16 | 0.9500 |
N1—C5 | 1.4636 (13) | C21—C22 | 1.3905 (16) |
N1—C2 | 1.4686 (13) | C21—C26 | 1.3909 (15) |
N1—C1 | 1.4770 (14) | C22—C23 | 1.3888 (17) |
N2—C3 | 1.4906 (14) | C22—H22 | 0.9500 |
N2—C4 | 1.4947 (14) | C23—C24 | 1.3734 (18) |
N2—H721 | 0.909 (17) | C23—H23 | 0.9500 |
N2—H722 | 0.926 (16) | C24—C25 | 1.3711 (19) |
C1—C21 | 1.5202 (15) | C25—C26 | 1.3893 (18) |
C1—C11 | 1.5258 (15) | C25—H25 | 0.9500 |
C1—H1 | 1.0000 | C26—H26 | 0.9500 |
C2—C3 | 1.5158 (15) | O1—C31 | 1.2587 (13) |
C2—H2A | 0.9900 | O31—N3 | 1.2221 (15) |
C2—H2B | 0.9900 | O32—N3 | 1.2179 (14) |
C3—H3A | 0.9900 | O41—N4 | 1.2245 (16) |
C3—H3B | 0.9900 | O42—N4 | 1.2282 (16) |
C4—C5 | 1.5140 (15) | O51—N5 | 1.2073 (14) |
C4—H4A | 0.9900 | O52—N5 | 1.2143 (15) |
C4—H4B | 0.9900 | N3—C32 | 1.4580 (14) |
C5—H5A | 0.9900 | N4—C34 | 1.4501 (15) |
C5—H5B | 0.9900 | N5—C36 | 1.4630 (15) |
C11—C12 | 1.3854 (16) | C31—C32 | 1.4383 (15) |
C11—C16 | 1.3869 (17) | C31—C36 | 1.4418 (15) |
C12—C13 | 1.3926 (18) | C32—C33 | 1.3757 (16) |
C12—H12 | 0.9500 | C33—C34 | 1.3841 (17) |
C13—C14 | 1.369 (2) | C33—H33 | 0.9500 |
C13—H13 | 0.9500 | C34—C35 | 1.3891 (18) |
C14—C15 | 1.370 (2) | C35—C36 | 1.3721 (17) |
C15—C16 | 1.3870 (18) | C35—H35 | 0.9500 |
C5—N1—C2 | 107.93 (8) | C14—C15—C16 | 118.33 (13) |
C5—N1—C1 | 113.08 (8) | C14—C15—H15 | 120.8 |
C2—N1—C1 | 111.77 (8) | C16—C15—H15 | 120.8 |
C3—N2—C4 | 111.54 (8) | C11—C16—C15 | 121.35 (12) |
C3—N2—H721 | 111.0 (10) | C11—C16—H16 | 119.3 |
C4—N2—H721 | 109.4 (10) | C15—C16—H16 | 119.3 |
C3—N2—H722 | 112.3 (10) | C22—C21—C26 | 118.73 (11) |
C4—N2—H722 | 107.0 (10) | C22—C21—C1 | 121.76 (10) |
H721—N2—H722 | 105.3 (14) | C26—C21—C1 | 119.49 (10) |
N1—C1—C21 | 110.43 (8) | C23—C22—C21 | 121.20 (11) |
N1—C1—C11 | 110.40 (9) | C23—C22—H22 | 119.4 |
C21—C1—C11 | 110.24 (9) | C21—C22—H22 | 119.4 |
N1—C1—H1 | 108.6 | C24—C23—C22 | 118.01 (12) |
C21—C1—H1 | 108.6 | C24—C23—H23 | 121.0 |
C11—C1—H1 | 108.6 | C22—C23—H23 | 121.0 |
N1—C2—C3 | 109.67 (9) | F2—C24—C25 | 118.85 (11) |
N1—C2—H2A | 109.7 | F2—C24—C23 | 118.32 (12) |
C3—C2—H2A | 109.7 | C25—C24—C23 | 122.84 (11) |
N1—C2—H2B | 109.7 | C24—C25—C26 | 118.46 (11) |
C3—C2—H2B | 109.7 | C24—C25—H25 | 120.8 |
H2A—C2—H2B | 108.2 | C26—C25—H25 | 120.8 |
N2—C3—C2 | 110.27 (9) | C25—C26—C21 | 120.76 (11) |
N2—C3—H3A | 109.6 | C25—C26—H26 | 119.6 |
C2—C3—H3A | 109.6 | C21—C26—H26 | 119.6 |
N2—C3—H3B | 109.6 | O32—N3—O31 | 123.16 (11) |
C2—C3—H3B | 109.6 | O32—N3—C32 | 118.00 (11) |
H3A—C3—H3B | 108.1 | O31—N3—C32 | 118.83 (10) |
N2—C4—C5 | 109.93 (9) | O41—N4—O42 | 123.52 (12) |
N2—C4—H4A | 109.7 | O41—N4—C34 | 118.30 (11) |
C5—C4—H4A | 109.7 | O42—N4—C34 | 118.16 (12) |
N2—C4—H4B | 109.7 | O51—N5—O52 | 122.53 (12) |
C5—C4—H4B | 109.7 | O51—N5—C36 | 118.60 (11) |
H4A—C4—H4B | 108.2 | O52—N5—C36 | 118.81 (10) |
N1—C5—C4 | 109.94 (9) | O1—C31—C32 | 123.95 (10) |
N1—C5—H5A | 109.7 | O1—C31—C36 | 123.74 (10) |
C4—C5—H5A | 109.7 | C32—C31—C36 | 112.31 (10) |
N1—C5—H5B | 109.7 | C33—C32—C31 | 124.42 (10) |
C4—C5—H5B | 109.7 | C33—C32—N3 | 116.94 (10) |
H5A—C5—H5B | 108.2 | C31—C32—N3 | 118.60 (10) |
C12—C11—C16 | 118.26 (11) | C32—C33—C34 | 118.57 (11) |
C12—C11—C1 | 120.70 (11) | C32—C33—H33 | 120.7 |
C16—C11—C1 | 121.04 (10) | C34—C33—H33 | 120.7 |
C11—C12—C13 | 121.27 (12) | C33—C34—C35 | 121.51 (11) |
C11—C12—H12 | 119.4 | C33—C34—N4 | 119.03 (11) |
C13—C12—H12 | 119.4 | C35—C34—N4 | 119.41 (11) |
C14—C13—C12 | 118.23 (12) | C36—C35—C34 | 118.68 (11) |
C14—C13—H13 | 120.9 | C36—C35—H35 | 120.7 |
C12—C13—H13 | 120.9 | C34—C35—H35 | 120.7 |
F1—C14—C13 | 119.08 (12) | C35—C36—C31 | 124.32 (11) |
F1—C14—C15 | 118.38 (13) | C35—C36—N5 | 117.23 (10) |
C13—C14—C15 | 122.51 (12) | C31—C36—N5 | 118.45 (10) |
C5—N1—C1—C21 | 175.43 (9) | C22—C23—C24—C25 | −0.79 (19) |
C2—N1—C1—C21 | −62.52 (11) | F2—C24—C25—C26 | 179.53 (11) |
C5—N1—C1—C11 | 53.26 (12) | C23—C24—C25—C26 | −0.13 (18) |
C2—N1—C1—C11 | 175.31 (9) | C24—C25—C26—C21 | 1.15 (18) |
C5—N1—C2—C3 | −63.90 (11) | C22—C21—C26—C25 | −1.20 (17) |
C1—N1—C2—C3 | 171.15 (9) | C1—C21—C26—C25 | 177.04 (11) |
C4—N2—C3—C2 | −53.24 (12) | O1—C31—C32—C33 | 175.18 (11) |
N1—C2—C3—N2 | 58.60 (12) | C36—C31—C32—C33 | −3.91 (16) |
C3—N2—C4—C5 | 53.23 (12) | O1—C31—C32—N3 | −2.65 (17) |
C2—N1—C5—C4 | 64.26 (11) | C36—C31—C32—N3 | 178.26 (10) |
C1—N1—C5—C4 | −171.57 (9) | O32—N3—C32—C33 | −32.04 (17) |
N2—C4—C5—N1 | −58.93 (12) | O31—N3—C32—C33 | 147.48 (12) |
N1—C1—C11—C12 | −116.94 (12) | O32—N3—C32—C31 | 145.96 (12) |
C21—C1—C11—C12 | 120.78 (12) | O31—N3—C32—C31 | −34.53 (17) |
N1—C1—C11—C16 | 62.58 (14) | C31—C32—C33—C34 | 4.57 (18) |
C21—C1—C11—C16 | −59.70 (14) | N3—C32—C33—C34 | −177.56 (10) |
C16—C11—C12—C13 | −2.0 (2) | C32—C33—C34—C35 | −1.18 (18) |
C1—C11—C12—C13 | 177.51 (12) | C32—C33—C34—N4 | −178.72 (11) |
C11—C12—C13—C14 | 0.2 (2) | O41—N4—C34—C33 | 4.97 (17) |
C12—C13—C14—F1 | 179.46 (13) | O42—N4—C34—C33 | −176.16 (12) |
C12—C13—C14—C15 | 1.4 (2) | O41—N4—C34—C35 | −172.63 (12) |
F1—C14—C15—C16 | −179.17 (13) | O42—N4—C34—C35 | 6.24 (18) |
C13—C14—C15—C16 | −1.1 (2) | C33—C34—C35—C36 | −2.44 (18) |
C12—C11—C16—C15 | 2.3 (2) | N4—C34—C35—C36 | 175.09 (11) |
C1—C11—C16—C15 | −177.19 (12) | C34—C35—C36—C31 | 3.01 (18) |
C14—C15—C16—C11 | −0.8 (2) | C34—C35—C36—N5 | −176.52 (11) |
N1—C1—C21—C22 | −30.91 (14) | O1—C31—C36—C35 | −179.08 (11) |
C11—C1—C21—C22 | 91.36 (12) | C32—C31—C36—C35 | 0.01 (16) |
N1—C1—C21—C26 | 150.90 (10) | O1—C31—C36—N5 | 0.44 (17) |
C11—C1—C21—C26 | −86.83 (12) | C32—C31—C36—N5 | 179.53 (10) |
C26—C21—C22—C23 | 0.24 (18) | O51—N5—C36—C35 | −34.90 (18) |
C1—C21—C22—C23 | −177.96 (11) | O52—N5—C36—C35 | 142.36 (14) |
C21—C22—C23—C24 | 0.73 (19) | O51—N5—C36—C31 | 145.55 (14) |
C22—C23—C24—F2 | 179.55 (11) | O52—N5—C36—C31 | −37.19 (18) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H721···O1i | 0.909 (17) | 1.924 (17) | 2.7696 (12) | 154.0 (14) |
N2—H721···O52i | 0.909 (17) | 2.369 (16) | 3.0018 (14) | 126.7 (12) |
N2—H722···O1ii | 0.926 (16) | 1.927 (16) | 2.7402 (13) | 145.4 (14) |
N2—H722···O31ii | 0.926 (16) | 2.345 (16) | 3.0791 (15) | 136.0 (13) |
C3—H3A···O52i | 0.99 | 2.60 | 3.0002 (16) | 104 |
C13—H13···O32iii | 0.95 | 2.39 | 3.2159 (16) | 145 |
C23—H23···O42iv | 0.95 | 2.61 | 3.2827 (17) | 129 |
Symmetry codes: (i) x+1, −y+1/2, z+1/2; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1, −y+1, −z; (iv) −x, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C17H19F2N2+·C6H2N3O7− |
Mr | 517.45 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 200 |
a, b, c (Å) | 8.9425 (2), 11.8286 (2), 23.0922 (4) |
β (°) | 105.720 (1) |
V (Å3) | 2351.27 (8) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 0.52 × 0.49 × 0.41 |
Data collection | |
Diffractometer | Bruker APEXII CCD |
Absorption correction | Multi-scan (SADABS: Bruker, 2008) |
Tmin, Tmax | 0.928, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 20823, 5842, 5041 |
Rint | 0.013 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.111, 1.03 |
No. of reflections | 5842 |
No. of parameters | 342 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.32, −0.31 |
Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), ORTEPIII (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H721···O1i | 0.909 (17) | 1.924 (17) | 2.7696 (12) | 154.0 (14) |
N2—H721···O52i | 0.909 (17) | 2.369 (16) | 3.0018 (14) | 126.7 (12) |
N2—H722···O1ii | 0.926 (16) | 1.927 (16) | 2.7402 (13) | 145.4 (14) |
N2—H722···O31ii | 0.926 (16) | 2.345 (16) | 3.0791 (15) | 136.0 (13) |
C3—H3A···O52i | 0.99 | 2.60 | 3.0002 (16) | 104.2 |
C13—H13···O32iii | 0.95 | 2.39 | 3.2159 (16) | 145.2 |
C23—H23···O42iv | 0.95 | 2.61 | 3.2827 (17) | 128.5 |
Symmetry codes: (i) x+1, −y+1/2, z+1/2; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1, −y+1, −z; (iv) −x, y−1/2, −z+1/2. |
Acknowledgements
ASD thanks the University of Mysore for research facilities.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
4,4'-Difluorobenzhydryl piperazine is an intermediate for the preparation of flunarizine which is a calcium channel blocker. Piperazines are among the most important building blocks in today's drug discovery. They are found in biologically active compounds across a number of different therapeutic areas such as antifungal, antibacterial, antimalarial, antipsychotic, antidepressant and antitumour activity against colon, prostate, breast, lung and leukemia tumors (Brockunier et al., 2004; Bogatcheva et al., 2006). The crystal structures of some related salts viz., levocetirizinium dipicrate (Jasinski et al., 2010), cinnarizinium dipicrate (Jasinski et al., 2011), 1-methylpiperazine-1,4-diium dipicrate (Dutkiewicz et al., 2011), have been reported. In the course of our studies on picrates of simple organic cations and in view of the importance of piperazines, we have determined the crystal and molecular structure of the title salt.
Protonation occurred at the nitrogen atom that is part of the secondary amine functionality. The non-aromatic heterocycle adopts a chair conformation (1C4, N1CN2) according to a conformation analysis (Cremer & Pople, 1975). The least-squares planes defined by the carbon atoms of the two fluorophenyl moieties intersect at an angle of 73.71 (4) °. The planes defined by the atoms of the nitro groups on the picrate anion enclose angles of 7.62 (14) °, 33.52 (18) ° and 37.08 (17) °, respectively with the aromatic system they are bonded to (Fig. 1).
In the crystal, hydrogen bonds of the N–H···O type as well as C–H···O contacts are present. Both classical hydrogen bonds show bifurcation between the phenolic O atom as well as one of the nitro group's O atoms. The C–H···O contacts are supported by one of the hydrogen atoms of the non-aromatic heterocycle as well as one of the hydrogen atoms in ortho position to F atom in each of the fluorophenyl moieties. Apart from one O atom of a nitro group that forms a N–O···Cg contact with a neighbouring picrate anion, all O atoms act as acceptors for hydrogen atoms. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the classical hydrogen bonds is DDDD on the unitary level while the C–H···O contacts require a DD descriptor on the same level. In total, the entities of the title compound are connected to a three-dimensional network in the crystal. The shortest intercentroid distance between two centers of gravity was found at 4.0808 (7) Å and is apparent between one of the fluorophenyl moieties and the picrate anion (Fig. 2).
The packing of the title compound in the crystal structure is shown in Figure 3.