3,5-Bis(4-fluoro­phen­yl)-1-phenyl-4,5-dihydro-1H-pyrazole

Jasinski, J.P.; Guild, C.J.; Samshuddin, S.; Narayana, B.; Yathirajan, H.S.

doi:10.1107/S1600536810026036

organic compounds

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ISSN: 2056-9890

Volume 66| Part 8| August 2010| Pages o1948-o1949

https://doi.org/10.1107/S1600536810026036

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3,5-Bis(4-fluorophenyl)-1-phenyl-4,5-dihydro-1H-pyrazole

Jerry P. Jasinski,^a ^* Curtis J. Guild,^a S. Samshuddin,^b B. Narayana ^b and H. S. Yathirajan ^c

^aDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, ^bDepartment of Studies in Chemistry, Mangalore University, Mangalagangotri 574 199, India, and ^cDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
^*Correspondence e-mail: jjasinski@keene.edu

(Received 25 June 2010; accepted 1 July 2010; online 7 July 2010)

In the title compound, C₂₁H₁₆F₂N₂, the dihedral angle between the fluorophenyl groups is 66.34 (8)°, and the dihedral angle between the envelope-configured pyrazole group (N/N/C/C/C) and the benzene ring is 11.50 (9)°. The dihedral angles between the benzene and the two fluoro-substituted phenyl groups are 77.7 (6) and 16.7 (5)°. Weak C—H⋯π interactions contribute to the stability of the crystal structure.

Related literature

For background to the chemistry and biological activity of pyrazolines, see: Amir et al. (2008 ); Bhaskarreddy et al. (1997 ); Fustero et al. (2009 ); Hes et al. (1978 ); Klimova et al. (1999 ); Regaila et al. (1979 ); Sarojini et al. (2010 ); Wiley et al. (1958 ); Spek (2009 ). For related structures, see: Butcher et al. (2007 ); Fun, Quah et al. (2009 ); Fun, Yeap et al. (2009 ); Fun et al. (2010 ); Guo et al. (2006 , 2007 ); Li (2007a ,b ); Loh et al. (2010 ); Yathirajan et al. (2007a ,b ).

Experimental

Crystal data

C₂₁H₁₆F₂N₂
M_r = 334.36
Monoclinic, P 2₁ /c
a = 12.2880 (3) Å
b = 13.1678 (3) Å
c = 11.3245 (3) Å
β = 112.661 (3)°
V = 1690.91 (7) Å³
Z = 4
Cu Kα radiation
μ = 0.77 mm⁻¹
T = 100 K
0.28 × 0.24 × 0.23 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Cu) detector
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 $[Oxford Diffraction (2007). CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ) T_min = 0.774, T_max = 1.000
7737 measured reflections
3541 independent reflections
2740 reflections with I > 2σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.116
S = 1.05
3541 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Table 1
Y—X⋯Cg π ring interactions (Å, °)

Cg4 is the centroid of ring C16–C21 and Cg2 is the centroid of the ring C1–C6.

X—H⋯CgX	X⋯Cg	H⋯Cg	X⋯Perp
C9—H9⋯Cg4ⁱ	3.6677 (16)	2.82	2.76
C12—H12⋯Cg2ⁱⁱ	3.6061 (18)	2.88	−2.79
Symmetry codes: (i) 1 − x, 1 − y, 1 − z; (ii) −x, − $[{1\over 2}]$ + y, $[{1\over 2}]$ − z.

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 $[Oxford Diffraction (2007). CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 $[Oxford Diffraction (2007). CrysAlis PRO and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810026036/tk2686sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810026036/tk2686Isup2.hkl

checkCIF report

Comment top

Pyrazolines are well known as important nitrogen-containing five-membered heterocyclic compounds and various methods have been worked out for their synthesis (Fustero et al., 2009). The pyrazoline function is quite stable and has inspired chemists to utilize this stable fragment in bioactive moieties to synthesize new compounds possessing biological activities, and the presence of fluorine in the molecules at strategic positions alters their activity. Several pyrazoline derivatives have been found to possess considerable biological activities, which stimulated research activity in this field. In particular, they are used as antitumor, antibacterial, antifungal, antiviral, anti-parasitic, anti-tubercular and insecticidal agents (Hes et al., 1978; Amir et al., 2008). Some of these compounds have also anti-inflammatory, anti-diabetic, anaesthetic and analgesic properties (Sarojini et al., 2010; Regaila et al., 1979). Several 1,3,5-triaryl-2 -pyrazolines were also used as scintillation solutes (Wiley et al., 1958). In addition, pyrazolines have played a crucial part in the development of theory in heterocyclic chemistry and also used extensively in organic synthesis (Klimova et al., 1999; Bhaskarreddy et al., 1997).

The crystal structures of some substituted 4,5-dihydro N– phenyl pyrazoles viz., 6-chloro-3-[5-(4-fluorophenyl)-1-phenyl-4,5- dihydro-1H-pyrazol-3-yl]-2-methyl-4-phenyl quinoline (Loh et al., 2010), 6-chloro-3-[5-(3-methoxy-8-methyl-4- quinolyl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-2-methyl-4-phenyl quinoline (Fun et al., 2009a), 6-chloro-2-methyl-4-phenyl- 3-[1-phenyl-5-(2-thienyl)-4,5-dihydro-1H-pyrazol-3-yl] quinoline (Fun et al., 2009b), 3-(4-fluorophenyl)-1,5-diphenyl-2-pyrazoline (Guo et al., 2006), 3-(4-bromophenyl)-5- (2-chlorophenyl)-1-phenyl-2-pyrazoline, (Guo et al., 2007), 5-(p-fluorophenyl)-1,3-diphenyl-2-pyrazoline, 3-(4-bromophenyl)-5 -(4-fluorophenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (Li, 2007a,b) have been reported. In continuation of our work on pyrazoline derivatives (Fun et al., 2010; Yathirajan et al., 2007a,b; Butcher et al., 2007) and in view of the importance of these derivatives, the title compound C₂₁H₁₅N₂F₂ (I) was synthesized and its crystal structure is reported here.

The title compound (I) contains two p-florophenyl groups and a benzene ring attached to an envelope configured pyrazole ring (Fig. 1). The dihedral angle between the two flourophenyl groups is 66.34 (8)° and the dihedral angle between the pyrazole and benzene rings is 11.50 (9) °. Also, the dihedral angles between the benzene ring and the two fluoro-substituted phenyl groups are 77.7 (6) and 16.7 (5) °, respectively. Two C–H···π interactions (Table 1) contribute to the stability of the crystal structure (Fig. 2).

Related literature top

For background to the chemistry and biological activity of pyrazolines, see: Amir et al. (2008); Bhaskarreddy et al. (1997); Fustero et al. (2009); Hes et al. (1978); Klimova et al. (1999); Regaila et al. (1979); Sarojini et al., (2010); Wiley et al. (1958); Spek (2009). For related structures, see: Butcher et al. (2007); Fun, Quah et al. (2009); Fun, Yeap et al. (2009); Fun et al. (2010); Guo et al. (2006, 2007); Li (2007a,b); Loh et al. (2010); Yathirajan et al. (2007a,b).

Experimental top

A mixture of (2E)-1,3-bis(4-fluorophenyl)prop-2-en-1-one (2.44 g, 0.01 mol) and phenyl hydrazine (1.08 g, 0.01 mol) in ethanol (20 ml) in the presence of glacial acetic acid (5 ml) was refluxed for 5 h. The reaction mixture was cooled and poured into ice-cold water (50 ml). The precipitate was collected by filtration and purified by recrystallization from ethanol. The single-crystal was grown from toluene by the slow evaporation method. The yield of the compound was 84%; m.pt. 387 K. Analytical data: Found (Calculated): C %: 67.86 (67.99); H %: 4.62 (4.70); N %: 9.29 (9.33).

Structure description top

For background to the chemistry and biological activity of pyrazolines, see: Amir et al. (2008); Bhaskarreddy et al. (1997); Fustero et al. (2009); Hes et al. (1978); Klimova et al. (1999); Regaila et al. (1979); Sarojini et al., (2010); Wiley et al. (1958); Spek (2009). For related structures, see: Butcher et al. (2007); Fun, Quah et al. (2009); Fun, Yeap et al. (2009); Fun et al. (2010); Guo et al. (2006, 2007); Li (2007a,b); Loh et al. (2010); Yathirajan et al. (2007a,b).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell refinement: CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. Molecular structure of (I), with 50% probability displacement ellipsoids.
	Fig. 2. Packing diagram for (I), viewed down the c axis.

3,5-Bis(4-fluorophenyl)-1-phenyl-4,5-dihydro-1H-pyrazole top

Crystal data top

C₂₁H₁₆F₂N₂	F(000) = 696
M_r = 334.36	D_x = 1.313 Mg m⁻³
Monoclinic, P2₁/c	Cu Kα radiation, λ = 1.54184 Å
Hall symbol: -P 2ybc	Cell parameters from 3839 reflections
a = 12.2880 (3) Å	θ = 4.5–77.2°
b = 13.1678 (3) Å	µ = 0.77 mm⁻¹
c = 11.3245 (3) Å	T = 100 K
β = 112.661 (3)°	Block, colorless
V = 1690.91 (7) Å³	0.28 × 0.24 × 0.23 mm
Z = 4

Data collection top

Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Cu) detector	3541 independent reflections
Radiation source: fine-focus sealed tube	2740 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.016
Detector resolution: 10.5081 pixels mm^-1	θ_max = 77.4°, θ_min = 5.2°
ω scans	h = −11→15
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)	k = −16→14
T_min = 0.774, T_max = 1.000	l = −13→14
7737 measured reflections

Refinement top

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) = 0.116	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.060P)² + 0.1618P] where P = (F_o² + 2F_c²)/3
3541 reflections	(Δ/σ)_max < 0.001
226 parameters	Δρ_max = 0.15 e Å⁻³
0 restraints	Δρ_min = −0.16 e Å⁻³

Crystal data top

C₂₁H₁₆F₂N₂	V = 1690.91 (7) Å³
M_r = 334.36	Z = 4
Monoclinic, P2₁/c	Cu Kα radiation
a = 12.2880 (3) Å	µ = 0.77 mm⁻¹
b = 13.1678 (3) Å	T = 100 K
c = 11.3245 (3) Å	0.28 × 0.24 × 0.23 mm
β = 112.661 (3)°

Data collection top

Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Cu) detector	3541 independent reflections
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)	2740 reflections with I > 2σ(I)
T_min = 0.774, T_max = 1.000	R_int = 0.016
7737 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.116	H-atom parameters constrained
S = 1.05	Δρ_max = 0.15 e Å⁻³
3541 reflections	Δρ_min = −0.16 e Å⁻³
226 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
F1	0.14722 (10)	0.03973 (7)	0.26845 (11)	0.0891 (3)
F2	0.03475 (11)	0.92804 (9)	0.61215 (12)	0.0958 (4)
N1	0.27887 (10)	0.60196 (9)	0.37791 (11)	0.0583 (3)
N2	0.31295 (11)	0.50566 (9)	0.35601 (11)	0.0594 (3)
C1	0.11598 (14)	0.67082 (12)	0.57694 (14)	0.0649 (4)
H1	0.1090	0.6062	0.6064	0.078*
C2	0.06799 (15)	0.75266 (13)	0.61618 (15)	0.0710 (4)
H2	0.0288	0.7437	0.6712	0.085*
C3	0.07946 (15)	0.84700 (12)	0.57224 (15)	0.0682 (4)
C4	0.13479 (15)	0.86269 (12)	0.48921 (17)	0.0725 (4)
H4	0.1398	0.9276	0.4593	0.087*
C5	0.18302 (14)	0.78039 (12)	0.45068 (15)	0.0643 (4)
H5	0.2215	0.7902	0.3951	0.077*
C6	0.17452 (12)	0.68283 (10)	0.49427 (12)	0.0549 (3)
C7	0.22462 (12)	0.59450 (11)	0.45457 (12)	0.0554 (3)
C8	0.21469 (15)	0.48688 (11)	0.49360 (15)	0.0644 (4)
H8A	0.1353	0.4608	0.4505	0.077*
H8B	0.2374	0.4812	0.5854	0.077*
C9	0.30233 (13)	0.43192 (10)	0.44948 (13)	0.0563 (3)
H9	0.3785	0.4265	0.5218	0.068*
C10	0.26207 (11)	0.32735 (10)	0.39674 (12)	0.0515 (3)
C11	0.18963 (13)	0.31090 (11)	0.26960 (13)	0.0603 (3)
H11	0.1665	0.3654	0.2132	0.072*
C12	0.15145 (14)	0.21357 (13)	0.22594 (14)	0.0658 (4)
H12	0.1039	0.2020	0.1405	0.079*
C13	0.18527 (14)	0.13539 (11)	0.31124 (15)	0.0632 (4)
C14	0.25607 (15)	0.14782 (11)	0.43752 (15)	0.0662 (4)
H14	0.2775	0.0929	0.4934	0.079*
C15	0.29473 (14)	0.24498 (11)	0.47929 (14)	0.0605 (3)
H15	0.3437	0.2553	0.5646	0.073*
C16	0.39681 (12)	0.49799 (11)	0.30110 (13)	0.0567 (3)
C17	0.46147 (13)	0.40957 (13)	0.31169 (15)	0.0660 (4)
H17	0.4526	0.3556	0.3602	0.079*
C18	0.53935 (14)	0.40141 (15)	0.25016 (18)	0.0769 (5)
H18	0.5818	0.3417	0.2573	0.092*
C19	0.55439 (16)	0.48058 (17)	0.17879 (18)	0.0853 (5)
H19	0.6060	0.4745	0.1369	0.102*
C20	0.49212 (17)	0.56887 (17)	0.17010 (18)	0.0838 (5)
H20	0.5032	0.6231	0.1232	0.101*
C21	0.41337 (15)	0.57872 (13)	0.22966 (15)	0.0679 (4)
H21	0.3716	0.6389	0.2222	0.081*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.1227 (8)	0.0572 (5)	0.1070 (7)	−0.0245 (5)	0.0660 (7)	−0.0303 (5)
F2	0.1130 (8)	0.0748 (7)	0.1084 (8)	0.0252 (6)	0.0524 (7)	−0.0023 (6)
N1	0.0659 (6)	0.0496 (6)	0.0595 (6)	−0.0020 (5)	0.0243 (5)	0.0031 (5)
N2	0.0710 (7)	0.0487 (6)	0.0649 (6)	−0.0046 (5)	0.0332 (6)	0.0029 (5)
C1	0.0796 (9)	0.0579 (8)	0.0594 (8)	0.0042 (7)	0.0292 (7)	0.0100 (6)
C2	0.0806 (10)	0.0748 (11)	0.0610 (8)	0.0123 (8)	0.0309 (7)	0.0080 (7)
C3	0.0734 (9)	0.0615 (9)	0.0660 (8)	0.0099 (7)	0.0226 (7)	−0.0019 (7)
C4	0.0819 (10)	0.0501 (8)	0.0846 (10)	0.0001 (7)	0.0310 (8)	0.0051 (7)
C5	0.0739 (9)	0.0559 (8)	0.0653 (8)	−0.0043 (7)	0.0294 (7)	0.0037 (6)
C6	0.0608 (7)	0.0511 (7)	0.0482 (6)	−0.0024 (6)	0.0160 (5)	0.0006 (5)
C7	0.0637 (7)	0.0505 (7)	0.0492 (6)	−0.0054 (6)	0.0186 (6)	0.0013 (5)
C8	0.0879 (10)	0.0489 (7)	0.0653 (8)	−0.0086 (7)	0.0392 (8)	−0.0038 (6)
C9	0.0655 (7)	0.0490 (7)	0.0521 (7)	−0.0080 (6)	0.0199 (6)	0.0009 (5)
C10	0.0568 (7)	0.0468 (6)	0.0521 (6)	−0.0041 (5)	0.0224 (5)	−0.0005 (5)
C11	0.0666 (8)	0.0574 (8)	0.0536 (7)	−0.0053 (6)	0.0193 (6)	0.0030 (6)
C12	0.0689 (8)	0.0707 (9)	0.0574 (8)	−0.0129 (7)	0.0238 (7)	−0.0140 (7)
C13	0.0790 (9)	0.0481 (7)	0.0783 (9)	−0.0110 (7)	0.0479 (8)	−0.0148 (7)
C14	0.0893 (10)	0.0472 (7)	0.0713 (9)	0.0007 (7)	0.0409 (8)	0.0036 (6)
C15	0.0748 (8)	0.0518 (7)	0.0532 (7)	−0.0019 (6)	0.0229 (6)	0.0018 (6)
C16	0.0554 (7)	0.0578 (8)	0.0543 (7)	−0.0101 (6)	0.0183 (6)	−0.0038 (6)
C17	0.0608 (7)	0.0643 (9)	0.0730 (9)	−0.0073 (7)	0.0260 (7)	0.0002 (7)
C18	0.0634 (8)	0.0789 (11)	0.0888 (11)	−0.0029 (8)	0.0296 (8)	−0.0106 (9)
C19	0.0762 (10)	0.1065 (15)	0.0854 (11)	−0.0113 (10)	0.0445 (9)	−0.0060 (11)
C20	0.0886 (11)	0.0945 (13)	0.0772 (11)	−0.0122 (10)	0.0420 (9)	0.0117 (9)
C21	0.0735 (9)	0.0678 (9)	0.0649 (8)	−0.0065 (7)	0.0295 (7)	0.0055 (7)

Geometric parameters (Å, º) top

F1—C13	1.3658 (16)	C9—H9	0.9800
F2—C3	1.3551 (19)	C10—C15	1.3865 (19)
N1—C7	1.2859 (19)	C10—C11	1.3873 (19)
N1—N2	1.3875 (17)	C11—C12	1.389 (2)
N2—C16	1.3973 (19)	C11—H11	0.9300
N2—C9	1.4787 (17)	C12—C13	1.363 (2)
C1—C2	1.382 (2)	C12—H12	0.9300
C1—C6	1.392 (2)	C13—C14	1.367 (2)
C1—H1	0.9300	C14—C15	1.383 (2)
C2—C3	1.366 (2)	C14—H14	0.9300
C2—H2	0.9300	C15—H15	0.9300
C3—C4	1.372 (3)	C16—C17	1.388 (2)
C4—C5	1.384 (2)	C16—C21	1.398 (2)
C4—H4	0.9300	C17—C18	1.388 (2)
C5—C6	1.395 (2)	C17—H17	0.9300
C5—H5	0.9300	C18—C19	1.374 (3)
C6—C7	1.465 (2)	C18—H18	0.9300
C7—C8	1.503 (2)	C19—C20	1.374 (3)
C8—C9	1.532 (2)	C19—H19	0.9300
C8—H8A	0.9700	C20—C21	1.382 (3)
C8—H8B	0.9700	C20—H20	0.9300
C9—C10	1.5066 (18)	C21—H21	0.9300

C7—N1—N2	108.75 (11)	C15—C10—C11	118.74 (13)
N1—N2—C16	118.08 (11)	C15—C10—C9	118.83 (12)
N1—N2—C9	110.87 (11)	C11—C10—C9	122.38 (12)
C16—N2—C9	123.69 (12)	C10—C11—C12	120.48 (13)
C2—C1—C6	121.53 (15)	C10—C11—H11	119.8
C2—C1—H1	119.2	C12—C11—H11	119.8
C6—C1—H1	119.2	C13—C12—C11	118.43 (13)
C3—C2—C1	118.40 (16)	C13—C12—H12	120.8
C3—C2—H2	120.8	C11—C12—H12	120.8
C1—C2—H2	120.8	C12—C13—F1	118.43 (14)
F2—C3—C2	118.86 (16)	C12—C13—C14	123.25 (13)
F2—C3—C4	118.80 (15)	F1—C13—C14	118.31 (14)
C2—C3—C4	122.34 (15)	C13—C14—C15	117.69 (14)
C3—C4—C5	118.93 (15)	C13—C14—H14	121.2
C3—C4—H4	120.5	C15—C14—H14	121.2
C5—C4—H4	120.5	C14—C15—C10	121.40 (13)
C4—C5—C6	120.67 (15)	C14—C15—H15	119.3
C4—C5—H5	119.7	C10—C15—H15	119.3
C6—C5—H5	119.7	C17—C16—N2	121.18 (13)
C1—C6—C5	118.12 (14)	C17—C16—C21	118.80 (14)
C1—C6—C7	120.21 (13)	N2—C16—C21	119.97 (14)
C5—C6—C7	121.67 (13)	C18—C17—C16	120.26 (16)
N1—C7—C6	122.33 (13)	C18—C17—H17	119.9
N1—C7—C8	113.11 (13)	C16—C17—H17	119.9
C6—C7—C8	124.52 (13)	C19—C18—C17	120.75 (18)
C7—C8—C9	101.68 (12)	C19—C18—H18	119.6
C7—C8—H8A	111.4	C17—C18—H18	119.6
C9—C8—H8A	111.4	C20—C19—C18	119.11 (17)
C7—C8—H8B	111.4	C20—C19—H19	120.4
C9—C8—H8B	111.4	C18—C19—H19	120.4
H8A—C8—H8B	109.3	C19—C20—C21	121.30 (17)
N2—C9—C10	114.99 (11)	C19—C20—H20	119.4
N2—C9—C8	100.96 (11)	C21—C20—H20	119.4
C10—C9—C8	113.34 (11)	C20—C21—C16	119.77 (17)
N2—C9—H9	109.1	C20—C21—H21	120.1
C10—C9—H9	109.1	C16—C21—H21	120.1
C8—C9—H9	109.1

C7—N1—N2—C16	−164.89 (12)	N2—C9—C10—C15	153.43 (13)
C7—N1—N2—C9	−13.70 (16)	C8—C9—C10—C15	−91.13 (16)
C6—C1—C2—C3	−0.2 (2)	N2—C9—C10—C11	−29.19 (19)
C1—C2—C3—F2	−178.70 (14)	C8—C9—C10—C11	86.26 (17)
C1—C2—C3—C4	1.2 (3)	C15—C10—C11—C12	−0.5 (2)
F2—C3—C4—C5	178.47 (14)	C9—C10—C11—C12	−177.88 (13)
C2—C3—C4—C5	−1.4 (3)	C10—C11—C12—C13	1.0 (2)
C3—C4—C5—C6	0.7 (2)	C11—C12—C13—F1	179.67 (13)
C2—C1—C6—C5	−0.5 (2)	C11—C12—C13—C14	−0.8 (2)
C2—C1—C6—C7	179.91 (14)	C12—C13—C14—C15	−0.1 (2)
C4—C5—C6—C1	0.2 (2)	F1—C13—C14—C15	179.47 (14)
C4—C5—C6—C7	179.85 (14)	C13—C14—C15—C10	0.7 (2)
N2—N1—C7—C6	−178.39 (12)	C11—C10—C15—C14	−0.4 (2)
N2—N1—C7—C8	−0.60 (16)	C9—C10—C15—C14	177.09 (14)
C1—C6—C7—N1	179.65 (13)	N1—N2—C16—C17	160.01 (13)
C5—C6—C7—N1	0.0 (2)	C9—N2—C16—C17	12.8 (2)
C1—C6—C7—C8	2.1 (2)	N1—N2—C16—C21	−22.60 (19)
C5—C6—C7—C8	−177.51 (14)	C9—N2—C16—C21	−169.85 (13)
N1—C7—C8—C9	13.51 (16)	N2—C16—C17—C18	176.23 (14)
C6—C7—C8—C9	−168.75 (12)	C21—C16—C17—C18	−1.2 (2)
N1—N2—C9—C10	143.41 (12)	C16—C17—C18—C19	0.5 (2)
C16—N2—C9—C10	−67.31 (17)	C17—C18—C19—C20	0.7 (3)
N1—N2—C9—C8	21.03 (14)	C18—C19—C20—C21	−1.2 (3)
C16—N2—C9—C8	170.31 (12)	C19—C20—C21—C16	0.5 (3)
C7—C8—C9—N2	−19.28 (13)	C17—C16—C21—C20	0.7 (2)
C7—C8—C9—C10	−142.80 (12)	N2—C16—C21—C20	−176.72 (15)

Experimental details

Crystal data
Chemical formula	C₂₁H₁₆F₂N₂
M_r	334.36
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	12.2880 (3), 13.1678 (3), 11.3245 (3)
β (°)	112.661 (3)
V (Å³)	1690.91 (7)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	0.77
Crystal size (mm)	0.28 × 0.24 × 0.23

Data collection
Diffractometer	Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Cu) detector
Absorption correction	Multi-scan (CrysAlis RED; Oxford Diffraction, 2007)
T_min, T_max	0.774, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	7737, 3541, 2740
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.633

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.116, 1.05
No. of reflections	3541
No. of parameters	226
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.15, −0.16

Computer programs: CrysAlis PRO (Oxford Diffraction, 2007), CrysAlis RED (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Y-X···Cg π ring interactions, Cg4 is the centroid of ring C16-C21, and Cg2 is the centroid of the ring C1-C6. [Symmetry codes: (i) 1-x,1-y,1-z ; (ii) -x,-1/2+y,1/2-z] top

X–H···CgX (Å)	X···Cg, (Å)	H···Cg	X···Perp (Å)
C9–H9···Cg4ⁱ	3.6677 (16)	2.82	2.76
C12–H12···Cg2²	3.6061 (18)	2.88	-2.79

Acknowledgements

SS thanks Mangalore University for research facilities and HSY thanks the University of Mysore for sabbatical leave. JPJ thanks Dr Ray Butcher and Howard University for assistance with the data collection.

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