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Acta Crystallogr Sect E Struct Rep Online. 2009 August 1; 65(Pt 8): o1965–o1966.
Published online 2009 July 25. doi:  10.1107/S1600536809028517
PMCID: PMC2977262

A second polymorph of (2E)-1-(4-fluoro­phen­yl)-3-(3,4,5-trimethoxy­phen­yl)prop-2-en-1-one

Abstract

The crystal structure of the title compound, C18H17FO4, reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007), 461, 123–130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups is 28.7 (1)° compared to 20.8 (6)° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups are 30.3 (4) and 7.4 (7)°, respectively, in contast to 10.7 (3) and 12.36° for the polymorph. While the two 3-meth­oxy groups are in the plane of the trimeth­oxy-substituted ring, the 4-meth­oxy group is in a synclinical [−sc = −78.1 (2)°] or anti­clinical [+ac = 104.0 (4)°] position, compared to a +sc [53.0 (4)°] or −ac [−132.4 (7)°] position. While no classical hydrogen bonds are present, weak inter­molecular C—H(...)π-ring inter­actions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P21/c, but have different cell parameters for the a, b and c axes and the β angle. A comparison of the mol­ecular geometries of both polymorphs to a geometry optimized density functional theory (DFT) calculation at the B3-LYP/6–311+G(d,p) level for each structure provides additional support to these observations.

Related literature

For general background to the biological activity of similar compounds, see: Dimmock et al. (1999 [triangle]); Lin et al. (2002 [triangle]); Nakamura et al. (2002 [triangle]); Nowakowska (2007 [triangle]); Opletalova & Sedivy (1999 [triangle]). For related structures, see: Butcher et al. (2006 [triangle], 2007 [triangle]); Chopra et al. (2007 [triangle]); Fun et al. (2008 [triangle]); Jasinski et al. (2009 [triangle]); Patil et al. (2007 [triangle]); Qiu et al. (2006 [triangle]); Teh et al. (2007 [triangle]). For density functional theory (DFT), see: Becke (1988 [triangle], 1993 [triangle]); Hehre et al. (1986 [triangle]); Lee et al. (1988 [triangle]); Schmidt & Polik (2007 [triangle]). For a description of the Cambridge Structural Database, see: Allen (2002 [triangle]). For the GAUSSIAN03 program package, see: Frisch et al. (2004 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o1965-scheme1.jpg

Experimental

Crystal data

  • C18H17FO4
  • M r = 316.32
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1965-efi1.jpg
  • a = 12.4250 (2) Å
  • b = 8.6280 (1) Å
  • c = 14.9038 (2) Å
  • β = 98.3217 (12)°
  • V = 1580.91 (4) Å3
  • Z = 4
  • Cu Kα radiation
  • μ = 0.85 mm−1
  • T = 295 K
  • 0.47 × 0.40 × 0.22 mm

Data collection

  • Oxford Diffraction Gemini R diffractometer
  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 [triangle]) T min = 0.557, T max = 0.830
  • 8137 measured reflections
  • 3216 independent reflections
  • 2396 reflections with I > 2σ(I)
  • R int = 0.018

Refinement

  • R[F 2 > 2σ(F 2)] = 0.040
  • wR(F 2) = 0.126
  • S = 1.10
  • 3216 reflections
  • 211 parameters
  • H-atom parameters constrained
  • Δρmax = 0.13 e Å−3
  • Δρmin = −0.18 e Å−3

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

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809028517/sj2632sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809028517/sj2632Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

KV thanks the UGC-SAP for the award of a Junior Research Fellowship. RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

Chalcones are unique molecules with significant biological activity (Dimmock et al. 1999). Chalcones and their analogs have been shown to have potential antifungal (Opletalova & Sedivy, 1999), anti-tuberculosis (Lin et al. 2002), anti-infective and anti-inflammatory properties (Nowakowska, 2007). The synthesis and biological activity of some fluorinated chalcone derivatives have also been reported (Nakamura et al. 2002). Structures of a series of substituted (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-phenylprop-2-en-1-ones have also been reported. (Chopra et al. 2007). As a continuation of our work on chalcones (Jasinski et al. 2009) and in view of the importance of fluoro-chalcones, this paper describes a new polymorphic form of (I), C18H17FO4, (2E)-1-(4-fluorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one, first reported by Patil et al. (2007). Substantial changes in the cell parameters provides solid support for the recognition of this new polymorphic form for (I).

The title compound,(I), is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone moiety, the biologically active region (Fig. 1). The dihedral angle between the mean planes of the phenyl rings with the 4-fluorophenyl and trimethoxyphenyl substituents is 28.7 (1)° compared to 20.8 (6)° in the polymorph. The angles between the mean plane of the prop-2-ene-1-one group and those of the 4-fluorophenyl and trimethoxyphenyl rings are 30.3 (4)° and 7.4 (7)°, respectively, compared to 10.7 (3)° and 12.36° as reported by Patil et al (2007). While the two meta -methoxy groups are in the plane of the trimethoxy substituted phenyl ring, the para -methoxy group is in a synclinical (-sc) (torsion angle C(12)-C(13)-C(17)-O(3) = -78.1 (2)°) or anticlinical (+ac) (torsion angle C(14)-C(13)-C(17)-O(3) = 104.0 (4)°) orientation, compared to the (+sc) (torsion angle C(12)-C(13)-C(17)-O(3) = 53.0 (4)°) or -ac (torsion angle C(14)-C(13)-C(17)-O(3) =-132.4 (7)°) orientation as reported by Patil et al. (2007). While no classical hydrogen bonds are present, weak C(3)-H(3A)···Cg2 [C(3)-H(3A)···Cg2 = 138°; C(3)···Cg2 = 3.6571 (19) Å; x,3/2-y, -1/2+z; where Cg2 = C(10)-C(15)] C—H···π-ring intermolecular interactions are observed which contribute to the stability of the crystal packing (Fig. 2). The two polymorphs crystallize in the same space group,P21/c, but have different cell parameters for the a [12.4250 (2)Å vs 7.693 (0)Å], b [8.62800 (10)Å vs 15.232 (1)Å], c [14.9038 (2)Å vs 14.128 (1)Å] axes and β angle [98.3217 (12)° vs 106.60 (0)°].

A geometry optimized density functional theory (DFT) calculation (Schmidt & Polik, 2007) was performed for each of the two polymorphs, with the GAUSSIAN03 program package (Frisch et al. 2004) employing the B3-LYP (Becke three parameter Lee-Yang-Parr) exchange correlation functional, which combines the hybrid exchange functional of Becke (Becke, 1988,1993) with the gradient-correlation functional of Lee, Yang and Parr (Lee et al. 1988) and the 6–311+G(d,p) basis set (Hehre et al. 1986). Starting geometries were taken from X-ray refinement data for (I) and from coordinates from the Cambridge Structural Database (CSD) (Allen, 2002) for the Patil et al. (2007) structure (SIRDUT). Interestingly, both structures converged to nearly the same geometric state. The dihedral angle between the mean planes of the phenyl rings within the 4-fluorophenyl and trimethoxyphenyl groups became 18.0 (9)° compared to 19.3 (6)° (SIRDUT). The angle between the mean plane of the prop-2-ene-1-one group and the mean plane of phenyl rings within the 4-fluorophenyl and trimethoxyphenyl groups became 14.0 (3)° and 5.2 (3)°, respectively, versus 14.4 (9)° and 5.2 (5)° (SIRDUT), significantly different from that observed in the crystalline state for each polymorph. In addition, the para methoxy group became synclinical (-sc) (torsion angle C(12)—C(13)—C(17)—O(3) = -77.8 (2)°) or anticlinical (+ac) (torsion angle C(14)—C(13)—C(17)—O(3) = 106.2 (8)°) in (I), compared to a (+sc) (torsion angle C(12)—C(13)—C(17)—O(3) = 79.2 (4)°°) or -ac (torsion angle C(14)—C(13)—C(17)—O(3) = -104.9 (5)°) in SIRDUT. It is clear that each polymeric form adjusted itself in different ways to achieve the DFT calculated geometric state. Bond distances and bond angles are relatively unchanged between the DFT calculated values and the observed values in (I) and SIRDUT with the exception of the para methoxy group as described earlier.

Experimental

The title compound was synthesized by the reported procedure (Patil et al., 2007). The solid product obtained was filtered and recrystallized from ethanol. X-ray quality crystals were grown from ethyl acetate solution by slow evaporation (m.p.: 362-364 K). Analysis for C18H17FO4: Found (calculated): C: 68.27 (68.35%); H:5.36 (5.42%).

Refinement

All of the H atoms were placed in their calculated positions and then refined using the riding model with C—H = 0.93–0.96 Å, and with Uiso(H) = 1.18–1.50 Ueq(C).

Figures

Fig. 1.
Molecular structure of C18H17FO4 showing the atom labeling scheme and 50% probability displacement ellipsoids.
Fig. 2.
Packing diagram of the title compound, (I), viewed down the a axis.
Fig. 3.
The formation of the title compound.

Crystal data

C18H17FO4F(000) = 664
Mr = 316.32Dx = 1.329 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54184 Å
Hall symbol: -P 2ybcCell parameters from 4493 reflections
a = 12.4250 (2) Åθ = 4.3–77.3°
b = 8.6280 (1) ŵ = 0.85 mm1
c = 14.9038 (2) ÅT = 295 K
β = 98.3217 (12)°Prism, colorless
V = 1580.91 (4) Å30.47 × 0.40 × 0.22 mm
Z = 4

Data collection

Oxford Diffraction Gemini R diffractometer3216 independent reflections
Radiation source: fine-focus sealed tube2396 reflections with I > 2σ(I)
graphiteRint = 0.018
Detector resolution: 10.5081 pixels mm-1θmax = 77.9°, θmin = 5.9°
[var phi] and ω scansh = −14→15
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)k = −10→9
Tmin = 0.557, Tmax = 0.830l = −18→18
8137 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.126H-atom parameters constrained
S = 1.10w = 1/[σ2(Fo2) + (0.0683P)2 + 0.1035P] where P = (Fo2 + 2Fc2)/3
3216 reflections(Δ/σ)max < 0.001
211 parametersΔρmax = 0.13 e Å3
0 restraintsΔρmin = −0.18 e Å3

Special details

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)

xyzUiso*/Ueq
O40.54332 (9)0.78663 (17)0.56646 (8)0.0813 (4)
F0.12194 (11)0.38071 (16)−0.04098 (8)0.0982 (4)
O10.01131 (9)0.41222 (15)0.35678 (8)0.0737 (3)
O20.33800 (9)0.64264 (16)0.79007 (7)0.0751 (3)
O30.51516 (9)0.76879 (15)0.74012 (8)0.0716 (3)
C10.10184 (11)0.43862 (16)0.22896 (11)0.0576 (3)
C20.16144 (13)0.54012 (19)0.18363 (12)0.0684 (4)
H2A0.19800.62190.21520.082*
C30.16769 (15)0.5225 (2)0.09261 (12)0.0745 (4)
H3A0.20710.59200.06250.089*
C40.11452 (13)0.4002 (2)0.04776 (12)0.0698 (4)
C50.05441 (14)0.2970 (2)0.08954 (14)0.0765 (5)
H5A0.01890.21490.05740.092*
C60.04768 (13)0.31760 (19)0.17996 (13)0.0695 (4)
H6A0.00610.24930.20900.083*
C70.09279 (11)0.45582 (16)0.32705 (11)0.0591 (3)
C80.18590 (12)0.52523 (19)0.38636 (11)0.0633 (4)
H8A0.24410.56430.36050.076*
C90.18866 (11)0.53327 (18)0.47527 (11)0.0612 (4)
H9A0.12750.49640.49780.073*
C100.27643 (11)0.59319 (17)0.54241 (10)0.0572 (3)
C110.26418 (11)0.58419 (18)0.63367 (10)0.0605 (4)
H11A0.20190.53980.65050.073*
C120.34453 (11)0.64123 (18)0.69953 (10)0.0587 (3)
C130.43756 (12)0.70811 (18)0.67455 (10)0.0591 (3)
C140.44971 (11)0.71778 (19)0.58304 (10)0.0611 (4)
C150.36992 (12)0.66065 (19)0.51690 (10)0.0611 (4)
H15A0.37830.66700.45600.073*
C160.25626 (17)0.5508 (3)0.82150 (13)0.0855 (5)
H16A0.18580.58750.79500.128*
H16B0.26300.55810.88630.128*
H16C0.26470.44480.80440.128*
C170.60831 (14)0.6733 (3)0.75995 (13)0.0836 (5)
H17A0.58740.57460.78170.125*
H17B0.65970.72190.80560.125*
H17C0.64100.65860.70600.125*
C180.56292 (15)0.7943 (3)0.47481 (13)0.0864 (6)
H18A0.56080.69180.44960.130*
H18B0.63320.83920.47270.130*
H18C0.50800.85710.44030.130*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O40.0623 (7)0.1152 (10)0.0677 (7)−0.0271 (7)0.0134 (5)−0.0012 (6)
F0.1049 (8)0.1062 (9)0.0868 (7)−0.0161 (7)0.0246 (6)−0.0256 (6)
O10.0523 (6)0.0813 (8)0.0886 (8)−0.0117 (5)0.0137 (5)0.0053 (6)
O20.0684 (7)0.0970 (8)0.0630 (6)−0.0017 (6)0.0201 (5)0.0015 (6)
O30.0601 (6)0.0861 (8)0.0679 (6)−0.0012 (5)0.0075 (5)−0.0097 (5)
C10.0414 (6)0.0491 (7)0.0814 (9)−0.0007 (6)0.0063 (6)−0.0042 (6)
C20.0646 (9)0.0594 (9)0.0810 (10)−0.0177 (7)0.0099 (7)−0.0098 (7)
C30.0732 (10)0.0666 (10)0.0854 (11)−0.0157 (8)0.0173 (8)−0.0035 (8)
C40.0600 (8)0.0715 (10)0.0785 (10)−0.0014 (7)0.0121 (7)−0.0144 (8)
C50.0625 (9)0.0657 (10)0.1020 (13)−0.0142 (8)0.0148 (8)−0.0260 (9)
C60.0559 (8)0.0569 (8)0.0981 (12)−0.0121 (7)0.0188 (8)−0.0114 (8)
C70.0456 (7)0.0498 (7)0.0817 (9)0.0004 (6)0.0092 (6)0.0014 (6)
C80.0479 (7)0.0645 (9)0.0787 (10)−0.0036 (6)0.0135 (6)−0.0061 (7)
C90.0474 (7)0.0602 (8)0.0763 (9)0.0007 (6)0.0098 (6)0.0070 (7)
C100.0474 (7)0.0563 (8)0.0683 (8)0.0046 (6)0.0094 (6)0.0031 (6)
C110.0493 (7)0.0617 (8)0.0728 (9)0.0039 (6)0.0167 (6)0.0076 (7)
C120.0522 (7)0.0622 (8)0.0633 (8)0.0106 (6)0.0137 (6)0.0038 (6)
C130.0511 (7)0.0624 (8)0.0645 (8)0.0053 (6)0.0103 (6)−0.0023 (6)
C140.0486 (7)0.0690 (9)0.0670 (9)−0.0016 (6)0.0128 (6)0.0014 (7)
C150.0527 (7)0.0716 (9)0.0600 (8)0.0002 (7)0.0113 (6)0.0022 (7)
C160.0891 (12)0.0958 (13)0.0777 (11)−0.0033 (10)0.0325 (9)0.0095 (9)
C170.0593 (9)0.1147 (15)0.0747 (11)0.0075 (10)0.0026 (8)−0.0003 (10)
C180.0681 (10)0.1196 (16)0.0749 (11)−0.0239 (11)0.0224 (8)0.0043 (10)

Geometric parameters (Å, °)

O4—C141.3602 (18)C8—H8A0.9300
O4—C181.423 (2)C9—C101.463 (2)
F—C41.350 (2)C9—H9A0.9300
O1—C71.2218 (18)C10—C111.393 (2)
O2—C121.3635 (18)C10—C151.400 (2)
O2—C161.420 (2)C11—C121.385 (2)
O3—C131.3734 (19)C11—H11A0.9300
O3—C171.417 (2)C12—C131.390 (2)
C1—C21.384 (2)C13—C141.396 (2)
C1—C61.391 (2)C14—C151.384 (2)
C1—C71.490 (2)C15—H15A0.9300
C2—C31.378 (2)C16—H16A0.9600
C2—H2A0.9300C16—H16B0.9600
C3—C41.367 (2)C16—H16C0.9600
C3—H3A0.9300C17—H17A0.9600
C4—C51.368 (3)C17—H17B0.9600
C5—C61.374 (3)C17—H17C0.9600
C5—H5A0.9300C18—H18A0.9600
C6—H6A0.9300C18—H18B0.9600
C7—C81.477 (2)C18—H18C0.9600
C8—C91.322 (2)
C14—O4—C18117.66 (13)C12—C11—C10120.19 (13)
C12—O2—C16117.99 (14)C12—C11—H11A119.9
C13—O3—C17113.25 (13)C10—C11—H11A119.9
C2—C1—C6118.10 (15)O2—C12—C11124.36 (13)
C2—C1—C7122.51 (13)O2—C12—C13115.61 (13)
C6—C1—C7119.38 (13)C11—C12—C13119.98 (13)
C3—C2—C1121.37 (15)O3—C13—C12119.54 (13)
C3—C2—H2A119.3O3—C13—C14120.55 (13)
C1—C2—H2A119.3C12—C13—C14119.88 (14)
C4—C3—C2118.33 (16)O4—C14—C15124.71 (14)
C4—C3—H3A120.8O4—C14—C13114.82 (13)
C2—C3—H3A120.8C15—C14—C13120.47 (13)
F—C4—C3118.60 (16)C14—C15—C10119.45 (14)
F—C4—C5118.96 (15)C14—C15—H15A120.3
C3—C4—C5122.45 (16)C10—C15—H15A120.3
C4—C5—C6118.50 (15)O2—C16—H16A109.5
C4—C5—H5A120.8O2—C16—H16B109.5
C6—C5—H5A120.8H16A—C16—H16B109.5
C5—C6—C1121.24 (15)O2—C16—H16C109.5
C5—C6—H6A119.4H16A—C16—H16C109.5
C1—C6—H6A119.4H16B—C16—H16C109.5
O1—C7—C8121.74 (15)O3—C17—H17A109.5
O1—C7—C1120.62 (13)O3—C17—H17B109.5
C8—C7—C1117.64 (12)H17A—C17—H17B109.5
C9—C8—C7121.69 (14)O3—C17—H17C109.5
C9—C8—H8A119.2H17A—C17—H17C109.5
C7—C8—H8A119.2H17B—C17—H17C109.5
C8—C9—C10127.76 (14)O4—C18—H18A109.5
C8—C9—H9A116.1O4—C18—H18B109.5
C10—C9—H9A116.1H18A—C18—H18B109.5
C11—C10—C15120.04 (13)O4—C18—H18C109.5
C11—C10—C9118.17 (13)H18A—C18—H18C109.5
C15—C10—C9121.77 (13)H18B—C18—H18C109.5
C6—C1—C2—C3−0.2 (2)C16—O2—C12—C1114.4 (2)
C7—C1—C2—C3−179.40 (14)C16—O2—C12—C13−168.15 (15)
C1—C2—C3—C4−0.9 (3)C10—C11—C12—O2177.51 (14)
C2—C3—C4—F−178.84 (16)C10—C11—C12—C130.2 (2)
C2—C3—C4—C51.0 (3)C17—O3—C13—C12104.04 (17)
F—C4—C5—C6179.78 (15)C17—O3—C13—C14−78.13 (19)
C3—C4—C5—C6−0.1 (3)O2—C12—C13—O30.4 (2)
C4—C5—C6—C1−1.0 (3)C11—C12—C13—O3177.92 (13)
C2—C1—C6—C51.2 (2)O2—C12—C13—C14−177.47 (13)
C7—C1—C6—C5−179.61 (15)C11—C12—C13—C140.1 (2)
C2—C1—C7—O1149.90 (16)C18—O4—C14—C15−2.9 (3)
C6—C1—C7—O1−29.3 (2)C18—O4—C14—C13177.40 (16)
C2—C1—C7—C8−30.8 (2)O3—C13—C14—O41.6 (2)
C6—C1—C7—C8150.00 (14)C12—C13—C14—O4179.41 (14)
O1—C7—C8—C94.9 (2)O3—C13—C14—C15−178.09 (15)
C1—C7—C8—C9−174.35 (14)C12—C13—C14—C15−0.3 (2)
C7—C8—C9—C10177.60 (14)O4—C14—C15—C10−179.47 (15)
C8—C9—C10—C11−177.15 (15)C13—C14—C15—C100.2 (2)
C8—C9—C10—C154.0 (2)C11—C10—C15—C140.1 (2)
C15—C10—C11—C12−0.3 (2)C9—C10—C15—C14178.96 (14)
C9—C10—C11—C12−179.18 (14)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C3—H3A···Cg2i0.932.913.6571 (19)138

Symmetry codes: (i) x, −y+3/2, z−1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ2632).

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