supplementary materials


xu5392 scheme

Acta Cryst. (2012). E68, o82    [ doi:10.1107/S160053681105166X ]

(Z)-1,1-Dicyano-2-(4-fluorophenyl)-3-(1-hexylpyridin-1-ium-4-yl)prop-2-en-1-ide

W.-H. Hao, C. Wang, G. Qian and Z.-Y. Wang

Abstract top

The title compound, C22H22FN3, exists as a zwitterion with the negative charge on the dicyanomethanide group and the positive charge on the pyridinium N atom. The molecule adopts a Z conformation about the central C=C bond. The dihedral angle between the pyridinium and benzene rings is 65.65 (5)°. Weak C-H...N hydrogen bonding is present in the crystal structure.

Comment top

Structure determination of the title compound (I), C22H22FN3 (Fig. 1), was performed as a part of a project in our laboratory on the synthesis of new series of D+-π-A- zwitterionic chromophores for electro-optic and near infrared chemosensor applications (Hao, 2011; Hao et al., 2011).

The title compound (I) crystallizes as a zwitterion in which the negative charge on the dicyanomethanide (–C(CN)2) group and the positive charge on the N atom in the pyridinium ring. It presents a Z configuration of the central C7C11 double bond with the torsion angle C12—C11—C7—C8 being -168.25 (17) °.

The bond length between C7 and C11 (1.3837 (19) Å) is similar to the value observed in other zwitterionic compounds (Metzger & Heimer, 1984; Bell et al., 2002), which clearly indicates the double bond π-bridge separating the pyridinium and dicyanomethanide groups. A significant displacement of electron density (or charge transfer)from the pyridinium ring (donor) to the –C(CN)2 group (acceptor) was confirmed, corresponding to a large contribution of the zwitterionic resonance structure in compound (I).

The bond lengths between C7 and C8 (1.4078 (20) Å), C7 and C11 (1.3837 (19) Å) suggest electron delocalization among the three carbon atoms. However, more single bond characteristic is observed between C7 and C8;also evident from the observed two C—CN bonds (1.4111 (22) Å and 1.4201 (23) Å) in compound (I) versus 1.427 Å in typical 7,7,8,8-tetracyanoquino-dimethanes(TCNQs), indicating substantial negative charge localization within the –C(CN)2 group, and elongated CN (1.1514 (20) Å and 1.1472 (20) Å) bond compared to that in typical TCNQs (1.144 Å) (Allen et al., 1987) indicating a result of charge resonant stabilization via the two CN groups.

Although the bond lengths in the conjugated bridge and acceptor part clearly demonstrated a zwitterionic molecular structure of compound (I), the bond length of the pyridinium ring is quinoidal rather than aromatic. The C13—C14 and C15—C16 bonds (with bond lengths of 1.3516 (20) Å, 1.3491 (21) Å) are shorter than the C12—C13 and C12—C15 bonds (1.4088 (21) Å and 1.4125 (20) Å). Similar phenomena have also been reported for several TCNQ and 7,8-di(alkoxycarbonyl)-7,8- dicyanoquinodimethane zwitterionic adducts (Cole et al., 1997; Szablewski et al., 1997; Xiong et al., 2008). Therefore, the best description of the ground state structure of compound (I) is the combination of the two limiting forms (Fig. 3), zwitterionic and neutral forms with predominantly zwitterionic structure.

As shown in Fig.2, two types of weak intermolecular C–H..N hydrogen bonds connect adjacent molecules, forming a 2-D layer structure in the bc plane with the bond lengths and angles being 3.354 (3) Å, 150.77 (1) ° (C16—H16A···N1) and 3.535 (2) Å, 174.79 (1) ° (C3—H3A···N2).

Related literature top

For details of zwitterionic chromophores and their applications, see: Hao (2011); Hao et al. (2011). For related structures, see: Metzger & Heimer (1984); Bell et al. (2002); Cole et al. (1997); Szablewski et al. (1997); Xiong et al.(2008). For the synthesis, see: Hao (2011). For standard bond lengths, see: Allen et al. (1987).

Experimental top

Under anhydrous and oxygen-free conditions, to a 50 ml round-bottomed flask malononitrile (0.50 g, 7.4 mmol), sodium hydride (0.30 g, 60%, 7.5 mmol) and 2-(4-fluorophenyl)-3-pyridine-4-yl-acrylonitrile bromide salt (Hao, 2011) (1.0 g, 2.6 mmol) in 20 ml of THF were added at 0°C. After 30 min, the insoluble inorganic salt was removed by filtration, and the filtrate solution was concentrated under reduced pressure. The residue was purified by column chromatography (flash, mixture of acetone and hexane with the ratio 1:1) to produce (I) (0.56 g, 63% yield). Orange-red crystals were obtained from a hexane/acetone solution of (I) by slow evaporation at room temperature.

Refinement top

The H atoms attached to the carbon atoms were placed in calculated positions, with C—H = 0.93–0.97 Å, and were refined in the riding-model approximation with Uiso(H) = 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) for the others,

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The Molecular structure of compound (I) with displacement ellipsoids drawn at the 30% probability level. Hydrogen atoms were omitted for clarity.
[Figure 2] Fig. 2. Partial packing view showing the 2-D layer structure of compound (I) through two types of weak intermolecular C–H..N hydrogen bonds. Hydrogen bonds are shown by dashed lines.
[Figure 3] Fig. 3. Resonance structures of the title compound.
(Z)-1,1-Dicyano-2-(4-fluorophenyl)-3-(1-hexylpyridin-1-ium-4- yl)prop-2-en-1-ide top
Crystal data top
C22H22FN3F(000) = 736
Mr = 347.43Dx = 1.193 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 7543 reflections
a = 10.485 (3) Åθ = 2.0–25.0°
b = 8.809 (2) ŵ = 0.08 mm1
c = 21.313 (5) ÅT = 295 K
β = 100.628 (4)°Prism, red
V = 1934.7 (8) Å30.24 × 0.21 × 0.18 mm
Z = 4
Data collection top
Rigaku R-AXIS RAPID
diffractometer
3406 independent reflections
Radiation source: fine-focus sealed tube2154 reflections with I > 2σ(I)
graphiteRint = 0.046
Detector resolution: 10.000 pixels mm-1θmax = 25.0°, θmin = 1.9°
ω scansh = 129
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
k = 1010
Tmin = 0.982, Tmax = 0.986l = 2425
9762 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.043Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.080H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.0208P)2]
where P = (Fo2 + 2Fc2)/3
3406 reflections(Δ/σ)max < 0.001
237 parametersΔρmax = 0.13 e Å3
0 restraintsΔρmin = 0.14 e Å3
Crystal data top
C22H22FN3V = 1934.7 (8) Å3
Mr = 347.43Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.485 (3) ŵ = 0.08 mm1
b = 8.809 (2) ÅT = 295 K
c = 21.313 (5) Å0.24 × 0.21 × 0.18 mm
β = 100.628 (4)°
Data collection top
Rigaku R-AXIS RAPID
diffractometer
3406 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
2154 reflections with I > 2σ(I)
Tmin = 0.982, Tmax = 0.986Rint = 0.046
9762 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.043H-atom parameters constrained
wR(F2) = 0.080Δρmax = 0.13 e Å3
S = 1.01Δρmin = 0.14 e Å3
3406 reflectionsAbsolute structure: ?
237 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. Melting point: 167 °C; UV-Vis: λmax = 486 nm (DMF); FTIR (KBr, cm-1): 2192, 1640, 1571, 1450; 1H NMR (400 MHz, (CD3)2SO): (δ p.p.m.): 7.81 (2H, d, J = 7.1 Hz), 7.36 (2H, d, J = 8.7 Hz), 7.32 (2H, d, J = 8.7 Hz), 6.34 (2H, d, J = 7.1 Hz), 5.88 (1H, s), 3.92 (2H, t), 1.22 (6H, m), 0.83 (3H, t); 13 C NMR (100 MHz, (CD3)2SO: (δ p.p.m.): 161.2, 151.4, 139.8, 133.7, 130.0, 129.9, 119.8, 119.2, 118.2, 116.6, 116.4, 101.7, 56.7, 30.4,29.8, 24.9, 21.8, 13.7; TOF HRMS (ESI, DMF/Acetonitrile 1:1, m/z): Calculated value: 347.1798 [M]+. Found: 348.1776 [M + H]+, 370.1608 [M + Na]+.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
F0.00950 (11)0.32278 (14)0.14713 (6)0.0895 (4)
N10.52466 (16)0.0019 (2)0.21926 (7)0.0776 (6)
N20.79360 (16)0.0489 (2)0.08676 (7)0.0706 (5)
N30.31701 (13)0.49453 (16)0.14317 (6)0.0446 (4)
C10.12274 (18)0.2874 (2)0.12778 (9)0.0548 (5)
C20.11792 (17)0.1996 (2)0.07511 (9)0.0544 (5)
H2A0.03920.16290.05300.065*
C30.23295 (17)0.16598 (19)0.05513 (8)0.0472 (5)
H3A0.23140.10670.01890.057*
C40.35090 (15)0.21967 (18)0.08855 (7)0.0384 (4)
C50.34999 (16)0.30647 (19)0.14272 (8)0.0457 (5)
H5A0.42820.34110.16620.055*
C60.23523 (19)0.3429 (2)0.16267 (8)0.0546 (5)
H6A0.23490.40290.19850.065*
C70.47440 (15)0.17940 (18)0.06776 (7)0.0384 (4)
C80.56746 (16)0.10162 (19)0.11230 (7)0.0416 (4)
C90.54269 (17)0.0483 (2)0.17131 (9)0.0507 (5)
C100.6924 (2)0.0696 (2)0.09897 (8)0.0483 (5)
C110.49704 (15)0.21053 (18)0.00714 (7)0.0429 (4)
H11A0.56800.16010.00350.051*
C120.43029 (15)0.30640 (18)0.04143 (7)0.0394 (4)
C130.33424 (16)0.4152 (2)0.03586 (8)0.0474 (5)
H13A0.30670.42610.00300.057*
C140.28129 (16)0.5040 (2)0.08563 (8)0.0487 (5)
H14A0.21800.57400.08000.058*
C150.46572 (16)0.30234 (19)0.10225 (8)0.0474 (5)
H15A0.53030.23530.10910.057*
C160.40928 (17)0.3923 (2)0.15072 (8)0.0503 (5)
H16A0.43430.38380.19020.060*
C170.25548 (16)0.5900 (2)0.19749 (8)0.0493 (5)
H17A0.32140.62520.22060.059*
H17B0.21670.67840.18140.059*
C180.15272 (17)0.5044 (2)0.24250 (8)0.0600 (5)
H18A0.09280.45870.21830.072*
H18B0.19350.42310.26230.072*
C190.07691 (18)0.6055 (2)0.29453 (8)0.0680 (6)
H19A0.00740.54590.31920.082*
H19B0.03720.68690.27430.082*
C200.15573 (18)0.6746 (2)0.33983 (8)0.0630 (6)
H20A0.20310.59480.35690.076*
H20B0.21870.74430.31640.076*
C210.07270 (19)0.7591 (3)0.39474 (9)0.0756 (6)
H21A0.00560.69150.41620.091*
H21B0.03030.84360.37780.091*
C220.1496 (2)0.8187 (2)0.44271 (9)0.0883 (7)
H22A0.21800.88310.42150.132*
H22B0.09350.87570.47500.132*
H22C0.18630.73500.46220.132*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F0.0586 (8)0.1145 (11)0.1030 (10)0.0154 (7)0.0347 (7)0.0070 (8)
N10.0966 (14)0.0953 (15)0.0443 (11)0.0314 (10)0.0222 (9)0.0153 (10)
N20.0533 (12)0.0938 (14)0.0638 (12)0.0117 (10)0.0080 (9)0.0081 (10)
N30.0499 (10)0.0481 (9)0.0359 (9)0.0020 (7)0.0080 (7)0.0045 (7)
C10.0471 (13)0.0640 (14)0.0584 (13)0.0105 (10)0.0230 (10)0.0063 (11)
C20.0425 (12)0.0657 (14)0.0529 (13)0.0029 (10)0.0036 (9)0.0041 (11)
C30.0491 (12)0.0540 (12)0.0378 (10)0.0025 (9)0.0058 (9)0.0035 (9)
C40.0431 (11)0.0412 (11)0.0308 (10)0.0009 (8)0.0064 (8)0.0034 (8)
C50.0461 (12)0.0481 (12)0.0419 (11)0.0000 (9)0.0050 (9)0.0025 (9)
C60.0626 (14)0.0568 (13)0.0466 (12)0.0067 (10)0.0162 (10)0.0075 (10)
C70.0427 (11)0.0378 (10)0.0345 (10)0.0032 (8)0.0069 (8)0.0035 (8)
C80.0423 (12)0.0500 (12)0.0327 (10)0.0035 (8)0.0078 (8)0.0015 (9)
C90.0554 (13)0.0590 (13)0.0364 (11)0.0131 (9)0.0051 (9)0.0009 (10)
C100.0531 (13)0.0527 (12)0.0360 (11)0.0030 (10)0.0001 (9)0.0029 (9)
C110.0445 (11)0.0463 (11)0.0389 (10)0.0054 (8)0.0104 (8)0.0001 (9)
C120.0408 (10)0.0416 (11)0.0360 (10)0.0034 (8)0.0077 (8)0.0014 (9)
C130.0591 (13)0.0512 (12)0.0338 (10)0.0060 (10)0.0136 (9)0.0021 (9)
C140.0555 (12)0.0523 (12)0.0405 (11)0.0069 (9)0.0143 (9)0.0007 (9)
C150.0530 (12)0.0501 (12)0.0417 (11)0.0074 (9)0.0157 (9)0.0048 (9)
C160.0606 (13)0.0563 (13)0.0370 (11)0.0024 (10)0.0169 (9)0.0022 (10)
C170.0556 (12)0.0484 (12)0.0424 (11)0.0014 (9)0.0052 (9)0.0074 (9)
C180.0687 (14)0.0573 (13)0.0498 (12)0.0091 (10)0.0000 (10)0.0008 (10)
C190.0644 (15)0.0843 (16)0.0499 (12)0.0054 (11)0.0041 (10)0.0061 (12)
C200.0703 (15)0.0679 (15)0.0481 (12)0.0004 (11)0.0033 (10)0.0008 (11)
C210.0822 (16)0.0874 (17)0.0520 (13)0.0048 (12)0.0011 (11)0.0134 (12)
C220.1049 (19)0.0948 (19)0.0611 (15)0.0152 (14)0.0048 (13)0.0105 (13)
Geometric parameters (Å, °) top
F—C11.3629 (19)C13—C141.352 (2)
N1—C91.148 (2)C13—H13A0.9300
N2—C101.153 (2)C14—H14A0.9300
N3—C141.3493 (19)C15—C161.349 (2)
N3—C161.353 (2)C15—H15A0.9300
N3—C171.4793 (19)C16—H16A0.9300
C1—C21.356 (2)C17—C181.506 (2)
C1—C61.364 (2)C17—H17A0.9700
C2—C31.383 (2)C17—H17B0.9700
C2—H2A0.9300C18—C191.526 (2)
C3—C41.391 (2)C18—H18A0.9700
C3—H3A0.9300C18—H18B0.9700
C4—C51.386 (2)C19—C201.510 (2)
C4—C71.487 (2)C19—H19A0.9700
C5—C61.386 (2)C19—H19B0.9700
C5—H5A0.9300C20—C211.519 (2)
C6—H6A0.9300C20—H20A0.9700
C7—C111.384 (2)C20—H20B0.9700
C7—C81.407 (2)C21—C221.508 (2)
C8—C91.411 (2)C21—H21A0.9700
C8—C101.419 (2)C21—H21B0.9700
C11—C121.417 (2)C22—H22A0.9600
C11—H11A0.9300C22—H22B0.9600
C12—C131.411 (2)C22—H22C0.9600
C12—C151.413 (2)
C14—N3—C16118.26 (14)C16—C15—H15A118.8
C14—N3—C17121.48 (15)C12—C15—H15A118.8
C16—N3—C17120.24 (14)C15—C16—N3121.49 (16)
C2—C1—F118.64 (18)C15—C16—H16A119.3
C2—C1—C6123.51 (17)N3—C16—H16A119.3
F—C1—C6117.85 (18)N3—C17—C18111.79 (14)
C1—C2—C3118.38 (17)N3—C17—H17A109.3
C1—C2—H2A120.8C18—C17—H17A109.3
C3—C2—H2A120.8N3—C17—H17B109.3
C2—C3—C4120.85 (17)C18—C17—H17B109.3
C2—C3—H3A119.6H17A—C17—H17B107.9
C4—C3—H3A119.6C17—C18—C19112.70 (15)
C5—C4—C3118.16 (15)C17—C18—H18A109.1
C5—C4—C7121.33 (15)C19—C18—H18A109.1
C3—C4—C7120.47 (15)C17—C18—H18B109.1
C6—C5—C4121.53 (16)C19—C18—H18B109.1
C6—C5—H5A119.2H18A—C18—H18B107.8
C4—C5—H5A119.2C20—C19—C18115.26 (16)
C1—C6—C5117.55 (17)C20—C19—H19A108.5
C1—C6—H6A121.2C18—C19—H19A108.5
C5—C6—H6A121.2C20—C19—H19B108.5
C11—C7—C8120.62 (15)C18—C19—H19B108.5
C11—C7—C4122.68 (14)H19A—C19—H19B107.5
C8—C7—C4116.66 (14)C19—C20—C21112.76 (16)
C7—C8—C9123.00 (16)C19—C20—H20A109.0
C7—C8—C10120.83 (15)C21—C20—H20A109.0
C9—C8—C10116.15 (15)C19—C20—H20B109.0
N1—C9—C8178.3 (2)C21—C20—H20B109.0
N2—C10—C8177.3 (2)H20A—C20—H20B107.8
C7—C11—C12130.83 (16)C22—C21—C20112.99 (17)
C7—C11—H11A114.6C22—C21—H21A109.0
C12—C11—H11A114.6C20—C21—H21A109.0
C13—C12—C15114.01 (15)C22—C21—H21B109.0
C13—C12—C11127.40 (15)C20—C21—H21B109.0
C15—C12—C11118.49 (16)H21A—C21—H21B107.8
C14—C13—C12121.53 (16)C21—C22—H22A109.5
C14—C13—H13A119.2C21—C22—H22B109.5
C12—C13—H13A119.2H22A—C22—H22B109.5
N3—C14—C13122.33 (17)C21—C22—H22C109.5
N3—C14—H14A118.8H22A—C22—H22C109.5
C13—C14—H14A118.8H22B—C22—H22C109.5
C16—C15—C12122.35 (17)
F—C1—C2—C3179.02 (15)C4—C7—C11—C1214.2 (3)
C6—C1—C2—C30.9 (3)C7—C11—C12—C1311.4 (3)
C1—C2—C3—C40.6 (3)C7—C11—C12—C15172.34 (16)
C2—C3—C4—C50.6 (2)C15—C12—C13—C141.1 (2)
C2—C3—C4—C7178.29 (15)C11—C12—C13—C14177.44 (16)
C3—C4—C5—C61.6 (2)C16—N3—C14—C130.1 (3)
C7—C4—C5—C6179.27 (15)C17—N3—C14—C13178.42 (15)
C2—C1—C6—C50.1 (3)C12—C13—C14—N30.2 (3)
F—C1—C6—C5179.97 (15)C13—C12—C15—C161.7 (2)
C4—C5—C6—C11.4 (3)C11—C12—C15—C16178.44 (16)
C5—C4—C7—C11125.40 (18)C12—C15—C16—N31.6 (3)
C3—C4—C7—C1157.0 (2)C14—N3—C16—C150.6 (3)
C5—C4—C7—C857.0 (2)C17—N3—C16—C15179.09 (15)
C3—C4—C7—C8120.63 (17)C14—N3—C17—C1899.45 (19)
C11—C7—C8—C9170.88 (16)C16—N3—C17—C1879.0 (2)
C4—C7—C8—C96.8 (2)N3—C17—C18—C19173.21 (15)
C11—C7—C8—C107.7 (2)C17—C18—C19—C2063.6 (2)
C4—C7—C8—C10174.63 (15)C18—C19—C20—C21173.53 (17)
C8—C7—C11—C12168.25 (17)C19—C20—C21—C22175.80 (17)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C3—H3A···N2i0.932.613.535 (3)175
C16—H16A···N1ii0.932.513.354 (3)151
Symmetry codes: (i) −x+1, −y, −z; (ii) x, −y+1/2, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
C3—H3A···N2i0.932.613.535 (3)175
C16—H16A···N1ii0.932.513.354 (3)151
Symmetry codes: (i) −x+1, −y, −z; (ii) x, −y+1/2, z−1/2.
Acknowledgements top

We acknowledge financial support for research from the Natural Sciences and Engineering Research Council of Canada, and NSFC grant No. 21110402016.

references
References top

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Bell, N. A., Crouch, D. J., Simmonds, D. J., Goeta, A. E., Gelbrich, T. & Hursthouse, M. B. (2002). J. Mater. Chem. 12, 1274–1279.

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