4,4′-Bipyridine–2,4,5,6-tetra­fluoro-1,3-diiodo­benzene (1/1)

The self-assembly of 1,3-diiodo­tetra­fluoro­benzene (13DITFB) and bipyridine (44BPY), C₁₀H₈N₂·C₆F₄I₂, is driven by halogen bonding. It results in infinite wave-like chains, with the two mol­ecules in a 1:1 mole ratio. Both molecules lie on crystallographic mirror planes, bisecting the central 44BPY C—C bond and passing through two opposite CF groups of 13DITFB. The N...I halogen-bonding inter­action is 2.902 (4) Å, and the C—I...N angle is almost linear [175.6 (2)°]. The chain ...13DITFB...44BPY... is polar, with all 13DITFB on the wave crest and all 44BPY at the bottom. This is in contrast to similar complexes obtained on self-assembly of 44BPY with 1,3-dibromo­tetra­fluoro­benzene (13DBrTFB), 1,4-diiodo­tetra­fluoro­benzene (14DITFB) or 1,2-diiodo­tetra­fluoro­benzene (12DITFB), where centrosymmetric wave-like chains are observed.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.030
• wR factor = 0.074
• Data-to-parameter ratio = 15.4

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT431_ALERT_2_A Short Inter HL..A Contact  I1     ..  N1      ..       2.90 Ang.

Author Response: The Contact I...N between iodoperfluorocarbons and amines or pyridines is normally in the range 2.7 - 3.3 A\% as can be seen for example in Fig. 1 of Metrangolo, P., Neukirch, H., Pilati, T., & G. Resnati (2005). Acc. Chem. Res., 38, 386-395.

Alert level B
PLAT060_ALERT_3_B Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.52

Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.785     1.000
            Tmin and Tmax expected:      0.418     0.799
            RR =      1.499
            Please check that your absorption correction is appropriate.
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.80
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.57
PLAT164_ALERT_4_C Nr. of Refined C-H H-Atoms in Heavy-At Struct...          4
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C7
PLAT410_ALERT_2_C Short Intra H...H Contact  H6     ..  H6      ..       1.95 Ang.

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.799
            Tmax scaled      0.799 Tmin scaled      0.627
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.51
           From the CIF: _reflns_number_total               2020
           Count of symmetry unique reflns         1113
           Completeness (_total/calc)            181.49%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       907
           Fraction of Friedel pairs measured     0.815
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         15

   1 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

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

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S1. Comment

The construction of supramolecular architectures by XB is a topic of current interest due to the efficiency and reliability of the interaction (Metrangolo & Resnati, 2001; Metrangolo et al., 2005; Metrangolo et al., 2007). In the present study, we report the first use of 1,3-diiodotetrafluorobenzene (Neenan & Whitesides, 1988) in crystal engineering. Both molecules in the co-crystal lie on a crystallographic mirror (Figure 1). When interacting each other the perfluoroarene acts as a bidentate electron acceptor and 4,4'-bipyridine as a bidentate donor. An halogen bonded system in which the modules alternate is formed (Figure 2). The two rings connected by halogen bonding are twisted each other by an angle of 64.9 (2) °, while 44BPY and 13DITFB, related by the n glide, are nearly parallel. The bipyridine core shows a bent conformation, being 9.2 (2) ° the angle between the two pyridine rings. The crystallographic analysis revealed that the N1···I1 distance is 2.902 (4) Å. This value is shorter than those found in the complex between of 12DITFB and bipyridine (2.909–2.964) Å. The C2—I1···N1 angle slightly deviates from linearity (175.6 (2) °). The 4,4'-bipyridine gives an unlimited 1:1 chain also in the presence of 1,2-diiodotetrafluorobenzene and 1,4-diiodotetrafluorobenzene. The XB properties of the chain in the three complexes are quite similar, the N···I length and N···I—C angles being 2.909–2.964 Å and 172.1–176.2 ° for the complex 44BPY-12DITFB (four independent values, Liantonio et al., 2002), 2.851–2.864 Å and 176.9–177.3 ° for 44BPY-14DITFB (Walsh et al., 2001; Messina et al., 2001). Also in these two complexes the 44BPY and the DITFB mean planes are nearly orthogonal. In these two structures, 44BPY, rather than bent, is slightly twisted, as shown by Figure 3, where the main differences among the waves of the three structures are evidenced. While the 44BPY-14DITFB chain is nearly linear, the 44BPY-12DITFB chain is much more winding than the 44BPY-13DITFB chain. While the structures of 44BPY-12DITFB and 44BPY-14DITFB are both centrosymmetric (as the single chains), in the complex 44BPY-13DITFB both the structure and the chain are polar. This is even more surprising if we consider that 44BPY-13DBrTFB, the complex between 44BPY and 1,3-dibromotetrafluorobenzene, that could be exspected to be isomorphous to 44BPY-14DITFB, is centric with two independent 44BPY-13DBrTFB waves, the first lying along a line of symmetry centres, and the second lined up to a 2₁ screw axis, but having a conformation very near to the first one (Figure 4, De Santis, Forni,Liantonio, Metrangolo, Pilati & Resnati, 2003).

Related literature

For related literature, see: De Santis et al. (2003); Liantonio et al. (2002); Messina et al. (2001); Metrangolo & Resnati (2001); Metrangolo et al. (2005, 2007); Neenan & Whitesides (1988); Walsh et al. (2001).

For related literature, see: Altomare et al. (1994).

S2. Experimental

The starting materials were commercially available from Aldrich. 1,3-Diiodotetrafluorobenzene was prepared as already reported (Neenan & Whitesides, 1988). The 1:1 adduct was obtained by dissolving in chloroform, at room temperature and in a vial, equimolecular amounts of 1,3-diiodotetrafluorobenzene and bipyridine. The open vial was closed in a cylindrical bottle containing vaseline oil. Volatile solvents were allowed to diffuse at room temperature and, after one day, the resulting crystals were filtered. IR (cm^-1, selected bands): 3032, 1589, 1459, 1404, 1219, 1067, 1043, 1037, 860,799.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. Molecular plot of the complex with the numbering scheme, showings 50% probability displacement ellipsoids; H atom not to scale. Dashed lines represent the XB. The view is parallel to the crystallographic mirror planes passing through the atoms C1, C4, F1 and F3 for 1,3-diiodotetrafluorobenzene and at the middle of the N1···N1(-x,y,z) axis for bipyridine.
	Fig. 2. Top: two waves of 44BPY···13DITFB··· projected on the plane of a 44BPY; H atoms omitted for clarity; bottom: the same waves projected along the a axis.
	Fig. 3. Single waves of the complexes 44BPY···14DITF (top), B44BPY···13DITFB (middle), and 44BPY···12DITFB (bottom), showed in the plane defined by the normal to 44BPY and the wave elongation axis.
	Fig. 4. The two independent waves of the complexes 44BPY···14DBrTF both projected parallel to a 44BPY plane. Top: this waves is formed by molecules correlated by centres of symmetry. Bottom: a wave formed by molecules along a screw axis; it may easily seen that also this wave is nearly centro-symmetric.

4,4'-Bipyridine–2,4,5,6-tetrafluoro-1,3-diiodobenzene (1/1)

Crystal data

C10H8N2·C6F4I2	Dx = 2.179 Mg m^−3
Mr = 558.04	Melting point: 368 K
Orthorhombic, Pmn21	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: P 2ac -2	Cell parameters from 934 reflections
a = 18.069 (3) Å	θ = 2.5–23.2°
b = 8.2939 (12) Å	µ = 3.74 mm^−1
c = 5.6759 (8) Å	T = 297 K
V = 850.6 (2) Å^3	Tabular, yellow
Z = 2	0.28 × 0.20 × 0.06 mm
F(000) = 520

Data collection

Bruker SMART 1000 CCD diffractometer	2020 independent reflections
Radiation source: fine-focus sealed tube	1710 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
ω and φ scans	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −23→23
Tmin = 0.785, Tmax = 1.000	k = −10→10
7436 measured reflections	l = −7→7

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.030	All H-atom parameters refined
wR(F^2) = 0.074	w = 1/[σ^2(Fo^2) + (0.0395P)^2 + 0.0579P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.005
2020 reflections	Δρmax = 0.77 e Å^−3
131 parameters	Δρmin = −0.30 e Å^−3
15 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.02 (4)

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.

H atoms were refined by SHELX97 with the following restraints: FLAT C5 C6 C7 C8 C9 N1 H5 H6 H8 H9; SADI C5 H5 C6 H6 C8 H8 C9 H9; SADI H5 H6 H8 H9

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
I1	0.333096 (14)	0.22991 (3)	0.34245 (12)	0.06844 (14)
F1	0.5000	0.2934 (6)	0.4760 (9)	0.0691 (11)
F2	0.3712 (2)	0.0212 (4)	−0.1240 (7)	0.0933 (11)
F3	0.5000	−0.0625 (6)	−0.3226 (8)	0.1003 (17)
C1	0.5000	0.2039 (8)	0.2766 (11)	0.0526 (17)
C2	0.4325 (3)	0.1604 (5)	0.1831 (8)	0.0560 (10)
C3	0.4346 (3)	0.0699 (6)	−0.0198 (8)	0.0637 (12)
C4	0.5000	0.0246 (8)	−0.1196 (11)	0.0668 (18)
N1	0.1965 (2)	0.3500 (6)	0.5460 (8)	0.0679 (11)
C5	0.1578 (3)	0.2874 (7)	0.7222 (12)	0.0699 (14)
H5	0.181 (3)	0.232 (4)	0.830 (11)	0.071 (14)*
C6	0.0820 (3)	0.2952 (6)	0.7403 (9)	0.0611 (11)
H6	0.054 (3)	0.251 (4)	0.848 (11)	0.081 (16)*
C7	0.0410 (2)	0.3727 (5)	0.5671 (7)	0.0451 (9)
C8	0.0815 (3)	0.4426 (7)	0.3889 (8)	0.0607 (13)
H8	0.063 (3)	0.498 (5)	0.274 (9)	0.078 (19)*
C9	0.1586 (3)	0.4285 (8)	0.3845 (12)	0.0740 (18)
H9	0.190 (3)	0.460 (7)	0.275 (11)	0.17 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.05658 (18)	0.0705 (2)	0.0783 (2)	0.00068 (10)	−0.0055 (4)	0.0075 (4)
F1	0.062 (3)	0.077 (3)	0.068 (3)	0.000	0.000	−0.027 (2)
F2	0.108 (2)	0.0919 (19)	0.080 (3)	−0.0149 (16)	−0.038 (2)	0.000 (2)
F3	0.162 (5)	0.089 (3)	0.050 (2)	0.000	0.000	−0.017 (2)
C1	0.066 (4)	0.042 (3)	0.051 (5)	0.000	0.000	0.002 (2)
C2	0.061 (3)	0.050 (2)	0.057 (3)	0.001 (2)	−0.009 (2)	0.0050 (19)
C3	0.089 (4)	0.050 (2)	0.052 (2)	−0.007 (2)	−0.015 (3)	0.005 (2)
C4	0.110 (5)	0.057 (3)	0.033 (4)	0.000	0.000	−0.002 (3)
N1	0.048 (2)	0.075 (3)	0.081 (3)	0.000 (2)	−0.008 (2)	−0.002 (2)
C5	0.061 (3)	0.076 (3)	0.073 (3)	0.004 (2)	−0.016 (3)	0.011 (3)
C6	0.058 (3)	0.071 (3)	0.054 (2)	−0.004 (2)	−0.005 (2)	0.007 (2)
C7	0.049 (2)	0.045 (2)	0.042 (2)	−0.0041 (16)	−0.0069 (17)	−0.0112 (16)
C8	0.053 (2)	0.073 (3)	0.056 (3)	0.0057 (19)	−0.001 (2)	0.014 (2)
C9	0.052 (2)	0.088 (3)	0.082 (5)	−0.003 (2)	0.013 (3)	0.006 (3)

Geometric parameters (Å, º)

I1—C2	2.092 (5)	N1—C5	1.326 (8)
F1—C1	1.353 (8)	C5—C6	1.375 (8)
F2—C3	1.350 (5)	C5—H5	0.88 (4)
F3—C4	1.360 (7)	C6—C7	1.388 (6)
C1—C2	1.378 (5)	C6—H6	0.88 (5)
C1—C2^i	1.378 (5)	C7—C8	1.377 (6)
C2—C3	1.375 (6)	C7—C7^ii	1.482 (8)
C3—C4	1.364 (6)	C8—C9	1.398 (7)
C4—C3^i	1.364 (6)	C8—H8	0.87 (4)
N1—C9	1.316 (8)	C9—H9	0.88 (5)
F1—C1—C2	117.8 (3)	N1—C5—H5	119 (4)
F1—C1—C2^i	117.8 (3)	C6—C5—H5	117 (4)
C2—C1—C2^i	124.5 (6)	C5—C6—C7	120.0 (5)
C3—C2—C1	116.2 (5)	C5—C6—H6	127 (4)
C3—C2—I1	122.4 (4)	C7—C6—H6	112 (4)
C1—C2—I1	121.4 (4)	C8—C7—C6	115.6 (4)
F2—C3—C4	118.1 (4)	C8—C7—C7^ii	122.1 (3)
F2—C3—C2	120.5 (5)	C6—C7—C7^ii	122.2 (3)
C4—C3—C2	121.4 (5)	C7—C8—C9	120.5 (5)
F3—C4—C3	119.9 (3)	C7—C8—H8	124 (4)
F3—C4—C3^i	119.9 (3)	C9—C8—H8	115 (4)
C3—C4—C3^i	120.2 (6)	N1—C9—C8	123.1 (6)
C9—N1—C5	116.4 (5)	N1—C9—H9	108 (5)
N1—C5—C6	124.3 (5)	C8—C9—H9	129 (5)
F1—C1—C2—C3	179.8 (5)	F2—C3—C4—C3^i	−179.5 (4)
C2^i—C1—C2—C3	−1.2 (9)	C2—C3—C4—C3^i	−0.5 (9)
F1—C1—C2—I1	0.0 (7)	C9—N1—C5—C6	2.3 (8)
C2^i—C1—C2—I1	179.0 (4)	N1—C5—C6—C7	−0.1 (8)
C1—C2—C3—F2	179.8 (5)	C5—C6—C7—C8	−2.2 (6)
I1—C2—C3—F2	−0.4 (6)	C5—C6—C7—C7^ii	174.7 (4)
C1—C2—C3—C4	0.8 (7)	C6—C7—C8—C9	2.3 (7)
I1—C2—C3—C4	−179.4 (4)	C7^ii—C7—C8—C9	−174.6 (4)
F2—C3—C4—F3	2.2 (8)	C5—N1—C9—C8	−2.2 (9)
C2—C3—C4—F3	−178.8 (5)	C7—C8—C9—N1	−0.1 (9)

Symmetry codes: (i) −x+1, y, z; (ii) −x, y, z.