Supporting Information © Wiley-VCH 2006

69451 Weinheim, Germany

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Molecular and Supramolecular Homochirality: Enantiopure Perfluorocarbon

Rotamers and Halogen-Bonded Fluorous Double Helixes

Alessandro Casnati, Rosalba Liantonio, Pierangelo Metrangolo,* Giuseppe Resnati,*

Rocco Ungaro, and Franco Ugozzoli*

NFMLab - DCMIC “G. Natta” and Campus of Como, Politecnico di Milano, via L. Mancinelli 7,

20131 Milano, and via Castelnuovo 7, 22100 Como, Italy, web-site: http://nfmlab.chem.polimi.it,

Department of Organic and Industrial Chemistry, and Department of General and Inorganic

Chemistry, Università degli Studi di Parma

via Università 12, 43100 Parma, Italy

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Synthesis

Scheme 1. Synthesis of the complex 1⊂BaI2.

Scheme 2. Synthesis of the halogen bonded adduct 4.

OO OO

Et2N OEt2N

O O NEt2ONEt2

OO OO

Et2N OEt2N O O NEt2O

NEt2

I

IF

F

F

F

2 I-

IF F

FF

FF

F

FF

F FF

FF

I

FF

IF F

FF

FF

F

FF

F FF

FF

I

FF

I-

IFF

F F

FF

F

FF

FFF

FF

I

FF

IFF

F F

FF

F

FF

FFF

FF

I

FF

I-

Ba2+Ba2+

+ ()4 EtOH

1 ⊂ BaI2 3 4

OO OO

Et2N OEt2N O O NEt2O

NEt2

OO OO

Et2N OEt2N O O NEt2O

NEt2

2 I-

CH3CN/CH3OHBa2+

1 ⊂ BaI2

BaI2·2 H2O (2)

1

3

General:

The inorganic salt (BaI2⋅2H2O) and the diiodoperfluorinated alkane were commercially available (Aldrich and Apollo Scientific) and were used without further purification. Reagents grade solvents were used without further purification. For the preparation of the p-t-butylcalix[4]arene tetraethyl amide (1), see ref. J. Chem. Soc., Chem. Comm., 1987, 5, 344-346. The IR spectra were recorded with a Nicolet Nexus FT-IR spectrophotometer equipped with the Smart Endurance system (UATR). 19F NMR and 1H NMR spectra were recorded on a Bruker ADVANCE 500 at 25 °C. CFCl3 and TMS were used as internal standard.

Complex between p-t-butylcalix[4]arene tetraethyl amide (1) and BaI2·2 H2O (2): 1 (0.045 mmol, 50 mg) and 2 (0.045 mmol, 20 mg) were dissolved in CH3CN and methanol, respectively. The two solutions were mixed and the resulting mixture was stirred and refluxed for 1 hour. At the end, the slow evaporation of the solvent afforded yellowish crystals of 1⊂BaI2⋅xH2O. M.p.: >280 °C. IR (pure, cm-1, selected bands): 2965, 2868, 1652, 1481, 1196, 1058.

Complex 4: 1⊂BaI2⋅xH2O (0.026 mmol, 40 mg) and 1,8-diiodoperfluorooctane (3) (0.078 mmol, 51 mg) were dissolved in a vial of clear borosilicate glass at room temperature. Ethanol was used as solvent. The open vial was closed in a cylindrical wide-mouth bottle containing paraffine oil. After few days at room temperature, the slow evaporation of the solvent provides with colourless crystals. M.p. 170-190 °C (dec). IR (pure, cm-1, selected bands) complex 4: 2966, 2873, 1628, 1479, 1208, 1186, 1135, 1043, 677. 1H-NMR (500 MHz, MeOD): δ 1.14-1.28 (s + m, 60 H), 3.25-3.31 (s + d, 16+4 H), 4.37 (d, 4H), 4.85 (s, 8H), 7.42 (s, 8H). 1H-NMR (470.6 MHz, MeOD): δ -60.02 (t, 4F), -113.06 (s, 4F), -120.24 (s, 4F), -121.08 (s, 4F).

X-ray crystal structure analysis. A single crystal of the complex 4·suitable for X-ray analysis was mounted on a glass rod and cooled to 173 K with a temperature-controlled cold nitrogen-gas flow. The X-ray measurements were carried on a Enraf-Nonius CAD4 diffractometer using graphite monochromatized Cu-Kα radiation (λ = 1.54178 Å) with a fine-focus shield tube (40kV, 20 mA). The crystal data and the most relevant experimental parameters used in the X-ray measurements and in the crystal structure analysis are reported in Table 1. The intensities were calculated from profile analysis according to the Lehmann and Larsen method [1]. During the systematic data collection two standard reflections, collected every 100, showed no significant fluctuations. The intensities were corrected for Lorentz and polarization. Absorption correction was applied at end of the isotropic refinement by numerical method using the program Newabs92 [2]; maximum and minimum transmission factors 1.45 and 0.408. The structure was solved by Direct Methods using SIR92 [3], completed by Fourier ∆F map and then refined by full-matrix least-squares methods on F2 using SHELXL-97 [4]. Parameters refined were: the overall scale factor, the atomic coordinates and anisotropic thermal parameters for all the non-hydrogen atoms. All the hydrogen atoms were placed at their calculated positions with the geometrical constraint C-H 0.96 Å and refined “riding” on their corresponding parent atoms. Being the I422 space group chiral we have also tested the inverted structure which however converged at greater R values and to a Flack parameter close to 1 [0.96(2)]. The geometrical calculations were obtained by PARST97 [5].

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References. [1] M. S. Lehmann, F. K. Larsen, Acta Crystallogr. 1974, sect A, 580. [2] Newabs92. Updated version of ABSORB [F. Ugozzoli, ABSORB, Comput. & Chem., 1987, 11, 109]. [3] A. Altomare, M. C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo, A. Guagliardi, G. Polidori, SIR92, J. App. Crystallogr. 1994, 27, 435. [4] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement, University of Göttingen, 1997; http://shelx.uni-ac.gwdg.de/shelx/index.html. [5] M. Nardelli, PARST97, updated version of PARST95, J. Appl. Crystallogr. 1995, 28, 659-659.

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Table 1

Crystallographic parameters for 4.

Complex 4

Crystal data

Empirical formula C68H100N4O8Ba4I2•2C8F16I2•H2O Formula weight 2818.467 Crystal size (mm) 0.17 x 0.20 x 0.50 Crystal system tetragonal Space group I422(no. 97) a (Å) 17.833(5) b (Å) 17.833(5) c (Å) 35.716(5) α (°) 90 β (°) 90 γ (°) 90 V (Å3 ) 11358(5) Z 4 Dcalc (g/cm-3) 1.648 F(000) 5472 Data collection Temperature (K) 173 θ Range (°) 3 to 70 Index ranges 0≤h≥21

0≤k≥21 0≤l≥43

Refl. measured 5861 Indep. Refl. 5373 (Rint= 0.089) Obs. Refl. 3360 (Fo≥4σ(Fo)) Structure refinement Final R indices (obs. data)

R1=0.0825 wR2=0.254a

S 0.847 Max. and av. ∆/σ 0.03, 0.00 Min. and max. residual ρ(e/Å3)

-1.31, 3.29

a R1 = Σ || Fo|- | Fc||/ Σ | Fo|, wR2 = [Σ w(Fo2-Fc2)2/ ΣwFo4]1/2. goodness-of-fit S= [Σ w(Fo2-Fc2)2/ (n-p)] 1/2, where n is the number of reflections and p the number of parameters.

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(a) (b)

Figure S1. Crystal packing of the complex 4 with one supramolecular double helix evidenced by van der Waals spheres: (a) View orthogonal to the crystallographic c axis. (b) View along the crystallographic c axis.

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Figure S2. View orthogonal to the crystallographic c axis of the supramolecular double helix in three different orientations. Green lines for halogen bonds. Violet for iodide anions.

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(a) (b)

Figure S3. Perspective views of the cationic complex 1⊂Ba2+. a) View orthogonal to the crystallographic c axis with interatomic distances of the cation and of the water molecule inside the intramolecular cavity of the calix[4]arene receptor. b) View along the crystallographic c axis with the rigth-handed conformation of the square antiprism in the coordination sphere of the cation.

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Figure S4. Perspective view orthogonal to the crystallographic c axis of the columnar packing (folded around the crystallographic C4 axes) of the cationic complex 1⊂Ba2+. Water molecules have been omitted.

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(a) (b) Figure S5. Perspective views of the perfluoroalkanes’ sub-lattice. a) View orthogonal to the crystallographic c axis with one right-handed double helix evidenced in yellow and red. Only one-half of the pitch of the double helix is indicated. b) View along the crystallographic c axis.

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Figure S6. Perspective views of the crystal packing of the complex 1⊂KI, showing the columnar stacking of the 1⊂K+ supercations intercalated by naked anions. This arrangement leaves voids parallel to the stacking direction.

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Figure S7. Perspective view of the crystal packing of the complex 1⊂ Sr(Pic)2 (Pic = picrate); the picrate anions are segregated in the channels parallel to the columnar stacking of 1⊂Sr2+ supercations.