76
S. De et al. / Journal of Molecular Structure 479 (1999) 75–81
Table 1
before undertaking an elaborate program for their
synthesis, we sought to secure information on simple
structural perfluorocarbon derivatives in terms of
conformational details. In this article, the crystal
structure of 2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadeca-
fluorodecyl 1,10-ditosylate (2) is reported, a precursor
for surfactant synthesis.
Crystal data and experimental crystallographic details
Empirical formula
Formula weight
Temperature
Crystal system, space group Triclinic, P1
Unit cell dimensions
C24H18F16O6S2
770.5
293 (2) K
˚
a 7.915 (3) A, a 91.93 (3)Њ
˚
˚
b 17.800 (5) A, b 104.94 (3)Њ
c 5.371 (3) A, g 99.49 (2)Њ
3
˚
Volume
718.8 (5) A
Z, calculated density
Absorption coefficient
F (000)
1, 1.780 Mg/m3
0.330 mmϪ1
386
Crystal shape
Crystal color
Rectangular
Colorless
Crystal size
0.3 × 0.25 × 0.2 mm
On the diffractometer:
u range for accurate cell
dimensions (Њ)
Index ranges
2.33–22.50Њ
0 Ͻ h Ͻ 8, Ϫ 19 Ͻ k Ͻ
18, Ϫ 5 Ͻ 1 Ͻ 5
Reflections collected/unique 2052/1885 [R(int) 0.0178]
Completeness to 2u 22.50 99.9%
Standard reflections
2. Experimental
Number
Interval
3
200
2.1. Materials
Decay
Ϫ 4.2
None
Perfluorosebacic acid was purchased from Aldrich
Chemical Co. Thin layer chromatography was
performed on silica gel-G purchased from Merck.
The plates were visualized by putting them in iodine
chamber. Column chromatography was done on silica
gel (60–120 mesh) obtained from Acme Synthetic
Chemicals. All the reagents and solvents were
obtained from commercial source and were purified,
dried or freshly distilled as required according to a
literature procedure [12].
Absorption correction
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I Ͼ 2s1]
R indices (all data)
Extinction coefficient
Max. shift/s
Full-matrix least-squares on F2
1885/0/218
1.025
R1 0.0422, wR2 0.1224
R1 0.0466, wR2 0.1260
0.012 (3)
0.001
Largest diff. Peak and hole 0.371 and Ϫ 0.276 e.AϪ3
2.2.1. Diethyl perfluorosebacate (4)
2.2. Synthesis
Perfluorosebacic acid 3 (1.5 g, 4.08 mmol) was
refluxed with excess dry EtOH in presence of one
drop of conc. H2SO4 for 24 h. After removal of
EtOH, the organic layer was dissolved in CHCl3 and
washed successively with water and NaHCO3 (sat.).
The product was passed through anhydrous Na2SO4
and upon concentration, a colorless liquid was
Melting points were recorded in open capillary
tubes and are uncorrected. H-NMR spectra (TMS
1
as an internal standard) were recorded on either a
JEOL-FX-90Q (90 MHz), a 200 MHz or a 270 MHz
1
Bruker NMR spectrometer. H-decoupled 19F-NMR
spectra were recorded in 400 MHz Bruker NMR spec-
trometer. Chemical shifts (d) are reported in ppm
downfield from the internal standard. IR spectra
were recorded in a Perkin Elmer Model 781 spectro-
meter and are reported in wave numbers (cmϪ1).
Microanalyses were performed on a Carlo Erba
elemental analyzer model 1106.
1
obtained (yield ca. 99%). IR (nujol) 1770 cmϪ1; H-
NMR (CDCl3, 90 MHz) d 1.33 (t, 6H), 4.4 (q, 4H);
19F-NMR (CDCl3, 376.5 MHz) d Ϫ86.51 (t), Ϫ 83.48
(br s), Ϫ83.3 (br s), Ϫ82.41 (br s); 13C-NMR (CDCl3,
22.5 MHz) d 13:75, 64.82; LRMS, EI, m/z (%) 547
(20).