Unusual self-condensation of polyfluorinated
 -diimines
in a medium of perfluorocarbonic acids esters
* * M.A. Kurikin, D.Yu.Vebritsky, O.E.Petrova, V.N.Khrustalev
The establishment of Russian Academy of Sciences A.N.Nesmeyanov
Institute of Organoelement Compounds RAS,
Russian Federation, 119991 Moscow, Vavilova st. 28
Fax: (499) 135 5085. E-mail: mak@ineos.ac.ru
An unusual conversion of polyfluorinated ?-diimines resulted in
tetraazabicylo compounds has been found.
Polyfluorinated
 -diimines (1) in reactions with carbonyl compounds
[1,2]
as well as with acylhalides [3] form pyridines and pyrimidines with
fluorine containing substituents.
Throughout the investigation of reactivity of (1) we have studied
interaction of these compounds with perfluorocarbonic acids esters (2).
Esters (2) were supposed to be condensed with diimines (1), similarly to perfluoroacyhalides, to afford perfluorinated pyrimidines (3).
However -diimine (1a) at heating in ester solutions (2) was found to
form polyfluorinated tetraazabicyclononadiene (4). At that esters serves
just as a medium in which the observed self-condensation of diimine (1a)
occurs. No one case of the presence of expected pyrimidines (3) in the
reaction mass was registered.
The isolated bicyclodiene (4) is a white cotton-like substance. We
failed to determine its melting temperature because at heating even in a
sealed off capillary there was observed full sublimation of the sample
(without decomposition).
Three types of signals are observed in the 19F NMR spectrum ( d6-DMSO),
two of them belong to CF3 group (-8.1 and -1.6 ppm) and one to CFH group
with a characteristic chemical shift ( 136.9 ppm from CF3COOH) and JF-H
= 47 Hz.
In the 1H NNR spectrum there were observed one signal belonging to CFH
group (6.0 ppm) and two separate signals of NH groups (10.7 and 11.0 ppm).
The composition of the obtained compound (4) was also confirmed by the
data of mass-spectrometry (M+; m/z 414) and elemental analysis ( see
Experimental).
The structure of compound (4) has been finally determined according to
X-ray data (Fig.1).
Fig.1. Molecular structure of compound (4) in representation of
non-hydrogen atoms by 40%-probabilistic ellipsoids of anisotropic
shifts. Alternative positions of disordered H and F atoms are shown in
dashed lines.
Experimental
The 1H and 19F NMR spectra were recorded on a "Bruker AC-200F"
spectrometer ( 200 and 188.3 MHz) with regard to TMS and CF3COOH
accordingly (external standards). The mass
spectra were recorded on a VG 7070 E spectrometer at ionizing
irradiation of 70 eV.
Monocrystals of compound (4) were obtained by crystallization from a
benzene-methanol mixture ( 1:1 ratio). Colorless crystals (4)
(C9H3N4F13, M = 414.15) are
rhomb's, space group Cmcm; at T = 100 K: a =
13.686(2), b = 9.5965(18), c = 9.7178(18)
 , V = 1276.3(4)
3, Z = 4, dc
= 2.155 g/cm3, F(000) = 808,
 = 0.267 mm-1.
The parameters of the unit cell and intensities of 5829 reflections were
measured on an automatic Bruker SMART APEX II CCD diffractometer (T =
100 K,
 -radiation, graphite monochromator,
 and
 -scanning, 2  52o). The structure was determined by the direct method and specified by
full matrix least-squares method in anisotropic approximation for
non-hydrogen atoms.
The positions of hydrogen atoms were calculated geometrically and were
specified in isotropic approximation with fixed positional and heat parameters. The final divergence factors R1 = 0.056 for
517 independent reflections with I>2 and wR2 = 0.153 for all 683
independent reflections, S = 1.010. All the calculations were performed
using SHELXTL4 program complex.
A solution of 3.0g of diimine (1a) in 12 ml of perfluorocaproic
acid methyl ester was boiled with a back flow condenser for 20
minutes. The precipitated residue was separated by filtration, washed
with chloroform (3x30 ml) dried under vacuum. There was obtained 1.5g
(54%) of compound (4).
19F NMR spectrum (DMSO-d6,
 , ppm, J/Hz): -8.1 (d, 6 F, F(1), F(2));
-1.6 (s, 6 F, F(3), F(4)); 136.9 (m, 1 F, F(5)).
1H NMR spectrum: (DMSO-d6,
, ppm, J/Hz): 6.0 (d, 1 H, H(6), J = 50),
10.7 and 11.0 (both s, 1 H, H(7), H(8)).
Found (%):C, 26.16; H, 0.78; F, 60.51; N, 13.61. C9H9F13N4.
Calculated (%):C, 26.10; H, 0.73; F, 59.64; N, 13.53.
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