Anthony KERMAGORET - THESES ET MEMOIRES DE L'UDS

Chapitre V
spin system 1) and 3.06 and 3.23 ppm (ABX spin system 2) for 13 and 3.23 and 4.04 ppm
(ABX spin system 1) and 3.49 and 3.57 ppm (ABX spin system 2) for 14 integrating for two
protons each and corresponding to the signals of PCHAHB of the coordinated oxazoline and
the free oxazoline. According to the HMBC NMR spectrum of 14, the signal at 3.23 and 4.04
ppm correspond to the PCHAHB protons of the coordinated oxazoline moiety. In the 1 H NMR
spectra of 13 and 14, the methyl protons appear as four singlets and the OCH2 protons form
two distinct AB spin systems. The mutual cis-coordination of the phosphorus and the methyl
group complex 13 is indicated by the doublet at 0.78 ppm with a 3 JPH of 3.6 Hz.
In contrast to 13 and 14, the 13 C{ 1 H} NMR spectrum of 15 contains a singlet for the C atoms
in α position to the methyls at 68.4 ppm, a singlet for the OCH2 carbon atoms at 83.4 ppm, a
doublet for C=N at 174.7 ppm ( 2 JPC = 19.8 Hz) and a doublet for the PCH2 carbon atoms at
29.6 ppm ( 1 JPC = 41.8 Hz). Its 1 H NMR spectrum shows an AB spin system for the OCH2
protons at 4.44 and 4.57 ppm (JAB = 8.9 Hz) and an ABX spin system for the PCH2 protons at
3.54 and 4.35 ppm. Its 31 P{ 1 H} NMR spectrum contains a singlet at 43.92 ppm. The IR
spectrum of 15 presents an unique band for the C=N vibrations at 1613 cm -1 . According to the
NMR and IR spectra, we conclude that ligand 3 coordinates the metal center in a tridentate
fashion and that the molecule has a mirror plane passing through the P,Pd and the NMeCN
atoms . The coordination of a MeCN molecule stabilizes the complex. 39
2.5 Synthesis of the cobalt complexes
In order to study the coordination of the tridentate ligands (NOPON Me2 ), 1-3 to a
cobalt centre, complexes 16-19 have been synthesized, respectively (Scheme 6). The three
complexes were obtained in high yield by reaction of the corresponding ligands with
anhydrous CoCl2 in THF at room temperature.
O
N
O
Ph
P
16
O
Co Cl
Cl
N
O
N
Cl
Ph Ph
P
Co
17
Scheme 6. Co(II) complexes 16-19
Cl
N
O
P
N Co N
18 R = H
19 R = Me
O
Cl Cl
R R R
R
Complexes 16-19 proved to be paramagnetic in solution and their magnetic moments of 3.8,
44, 46, 47
4.1, 4.0 and 4.0 µB, respectively, were determined by the Evans method in CD2Cl2.
These values are slightly lower than expected for high spin d 7 Co(II). 24, 29 Complex 17 was
15