L’évolution législative récente relative à la fin de vie, qui tend à substituer la procédure à la relation, interroge. Aujourd’hui, chaque question semble devoir être obstinément transformée en ...problème à résoudre, et donc à résoudre techniquement. Nous évoluons dans un contexte marqué par la primauté de la technique et du droit sur le sens et sur le rapport humain. Ce paradigme, confronté à nos limites, accentue la double angoisse de la fin de vie : la peur de souffrir et la peur de mourir. Il favorise également une compréhension nominaliste de la liberté : l’autonomie n’est plus comprise comme un accomplissement, mais comme un refus, une émancipation du réel. La loi du 2 février 2016 rend compte de ce déplacement, elle qui nous invite à placer notre confiance non plus dans la personne mais « dans le dispositif ». Ainsi des directives anticipées, dont la finalité est de faire droit à l’autonomie, réduite à la maîtrise, au contrôle des conditions du mourir. Le dispositif, qui fera dépendre l’autonomie d’une exigence de conformité à la technique, devient le symptôme d’une profonde désubjectivation. La médicalisation de la mort obère la question de la mort. Et cette désymbolisation de la mort va de pair avec son individualisation, le sujet étant laissé de plus en plus seul. Il conviendrait de rendre à la parole et au sens leur souveraineté. Car les enjeux de la fin de vie sont des enjeux de sens — non de moyens.
The recent French legislative evolution concerning the end of life, which tends to substitute the procedure for the relationship, raises questions. Today, every question seems to have to be obstinately transformed into a problem to be evolving in a context marked by the primacy of technique and law over meaning and human relationships. This paradigm, when confronted with our limitations, accentuates the double anguish of the end of life: fear of suffering and fear of dying. It also favors a nominalist understanding of freedom: autonomy is no longer understood as an achievement but as a refusal, an emancipation from reality. The French law of February 2, 2016, reflects this shift, inviting us to place our trust not in the person but “in the device”. Thus, the advance directives, whose purpose is to give the right to autonomy, are reduced to mastery, the control of the conditions of dying. The device, which makes autonomy depend on a requirement of conformity to technique, becomes the symptom of a profound de-subjectification. The medicalization of death fetters the question of death. And this desymbolization of death goes hand in hand with its individualization, the subject being left more and more alone. It would be advisable to give back to speech and the meaning of their sovereignty. The issues at stake at the end of life are issues of meaning —not of means.
Four new Fe(III) catecholate complexes, (bispicMe2en)FeIII(DBC)+, (bispicCl2Me2en)FeIII(DBC)+, (trispicMeen)FeIII(DBC)+, and (BQPA)FeIII(DBC)+, which all contain aminopyridine ligands, were ...synthesized. The structure of (bispicMe2en)FeIII(DBC)+ was determined by X-ray diffraction. It crystallizes in the triclinic space group P with a = 10.666(3) Å, b = 13.467(5) Å, c = 17.685(2) Å, α = 93.46(2)°, β = 93.68(2)°, γ = 109.0(3)°, V = 2387.4 Å3, and Z = 2. All of these complexes were found to be active toward oxidation of catechol by O2 in DMF at 20 °C to afford intradiol cleavage products. The catechol was quantitatively oxidized, mainly (90%) into 3,5-di-tert-butyl-5-(carboxymethyl)-2-furanone. Reaction rates were measured, and for the first three (topologically similar) complexes, a correlation of the second-order kinetic constants k with the optical parameters of the two LMCT O(DBC) → Fe(III) bands was found. In particular, k increases with the εmax of the charge-transfer bands. The k value of the complex (BQPA)FeIII(DBC)+, containing a tripodal ligand, is smaller than expected on the basis of these correlations. This discrepancy could be related to steric hindrance induced by the BQPA ligand. However, the much lower activity of the bispicen-Fe(III)-type complexes compared to that of the (TPA)FeIII(DBC)+ complex synthesized by Jang et al. (J. Am. Chem. Soc. 1991, 113, 9200−9204), despite similar εmax values, shows that a knowledge of optical and NMR parameters values is not sufficient to explain the dioxygenase activity rate. In their study of protocatechuate 3,4-dioxygenase, Orville et al. (Biochemistry 1997, 36, 10052−10066) suggested that asymmetric chelation of the catecholate to Fe(III) is of great importance in the efficiency of the intradiol dioxygenase reaction. Indeed, a comparison of the X-ray structures of (TPA)FeIII(DBC)+ and (bispicMe2en)FeIII(DBC)+ shows that the Fe(III)−O bonds differ by 0.019 Å in the former and are identical in the latter. Asymmetry could also play a role in the model complexes. An alternative explanation is the possible existence of a low-spin state for (TPA)FeIII(DBC)+, as recently identified in (TPA)FeIII(cat)+ by Simaan et al. (Angew. Chem., Int. Ed. Engl. 2000, 39, 196−198).
The complexes L5FeIIClBPh4 and L5FeII(H2O)(BPh4)2 (L5 = N,N,N‘-tris(2-pyridylmethyl)-N‘-methyl-ethane-1,2-diamine) have been isolated. Bernal et al. (Bernal, J.; et al. J. Chem. Soc., Dalton Trans. ...1995, 3667−3675) have prepared this ligand and the corresponding complex L5FeIIClPF6. We obtained the structural data of L5FeIIClBPh4 by X-ray diffraction. It crystallizes in the orthorhombic space group P212121 with a = 17.645(7) Å, b = 16.077(6) Å, c = 13.934(5) Å, V = 3953(3) Å3, and Z = 4. It presents Fe(II)−N bond lengths close to 2.2 Å, typical of high-spin Fe(II). In solution the L5FeII(H2O)(BPh4)2 complex showed a dependence of spin state upon the nature of the solvent. It was high spin in acetone and changed to low spin in acetonitrile. This was detected by UV−vis spectroscopy and by 1H NMR. Bernal et al. (ibidem) showed that these complexes in the presence of an excess of H2O2 give a purple species, very likely the L5FeIII(OOH)2+ derivative, with spectroscopic signatures analogous to those of “activated bleomycin”. The formation of L5FeIII(OOH)2+ is confirmed here by electrospray ionization mass spectrometry. We found that a L5/Fe system gave single-strand breaks on plasmid DNA in the presence of either a reducing agent (ascorbate) and air or oxidants (H2O2, KHSO5, MMPP) at 0.1 μM concentration. The methyl group in L5 was substituted by a (CH2)5N(CH3)3 + group in order to get higher affinity with DNA. The corresponding ligand L5 + was used to prepare the complexes L5 +FeIIClY2 (Y = BPh4 -, PF6 -, ClO4 -) and L5 +FeIIBr(PF6)2. The crystal structure of L5 +FeIICl(ClO4)2 was solved. It crystallizes in the monoclinic space group P21/a with a = 14.691(2) Å, b = 13.545(2) Å, c = 17.430(2) Å, β = 93.43(1)°, V = 3462(1) Å3, and Z = 4. The Fe(II)−ligand distances are similar to those of L5FeIIClBPh4. At the relatively low concentration of 0.01 μM, L5 +FeIIBr2+ promoted DNA breaks. The reaction was not inhibited by hydroxyl radical scavengers. The reaction might involve a nondiffusible oxygen reactive species, either a coordinated hydroperoxide or a high-valent metal−oxo entity.
Three new complexes, Fe(LN4H2)Cl2+, Fe(LN4H2)(Cat)+, and Fe(LN4H2)(DBC)+, were synthesized by using the tetradentate macrocyclic ligand LN4H2 (where LN4H2, Cat, and DBC stand for 2,11‐diaza3,3(2,6) ...pyridinophane, catecholate, and 3,5‐di‐tert‐butylcatecholate, respectively). The structure of Fe(LN4H2)Cl2+ was determined by X‐ray diffraction. It crystallizes in the monoclinic space group C2/c with a = 9.613(1), b = 11.589(1), c = 14.063(2) Å, β=110.20(2)°, V = 1541.9(3) Å3, and Z = 4. These complexes were found to catalyze the oxidation of catechol groups using O2. This was performed in various organic solvents at 20 °C. The reaction rates were measured for the stoichiometric complexes Fe(LN4H2)(Cat)+ and Fe(LN4H2)(DBC)+. It was found that despite the relatively high energy of the ligand‐to‐metal charge transfer O(DBC or Cat)→FeIII, their activity was comparable to that of the fast TPA systems TPA indicates tris(2‐pyridylmethyl)amine. The oxidation products of DBCH2 have been studied. It has then been shown that the LN4H2 systems catalyse by means of both intra‐ and extradiol cleavage of catechol groups. The existence of multiple reactive pathways can account for the fast reactivity observed.
The strong oxophilic character of the Gd(III) ion has been utilized to protect one of the carbonyl functions of 2,6-diformyl-4-methylphenol, which has allowed the quantitative synthesis of ...mono(Schiff bases), then dissymmetric di(Schiff bases). The synthetic process is as follows: the reaction of 2,6-diformyl-4-methylphenol with a primary amine RNHsub 2 in the presence of Gd(III) affords a complex in which Gd(III) is coordinated to two mono(Schiff bases) through their carbonyl and phenolic oxygen atoms. The mono(Schiff base) may be isolated by precipitation of Gd(III) in the form of gadolinium(III) oxalate. The reaction of another primary amine, RprimeNHsub 2, on this mono(Schiff base) affords a dissymmetric di(Schiff base), from which dissymmetric dinuclear compounds can be synthesized. For example, this reaction has been carried out with RNHsub 2 = 2-(2-aminoethyl)pyridine and RprimeNHsub 2 = N,N-dimethylpropylenediamine. The mono(Schiff base) 2-formyl-6-(N-(2-pyridylethyl)formimidoyl)-4-methylphenol (HL) and the di(Schiff base) 2-N-(2-pyridylethyl)formimidoyl-6-N-((dimethylamino)propyl)formimidoyl-4-methylphenol (HLprime) have been unambiguously characterized from their sup 1H NMR spectra. The copper(II) dinuclear compound CuLprime(OH)(ClOsub 4)sub 2center dotHsub 2O obtained from this di(Schiff base) has been synthesized, and its crystal structure has been solved. 36 refs., 2 figs., 5 tabs.
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