Halle, Universiẗat, Diss., 2000.

Ce travail porte sur la synthèse et la caractérisation de nouveaux pigments thermochromes irréversibles avec le cobalt divalent pour chromophore principal en vue de les intégrer à une peinture thermosensible commerciale.Le travail a été réalisé en suivant trois phases. La première phase a consisté en l’identification de matrices thermosensibles présentant des évolutions structurales irréversibles en température dues à des transitions de phase du premier ordre ou des dégradations chimiques. Puis la synthèse de ces matrices a été effectuée par des voies compatibles avec les méthodes d’élaboration industrielle et permettant un dopage au cobalt. Enfin la troisième et dernière étape est l’étude in-situ et ex-situ des propriétés thermosensibles des pigments synthétisés à l’aide de techniques comme la diffraction des rayons X et des neutrons en température, l’analyse thermogravimétrique et la réflexion diffuse en température.À l’issue de ce travail de recherche, les solutions les plus efficaces ont été synthétisées à l’échelle industrielle puis intégrées à une peinture commerciale en phase aqueuse. / This work deals with the development of new thermochromic pigment which will be the active part of an irreversible thermochromic paint.The studies moved towards three steps. Firstly, an identification of crystalline matrix offering structural rearrangement in temperature because of first order phase transition or chemical degradation were performed. Then the identified matrix were synthesised thanks to synthesis routes compatible with industrial procedures. The third and last step consisted in the in-situ and ex-situ characterization of thermochromic properties of the synthesized compounds with technics like temperature coupled X-ray and neutrons diffraction, thermogravimetric analysis and temperature coupled diffuse reflectance analysis.The most efficient compounds were then industrially synthesized and integrated to a commercial aqueous paint.

Halle, Universiẗat, Diss., 1999.

O sistema cobalto(II)/tiocianato foi estudado em meio aquoso com o objetivo de se obter dados reais das constantes de formação globais dos complexos. Foram utilizados os métodos potenciométrico indireto e espectrofotométrico em meio de força iônica 2,0 M (NaCl04) a 25,0 &#177; O,l&#176;C. O sistema cádmio(II)/tiocianato foi utilizado como indicador no método potenciométrico indireto com o eletrodo de gota pendente de amálgama de cádmio. As seguintes constantes de equilíbrio foram obtidas para os complexos formados entre o cádmio e o tiocianato, a 25&#176;C e força iônica 2,0 M (NaCl04): &#946;1 = 21,51 &#177; 0,09 M-1, &#946;2 = 123,3 &#177; 1,2 M-2, &#946;3 = 129,9 &#177; 3,1 M-3 e &#946;4 = 173,5 &#177; 1,2 M-4. Valores do número médio de ligantes, &#241;, foram obtidos para várias concentrações de tiocianato, até 2,0 M, pela adição de Co(Cl04)2 (0,1 M) à solução contendo cádmio(II) e tiocianato. A integração da curva de formação e o tratamento das funções de Leden, pelo método dos mínimos quadrados desenvolvido, levou às seguintes constantes de formação globais para o sistema cobalto(II)/tiocianato: &#946;1 = 11,0 M-1, &#946;2 = 22,0 M-2, &#946;3 = 11,2 M-3 e &#946;4 = 1,63 M-4. Um estudo do sistema zinco(II)/tiocianato foi realizado com o objetivo de avaliar o método potenciométrico indireto, visto que esse sistema foi anteriormente estudado por um método direto confiável. A curva de formação obtida apresenta uma boa concordância até &#241; = 1. Depois desse ponto um desvio negativo é observado, com relação a curva obtida pelo método direto, devido à causas não bem compreendidas. Várias curvas de absortividade molar média, &#949; vs. concentração analítica de ligante foram obtidas em três comprimentos de onda (515, 590 e 615 nm) em tres concentraçoes de cobalto(II) diferentes: 0,01, 0,05 e 0,1 M. A análise com base no método das soluções correspondentes permitiu obter a curva &#241; vs. concentração de tiocianato livre, com as seguintes constantes de equilíbrio: &#946;1 = 6,9 M-1, &#946;2 = 28,9 M-2, &#946;3 = 12,1 M-3</SUP e &#946;>SUB>4 = 1,30 M-4. Ambos os métodos revelaram uma tendência à formaçao de duas espécies e uma diminuição acentuada na afinidade com o ligante para formar os complexos &#8204;Co(SCN)3&#8204;- e &#8204;Co(SCN)4&#8204;2-. Uma relação linear entre o número médio de ligantes e a absortividade molar média foi observado em 515 nm, o que permitiu obter o valor de &#949;4. Entretanto, em 590 e 615 nm, observou-se somente uma linearidade entre &#949; e o grau de formação calculado, &#945;4, correspondente a espécie &#8204;Co(SCN)4&#8204;2-, com uma intersecção muito próxima da origem. Isto é uma evidência que &#8204;Co(SCN)4&#8204;2- existe virtualmente como uma espécie tetraédrica com absortividade molar relativamente alta. Foram obtidos os seguintes valores de &#949;n individuais: a) &#949;o = 4,31, &#949;1 = 22,6, &#949;2 = 26,3, &#949;3 = 42,8 e &#949;4 = 50,3 cm-1.M-1 em 515 nm; b) &#949;o = 0,29, &#949;1 = 1,3, &#949;2 = 3,2, &#949;3 = 3,9 e &#949;4 = 215 cm-1.M-1 em 590 nm; c) &#949;o = 0,20, &#949;1 = 0,90, &#949;2 1,5, &#949;3 = 2,2 e &#949;4 = 294 cm-1.M-1 em 615 nm. Especulações com os dados sugerem que somente 1% das espécies tetraédricas estão em equilíbrio com as espécies octaédricas correspondentes com 1,2 e 3 tiocianatos coordenados. Com o emprego de um computador foi realizado um estudo efetuando uma simulação dos métooos espectrofotométricos da razão molar e das variações contínuas. As Simulações, com sistemas reais e hipotéticos, foram muito úteis para mostrar as conclusões ambíguas que podem ser obtidas, a partir de dados experimentais, para se estimar o número de espécies complexas. / The cobalt (II) /thiocyanate system in aqueous medium was studied with the purpose to obtain reliables data of overall stepwise formation constants to complexes. An indirect potentiometric method and a spectrophotometric one were used at 2,0 M ionic strength (NaCl04), at 25,0 &#177; O,l&#176;oC. The cadmium(II)/thiocyanate system was used as indicator in the indirect potentiometric method with hanging drop electrode with cadmium amalgam. The following equilibrium constants of the cadmium(II)/thiocyanate complexes were obtained at 25&#176;C and 2,O M ionic strenght (NaCl04: &#946;1 = 21.51 &#177; 0.09 M-1, &#946;2 = 123.3 &#177; 1,2 M-2, &#946;3 = 129.9 &#177; 3.1 M-3 and &#946;4 = 173.5 &#177; 1.2 M-4. Average 1igands number data, &#241;, were obtained for several thiocyanate concentrations, up to 2 M, by adding Co(Cl04)2 (0.1 M) to the working solution of cadmium (II)/thiocyanate. The integration of the formation curve and treatment of Leden\'s functions by a self developed least square method, lead to the following overall formation constants of the cobalt(II)/thiocyanate system: &#946;1 = 11.0 M-1, &#946;2 = 22.0 M-2, &#946;3 = 11.2 M-3 and &#946;4 = 1.63 M-4. A study of the zinc(II)/thiocyanate system was performed with the purpose to check the indirect potentiometric method inasmuch as this system was formerly studied by a re1iable direct method. The formation curve presented a good agreement until the average ligand number 1. After this point a negative desviation is observed with regard the direct method by not well understood causes. Severa1 curves of average molar absorbtivity, &#949; vs the analytical ligand concentration were obtained at three wave lengths (515, 590 and 615 nm) and three differents cobalt(II) cation concentrations: 0.01, 0.05 and 0.1 M. The analysis on base of corresponding solutions permited to obtain &#241; vs free thiocyanate ion concentrations, with the following equilibrium constants: &#946;1 = 6.9 M-1, &#946;2 = 28.9 M-2, &#946;3 = 12.1 M-3</SUP e &#946; = 1.30 M-4. Both methods revealed a tendency to form two species and a marked decrease in affinity with the 1igand to form &#8204;Co(SCN)3&#8204;<SUP- and &#8204;Co(SCN)4&#8204;2-. A linear relationship between calculated &#241; and &#949; was observed at 515 nm and this permited to obtain &#949;4. However, at 590 and 615 nm linearity of &#949; was achieved only for calculated formation degree, &#945;4, corresponding to specie &#8204;Co(SCN)4&#8204;2-, with an intercept very close to the origin. This is an evidence that the &#8204;CoO(SCN)4&#8204;2- exists virtually as tetrahedra1 specie with relative1y high molar absorbtivity. The fol1owing individual &#949;n were obtained: a) &#949;0 = 4.31, &#949;1 = 22.6, &#949;2 = 26.3, &#949;3 = 42.8 and &#949;4 = 50.3 cm-1.M-1 at 515 nm; b) &#949;0 = 0.29, &#949;1 = 1.3, &#949;2 = 3.2, &#949;3 3.9 and &#949;4 = 215 cm-1.M-1 at 590 nm; c) &#949;0 = 0.20, &#949;1 = 0.90, &#949;2 1.5, &#949;3 = 2.2 and &#949;4 = 294 cm-1 .m-1 at 615 nm. Speculations with the data suggest that on1y 1% of tetrahedral species are in equi1ibrium with the corresponding octahedral ones with 1, 2 and 3 thiocyanate 1igands. An extension of the study was a computer assisted simulation of the molar ratio spectrophotometric titration as well as the continuous variations method. This simulation study with real and hypothetica1 systems,was very usefu1l to show how ambiguous can be the conclusions, taken from experimental data,when the number of species are to be estimated.

Thesis (MSc. (Chemistry)) --University of Limpopo, 2014 / This study deals with the synthesis and characterisation of cobalt complexes of nitrogen-donor imidazolyl- salicylaldimine ligands and their potential catalytic activity in the oxidation reactions of phenol and styrene. Five ligands were used in the study, four of which are new. Compound 2,4-di-tert-butyl-6{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L1), was synthesised according to a literature procedure. The other imidazole-based salicylaldimine compounds 2-ethoxy-6{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L2), 4-methoxy-6{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L3), 1{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-benzene (L4) and 4-methyl-1{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-benzene (L5) were prepared by Schiff base condensation reaction of histamine dihydrochloride with 3-ethoxy-2-hydroxybenzaldehyde, 5-methoxy-2-hydroxybenzaldehyde, benzaldehyde, 4-methylbenzaldehyde respectively. L1-L5 were characterised by 1H and 13C{1H} NMR, IR and UV-vis spectroscopy and high resolution mass spectrometry (HRMS). Reactions of L1-L5 with CoCl2 yielded complexes C1-C5, while complexes C6-C10 were synthesised by reactions of L1-L5 with CoBr2 all in a ratio of 1:1 of ligand to metal precursor. The cobalt(II) complexes were characterised by IR and UV-vis spectroscopy, elemental analysis and high resolution mass spectrometry due to their paramagnetic nature. All the characterisation data point to complexes C1-C10 being formulated as [Co(3-L)X] (where L = ligand and X = halide). However, single crystal X-ray diffraction showed that the prolonged stay of complex C6 in a solution gave a new structure as complex C11. The imidazole-based salicylaldimine cobalt(II) complexes (C1-C10) were tested as catalysts for the oxidation reactions of phenol and styrene with H2O2, O2 and 3-chloroperbenzoic acid as oxidants. The complexes were found not to be active for the oxidation of both substrates (phenol and styrene) with 0% conversion, even when the reactions were left for 1 week. Analysis of the oxidation reactions were performed with GC and 1H NMR spectroscopy. Both analysis methods showed the presence of unreacted substrates at the end of the reaction period. Effects of concentration of pre-catalysts, substrates and oxidants, time and temperature of reaction and nature of solvent on catalytic activity were also investigated, however the conversions remained at 0% conversion.

O sistema cobalto(II)/tiocianato foi estudado em meio aquoso com o objetivo de se obter dados reais das constantes de formação globais dos complexos. Foram utilizados os métodos potenciométrico indireto e espectrofotométrico em meio de força iônica 2,0 M (NaCl04) a 25,0 &#177; O,l&#176;C. O sistema cádmio(II)/tiocianato foi utilizado como indicador no método potenciométrico indireto com o eletrodo de gota pendente de amálgama de cádmio. As seguintes constantes de equilíbrio foram obtidas para os complexos formados entre o cádmio e o tiocianato, a 25&#176;C e força iônica 2,0 M (NaCl04): &#946;1 = 21,51 &#177; 0,09 M-1, &#946;2 = 123,3 &#177; 1,2 M-2, &#946;3 = 129,9 &#177; 3,1 M-3 e &#946;4 = 173,5 &#177; 1,2 M-4. Valores do número médio de ligantes, &#241;, foram obtidos para várias concentrações de tiocianato, até 2,0 M, pela adição de Co(Cl04)2 (0,1 M) à solução contendo cádmio(II) e tiocianato. A integração da curva de formação e o tratamento das funções de Leden, pelo método dos mínimos quadrados desenvolvido, levou às seguintes constantes de formação globais para o sistema cobalto(II)/tiocianato: &#946;1 = 11,0 M-1, &#946;2 = 22,0 M-2, &#946;3 = 11,2 M-3 e &#946;4 = 1,63 M-4. Um estudo do sistema zinco(II)/tiocianato foi realizado com o objetivo de avaliar o método potenciométrico indireto, visto que esse sistema foi anteriormente estudado por um método direto confiável. A curva de formação obtida apresenta uma boa concordância até &#241; = 1. Depois desse ponto um desvio negativo é observado, com relação a curva obtida pelo método direto, devido à causas não bem compreendidas. Várias curvas de absortividade molar média, &#949; vs. concentração analítica de ligante foram obtidas em três comprimentos de onda (515, 590 e 615 nm) em tres concentraçoes de cobalto(II) diferentes: 0,01, 0,05 e 0,1 M. A análise com base no método das soluções correspondentes permitiu obter a curva &#241; vs. concentração de tiocianato livre, com as seguintes constantes de equilíbrio: &#946;1 = 6,9 M-1, &#946;2 = 28,9 M-2, &#946;3 = 12,1 M-3</SUP e &#946;>SUB>4 = 1,30 M-4. Ambos os métodos revelaram uma tendência à formaçao de duas espécies e uma diminuição acentuada na afinidade com o ligante para formar os complexos &#8204;Co(SCN)3&#8204;- e &#8204;Co(SCN)4&#8204;2-. Uma relação linear entre o número médio de ligantes e a absortividade molar média foi observado em 515 nm, o que permitiu obter o valor de &#949;4. Entretanto, em 590 e 615 nm, observou-se somente uma linearidade entre &#949; e o grau de formação calculado, &#945;4, correspondente a espécie &#8204;Co(SCN)4&#8204;2-, com uma intersecção muito próxima da origem. Isto é uma evidência que &#8204;Co(SCN)4&#8204;2- existe virtualmente como uma espécie tetraédrica com absortividade molar relativamente alta. Foram obtidos os seguintes valores de &#949;n individuais: a) &#949;o = 4,31, &#949;1 = 22,6, &#949;2 = 26,3, &#949;3 = 42,8 e &#949;4 = 50,3 cm-1.M-1 em 515 nm; b) &#949;o = 0,29, &#949;1 = 1,3, &#949;2 = 3,2, &#949;3 = 3,9 e &#949;4 = 215 cm-1.M-1 em 590 nm; c) &#949;o = 0,20, &#949;1 = 0,90, &#949;2 1,5, &#949;3 = 2,2 e &#949;4 = 294 cm-1.M-1 em 615 nm. Especulações com os dados sugerem que somente 1% das espécies tetraédricas estão em equilíbrio com as espécies octaédricas correspondentes com 1,2 e 3 tiocianatos coordenados. Com o emprego de um computador foi realizado um estudo efetuando uma simulação dos métooos espectrofotométricos da razão molar e das variações contínuas. As Simulações, com sistemas reais e hipotéticos, foram muito úteis para mostrar as conclusões ambíguas que podem ser obtidas, a partir de dados experimentais, para se estimar o número de espécies complexas. / The cobalt (II) /thiocyanate system in aqueous medium was studied with the purpose to obtain reliables data of overall stepwise formation constants to complexes. An indirect potentiometric method and a spectrophotometric one were used at 2,0 M ionic strength (NaCl04), at 25,0 &#177; O,l&#176;oC. The cadmium(II)/thiocyanate system was used as indicator in the indirect potentiometric method with hanging drop electrode with cadmium amalgam. The following equilibrium constants of the cadmium(II)/thiocyanate complexes were obtained at 25&#176;C and 2,O M ionic strenght (NaCl04: &#946;1 = 21.51 &#177; 0.09 M-1, &#946;2 = 123.3 &#177; 1,2 M-2, &#946;3 = 129.9 &#177; 3.1 M-3 and &#946;4 = 173.5 &#177; 1.2 M-4. Average 1igands number data, &#241;, were obtained for several thiocyanate concentrations, up to 2 M, by adding Co(Cl04)2 (0.1 M) to the working solution of cadmium (II)/thiocyanate. The integration of the formation curve and treatment of Leden\'s functions by a self developed least square method, lead to the following overall formation constants of the cobalt(II)/thiocyanate system: &#946;1 = 11.0 M-1, &#946;2 = 22.0 M-2, &#946;3 = 11.2 M-3 and &#946;4 = 1.63 M-4. A study of the zinc(II)/thiocyanate system was performed with the purpose to check the indirect potentiometric method inasmuch as this system was formerly studied by a re1iable direct method. The formation curve presented a good agreement until the average ligand number 1. After this point a negative desviation is observed with regard the direct method by not well understood causes. Severa1 curves of average molar absorbtivity, &#949; vs the analytical ligand concentration were obtained at three wave lengths (515, 590 and 615 nm) and three differents cobalt(II) cation concentrations: 0.01, 0.05 and 0.1 M. The analysis on base of corresponding solutions permited to obtain &#241; vs free thiocyanate ion concentrations, with the following equilibrium constants: &#946;1 = 6.9 M-1, &#946;2 = 28.9 M-2, &#946;3 = 12.1 M-3</SUP e &#946; = 1.30 M-4. Both methods revealed a tendency to form two species and a marked decrease in affinity with the 1igand to form &#8204;Co(SCN)3&#8204;<SUP- and &#8204;Co(SCN)4&#8204;2-. A linear relationship between calculated &#241; and &#949; was observed at 515 nm and this permited to obtain &#949;4. However, at 590 and 615 nm linearity of &#949; was achieved only for calculated formation degree, &#945;4, corresponding to specie &#8204;Co(SCN)4&#8204;2-, with an intercept very close to the origin. This is an evidence that the &#8204;CoO(SCN)4&#8204;2- exists virtually as tetrahedra1 specie with relative1y high molar absorbtivity. The fol1owing individual &#949;n were obtained: a) &#949;0 = 4.31, &#949;1 = 22.6, &#949;2 = 26.3, &#949;3 = 42.8 and &#949;4 = 50.3 cm-1.M-1 at 515 nm; b) &#949;0 = 0.29, &#949;1 = 1.3, &#949;2 = 3.2, &#949;3 3.9 and &#949;4 = 215 cm-1.M-1 at 590 nm; c) &#949;0 = 0.20, &#949;1 = 0.90, &#949;2 1.5, &#949;3 = 2.2 and &#949;4 = 294 cm-1 .m-1 at 615 nm. Speculations with the data suggest that on1y 1% of tetrahedral species are in equi1ibrium with the corresponding octahedral ones with 1, 2 and 3 thiocyanate 1igands. An extension of the study was a computer assisted simulation of the molar ratio spectrophotometric titration as well as the continuous variations method. This simulation study with real and hypothetica1 systems,was very usefu1l to show how ambiguous can be the conclusions, taken from experimental data,when the number of species are to be estimated.

The work reported here is a detailed study of the proton magnetic resonance in single crystals of CoCl₂∙6H₂O. This substance is paramagnetic at high temperatures and becomes antiferromagnetic at about 2.25°K. The proton resonance frequency is a measure of the total magnetic field at the positions of the protons, which is the vector sum of the applied magnetic field with the internal field produced by the surrounding magnetic ions. At room temperature a single line about 6 gauss wide is observed. This line splits into a number of components at liquid helium temperatures. The position and number of lines strongly depend on temperature and on the direction of the externally applied magnetic field. The maximum overall splitting at 4.2°K is about 150 gauss in a field of 5000 gauss. At, 2.1°K the maximum splitting observed is about 2500 gauss. From the resonance lines in the paramagnetic phase it was possible to calculate the direction cosines of one proton-proton vector. The resonance spectra in both phases were found to agree well with the theory predicting the positions of the resonance lines and their dependence on crystal orientation. The transition temperature T[subscript N] was measured as a function of applied field and crystal orientation using the proton resonance lines, since they are very sensitive functions of temperature near T[subscript N]. T [subscript N] is found to be a complicated function of the applied field and crystal orientation, which cannot be described by T[subscript N](H,) = T(0) - const. H², as predicted by the Weiss Molecular field theory. The transition takes place over a temperature region of about 10[power -2] °K, and effects due to short range order are observed just above T[subscript N]. The magnetic susceptibility in zero field was measured along the preferred axis of antiferromagnetic alignment. This, together with specific heat data from published literature, was used to show a mutual consistency between thermodynamic variables and T[subscript N] obtained by NMR. The sublattice magnetization in the antiferromagnetic phase was measured as a function of temperature. It is found to depend logarithmically on T[subscript N] - T, but is independent of applied field and crystal orientation. Further experiments are suggested, which would add greatly to the understanding of the magnetic behaviour of CoCl₂∙6H₂0. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

Thesis advisor: X. Peter Zhang / Chapter 1. Co(II)-Based Metalloradical Catalysis for Stereoselective Radical Cyclopropanation of Alkenes This Account summarizes our group’s recent efforts in developing metalloradical catalysis as a one-electron approach for catalytic radical cyclopropanation of alkenes with diazo compounds. Chapter 2. Asymmetric Radical Process for General Synthesis of Chiral Heteroaryl Cyclopropanes We have developed a Co(II)-based metalloradical system that is highly effective for asymmetric radical cyclopropanation of alkenes with in situ-generated heteroaryldiazomethanes. Through fine-tuning the cavity-like environments of newly developed D2-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to pyridyl and other heteroaryldiazomethanes for asymmetric cyclopropanation of a wide range of alkenes, providing general access to valuable chiral heteroaryl cyclopropanes in high yields with excellent diastereoselectivities and enantioselectivities. Chapter 3. Enantioselective Metalloradical 1,6-C–H Alkylation of In Situ-Generated Alkyldiazomethanes for Synthesis of Chiral Piperidines We have disclosed an effective Co(II)-based metalloradical system as a fundamentally different approach to harness the potential of 1,6-HAA radical process, enabling asymmetric 1,6-C–H alkylation of in situ-generated alkyldiazomethanes to construct chiral piperidines. Supported by an optimal D2-symmetric chiral amidoporphyrin ligand, the Co(II)-catalyzed alkylation system is capable of activating a wide array of alkyldiazomethanes containing C(sp3)–H bonds with varied steric and electronic properties, providing access to chiral piperidines in good to high yields with high enantioselectivities from readily accessible 4-aminobutanal derivatives. In addition to practical attributes, such as operational simplicity and mild conditions, the metalloradical system is highlighted by its tolerance to different functional groups as well as compatibility with heteroaryl units. Chapter 4. Design and Synthesis of A Novel D2-Symmetric Chiral Porphyrin for Co(II)-Based Metalloradical Catalysis A novel D2-symmetric chiral amidoporphyrin derived from chiral cyclopropanecarboxamide containing diphenyl units has been effectively constructed based on Co(II)-catalyzed asymmetric cyclopropanation of alkenes. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Ce travail porte sur la synthèse et la caractérisation de nouveaux pigments thermochromes irréversibles avec le cobalt divalent pour chromophore principal en vue de les intégrer à une peinture thermosensible commerciale.Le travail a été réalisé en suivant trois phases. La première phase a consisté en l'identification de matrices thermosensibles présentant des évolutions structurales irréversibles en température dues à des transitions de phase du premier ordre ou des dégradations chimiques. Puis la synthèse de ces matrices a été effectuée par des voies compatibles avec les méthodes d'élaboration industrielle et permettant un dopage au cobalt. Enfin la troisième et dernière étape est l'étude in-situ et ex-situ des propriétés thermosensibles des pigments synthétisés à l'aide de techniques comme la diffraction des rayons X et des neutrons en température, l'analyse thermogravimétrique et la réflexion diffuse en température.À l'issue de ce travail de recherche, les solutions les plus efficaces ont été synthétisées à l'échelle industrielle puis intégrées à une peinture commerciale en phase aqueuse.