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Étude par spectroscopies moléculaires de la complexation de l'aluminium (III) par l'acide caféique : compétition avec les substances humiquesCaudron, Alexandra 06 December 2004 (has links) (PDF)
Les substances humiques sont des macromolécules possédant de nombreux sites pouvant chélater les métaux. De petites molécules organiques de faibles masses molaires leur sont associées. Bien que minoritaires, elles sont plus mobiles dans les sols et constituent un vecteur essentiel dans le transport des métaux. Les spectroscopies UV - visible et de fluorescence ont permis de déterminer la composition et la stabilité des complexes formés entre l'acide caféique et Al (III) en milieu aqueux à pH 5 et 6,5. On constate qu'une augmentation de pH favorise les complexes de haute stoechiométrie. La complexation d'Al (III) par l'acide humique et la compétition entre cette macromolécule et l'acide caféique ont également été étudiées. Lors de la complexation du métal sur l'acide humique, l'extinction de la fluorescence a permis de déterminer la constante de Stern Volmer. Une interaction entre les deux acides ainsi qu'un partage d'Al (III) pour arriver à un état quasi équilibré ont été observés.
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Synthesis, Structure and Reactivity of Bismuth(III) and Aluminum(III) Complexes Supported by Nitrogen Donor LigandsNekoueishahraki, Bijan 21 January 2010 (has links)
No description available.
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Apport des spectroscopies moléculaires à l'étude des mécanismes de fixation d'ions métalliques polluants par les substances humiques.<br />Complexation de Al(III), Pb(II) et Zn(II) par des systèmes modèles.Dangleterre, Laëtitia 12 December 2007 (has links) (PDF)
Les substances humiques (SH) sont issues de la dégradation de résidus organiques et représentent la partie la plus importante de la matière organique des systèmes naturels. Les SH sont capables de piéger de nombreux polluants comme les métaux lourds et jouent donc un rôle majeur dans la rétention des ions métalliques. Leurs propriétés complexantes sont dues principalement à certaines fonctions récurrentes : les groupements carboxyliques et phénoliques.<br />Dans une 1ère partie, l'étude de la complexation de molécules modèles possédant des sites similaires à ceux rencontrés dans les biopolymères naturels a permis d'évaluer les capacités complexantes des fonctions les plus répandues (catéchol, hydroxy-carbonyle et acide carboxylique). L'association de techniques spectroscopiques et de calculs de chimie quantique a permis d'établir un classement des pouvoirs chélatants des composés mono-sites vis-à-vis des ions métalliques Al(III), Pb(II) et Zn(II)), et a montré que ce type de classement est conservé lorsque les sites sont en compétition au sein d'une même structure.<br />Dans une 2nde partie, l'examen par fluorescence synchrone de la complexation des 3 métaux polluants par un acide humique standard (AH) a mis en évidence des comportements différents pour chacun d'eux, reflétant des mécanismes de fixation distincts et une spécificité des interactions métallo-humiques. Nous avons ainsi pu établir un classement du pouvoir complexant de AH vis à vis des 3 cations, en accord avec celui obtenu pour les modèles. Enfin, la compétition entre AH et deux molécules organiques de faible poids moléculaires a montré que les pourcentages de polluants extraits de l'acide humique sont faibles et que celui-ci reste un véritable « réservoir toxique » au sein des milieux naturels.
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[en] STUDY OF BINARY COMPLEXES OF ALUMINUM(III) WITH SULFUR AMINO ACIDS AND PHOSPHATE LIGANDS / [pt] ESTUDO DE COMPLEXOS BINÁRIOS DE ALUMÍNIO(III) COM AMINOÁCIDOS SULFURADOS E LIGANTES FOSFATADOSTHAIS VALERIA BARREIROS ALVES 30 August 2010 (has links)
[pt] O estudo de complexos binários de Al(III) com aminoácidos sulfurados (metionina, cisteína, homocisteína e penicilamina) e ligantes fosfatados (adenosina 5’-trifosfato e fosfocreatina) foi feito em solução aquosa por meio de titulações potenciométricas, de RMN de (13)C e (27)Al, de espectroscopia Raman, de modelagem molecular e de cálculos teóricos do espectro vibracional através do procedimento de cálculo DFT: B3LYP/6-311G. As titulações potenciométricas e o RMN de (13)C e (27)Al foram obtidos apenas para os complexos contendo aminoácidos. Através da potenciometria determinaram-se as constantes de estabilidade dos complexos binários de Al(III) com os aminoácidos e suas curvas de distribuição de espécies. Ao se analisar os valores de constantes obtidos percebe-se que o complexo Al-Penicilamina apresenta um valor maior que os demais complexos formados, indicando um comportamento distinto. Propôs-se que a penicilamina atuaria como tridentada através dos átomos de oxigênio do carboxilato, de nitrogênio da amina e de enxofre da sulfidrila, enquanto os outros atuariam como bidentados coordenando-se através dos átomos de oxigênio do carboxilato e de nitrogênio da amina. As distribuições de espécies em função do pH mostraram que no pH fisiológico há a predominância das espécies hidrolisadas do metal e do complexo. Os espetros de RMN de (13)C e de Raman e os cálculos teóricos confirmaram a possibilidade dos sítios coordenativos propostos para os aminoácidos. O RMN de (27)Al e a modelagem molecular mostraram que a geometria adotada pelo centro metálico é a octaédrica distorcida. Para os ligantes fosfatados, a espectroscopia Raman, a modelagem molecular e os cálculos teóricos indicaram que no complexo com a adenosina 5’-trifosfato a geometria deve ser octaédrica distorcida, com o ligante comportando-se como bidentado através dos átomos de oxigênio dos fosfatos terminais beta e gamma. Já no complexo com
a fosfocreatina, a geometria deve ser tetraédrica distorcida, com o ligante comportando-se como tridentado coordenando-se pelos átomos de oxigênio do grupamento fosfato, de oxigênio do grupamento carboxilato e de nitrogênio do grupamento guanidino. Estes resultados mostram a variedade do comportamento dos ligantes na complexação com o Al(III). / [en] The study of binary complexes of Al(III) with sulfur amino acids (methionine, cysteine, homocysteine and penicillamine) and phosphate ligands (adenosine 5 - triphosphate and phosphocreatine) was done in aqueous solution applying potentiometric titrations, (13)C and (27)Al NMR, Raman spectroscopy, molecular modeling and DFT: B3LYP/6-311G theoretical calculations of the vibrational spectra. The potentiometric titrations and (13)C and (27)Al NMR were performed only for the complexes with amino acids. The potentiometry was used to determine the stability constants of the Al(III)-amino acid binary complexes and the distribution graphs of their species. The comparison between the values obtained for the constants revealed a distinct behavior for the Al-Penicillamine complex, with higher stability constants than the other complexes. It is suggested that penicillamine might act as a tridentate ligand through the oxygen of the carboxylate, the nitrogen of the amine and the sulfur of the sulfhydryl, while others act as bidentate ligands coordinating through the oxygen of the carboxylate and the nitrogen of the amine. The graphs of the species distribution in function of pH showed that in biological pH there is a predominance of hydrolyzed species of the metal and the complex. Raman and (13)C NMR spectroscopy associated with theoretical calculations confirmed the coordination sites proposed for the amino acids. (27)Al NMR and molecular modeling showed that the geometry adopted by the metal center is distorted octahedral. For phosphate ligands, Raman spectroscopy, molecular modeling and theoretical calculations indicated that the geometry of adenosine 5 - triphosphate complex can be distorted octahedral with the ligand behaving as bidentate through one oxygen atom of each terminal (beta) and (gamma) phosphates. Nevertheless, for the phosphocreatine complex the geometry seems to be a distorted tetrahedron with the ligand behaving as a tridentate, one coordinating through one of the oxygens in the phosphate, the oxygen in the carboxylate and the nitrogen in the guanidine group. These results bring to light the multiplicity of ligand behaviors in the complexation with Al(III).
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Modeling of glyphosate and metal-glyphosate speciation in solution and at solution-mineral interfacesJonsson, Caroline January 2007 (has links)
Glyphosate (N-(phosphonomethyl)glycine, PMG, H3L) is a widely used organophosphorous herbicide. It interacts with metal ions and mineral surfaces, which may affect its mobility, degradation and bioavailability in the environment. However, these interactions are far from fully understood. This thesis is a summary of five papers discussing the complexation of PMG with metal ions in aqueous solution and the adsorption of PMG and/or Cd(II) on different mineral surfaces. The complexation of PMG with the metals Cd(II) or Al(III) in aqueous solution was investigated with macroscopic and molecular scale techniques. Potentiometric titration data were combined with EXAFS, ATR-FTIR and NMR spectroscopic data to generate solution equilibrium models. In the PMG-Cd(II) system, only mononuclear complexes were formed, while both mono and binuclear complexes were observed in the PMG-Al(III) system. EXAFS, ATR-FTIR, and XPS measurements showed that PMG adsorbs to the surfaces of goethite (α-FeOOH), aged γ-alumina (γ-Al2O3) and manganite (γ-MnOOH) through one oxygen of its phosphonate group to singly-coordinated surface sites. Surface complexation models consistent with these spectroscopic results were fit to adsorption data using the 1pK reaction formalism. Electrostatic effects were accounted using either the Extended Constant Capacitance Model (ECCM) or the Basic Stern Model (BSM), and the charge of the surface complexes was distributed over the different planes. The formation of the surface complexes was described according to the following reactions: ≡MeOH(0.5-) + H3L <=> ≡MeHL(1.5-) + H2O + H+ ≡MeOH(0.5-) + H3L <=> ≡MeL(2.5-) + H2O + 2H+ The coadsorption of PMG and Cd(II) on the surfaces of goethite and manganite results in the formation of ternary mineral-PMG-Cd(II) surface complexes, as suggested from EXAFS results. Previous EXAFS measurements have also established the coordination geometries for the binary goethite-Cd(II) and manganite-Cd(II) surface complexes. In addition to the surface reactions in the binary mineral-Cd(II) and mineral-PMG systems, a single ternary complex with the stoichiometry ≡MeLCd(OH)(1.5-) was sufficient to explain coadsorption data: ≡MeOH(0.5-) + H3L + Cd2+ <=> ≡MeLCd(OH)(1.5-) + 3H+ It was concluded that the affinity of PMG for the three mineral systems decreases within the series: goethite > aged γ-Al2O3 > manganite. The formation of the ternary surface complex is more significant on goethite surfaces than on manganite surfaces.
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Atomic layer deposition of Al²O³ on NF³-pre-treated grapheneJunige, Marcel, Oddoy, Tim, Yakimovab, Rositsa, Darakchievab, Vanya, Wenger, Christian, Lupinac, Grzegorz, Kitzmann, Julia, Albert, Matthias, Bartha, Johann W. 06 September 2019 (has links)
Graphene has been considered for a variety of applications including novel nanoelectronic device concepts. However, the deposition of ultra-thin high-k dielectrics on top of graphene has still been challenging due to graphene's lack of dangling bonds. The formation of large islands and leaky films has been observed resulting from a much delayed growth initiation. In order to address this issue, we tested a pre-treatment with NF³ instead of XeF² on CVD graphene as well as epitaxial graphene monolayers prior to the Atomic Layer Deposition (ALD) of Al²O³. All experiments were conducted in vacuo; i. e. the pristine graphene samples were exposed to NF³ in the same reactor immediately before applying 30 (TMA - H²O) ALD cycles and the samples were transferred between the ALD reactor and a surface analysis unit under high vacuum conditions. The ALD growth initiation was observed by in-situ real-time Spectroscopic Ellipsometry (irtSE) with a sampling rate above 1 Hz. The total amount of Al²O³ material deposited by the applied 30 ALD cycles was cross-checked by in-vacuo X-ray Photoelectron Spectroscopy (XPS). The Al²O³ morphology was determined by Atomic Force Microscopy (AFM). The presence of graphene and its defect status was examined by in-vacuo XPS and Raman Spectroscopy before and after the coating procedure, respectively.
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[en] STUDY OF CU(II) E AL(III) COMPLEXES WITH PHOSPHOCREATINE (PCR), ADENOSINE 5´ TRIPHOSPHATE (ATP) AND SOME AMINO ACIDS / [pt] ESTUDO DE COMPLEXOS DE COBRE(II) E ALUMÍNIO(III) COM A FOSFOCREATINA (PCR) , O ADENOSINA 5 TRIFOSFATO (ATP) E ALGUNS AMINOÁCIDOSANDREA DE MORAES SILVA 23 December 2003 (has links)
[pt] Foram estudados os sistemas binários de complexos de Cu(II)
e Al(III) formados com a fosfocreatina (PCr), o adenosina
5 trifosfato (ATP), a glicina (Gli), a serina (Ser), a
tirosina (Tir) e a treonina (Tre) e os sistemas ternários
(MLaLb) onde La foi o ATP ou a PCr e o Lb foi um dos quatro
aminoácidos. O estudo foi realizado em solução aquosa
através da técnica potenciométrica e das técnicas
espectroscópicas ultravioleta-visível, Raman, RMN e RPE. As
constantes de estabilidade foram determinadas pela
potenciometria. Considerando L como um dos aminoácidos, foi
observado que todos os complexos CuL são mais estáveis que
os complexos AlL correspondentes. Este fato pode ser
explicado pela grande afinidade entre o Cu(II) e o grupo
amino. Por outro lado, os complexos binários formados com
os fosfatos (ATP ou PCr) e o Al(III) apresentaram valores
maiores de log b, do que os complexos de Cu(II)
correspondentes. Este fato pode ser justificado pela grande
afinidade do Al(III) com os átomos de oxigênio dos
fosfatos. Pela mesma razão, todos os complexos ternários de
Al(III) apresentaram-se mais estáveis do que os de Cu(II)
correlacionados. Os valores das constantes de estabilidade
dos complexos poderiam ser divididos em dois grupos: o dos
complexos binários e o dos complexos ternários, com valores
mais altos. Para os complexos de cobre, este comportamento
foi confirmado pelo decréscimo dos valores dos comprimentos
de onda máximos no espectro de absorção e no aumento no
parâmetro Ao à medida que as constantes de estabilidade
aumentaram. Os comprimentos de onda máximos dos complexos
CuATPLb foram maiores que os dos complexos CuPCrLb, o que
indica que o ATP deve coordenar com o Cu(II) através de dois
átomos de oxigênio dos fosfatos e a PCr deve coordenar, nos
complexos CuPCrLb, através de um átomo de oxigênio e um
átomo de nitrogênio. O valor de D log K [log bCuLaLb) -
(log bCuLa + log bCuLb)] mostrou que, quando La foi o ATP,
os complexos ternários de Cu(II) e de Al(III) foram menos
estáveis do que os seus binários respectivos, sugerindo não
existir qualquer tipo de interação entre os ligantes.
Aplicando o mesmo cálculo para os sistemas de Cu(II) onde
La foi a PCr e Lb a serina ou a tirosina, o valor de D log
K foi maior do que zero, indicando que estes ligantes
favoreceram a formação de complexos ternários mais
estáveis, o que pode ser justificado pela interação do
grupo OH destes aminoácidos com o grupo livre (carboxilato
ou fosfato) da PCr. Para todos os complexos AlPCrLb, onde
Lb foi um dos quatro aminoácidos em estudo, os valores das
constantes de estabilidade dos ternários foram maiores do
que a soma das constantes dos seus binários. Este fato, não
pode ser justificado pela interação do grupo OH dos
aminoácidos com a PCr, já que a glicina não apresenta este
grupo. Provavelmente, a interação ocorre através do oxigênio
não coordenado do fosfato da PCr e do hidrogênio do grupo
amino do aminoácido. O estudo do sistema Al(III):Ser pela
espectroscopia Raman, mostrou que o complexo [Al(Ser)(H2O)4]
2+ é a espécie predominante e a serina atua como ligante
bidentado (átomo de N do grupo amino e átomo de oxigênio
do carboxilato). Este deve ser o comportamento de todos os
complexos de Al(III) com os aminoácidos. / [en] The binary systems of Cu(II) and Al(III) complexes with
adenosine triphosphate (ATP), phosphocreatine (PCr),
glycine (gly), serine (Ser), tyrosine (Tyr) and threonine
(Thr) and the ternary systems where La was ATP or PCr and
Lb was one of the four amino acids, were investigated. The
study was performed in aqueous solution using
potentiometry, ultraviolet visible, Raman, NMR and EPR
spectroscopies. The stability constants of the complexes
were determined by potentiometry. When L is one of the
amino acids, it can be observed that all the CuL complexes
are more stable than the correspondent AlL complexes. This
can be explained by the greater affinity between the Cu(II)
and the amino group. On the other hand, the binary
complexes formed by one of the phosphates (ATP or PCr) and
Al(III) have greater values of log b than the correspondent
complexes of Cu(II). This can be explained by the greater
affinity of Al(III) ion to the oxygen atoms of the
phosphates. For this same reason, all the ternary complexes
of Al(III) are more stable than the Cu(II) ones. The values
of the stability constants of the complexes could be
divided in two groups: one of the binary complexes and the
second of the ternary complexes, with higher values. For
the Cu(II) complexes this behavior was confirmed by the
decreasing of the maximum wavelength in the absorption
spectra and the increasing of the A0 parameter as the
stability constants increase. The maximum wavelength of the
CuATPLb complexes were greater than those of the CuPCrLb
complexes and this means that ATP must be bound to Cu(II)
ion through two oxygen atoms of the phosphates, whereas in
CuPCrLb complexes, PCr is bound through one oxygen atom and
one nitrogen atom and the amino acid is the same. Values of
DlogK (logbCuLaLb - (logbCuLa+ logbCuLb) showed that when
La was ATP, the ternary complexes of Cu(II) and Al(III)
were less stable than the binary ones suggesting that it
does not occur any interaction between the ligands in the
ternary complexes. When La was PCr, the stability constants
of the Cu(II) complexes where Lb was Ser or Tyr were
greater. This showed that these ligands favored more stable
ternary complexes and this must be due to the interaction
of the OH group of these amino acids and the phosphate or
carboxylate of PCr. For the AlPCrLb complexes, when Lb was
one of the four amino acids, the stability constants of the
complexes were greater. This shows that in this case, the
interaction cannot be between the OH groups of the amino
acid since glycine does not have any OH group. Probably the
interaction occur through the non coordinated oxygen of the
phosphate of PCr and the hydrogen of the amino group of the
aminoacid. The study of the sistem Al(III):Ser by Raman
spectroscopy, showed that [Al(Ser)(H2O)4]2+is the
predominant species and that Ser acts as bidentate ligand
(N atom of the amino group and O atom of the carboxylate).
This must be the behavior of all the complexes of Al(III)
and the amino acids.
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[pt] ESTUDO DE COMPLEXOS BINÁRIOS E TERNÁRIOS DE ALUMÍNIO(III) COM AMINOÁCIDOS E LIGANTES FOSFATADOS / [en] STUDY OF BINARY AND TERNARY COMPLEXES OF ALUMINUM(III) WITH AMINO ACIDS AND PHOSPHATE LIGANDS07 December 2021 (has links)
[pt] Neste trabalho investigou-se a complexação entre o íon alumínio e ligantes
como a adenosina 5-trifosfato, a fosfocreatina e aminoácidos pelas técnicas de
titulação potenciométrica, espectroscopia Raman e cálculos teóricos em solução
aquosa, para conhecer as características dos compostos formados. O estudo visou
subsidiar o entendimento dos mecanismos de absorção e biodisponibilidade do
alumínio. Tal compreensão poderia auxiliar as pesquisas clínicas relacionadas à
prevenção e ao tratamento de doenças neurodegenerativas. O alumínio está
presente na água e em vegetais, carnes, laticínios e aditivos alimentares. Soluções
de nutrição parenteral, fórmulas infantis e medicamentos podem conter alumínio
também. Em fluidos corporais, os nucleosídeos di e trifosfatos e os aminoácidos
são bons ligantes para o íon alumínio. Biomoléculas da baixa massa molecular
formam complexos que aumentam o pH de precipitação do íon e sua absorção
gastrointestinal. Esta pesquisa analisou seis complexos formados com o íon
alumínio em solução aquosa. Os compostos binários, tetraaquaadenosina5-
trifosfato alumínio(III) e aquafosfocreatina alumínio(III), foram estudados por
espectroscopia Raman e cálculos quantomecânicos. As análises dos complexos
ternários, adenosina5-trifosfatodiaquacisteína aluminato(III),
adenosina5-trifosfatotriaquametionina aluminato(III), aquacisteínafosfocreatina
aluminato(III) e aquafosfocreatinametionina aluminato(III), envolveram ainda a
potenciometria. Os cálculos computacionais usaram a teoria do funcional de
densidade com o funcional híbrido (B3LYP), a base 6-311++G(d,p) e
consideraram o efeito do solvente água pelo modelo de contínuo polarizável. Eles
englobaram a obtenção de parâmetros geométricos, o cálculo do espectro Raman e a descrição da superfície de contorno do potencial eletrostático e do mapa do
potencial eletrostático. No que tange os complexos binários, as análises
ratificaram o comportamento bidentado da adenosina 5-trifosfato por um
oxigênio do fosfato alfa e um oxigênio do fosfato beta. No complexo formado
entre o íon alumínio e a fosfocreatina, o ligante atua como tridentado por um
oxigênio do fosfato, um oxigênio do carboxilato e um nitrogênio. Os mapas do
potencial eletrostático apontaram a presença de regiões neutras ao redor dos
átomos e como as cargas totais das moléculas eram zero, elas devem ser solúveis
em lipídios. Nos complexos ternários, os modos de coordenação da adenosina
5-trifosfato e da fosfocreatina adotados nos compostos binários se mantêm. A
cisteína se comporta como bidentada por um oxigênio do carboxilato e um
nitrogênio. Na espécie adenosina5-trifosfatotriaquametionina aluminato(III), a
metionina atua como monodentada pelo oxigênio do carboxilato. A despeito da
carga total negativa dos complexos, as moléculas não apresentam um potencial
eletrostático tão negativo e possuem uma estrutura estável. Quatro outros sistemas
ternários, o alumínio(III):adenosina 5-trifosfato:homocisteína, o
alumínio(III):fosfocreatina:homocisteína, o alumínio(III):adenosina 5-trifosfato:
penicilamina e o alumínio(III):fosfocreatina:penicilamina, foram examinados
apenas por potenciometria. Ela mostrou a ocorrência de várias reações de
complexação e diversos complexos são formados de acordo com o pH.
Comumente, o alumínio(III) se torna insolúvel entre pH 2,5 a 5,5. Todavia, isso
não ocorreu. Os resultados exibiram a variedade do comportamento dos ligantes
na complexação com o íon alumínio. As pesquisas sugerem como podem estar
formados alguns complexos nos organismos vivos. / [en] This thesis investigated complexation reactions between aluminum(III) and
ligands such as adenosine 5-triphosphate, phosphocreatine and amino acids by
potentiometry, Raman spectroscopy and theoretical calculations in aqueous
solution, with the aim to know the proprieties of formed complexes. The study
was important to improve the knowledge about absorption mechanisms and
bioavailability of aluminum(III). This learning could help clinical researches
about prevention and treatment of neurodegenerative diseases. Aluminum is
present in water and in vegetables, animal products and food additives. Parenteral
nutrition solutions, infant formulas and medications also contain aluminum. In
fluids, di- and triphosphate nucleosides and amino acids are good ligands for
aluminum(III). Low molecular mass biomolecules form complexes which increase
the pH of precipitation of the metal ion and its gastrointestinal absorption. This
study analyzed six complexes with aluminum ions in aqueous solution. The binary
compounds tetraaquaadenosine 5-triphosphate aluminum(III) and
aquaphosphocreatine aluminum(III) were studied by Raman spectroscopy and
quantum mechanical calculations. The analysis of the ternary complexes
adenosine5-triphosphatediaquacysteine aluminate(III), adenosine5’-
triphosphatetriaquamethionine aluminate(III), aquacysteinephosphocreatine
aluminate(III) and aquaphosphocreatinemethionine aluminate(III) also involved
potentiometry. Computational calculations used density functional theory with the
hybrid functional B3LYP and the 6-311++G(d,p) basis set regarding water solvent
effects by the polarizable continuum model. They included the assessment of
geometrical parameters, Raman spectrum calculations and the description of
electrostatic potential contour surfaces and mapped electrostatic potential.
Regarding the binary complexes, analyses confirmed the bidentate behavior of
adenosine 5-triphosphate through one oxygen of the phosphate beta and one
oxygen of the phosphate gamma. In the complex that formed between
aluminum(III) and phosphocreatine, the ligand behaved as a tridentate,
coordinated through one oxygen in the phosphate, one oxygen in the carboxylate
and one nitrogen in the guanidine group. The electrostatic potential maps pointed
out the presence of neutral regions around atoms and, as the total charge of
these molecules was zero, they should be soluble in lipids. In the ternary
complexes, the coordination modes of adenosine 5-triphosphate and
phosphocreatine adopted in binary compounds remained. Cysteine behaved as a
bidentate ligand through one carboxylate oxygen and nitrogen. In the adenosine5-
triphosphatetriaquamethionine aluminate(III) species, methionine acted as a
monodentate ligand via the carboxylate oxygen. Despite the negative net charge
of the complexes, they did not exhibit a negative electrostatic potential and had
stable structures. The four other ternary systems, aluminum(III):adenosine 5-
triphosphate:homocysteine, aluminum(III):phosphocreatine:homocysteine,
aluminum(III):adenosine 5-triphosphate:penicillamine and aluminum(III):
phosphocreatine:penicillamine, were examined only by potentiometry. The results
showed the occurrence of various complexation reactions, and several complexes
are formed depending on the pH. Commonly, aluminum(III) becomes insoluble
between pH 2.5 to 5.5. However, this did not occur. These results bring to light
the multiplicity of ligand behaviors in complexation with aluminum(III). This
research also suggests that some complexes may be formed in living organisms.
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