Chapter 25 Complexes

Thompson, Larry C.

doi:10.1016/s0168-1273(79)03008-7

Cited by 18 publications

(3 citation statements)

References 338 publications

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“…1c), where Y 3+ resided on the octahedral plane. Such a coordination environment could minimize the inter-ligand repulsions (Thompson, 1979) and resembles the structure predicted for the Y 3+ aqua ion (Díaz-Moreno et al, 2000;Liu et al, 2012). The average Y 3+ -O distance was 2.41 Å, which was in good agreement with the values reported for the eight-fold coordinated Y 3+ in previous studies (i.e., 2.35 Å~2.46 Å) (Matsubara et al, 1990;Díaz-Moreno et al, 2000;Ikeda et al, 2004;Liu et al, 2012).…”

Section: Complex Structuressupporting

confidence: 88%

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

Zhang,

Liu,

et al. 2024

American Mineralogist

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Regolith-hosted rare earth elements (REEs) deposits received great attention due to the increasing incorporation of REEs in modern technologies. In lateritic Sc deposits and ion-adsorption deposits (IADs), Sc behaves quite differently from other REEs: REEs adsorb as outer-sphere complexes on clay surface in IADs while Sc could enter the lattice of clay minerals in lateritic Sc deposits. The unique behavior of Sc has not been well understood yet. Here, by using first-principles molecular dynamics techniques, we show that the complexation mechanisms of Y 3+ and Sc 3+ on clay edge surfaces are distinctly different. Y 3+ preferentially adsorbs on Al(OH) 2 SiO site with its coordination water protonated. Sc 3+ is found to behave similarly to other first-row transition metals (e.g. Ni 2+ ) due to its smaller ionic radius and prefers adsorbing on the vacancy site, from where Sc 3+ can be readily incorporated in the clay lattice. The H 2 O ligands of Sc 3+ get deprotonated upon complexation, providing new binding sites for further enrichment of Sc 3+ . These processes prevent Sc 3+ from being leached during weathering and lead to the formation of Sc-rich clay minerals found in lateritic deposits. Based on these results, it is revealed that the small ionic radius and high affinity to enter the vacancy on edge surfaces make Sc compatible with clay minerals and are the origin of its unique geochemical behavior.

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Section: Complex Structuressupporting

confidence: 88%

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

Zhang,

Liu,

et al. 2024

American Mineralogist

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“…The literature shows only few studies about complexes that have capability of act as a molecular light converter mechanism (DMCL). These kinds of complexes can have applications on luminescent markers, lasers, sensors for bioinorganic applications, solar cell, among others [1][2][3][4][5][6][7][8][9][10]. There have been also discussions on the synthesis, luminescence quantum yields, spectroscopic characteristics, structure, among others properties of these complexes, including the possibility to produce thin films [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Thermal Characterization of Luminescent Powers of Terbium (III) with Mixed Ligands

Morais

Lopes

Souza

et al. 2005

MSF

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This work deals with the synthesis and thermal decomposition of complexes of general formula: Ln(ß-dik)3L (where Ln=Tb+3, ß-dik=4,4,4-trifluoro-1-phenyl-1,3- butanedione(btfa) and L=1,10-fenantroline(phen) or 2,2-bipiridine(bipy). The powders were characterized by melting point, FTIR spectroscopy, UV-visible, elemental analysis, scanning differential calorimeter(DSC) and thermogravimetry(TG). The TG/DSC curves were obtained simultaneously in a system DSC-TGA, under nitrogen atmosphere. The experimental conditions were: 0.83 ml.s-1 carrier gas flow, 2.0±0.5 mg samples and 10°C.min-1 heating rate. The CHN elemental analysis of the Tb(btfa)3bipy and Tb(btfa)3phen complexes, are in good agreement with the expected values. The IR spectra evinced that the metal ion is coordinated to the ligands via C=O and C-N groups. The TG/DTG/DSC curves of the complexes show that they decompose before melting. The profiles of the thermal decomposition of the Tb(btfa)3phen and Tb(btfa)3bipy showed six and five decomposition stages, respectively. Our data suggests that the thermal stability of the complexes under investigation followed the order: Tb(btfa)3phen < Tb(btfa)3bipy.

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“…The literature shows only few studies about complexes that have the capable of act as a molecular light converter mechanism (DMCL), these kind of complexes which can have applications on luminescent markers, lasers, sensors for bioinorganic applications, solar cell, among others [2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Thermal Decomposition of Samarium Complexes

Morais

Lopes

Souza³

et al. 2004

JMNM

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This work deals with the synthesis, characterization and kinetics of the thermal decomposition of complexes of general formula: Ln(ß-dik) 3 L (where Ln = Sm +3 , ß-dik = 4,4,4-trifluoro-1-phenyl-1,3butanedione (btfa) and L = 1,10-fenantroline (phen) or 2,2-bipiridine (bipy). The complexes in the power form were synthesized from the direct reaction of SmCl 3 with ß-diketone and the ligands. The synthesized complexes presented a weak red luminescence. The powders were characterized by melting point, FTIR spectroscopy, UV-visible absorption spectrophotometry, elemental analysis, scanning differential calorimeter (DSC) and thermogravimetry (TG). The kinetic parameters were obtained from the thermogravimetric data by the non-isothermal integral methods proposed by Coats-Redfern and Madhusudanan, as well as by approximation methods proposed by Horowitz-Metzger and Van Krevelen. The kinetic parameters in the dynamic heating method were determined with the Coats-Redfern equation, using the thermal decomposition model with the data obtained in the isothermal heating experiments. The IR spectra evinced that the metal ion is coordinated to the ß-diketone via C=O and is coordinated to the ligand second via C-N groups. The TG/DTG/DSC curves of the complexes show that they decompose before melting. The profiles of the thermal decomposition of the Sm(btfa) 3 phen and Sm(btfa) 3 bipy showed three and four decomposition stages, respectively. Our data suggests that the thermal stability of the complexes under investigation followed the order: Sm(btfa) 3 phen > Sm(btfa) 3 bipy. The kinetic models that best described the thermal decomposition reaction for the Sm(btfa) 3 bipy was R2, for the Sm(btfa) 3 phen was F1.

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Chapter 25 Complexes

Cited by 18 publications

References 338 publications

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

Synthesis and Thermal Characterization of Luminescent Powers of Terbium (III) with Mixed Ligands

Synthesis, Characterization and Thermal Decomposition of Samarium Complexes

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