Ciência Cognitiva, Sistêmica e Filosofia Bergsoniana: uma reflexão acerca da vida em sua capacidade organizativa

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Probing Structural Changes in a Phosphonate-based Metal–Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Probing Structural Changes in a Phosphonate-based Metal–Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Probing Structural Changes in a Phosphonate-based Metal–Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Probing Structural Changes in a Phosphonate-based Metal–Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Probing Structural Changes in a Phosphonate-based Metal–Organic Framework Exhibiting Reversible Dehydration

A one-step hydrothermal synthesis with small amines and 1,3,5-benzenetriphosphonic acid was used to prepare single crystals of isostructural anionic metal–organic frameworks (MOF): Zn_2.5(H)_0.4–_0.5(C₆H₃O₉P₃)­(H₂O)_1.9–2(NH₄)_0.5–0.6 and Zn_2.5(H)_0.75(C₆H₃O₉P₃)­(H₂O)₂(CH₃NH₃)_0.25. The ammonium ions are exchangeable with lithium ions. The MOF exhibits reversible dehydration, and the process was studied by two complementary methods: solid state NMR and in situ X-ray diffraction. These experiments revealed three different phases. The crystal structures of all phases have been determined, showing loss in volume of the structure due to a phase change. The ammonium ions remain in the structure and are forced to occupy the larger pores due to a reduction in free volume. The change in positions of the guest molecules in the framework has an effect on the potential conductivity properties of the materials. Changes in framework and guest molecules due to negative expansion have an effect on other physical and chemical properties and need to be explored

Soft-Chemical Synthesis, Structure Evolution, and Insulator-to-Metal Transition in Pyrochlore-like λ‑RhO₂

λ-RhO2, a prototype 4d transition metal oxide, has been prepared by the oxidative delithiation of spinel LiRh2O4 using ceric ammonium nitrate. Average-structure studies of this RhO2 polytype, including synchrotron powder X-ray diffraction and electron diffraction, indicate the room-temperature structure to be tetragonal, in space group I41/amd, with a first-order structural transition to cubic Fd3̅m at T = 345 K on warming. Synchrotron X-ray pair distribution function analysis and 7Li solid-state nuclear magnetic resonance measurements suggest that the room-temperature structure displays local Rh–Rh bonding. The formation of these local dimers appears to be associated with a metal-to-insulator transition with a nonmagnetic ground state, as also supported by density functional theory-based electronic structure calculations. This contribution demonstrates the power of soft chemistry to kinetically stabilize a simple binary oxide compound

Structural Evolution of Reversible Mg Insertion into a Bilayer Structure of V₂O₅·<i>n</i>H₂O Xerogel Material

Functional multivalent intercalation cathodes represent one of the largest hurdles in the development of Mg batteries. While there are many reports of Mg cathodes, many times the evidence of intercalation chemistry is only circumstantial. In this work, direct evidence of Mg intercalation into a bilayer structure of V₂O₅·<i>n</i>H₂O xerogel is confirmed, and the nature of the Mg intercalated species is reported. The interlayer spacing of V₂O₅·<i>n</i>H₂O contracts upon Mg intercalation and expands for Mg deintercalation due to the strong electrostatic interaction between the divalent cation and the cathode. A combination of NMR, pair distribution function (PDF) analysis, and X-ray absorption near edge spectroscopy (XANES) confirmed reversible Mg insertion into the V₂O₅·<i>n</i>H₂O material, and structural evolution of Mg intercalation leads to the formation of multiple new phases. Structures of V₂O₅·<i>n</i>H₂O with Mg intercalation were further supported by the first principle simulations. A solvent cointercalated Mg in V₂O₅·<i>n</i>H₂O is observed for the first time, and the ²⁵Mg magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy was used to elucidate the structure obtained upon electrochemical cycling. Specifically, existence of a well-defined Mg–O environment is revealed for the Mg intercalated structures. Information reported here reveals the fundamental Mg ion intercalation mechanism in a bilayer structure of V₂O₅·<i>n</i>H₂O material and provides insightful design metrics for future Mg cathodes