Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates

Using N (phosphonomethyl)iminodiacetic acid (H4PMIDA), as a complexing agent, two new complexes, (NH4)La(PMIDA)(H2O)•H2O, 1 and (NH4)Yb(PMIDA), 2 have been synthesized hydrothermally. In both compounds, the metal ions are trapped in a three five-membered chelate rings by the chelating PMIDA anions giving a bi-capped trigonal prism LaO8N and capped trigonal prism YbO6N geometries for 1 and 2, respectively. The structure of 1 consists of La(PMIDA)(H2O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a double chain along the c-axis. The double chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures.The structure of 2 consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4 and 6 membered apertures in the bc plane. Under excitation of 330nm, compound 2 shows a broad emission band at λmax = 460nm, This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence

Reversible Dehydration Behavior Reveals Coordinatively Unsaturated Metal Sites in Microporous Aluminum Phosphonates

Incorporation of the same ligand into three different aluminum phenylenediphosphonates (Al­(H₂O)­(O₃PC₆H₄PO₃H) (<b>1</b>), Al₄(H₂O)₂­(O₃PC₆H₄PO₃)₃ (<b>2</b>), and Al₄(H₂O)₄­(O₃PC₆H₄PO₃)_2.84­(OH)_0.64 (<b>3</b>)) was accomplished by varying the synthetic conditions. The compounds have different sorption properties; however, all exhibit reversible dehydration behavior. The structures of the hydrated and dehydrated phases were determined from powder X-ray diffraction data. Compounds <b>2</b> and <b>3</b> were found to be microporous, while compound <b>1</b> was found to be nonporous. The stability of the dehydrated phase and the resulting porosity was found to be influenced by the change in the structure upon loss of water

Synthesis of Framework Isomer MOFs Containing Zinc and 4-Tetrazolyl Benzenecarboxylic Acid via a Structure Directing Solvothermal Approach

The solvothermal synthesis of framework isomers was carried out using the hybrid carboxylate and tetrazolate functional ligand, 4-tetrazolyl benzenecarboxylic acid (H2TBC, TBC = 4-tetrazolyl benzenecarboxylate) and zinc. H2TBC was also synthesized with the solvothermal approach, and is referred herein as structure 1. Using single-crystal X-ray diffraction, we found that the tetrazolate groups of TBC show an unusual “opposite-on” coordination mode with zinc. Three previously characterized metal-organic frameworks (MOFs) were obtained by systematically changing the solvents of the H2TBC-Zn reaction, (1) ZnTBC, 2, which has a non-porous structure; (2) Zn2(TBC)2(H2O), 3, which has an amphiphilic pore structure and (3) Zn2(TBC)2{guest}, 4, which is porous and has channels containing uncoordinated N heteroatoms. Fluorescence spectra of 4 reveal a strong blue emission mainly from the TBC ligands

From small structural modifications to adjustment of structurally dependent properties: 1-methyl-3,5-bis­[(E)-2-thienyl­idene]-4-piperidone and 3,5-bis­[(E)-5-bromo-2-thienyl­idene]-1-methyl-4-piperidone

The mol­ecules of the title compounds, C16H15NOS2, (I), and C16H13Br2NOS2, (II), are E,E-isomers and consist of an extensive conjugated system, which determines their mol­ecular geometries. Compound (I) crystallizes in the monoclinic space group P21/c. It has one thio­phene ring disordered over two positions, with a minor component contribution of 0.100 (3). Compound (II) crystallizes in the noncentrosymmetric ortho­rhom­bic space group Pca21 with two independent mol­ecules in the unit cell. These mol­ecules are related by a noncrystallographic pseudo-inversion center and possess very similar geometries. The crystal packings of (I) and (II) have a topologically common structural motif, viz. stacks along the b axis, in which the mol­ecules are bound by weak C—H⋯O hydrogen bonds. The noncentrosymmetric packing of (II) is governed by attractive inter­molecular Br⋯Br and Br⋯N inter­actions, which are also responsible for the very high density of (II) (1.861 Mg m−3)

Simple Setup Miniaturization with Multiple Benefits for Green Chemistry in Nanoparticle Synthesis

[Image: see text] The development of nanomaterials often relies on wet-chemical synthesis performed in reflux setups using round-bottom flasks. Here, an alternative approach to synthesize nanomaterials is presented that uses glass tubes designed for NMR analysis as reactors. This approach uses less solvent and energy, generates less waste, provides safer conditions, is less prone to contamination, and is compatible with high-throughput screening. The benefits of this approach are illustrated by an in breadth study with the synthesis of gold, iridium, osmium, and copper sulfide nanoparticles

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