Secondary Ammonium Dicarboxylate (SAD)A Supramolecular Synthon in Designing Low Molecular Weight Gelators Derived from Azo-Dicarboxylates

The supramolecular synthon namely secondary ammonium dicarboxylate (SAD) synthon has been exploited to design a new series of low molecular weight gelators (LMWGs) derived from azobenzene-4,4′-dicarboxylic acid and azobenzene-4,4′-diacrylic acid, and various secondary amines. Single crystal structures of six such salts exclusively established the presence of SAD synthon. Two such salts namely, dicyclohexylammonium azobenzene-4,4′-diacrylate (<b>2.DCHA</b>) and dihexylammonium azobenzene-4,4′-diacrylate (<b>2.DHA</b>) displayed intriguing gelation properties. Powder X-ray diffraction in combination with single crystal X-ray data established existence of SAD synthon in the structure of the gel network of <b>2.DCHA</b>. UV-irradiation of the salts as well as the gel did not show any trans<i>–</i>cis isomerization of the azo-moiety

Secondary Ammonium Dicarboxylate (SAD)A Supramolecular Synthon in Designing Low Molecular Weight Gelators Derived from Azo-Dicarboxylates

The supramolecular synthon namely secondary ammonium dicarboxylate (SAD) synthon has been exploited to design a new series of low molecular weight gelators (LMWGs) derived from azobenzene-4,4′-dicarboxylic acid and azobenzene-4,4′-diacrylic acid, and various secondary amines. Single crystal structures of six such salts exclusively established the presence of SAD synthon. Two such salts namely, dicyclohexylammonium azobenzene-4,4′-diacrylate (<b>2.DCHA</b>) and dihexylammonium azobenzene-4,4′-diacrylate (<b>2.DHA</b>) displayed intriguing gelation properties. Powder X-ray diffraction in combination with single crystal X-ray data established existence of SAD synthon in the structure of the gel network of <b>2.DCHA</b>. UV-irradiation of the salts as well as the gel did not show any trans<i>–</i>cis isomerization of the azo-moiety

Secondary Ammonium Dicarboxylate (SAD)A Supramolecular Synthon in Designing Low Molecular Weight Gelators Derived from Azo-Dicarboxylates

The supramolecular synthon namely secondary ammonium dicarboxylate (SAD) synthon has been exploited to design a new series of low molecular weight gelators (LMWGs) derived from azobenzene-4,4′-dicarboxylic acid and azobenzene-4,4′-diacrylic acid, and various secondary amines. Single crystal structures of six such salts exclusively established the presence of SAD synthon. Two such salts namely, dicyclohexylammonium azobenzene-4,4′-diacrylate (<b>2.DCHA</b>) and dihexylammonium azobenzene-4,4′-diacrylate (<b>2.DHA</b>) displayed intriguing gelation properties. Powder X-ray diffraction in combination with single crystal X-ray data established existence of SAD synthon in the structure of the gel network of <b>2.DCHA</b>. UV-irradiation of the salts as well as the gel did not show any trans<i>–</i>cis isomerization of the azo-moiety

Secondary Ammonium Dicarboxylate (SAD)A Supramolecular Synthon in Designing Low Molecular Weight Gelators Derived from Azo-Dicarboxylates

The supramolecular synthon namely secondary ammonium dicarboxylate (SAD) synthon has been exploited to design a new series of low molecular weight gelators (LMWGs) derived from azobenzene-4,4′-dicarboxylic acid and azobenzene-4,4′-diacrylic acid, and various secondary amines. Single crystal structures of six such salts exclusively established the presence of SAD synthon. Two such salts namely, dicyclohexylammonium azobenzene-4,4′-diacrylate (<b>2.DCHA</b>) and dihexylammonium azobenzene-4,4′-diacrylate (<b>2.DHA</b>) displayed intriguing gelation properties. Powder X-ray diffraction in combination with single crystal X-ray data established existence of SAD synthon in the structure of the gel network of <b>2.DCHA</b>. UV-irradiation of the salts as well as the gel did not show any trans<i>–</i>cis isomerization of the azo-moiety

Secondary Ammonium Dicarboxylate (SAD)A Supramolecular Synthon in Designing Low Molecular Weight Gelators Derived from Azo-Dicarboxylates

The supramolecular synthon namely secondary ammonium dicarboxylate (SAD) synthon has been exploited to design a new series of low molecular weight gelators (LMWGs) derived from azobenzene-4,4′-dicarboxylic acid and azobenzene-4,4′-diacrylic acid, and various secondary amines. Single crystal structures of six such salts exclusively established the presence of SAD synthon. Two such salts namely, dicyclohexylammonium azobenzene-4,4′-diacrylate (<b>2.DCHA</b>) and dihexylammonium azobenzene-4,4′-diacrylate (<b>2.DHA</b>) displayed intriguing gelation properties. Powder X-ray diffraction in combination with single crystal X-ray data established existence of SAD synthon in the structure of the gel network of <b>2.DCHA</b>. UV-irradiation of the salts as well as the gel did not show any trans<i>–</i>cis isomerization of the azo-moiety

Reinvestigation of Water Oxidation Catalyzed by a Dinuclear Cobalt Polypyridine Complex: Identification of CoO_<i>x</i> as a Real Heterogeneous Catalyst

Recently, a dinuclear cobalt complex, [(TPA)­Co^III(μ-OH)­(μ-O₂)­Co^III(TPA)]­(ClO₄)₃ (<b>1</b>; TPA = tris­(2-pyridylmethyl)­amine), has been reported as a homogeneous catalyst for electrochemical and photochemical water oxidation (Angew. Chem. Int. Ed. 2014, 53, 14499). During the reinvestigation of the reported water oxidation catalyst (WOC) of <b>1</b>, several characterizations such as EDTA and bipyridine titrations, electrochemistry, SEM, EDX, ICP-AES, TEM, XPS, and UV–vis spectroscopy have revealed that the water oxidation may happen due to the formation of CoO_<i>x</i> as a real heterogeneous WOC, and <b>1</b> itself lacks the ability to catalyze water oxidation. This paper presents a practical and simple procedure to clarify whether the water oxidation is truly catalyzed by a molecular catalyst or not

Dynamic Breathing of CO₂ by Hydrotalcite

The carbon cycle of carbonate solids (e.g., limestone) involves weathering and metamorphic events, which usually occur over millions of years. Here we show that carbonate anion intercalated layered double hydroxide (LDH), a class of hydrotalcite, undergoes an ultrarapid carbon cycle with uptake of atmospheric CO₂ under ambient conditions. The use of ¹³C-labeling enabled monitoring by IR spectroscopy of the dynamic exchange between initially intercalated ¹³C-labeled carbonate anions and carbonate anions derived from atmospheric CO₂. Exchange is promoted by conditions of low humidity with a half-life of exchange of ∼24 h. Since hydrotalcite-like clay minerals exist in Nature, our finding implies that the global carbon cycle involving exchange between lithosphere and atmosphere is much more dynamic than previously thought

Naked-Eye Discrimination of Methanol from Ethanol Using Composite Film of Oxoporphyrinogen and Layered Double Hydroxide

Methanol is a highly toxic substance, but it is unfortunately very difficult to differentiate from other alcohols (especially ethanol) without performing chemical analyses. Here we report that a composite film prepared from oxoporphyrinogen (OxP) and a layered double hydroxide (LDH) undergoes a visible color change (from magenta to purple) when exposed to methanol, a change that does not occur upon exposure to ethanol. Interestingly, methanol-induced color variation of the OxP-LDH composite film is retained even after removal of methanol under reduced pressure, a condition that does not occur in the case of conventional solvatochromic dyes. The original state of the OxP-LDH composite film could be recovered by rinsing it with tetrahydrofuran (THF), enabling repeated usage of the composite film. The mechanism of color variation, based on solid-state ¹³C–CP/MAS NMR and solution-state ¹³C NMR studies, is proposed to be anion transfer from LDH to OxP triggered by methanol exposure