Porphyrinic Metal–Organic Framework-Templated Fe–Ni–P/Reduced Graphene Oxide for Efficient Electrocatalytic Oxygen Evolution

The sluggish kinetics of oxygen evolution reaction (OER) hampers the H₂ production by H₂O electrolysis, and it is very important for the development of highly efficient and low-priced OER catalysts. Herein, a representative metalloporphyrinic MOF, PCN-600-Ni, integrated with graphene oxide (GO), serves as an ideal precursor and template to afford bimetallic iron–nickel phosphide/reduced graphene oxide composite (denoted as Fe–Ni–P/rGO-<i>T</i>; <i>T</i> represents pyrolysis temperature) via pyrolysis and subsequent phosphidation process. Thanks to the highly porous structure, the synergetic effect of Fe and Ni elements in bimetallic phosphide, and the good conductivity endowed by rGO, the optimized Fe–Ni–P/rGO-400 exhibits remarkable OER activity in 1 M KOH solution, affording an extremely low overpotential of 240 mV at 10 mA/cm², which is far superior to the commercial IrO₂ and among the best in all non-noble metal-based electrocatalysts

New eudesmane-type sesquiterpenoids from the root bark of <i>Pseudolarix kaempferi</i>

<div><p></p><p>The phytochemical investigation of the root bark of <i>Pseudolarix kaempferi</i> yielded eight eudesmane-type sesquiterpenoids, including three new ones, 1α-hydroxyl-4(14)-en-β-dihydroagarafuran (<b>1</b>), 1<i>α</i>, 2<i>α</i>-diacetoxy-8<i>β</i>-isobutanoyloxy-9<i>α</i>-benzoyl oxy-15-<i>β</i>-(<i>β</i>-furancarbonyloxy)-4<i>β</i>, 6<i>β</i>-dihydroxy-<i>β</i>-dihydroagarofuran (<b>7</b>), and 1<i>α</i>-acetoxy-2 <i>α</i>-furancarbonyloxy-8<i>β</i>-isobutanoyloxy-9<i>α</i>-benzoyloxy-15<i>β</i>-(<i>β</i>-acetoxy)-4<i>β</i>, 6<i>β</i>-dihydroxy-<i>β</i>-dihydroagarofuran (<b>8</b>). Herein the new compounds <b>7</b> and <b>8</b> were reported as a mixture. The molecular structures of the isolated compounds were elucidated on the basis of extensive spectroscopic analysis, including UV, IR, NMR, and MS, and comparison with the literature data.</p></div

Hydrogen Bonding Regulated Flexibility and Disorder in Hydrazone-Linked Covalent Organic Frameworks

Covalent organic framework (COF) chemistry is experiencing unprecedented development in recent decades. The current studies on COF chemistry are mainly focused on the discovery of novel covalent linkages, new topological structures, synthetic methodologies, and potential applications. However, despite the fact that noncovalent interactions are ubiquitous in COF chemistry, relatively little attention has been given to the role of noncovalent bonds on COF structures and their properties. In this work, a series of hydrazone-linked COFs involving noncovalent hydrogen bonds have been constructed, where the hydrogen-bonding interaction plays critical roles in the COF crystallinity and structures. The regulation of structural flexibility, the reversible transition between order and disorder, and the variety of host–guest interactions have been demonstrated in succession for the first time in COFs. The results obtained by the hydrogen-bonding-regulated strategy may also be extendable to other noncovalent interactions, such as π–π interactions, metal coordination interactions, Lewis acid–base interactions, etc. These findings will inspire future developments in the design, synthesis, structural regulation, and applications of COFs by manipulating noncovalent interactions

A Route to Metal–Organic Frameworks through Framework Templating

A microporous metal–organic framework (MOF), PCN-922 [Cu₄(ETTB)], containing a dendritic octatopic organic linker and a Cu₂-paddlewheel structural motif, has been synthesized by using a Zn₂-paddlewheel-based MOF as a template to prearrange the linkers for the Cu₂-based MOF target. PCN-922 shows permanent porosity and excellent gas adsorption capacity

A Route to Metal–Organic Frameworks through Framework Templating

A microporous metal–organic framework (MOF), PCN-922 [Cu₄(ETTB)], containing a dendritic octatopic organic linker and a Cu₂-paddlewheel structural motif, has been synthesized by using a Zn₂-paddlewheel-based MOF as a template to prearrange the linkers for the Cu₂-based MOF target. PCN-922 shows permanent porosity and excellent gas adsorption capacity

A Route to Metal–Organic Frameworks through Framework Templating

A microporous metal–organic framework (MOF), PCN-922 [Cu₄(ETTB)], containing a dendritic octatopic organic linker and a Cu₂-paddlewheel structural motif, has been synthesized by using a Zn₂-paddlewheel-based MOF as a template to prearrange the linkers for the Cu₂-based MOF target. PCN-922 shows permanent porosity and excellent gas adsorption capacity

Solvent-Induced Controllable Synthesis, Single-Crystal to Single-Crystal Transformation and Encapsulation of Alq3 for Modulated Luminescence in (4,8)-Connected Metal–Organic Frameworks

In this work, for the first time, we have systematically demonstrated that solvent plays crucial roles in both controllable synthesis of metal–organic frameworks (MOFs) and their structural transformation process. With solvent as the only variable, five new MOFs with different structures have been constructed, in which one MOF undergoes solvent-induced single-crystal to single-crystal (SCSC) transformation that involves not only solvent exchange but also the cleavage and formation of coordination bonds. Particularly, a significant crystallographic change has been realized through an unprecedented three-step SCSC transformation process. Furthermore, we have demonstrated that the obtained MOF could be an excellent host for chromophores such as Alq3 for modulated luminescent properties