Eosin Y, a well‐known economical alternative to metal catalysts in visible‐light‐driven single‐electron transfer‐based organic transformations, can behave as an effective direct hydrogen‐atom ...transfer catalyst for C−H activation. Using the alkylation of C−H bonds with electron‐deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y‐based photocatalytic hydrogen‐atom transfer strategy is promising for diverse functionalization of a wide range of native C−H bonds in a green and sustainable manner.
Neutral eosin Y has been employed as an effective direct hydrogen‐atom transfer photocatalyst to activate a wide range of native C−H bonds in a green and sustainable fashion. This transformation is distinguished by its operational simplicity and amenability to large‐scale synthesis using continuous‐flow technology (EWG=aldehyde, ketone, ester, amide, imide, cyanide, sulfone, nitro, pyridine).
Rigid molecular sieving materials work well for small molecules with the complete exclusion of large ones
, and molecules with matching physiochemical properties may be separated using dynamic ...molecular sieving materials
. Metal-organic frameworks (MOFs)
are known for their precise control of structures and functions on a molecular level
. However, the rational design of local flexibility in the MOF framework for dynamic molecular sieving remains difficult and challenging. Here we report a MOF material (JNU-3a) featuring one-dimension channels with embedded molecular pockets opening to propylene (C
H
) and propane (C
H
) at substantially different pressures. The dynamic nature of the pockets is revealed by single-crystal-to-single-crystal transformation upon exposure of JNU-3a to an atmosphere of C
H
or C
H
. Breakthrough experiments demonstrate that JNU-3a can realize high-purity C
H
(≥99.5%) in a single adsorption-desorption cycle from an equimolar C
H
/C
H
mixture over a broad range of flow rates, with a maximum C
H
productivity of 53.5 litres per kilogram. The underlying separation mechanism-orthogonal-array dynamic molecular sieving-enables both large separation capacity and fast adsorption-desorption kinetics. This work presents a next-generation sieving material design that has potential for applications in adsorptive separation.
Melatonin has been detected in plants in 1995; however, the function and signaling pathway of this putative phytohormone are largely undetermined due to a lack of knowledge about its receptor. Here, ...we discovered the first phytomelatonin receptor (CAND2/PMTR1) in Arabidopsis thaliana and found that melatonin governs the receptor‐dependent stomatal closure. The application of melatonin induced stomatal closure through the heterotrimeric G protein α subunit‐regulated H2O2 and Ca2+ signals. The Arabidopsis mutant lines lacking AtCand2 that encodes a candidate G protein‐coupled receptor were insensitive to melatonin‐induced stomatal closure. Accordingly, the melatonin‐induced H2O2 production and Ca2+ influx were completely abolished in cand2. CAND2 is a membrane protein that interacts with GPA1 and the expression of AtCand2 was tightly regulated by melatonin in various organs and guard cells. CAND2 showed saturable and specific 125I‐melatonin binding, with apparent Kd (dissociation constant) of 0.73 ± 0.10 nmol/L (r2 = .99), demonstrating this protein is a phytomelatonin receptor (PMTR1). Our results suggest that the phytomelatonin regulation of stomatal closure is dependent on its receptor CAND2/PMTR1‐mediated H2O2 and Ca2+signaling transduction cascade.
Hybrid materials integrated with a variety of physical properties, such as spin crossover (SCO) and fluorescence, may show synergetic effects that find applications in many fields. Herein we ...demonstrate a promising post‐synthetic approach to achieve such materials by grafting fluorophores (1‐pyrenecarboxaldehyde and Rhodamine B) on one‐dimensional SCO FeII structures. The resulting hybrid materials display expected one‐step SCO behavior and fluorescent properties, in particular showing a coupling between the transition temperature of SCO and the temperature where the fluorescent intensity reverses. Consequently, synergetic effect between SCO and fluorescence is incorporated into materials despite different fluorophores. This study provides an effective strategy for the design and development of novel magnetic and optical materials.
Two hybrid materials assembled from a 1D spin‐crossover structure and the fluorophores 1‐pyrenecarboxaldehyde and Rhodamine B were prepared. A synergetic effect between spin crossover and fluorescence was proposed.
The first radical alkoxycarboxylation of aryldiazonium salts using CO gas through visible‐light‐induced photoredox catalysis (16 W blue LEDs) has been developed. This reaction is entirely metal‐free, ...is carried out at room temperature with a low loading of an organic dye as a photocatalyst (0.5 mol %), and provides a wide range of arylcarboxylic acid esters in high yields. Importantly, this photocatalytic system can be successfully extended to other carboxylation reactions.
All lit up: The radical alkoxycarboxylation of aryldiazonium salts using CO gas was accomplished through visible‐light‐induced photoredox catalysis. The reaction is metal‐free, and proceeds at room temperature with a low loading of organic photocatalyst. A wide range of esters were conveniently synthesized in moderate to good yields. Importantly, this strategy can be further applied to other carboxylation reactions.
Early detection and accurate monitoring of chronic kidney disease (CKD) could improve care and retard progression to end-stage renal disease. Here, using untargeted metabolomics in 2155 participants ...including patients with stage 1-5 CKD and healthy controls, we identify five metabolites, including 5-methoxytryptophan (5-MTP), whose levels strongly correlate with clinical markers of kidney disease. 5-MTP levels decrease with progression of CKD, and in mouse kidneys after unilateral ureteral obstruction (UUO). Treatment with 5-MTP ameliorates renal interstitial fibrosis, inhibits IκB/NF-κB signaling, and enhances Keap1/Nrf2 signaling in mice with UUO or ischemia/reperfusion injury, as well as in cultured human kidney cells. Overexpression of tryptophan hydroxylase-1 (TPH-1), an enzyme involved in 5-MTP synthesis, reduces renal injury by attenuating renal inflammation and fibrosis, whereas TPH-1 deficiency exacerbates renal injury and fibrosis by activating NF-κB and inhibiting Nrf2 pathways. Together, our results suggest that TPH-1 may serve as a target in the treatment of CKD.
The construction of carbon–heteroatom bonds is one of the most active areas of research in organic chemistry because the function of organic molecules is often derived from the presence of ...heteroatoms. Although considerable advances have recently been achieved in radical-involved catalytic asymmetric C–N bond formation, there has been little progress in the corresponding C–O bond-forming processes. Here, we describe a photoinduced copper-catalyzed cross-coupling of readily available oxime esters and 1,3-dienes to generate diversely substituted allylic esters with high regio- and enantioselectivity (>75 examples; up to 95% ee). The reaction proceeds at room temperature under excitation by purple light-emitting diodes (LEDs) and features the use of a single, earth-abundant copper-based chiral catalyst as both the photoredox catalyst for radical generation and the source of asymmetric induction in C–O coupling. Combined experimental and density functional theory (DFT) computational studies suggest the formation of π-allylcopper complexes from redox-active oxime esters as bifunctional reagents and 1,3-dienes through a radical–polar crossover process.
As a rich green energy source, natural gas is widely used in many fields such as the chemical industry, automobile energy, and daily life. However, it is very challenging to separate and recover C
2
...H
6
and C
3
H
8
from natural gas. Metal-organic frameworks (MOFs) as an emerging type of multi-pore porous materials show huge potential in gas adsorption separation. Herein, we report pillar-layered MOFs, Ni (BDC)(DABCO)
0.5
(DMOF-X), modified by halogen atoms (F, Cl, Br), and investigate their CH
4
/C
2
H
6
/C
3
H
8
separation performance. The experimental results show that DMOF-Cl exhibited a extremely high adsorption capacity for C
3
H
8
and C
2
H
6
. Under the conditions of 298 K and 100 kPa, the adsorption capacities for C
3
H
8
and C
2
H
6
on DMOF-Cl are as high as 6.23 and 4.94 mmol g
−1
, which are superior to the values for most of the porous materials that have been reported. In addition, DMOF-Cl also shows high C
3
H
8
/CH
4
(5: 85, V/V) and C
2
H
6
/CH
4
(10: 85, V/V) separation selectivities, with values of 130.9 and 12.5, respectively. Finally, DMOF-Cl also demonstrated great potential as an adsorbent for separating C
3
H
8
/C
2
H
6
/CH
4
.
Pillar-layered MOFs, Ni (BDC)(DABCO)
0.5
(DMOF-X), modified by halogen atoms (F, Cl, Br), were investigated for CH
4
/C
2
H
6
/C
3
H
8
separation performance. DMOF-Cl demonstrated great potential as an adsorbent for the efficient separation of C
3
H
8
and C
2
H
6
from CH
4
.
The efficient separation of acetylene (C2H2) from its mixture with carbon dioxide (CO2) remains a challenging industrial process due to their close molecular sizes/shapes and similar physical ...properties. Herein, we report a microporous metal–organic framework (JNU-4) with square-planar mononuclear copper(ii) centers as nodes and tetrahedral organic linkers as spacers, allowing for two accessible binding sites per metal center for C2H2 molecules. Consequently, JNU-4 exhibits excellent C2H2 adsorption capacity, particularly at 298 K and 0.5 bar (200 cm3 g−1). Detailed computational studies confirm that C2H2 molecules are indeed predominantly located in close proximity to the square-planar copper centers on both sides. Breakthrough experiments demonstrate that JNU-4 is capable of efficiently separating C2H2 from a 50 : 50 C2H2/CO2 mixture over a broad range of flow rates, affording by far the largest C2H2 capture capacity (160 cm3 g−1) and fuel-grade C2H2 production (105 cm3 g−1, ≥98% purity) upon desorption. Simply by maximizing accessible open metal sites on mononuclear metal centers, this work presents a promising strategy to improve the C2H2 adsorption capacity and address the challenging C2H2/CO2 separation.
Interest in piezochromic luminescence has increased in recent decades, even though it is mostly limited to pure organic compounds and fluorescence. In this work, a Cu
3
Pz
3
(
Cu
3
, Pz: pyrazolate) ...cyclic trinuclear complex (CTC) with two different crystalline polymorphs, namely
1a
and
1b
, was synthesized. The CTC consists of two functional moieties: carbazole (
Cz
) chromophore and
Cu
3
units. In crystals of
1a
, discrete
Cz
-
Cu
3
-
Cu
3
-
Cz
stacking was found, showing abnormal pressure-induced phosphorescence enhancement (PIPE), which was 12 times stronger at 2.23 GPa compared to under ambient conditions. This novel observation is ascribed to cooperation between heavy-atom effects (
i.e.
, from Cu atoms) and metal-ligand charge-transfer promotion. The infinite π-π stacking of
Cz
motifs was observed in
1b
and it exhibited good piezochromism as the pressure increased. This work demonstrates a new concept in the design of piezochromic materials to achieve PIPE
via
combining organic chromophores and metal-organic phosphorescence emitters.
One molecule, two response mechanisms: a pair of newly-designed cyclic trinuclear Cu(
i
) complex crystalline polymorphs are engineered, which show excellent luminescent piezochromism and pressure-induced phosphorescence enhancement, respectively.
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