The hydro(solvo)thermal reactions of Zn(NO
3
)
2
·6H
2
O,
N
-(pyridin-3-yl)-4-(pyridin-4-yl)-1,8-naphthalimide (NI-bpy-34) and aromatic polycarboxylic acids afforded the corresponding zinc ...coordination polymers (CPs) Zn
2
(1,4-bdc)(1,4-Hbdc)
2
(NI-bpy-34)
2
(
1
, 1,4-H
2
bdc = benzene-1,4-dicarboxylic acid), Zn
2
(2,6-ndc)(2,6-Hndc)
2
(NI-bpy-34)
2
·H
2
O (
2
, 2,6-H
2
ndc = naphthalene-2,6-dicarboxylic acid), and Zn(Hbtc)(NI-bpy-34)(H
2
O)·H
2
O (
3
, H
3
btc = benzene-1,3,5-tricarboxylic acid). CP
1
features a 1D ladder structure with lateral arms which expands into a two-fold interweaved supramolecular 2D + 2D → 2D network through H-bonds. CP
2
adopts a complicated 2D thick-layer structure which expands into a 3D H-bonded (4,6)-connected net with a (4
4
6
2
)(4
4
6
11
) topology with three-fold interpenetration. CP
3
adopts a 2D grid-like (4,4)-layer structure. The three CPs all emit strong blue fluorescence in toluene suspension which is effectively turned off in the presence of a variety of electron-deficient aromatic nitro compounds. The quenching efficiencies and the Stern–Volmer quenching constants (
K
sv
) both indicate that 1,4-dinitrobenzene (79% quenching,
K
sv
= 2.11 × 10
3
M
−1
), 3-nitrophenol (95% quenching,
K
sv
= 1.61 × 10
4
M
−1
), and nitrobenzene (87% quenching,
K
sv
= 3.91 × 10
3
M
−1
) represent the highest quenching responses for CPs
1–3
, respectively, for which the limits of detection were calculated to be 8.45 (1.42), 2.47 (0.34), and 5.14 (0.63) μM (ppm), respectively. Thus, CPs
1–3
can be used as promising fluorescence sensors for the highly selective and sensitive detection of aromatic nitro compounds. The mechanism of the quenching sensing of aromatic nitro compounds can mainly be explained by a photoinduced electron transfer process. On the other hand, through metal-ion exchange, the framework Zn
2+
ions in CP
3
were partially substituted by Cu
2+
ions by about 45%
via
single-crystal to single-crystal (SCSC) transformations. The resulting Cu
2+
-exchanged material
3
-(Cu : Zn) displays decreased fluorescence emission due to paramagnetic fluorescence quenching caused by d
9
configuration Cu
2+
ions. Further, the exchange kinetics have been studied.
The design of efficient non‐noble metal catalysts for CO2 hydrogenation to fuels and chemicals is desired yet remains a challenge. Herein, we report that single Mo atoms with a MoN3 (pyrrolic) moiety ...enable remarkable CO2 adsorption and hydrogenation to CO, as predicted by density functional theory studies and evidenced by a high and stable conversion of CO2 reaching about 30.4 % with a CO selectivity of almost 100 % at 500 °C and very low H2 partial pressure. Atomically dispersed MoN3 is calculated to facilitate CO2 activation and reduces CO2 to CO* via the direct dissociation path. Furthermore, the highest transition state energy in CO formation is 0.82 eV, which is substantially lower than that of CH4 formation (2.16 eV) and accounts for the dominant yield of CO. The enhanced catalytic performances of Mo/NC originate from facile CO desorption with the help of dispersed Mo on nitrogen‐doped carbon (Mo/NC), and in the absence of Mo nanoparticles. The resulting catalyst preserves good stability without degradation of CO2 conversion rate even after 68 hours of continuous reaction. This finding provides a promising route for the construction of highly active, selective, and robust single‐atom non‐precious metal catalysts for reverse water–gas shift reaction.
Adsorption and hydrogenation of CO2 to CO is reported over single Mo atoms with a MoN3 (pyrrolic) moiety. Density functional theory studies and experimental studies provide additional evidence to support the observed activity. A high and stable conversion of CO2 is attained up to 30.4 % with a 100 % CO selectivity.
Two metal–salicyaldimine complexes both exist as ML2-type molecules in the solution and amorphous while 2D sql nets in the crystalline, of which Zn complex 1 acts as a dual-mode sensor in optical ...detection of Cu2+, Al3+, and Cr3+ and a fluorescence sensor for H2O detection in MeOH.
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•1 and 2 both adopt ML2-type molecule in solution and amorphous but 2D sql net in crystalline.•1 plays an absorption and fluorescence dual-mode sensor for Cu2+, Al3+, and Cr3+ detection.•Metal ion sensing is due to central metal displacement and analyte-induced decomplexation.•Zn complex 1 revealed fluorescence color change as varying the contents of H2O in MeOH.
Metal–salicyaldimine complexes M(sal-3-py)2 (1, M = Zn; 2, M = Cu), where Hsal-3-py = 3-(salicylideneimino)pyridine, have been synthesized. Nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS) indicated that 1 and 2 both have a ML2-type discrete molecular structure in the solution and amorphous phases. Single-crystal X-ray diffraction analysis and X-ray powder diffraction (XRPD), however, proven that 1 and 2 both possess an extended two-dimensional sql layer net in the crystalline phase. The electronic absorption spectra of 1 and 2 in MeOH exhibited intense intraligand charge transfer (ILCT) transitions in the UV region (200–340 nm) and metal–ligand charge transfer (CT) transition in the visible region (380–400 nm). The emission spectra of 1 displayed a cyan fluorescence band at 480 nm in solid-state and a green fluorescence band at 502 nm in MeOH solution. Optical detection of 1 in MeOH toward Cu2+, Al3+, and Cr3+ ions showed remarkable changes in electronic absorption spectra and ON–OFF–ON fluorescence color change from green to blue light emission. The sensing processes involves two stages, i.e., direct central metal displacement for Cu2+ detection and analyte-induced decomplexation for Al3+/Cr3+ detection, and subsequently further recognition through the 3-pyridyl functions of the salicyaldimine ligands. Further, 1 displayed remarkable fluorescence color change from green light in MeOH to cyan light in H2O, being potential candidate as H2O probe in methanol.
Reaction of NiCl₂∙6H₂O, d-camphoric acid (d-H₂cam), and
,
'-bis(pyraz-2-yl)piperazine (bpzpip) in pure water at 150 °C afforded a novel nickel(II) coordination layer, ...Ni₄(d-cam)₂(d-Hcam)₄(bpzpip)₄(H₂O)₂ (
), under hydro(solvo)thermal conditions. Single-crystal X-ray structure analysis reveals that
adopts a six-connected two-dimensional (2D) chiral layer structure with 3⁶-
topology. Dye adsorption explorations indicate that
readily adsorbs methyl blue (MyB) from water without destruction of crystallinity. On the contrary, methyl orange (MO) is not adsorbed at all. The pseudo-second-order kinetic model could be used to interpret the adsorption kinetics for MyB. Equilibrium isotherm studies suggest complicated adsorption processes for MyB which do not have good applicability for either the two-parameter Langmuir or Freundlich isotherm model. The saturated adsorption capacity of
for MyB calculated by Langmuir is 185.5 mg·g
at room temperature.
Hydro(solvo)thermal reactions of Cd(NO3)2, N-(pyridin-3-ylmethyl)-4-(pyridin-4-yl)-1,8-naphthalimide (NI-mbpy-34), and 5-bromobenzene-1,3-dicarboxylic acid (Br-1,3-H2bdc) afforded a luminescent ...coordination polymer, {Cd(Br-1,3-bdc)(NI-mbpy-34)(H2O)∙2H2O}n (1). Single-crystal X-ray diffraction analysis showed that 1 features a two-dimensional (2-D) gridlike sql layer with the point symbol of (44·62), where the Cd(II) center adopts a {CdO5N2} pentagonal bipyramidal geometry. Thermogravimetric (TG) analysis confirmed the thermal stability of 1 up to about 340 °C, whereas XRPD patterns proved the maintenance of crystallinity and framework integrity of 1 in CH2Cl2, H2O, CH3OH, and toluene. Photoluminescence studies indicated that 1 displayed intense blue fluorescence emissions in both solid-state and H2O suspension-phase. Owing to the good fluorescent properties, 1 could serve as an excellent turn-off fluorescence sensor for selective and sensitive Cr(VI) detection in water, with LOD = 15.15 μM for CrO42− and 14.91 μM for Cr2O72−, through energy competition absorption mechanism. In addition, 1 could also sensitively detect Cr3+, Fe3+, and Al3+ ions in aqueous medium via fluorescence-enhancement responses, with LOD = 2.81 μM for Cr3+, 3.82 μM for Fe3+, and 3.37 μM for Al3+, mainly through an absorbance-caused enhancement (ACE) mechanism.
•This study investigated the effect of the PILOT program on the multifaceted performance of elementary school students.•Students exposed to a high-level intervention demonstrated an increase in ...resilience, psychological flourishing, substance resistance self-efficacy, cognitive reappraisal, and a reduction in depressive symptoms and internet addiction tendency.•Students with low cognitive reappraisal and elevated depressive symptoms benefited the most from the intervention program.
This study aimed to investigate the intervention effects of the Positive Interpersonal and Life Orientation Training (PILOT) program on various positive psychological outcomes across two levels of intervention exposure. Most life skill-based intervention programs have been proven to be effective in preventing substance use behaviors and mental illness. However, the effects of these programs on positive psychological competence still needs to be explored. Additionally, the influence of intervention exposure on effectiveness has rarely been considered in most studies. Eight hundred and sixty-eight elementary school students participated in the PILOT program. Analysis of covariance and PROCESS were conducted to investigate the effects of PILOT on the outcome indicators. The results revealed that students exposed to high-level PILOT reported higher levels of resilience, psychological flourishing, substance resistance self-efficacy, cognitive reappraisal, lower levels of depressive symptoms, and internet addiction tendency than students in low-level PILOT in the post-test. The findings indicate that students with a low level of cognitive reappraisal and a high level of depressive symptoms can benefit more from PILOT. The effects of PILOT and their implications in helping students encounter the COVID-19 pandemic in an East Asian context and the influence of fidelity are discussed.
A Zn coordination polymer, Zn(H2dhbdc)(Cz-3,6-bpy) n (1, H4dhbdc = 2,5-dihydroxyterephthalic acid, Cz-3,6-bpy = 3,6-bis(pyridin-4-yl)-9H-carbazole), showing high thermal stability up to 407 °C, ...has been prepared under hydro(solvo)thermal conditions. Compound 1 has a two-dimensional (2D) undulated layer structure regarded as the topological sql grid, where the tetrahedral Zn(II) centers act as 4-connected nodes connecting by H2dhbdc2– and Cz-3,6-bpy ligands as linkers. Interestingly, the 2D undulated layers expanding in the bc plane are sequentially interwoven with each other in an offset manner along the a-axis, resulting in a condensed polyinterweaving 2D → 3D net. Compound 1 emits weak fluorescence at 522 nm in water suspensions; the intensity can be significantly enhanced by adding Al3+ ions, with low limit of detection (LOD) of 0.62 μM and high anti-interference ability over numerous competitive metal ions except Fe3+ ions. Moreover, the detection performance of 1 toward Al3+ retains high luminescence stability and reusability, being as an excellent candidate for Al3+ detection over a long period. Spectroscopic evidence from XRPD, EDS, IR, and XPS suggest the occurrence of weak framework–analyte interactions between the H2dhbdc2– ligand units in 1 and the Al3+ ions, resulting in luminescence turn-on sensing.
A Ni-rich cobalt-free layered cathode material (LiNi
x
Mn
1−
x
O
2
) is promising due to its low cost, excellent structural stability, and thermal stability. However, low Li-ion diffusion kinetics, ...highly reactive Ni
4+
, and stress-induced intragranular micro-cracking restrict its further application. Here, we report dual-functional boron-modification (doping and coating) on a cobalt-free single-crystal layered cathode (B-LiNi
0.75
Mn
0.25
O
2
)
via
a simple solid-state method. The boron atoms prefer to occupy the tetrahedral interstices in the Li layer during the sintering process, which enlarges the
c
-axis for fast Li-ion diffusion kinetics and can also serve as a pillar to achieve an ultra-low (1.62%)
c
-axis lattice contraction at 80% state of charge (SOC). And boron doping passivates the lattice O, inhibits the irreversible phase transition and provides excellent thermal stability at a high cut-off voltage of 4.5 V. On the other hand, the byproduct LiBO
2
can improve Li-ion diffusion and alleviate side reactions at the electrode/electrolyte interface by serving as a Li-ion conductive coating layer. As a result, B-LiNi
0.75
Mn
0.25
O
2
is almost free of inter- and intragranular micro-cracking with faster Li-ion diffusion kinetics. It delivers 176.6 mA h g
−1
at 1C and achieves 82.9% capacity retention after 200 cycles. This work not only provides a low-cost and scalable method to remove Co from conventional Ni-rich layered cathodes, but also reveals the commercial feasibility of highly safe single-crystal layered cathode materials.
Boron-modified cobalt-free single-crystal cathode enables to ultra-low
c
-axis lattice contraction and anchors lattice oxygen for high safety Li-ion batteries.
Cells adopt distinct signaling pathways to optimize cell locomotion in different physical microenvironments. However, the underlying mechanism that enables cells to sense and respond to physical ...confinement is unknown. Using microfabricated devices and substrate-printing methods along with FRET-based biosensors, we report that, as cells transition from unconfined to confined spaces, intracellular Ca2+ level is increased, leading to phosphodiesterase 1 (PDE1)-dependent suppression of PKA activity. This Ca2+ elevation requires Piezo1, a stretch-activated cation channel. Moreover, differential regulation of PKA and cell stiffness in unconfined versus confined cells is abrogated by dual, but not individual, inhibition of Piezo1 and myosin II, indicating that these proteins can independently mediate confinement sensing. Signals activated by Piezo1 and myosin II in response to confinement both feed into a signaling circuit that optimizes cell motility. This study provides a mechanism by which confinement-induced signaling enables cells to sense and adapt to different physical microenvironments.
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•Calcium is elevated via Piezo1 as cells transit from unconfined to confined spaces•PKA activity is suppressed in confined relative to unconfined spaces•Piezo1-dependent calcium increase negatively regulates PKA via PDE1 in confinement•Piezo1/PDE1/PKA and myosin II independently mediate confinement sensing
Hung et al. demonstrate that a Piezo1-dependent intracellular calcium increase negatively regulates protein kinase A (PKA) as cells transit from unconfined to confined spaces. The Piezo1/PKA and myosin II signaling modules constitute two confinement-sensing mechanisms. This study provides a paradigm by which signaling enables cells to sense and adapt to different microenvironments.
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