9 research outputs found
Nickel(0)-Catalyzed Denitrogenative Transannulation of Benzotriazinones with Alkynes: Mechanistic Insights of Chemical Reactivity and Regio- and Enantioselectivity from Density Functional Theory and Experiment
The
mechanism of Ni(0)-catalyzed denitrogenative transannulation
of 1,2,3-benzotriazin-4Â(<i>3H</i>)-ones with alkynes to
access isoquinolones has been comprehensively studied by a density
functional theory (DFT) calculation and control experimental investigation.
The results indicate that the transformations proceed via a sequential
nitrogen extrusion, carbometalation, Ni–C bond insertion, and
reductive elimination process. A frontier molecular orbital (FMO)
theory and natural bond orbital (NBO) analysis reveals that the advantages
of substituents on chemical reactivity and regioselectivity exist
for multiple reasons: (1) Phenyl groups on the N atom of benzotriazinone
and/or unsymmetrical alkynes mainly account for the high reactivity
and regioselectivity via its electronic effect. (2) The π···π
interaction between the phenyl substituent on the alkyne and triazole
ring might partially contribute to the high regioselectivity when
unsymmetrical alkynes were employed as the substrates. Furthermore,
DFT calculations successfully explain the origin of enantioselectivity
and discrepancy of reactivities between different <i>N</i>-substituted benzotriazinones for the asymmetric construction of
axially chiral isoquinolones in an atroposelective manner. The calculated
results indicate that high enantioselectivity is mainly determined
by the structural difference between these two transition states of
the key annulation step, which lies in the orientation of the naphthyl
substituent relative to the chiral ligand
Additional file 1 of Potential causal associations between leisure sedentary behaviors, physical activity, sleep traits, and myopia: a Mendelian randomization study
Supplementary Material
Co<sub>3</sub>O<sub>4</sub> Nanospheres Embedded in a Nitrogen-Doped Carbon Framework: An Electrode with Fast Surface-Controlled Redox Kinetics for Lithium Storage
Herein, we develop a Co<sub>3</sub>O<sub>4</sub>-based anode material with a hierarchical structure
similar to that of a lotus pod, where single yolk–shell-structured
Co<sub>3</sub>O<sub>4</sub>@Co<sub>3</sub>O<sub>4</sub> nanospheres
are well embedded in a nitrogen-doped carbon (N–C) conductive
framework (Co<sub>3</sub>O<sub>4</sub>@Co<sub>3</sub>O<sub>4</sub>/N–C). This distinctive architecture contains multiple advantages
of both the yolk–shell structure and conductive N–C
framework to improve the Li ion storage performance. Especially, the
doping of the N atom in N–C increases the interaction between
the carbon and adsorbents, which is confirmed by the theoretical calculations
in this work, making the carbon framework much more electrochemically
active. As a result, the Co<sub>3</sub>O<sub>4</sub>@Co<sub>3</sub>O<sub>4</sub>/N–C exhibits fast surface-controlled kinetics,
which corroborate the high counterion mobility and the ultrafast electron-transfer
kinetics of the electrode. Due to these synergetic effects, desired
capacity stability (1169.6 mAh g<sup>–1</sup> at 200 mA g<sup>–1</sup> after 100 cycles) and superior rate performance (633.4
mAh g<sup>–1</sup> at 10 A g<sup>–1</sup>) have been
realized in this Co<sub>3</sub>O<sub>4</sub>@Co<sub>3</sub>O<sub>4</sub>/N–C electrode
Dual-Porosity SiO<sub>2</sub>/C Nanocomposite with Enhanced Lithium Storage Performance
Mesoporous
SiO<sub>2</sub> nanospheres (MSNs) and carbon nanocomposite
with dual-porosity structure (DMSNs/C) were synthesized via a straightforward
approach. Both MSNs and DMSNs/C showed uniform pore size distribution,
high specific surface area, and large pore volume. When evaluated
as an anode material for lithium ion batteries (LIBs), the DMSNs/C
nanocomposite not only delivered an impressive reversible capacity
of 635.7 mAh g<sup>–1</sup> (based on the weight of MSNs in
the electrode material) over 200 cycles at 100 mA g<sup>–1</sup> with Coulombic efficiency (CE) above 99% but also exhibited excellent
rate capability. The significant improvement of the electrochemical
performance was attributed to synergetic effects of the dual-mesoporous
structure and carbon coating layer: (i) the dual-porosity structure
could increase the contact area and facilitate Li<sup>+</sup> diffusion
at the interface between the electrolyte and active materials, as
well as buffer the volume change of MSNs, and (ii) the homogeneous
carbon coating represented an excellent conductive layer, thus significantly
speeding the lithiation process of the MSNs significantly, while further
restraining the volume expansion. Considering the facile preparation
and good lithium storage abilities, the DMSNs/C nanocomposite holds
promise in applications in practical LIBs
Supplementary_1 – Supplemental material for Effects of Information Technology–Based Two-Way Referral on Diagnosis and Management of Cervical Lesions: A Cluster-Controlled Trial in China
<p>Supplemental material, Supplementary_1 for Effects of Information Technology–Based Two-Way Referral on Diagnosis and Management of Cervical Lesions: A Cluster-Controlled Trial in China by Long-Mei Jin, Ling Xu, Jun Xu, Xiao-Hua Zhang, Lin-Lin Zhang, Li-Hong Zhu, Hui-Bin Yang, Lei Zhang, Yan Yao and Hua Feng in Asia Pacific Journal of Public Health</p
A Novel Layered Sedimentary Rocks Structure of the Oxygen-Enriched Carbon for Ultrahigh-Rate-Performance Supercapacitors
In this paper, gelatin as a natural
biomass was selected to successfully
prepare an oxygen-enriched carbon with layered sedimentary rocks structure,
which exhibited ultrahigh-rate performance and excellent cycling stability
as supercapacitors. The specific capacitance reached 272.6 F g<sup>–1</sup> at 1 A g<sup>–1</sup> and still retained 197.0
F g<sup>–1</sup> even at 100 A g<sup>–1</sup> (with
high capacitance retention of 72.3%). The outstanding electrochemical
performance resulted from the special layered structure with large
surface area (827.8 m<sup>2</sup> g<sup>–1</sup>) and high
content of oxygen (16.215 wt %), which effectively realized the synergistic
effects of the electrical double-layer capacitance and pseudocapacitance.
Moreover, it delivered an energy density of 25.3 Wh kg<sup>–1</sup> even with a high power density of 34.7 kW kg<sup>–1</sup> and ultralong cycling stability (with no capacitance decay even
over 10 000 cycles at 2 A g<sup>–1</sup>) in a symmetric
supercapacitor, which are highly desirable for their practical application
in energy storage devices and conversion
Supplement_2-CONSORT_checklist – Supplemental material for Effects of Information Technology–Based Two-Way Referral on Diagnosis and Management of Cervical Lesions: A Cluster-Controlled Trial in China
<p>Supplemental material, Supplement_2-CONSORT_checklist for Effects of Information Technology–Based Two-Way Referral on Diagnosis and Management of Cervical Lesions: A Cluster-Controlled Trial in China by Long-Mei Jin, Ling Xu, Jun Xu, Xiao-Hua Zhang, Lin-Lin Zhang, Li-Hong Zhu, Hui-Bin Yang, Lei Zhang, Yan Yao and Hua Feng in Asia Pacific Journal of Public Health</p
Carbon-Free Porous Zn<sub>2</sub>GeO<sub>4</sub> Nanofibers as Advanced Anode Materials for High-Performance Lithium Ion Batteries
In
this work, carbon-free, porous, and micro/nanostructural Zn<sub>2</sub>GeO<sub>4</sub> nanofibers (p-ZGONFs) have been prepared via a dissolution-recrystallization-assisted
electrospinning technology. The successful electrospinning to fabricate
the uniform p-ZGONFs mainly benefits from the preparation of completely
dissolved solution, which avoids the sedimentation of common Ge-containing
solid-state precursors. Electrochemical tests demonstrate that the
as-prepared p-ZGONFs exhibit superior Li-storage properties in terms
of high initial reversible capacity of 1075.6 mA h g<sup>–1</sup>, outstanding cycling stability (no capacity decay after 130 cycles
at 0.2 A g<sup>–1</sup>), and excellent high-rate capabilities
(e.g., still delivering a capacity of 384.7 mA h g<sup>–1</sup> at a very high current density of 10 A g<sup>–1</sup>) when
used as anode materials for lithium ion batteries (LIBs). All these
Li-storage properties are much better than those of Zn<sub>2</sub>GeO<sub>4</sub> nanorods prepared by a hydrothermal process. The
much enhanced Li-storage properties should be attributed to its distinctive
structural characteristics including the carbon-free composition,
plentiful pores, and macro/nanostructures. Carbon-free composition
promises its high theoretical Li-storage capacity, and plentiful pores
cannot only accommodate the volumetric variations during the successive
lithiation/delithiation but can also serve as the electrolyte reservoirs
to facilitate Li interaction with electrode materials
Nanoscale Polysulfides Reactors Achieved by Chemical Au–S Interaction: Improving the Performance of Li–S Batteries on the Electrode Level
In this work, the chemical interaction
of cathode and lithium polysulfides
(LiPSs), which is a more targeted approach for completely preventing
the shuttle of LiPSs in lithium–sulfur (Li–S) batteries,
has been established on the electrode level. Through simply posttreating
the ordinary sulfur cathode in atmospheric environment just for several
minutes, the Au nanoparticles (Au NPs) were well-decorated on/in the
surface and pores of the electrode composed of commercial acetylene
black (CB) and sulfur powder. The Au NPs can covalently stabilize
the sulfur/LiPSs, which is advantageous for restricting the shuttle
effect. Moreover, the LiPSs reservoirs of Au NPs with high conductivity
can significantly control the deposition of the trapped LiPSs, contributing
to the uniform distribution of sulfur species upon charging/discharging.
The slight modification of the cathode with <3 wt % Au NPs has
favorably prospered the cycle capacity and stability of Li–S
batteries. Moreover, this cathode exhibited an excellent anti-self-discharge
ability. The slight decoration for the ordinary electrode, which can
be easily accessed in the industrial process, provides a facile strategy
for improving the performance of commercial carbon-based Li–S
batteries toward practical application