9 research outputs found
Photochemical C(sp<sup>3</sup>)–H Activation for Diversity-Oriented Synthesis of 3‑Functionalized Oxindoles
Heteroatom-adjacent C(sp3) radical cyclization
of N-arylacrylamides provides a straightforward pathway
to
synthesize valuable 3-functionalized oxindoles. Traditional cyclization
reactions normally require harsh conditions or transition-metal catalysts.
Here, we developed a metal-free, diversity-oriented synthesis of 3-functionalized
oxindoles via photochemically induced selective cleavage of C(sp3)–H bonds. A variety of 3-substituted oxindoles with
functionalities such as ethers, polyhalogens, benzyl, and formyl groups
can be obtained by a rational design. This strategy is characterized
by its simple operation and mild conditions, aligning well with the
developmental requirements for sustainable chemistry. The gram-scale
continuous-flow synthesis and efficient construction of bioactive
molecules highlight its practical utility
Electroplating Sludge-Derived Multiple-Metal-Doped Spinel with Superior CO Selectivity in Reverse Water–Gas-Shift Reaction
At
present, carbon reduction is one of the hottest topics and CO
is the raw source of many industrial products. For the first time,
this work reported CO2 conversion to CO with superior selectivity
via hydrogenation using an electroplating sludge-derived catalyst.
As a result, the optimized catalyst attained a best CO2 conversion of 45.88% and CO selectivity of 99.97% at 600 °C.
What is more, the catalyst stably maintained a high conversion of
55.39% and selectivity of 99.68% for 100 h at 550 °C. At the
same time, the total amount of byproducts was less than 0.32%. After
detailed characterizations, the catalyst was featured by CuFeMn-doped
ZnCr spinel, which had the ability of mild C–O dissociation
and weak CO adsorption. After all, above results show that electroplating
sludge is a good precursor for the synthesis of spinel for excellent
catalytic CO2 conversion to CO
Photoinduced Phosphination of Arenes Enabled by an Electron Donor–Acceptor Complex Using Thianthrenium Salts
Herein,
we describe a metal-free approach for the cross-coupling
of arenes or styryl–thianthrenium salts (TTs) with diarylphosphines
via an electron donor–acceptor (EDA) complex. Various tertiary
phosphines were obtained with high site selectivity and good functional
group tolerance. This method enables straightforward construction
of C–P bonds via C–H activation of arenes and allows
the late-stage functionalization of natural products or pharmaceutical
molecules. Mechanistic studies support the approach involving a photoinduced
EDA complex
Photosynthesis of C‑1-Deuterated Aldehydes via Chlorine Radical-Mediated Selective Deuteration of the Formyl C–H Bond
C-1-deuterated aldehydes are essential building blocks
in the synthesis
of deuterated chemicals and pharmaceuticals. This has led chemists
to devise mild methodologies for their efficient production. Ideally,
hydrogen–deuterium exchange (HDE) is the most effective approach.
However, the traditional HDE for creating C-1-deuterated aldehydes
often requires a complex system involving multiple catalysts and/or
ligands. In this study, we present a mild photocatalytic HDE of the
formyl C–H bond with D2O. This process is facilitated
by chlorine radicals that are generated in situ from
low-cost FeCl3. This strategy demonstrated a broad reaction
scope and high functional group tolerance, affording good yields and
≤99% D incorporation. To bridge the gap between research and
industrial applications, we designed a new flow photoreactor equipped
with a high-intensity light-emitting diode bucket, enabling the synthesis
of C-1-deuterated aldehydes on a scale of 85 g. Finally, we successfully
produced several important deuterated aldehydes that are integral
to the synthesis of deuterated pharmaceuticals
Data_Sheet_1_Childhood Experiences and Psychological Distress: Can Benevolent Childhood Experiences Counteract the Negative Effects of Adverse Childhood Experiences?.docx
BackgroundChildhood experiences can exert a huge impact on adult psychological conditions. Previous studies have confirmed the effects of adverse childhood experiences (ACEs) and benevolent childhood experiences (BCEs) on psychological distress (e.g., stress, depression, and suicidal ideation) separately, but few studies explored a combined effect of ACEs and BCEs on psychological distress. The aim of this study was to explore a combined effect of ACEs and BCEs on psychological distress among Chinese undergraduates.MethodsParticipants were undergraduates aged 17–24 years (N = 1,816) and completed a self-reported questionnaire. A series of regression analyses were conducted to examine the association between childhood experiences and psychological distress.ResultsA total of 65.7% of undergraduates had BCEs, 27.1% of undergraduates had ACEs, and 12.9% of undergraduates had ACEs and BCEs simultaneously. Logistic regression analysis indicated that undergraduates who experienced high ACEs were more likely to have a high risk of psychological distress [odds ratio (ORs) = 1.46, 1.84, and 3.15 for uncertainty stress, depressive symptoms, and suicidal ideation, respectively], while undergraduates who experienced High BCEs were less likely to have psychological distress (ORs = 0.33, 0.22, and 0.32 for uncertainty stress, depressive symptoms, and suicidal ideation, respectively) compared with Low-Both group. The combined effect of ACEs and BCEs (High-Both group) could also play as a protective factor in uncertainty stress (OR = 0.56) and depressive symptoms (OR = 0.47).ConclusionOur findings suggested that ACEs and BCEs could not only predict the psychological distress independently, but also BCEs could counteract the negative effect of ACEs in psychological problems. There is an even greater need to identify and support the victims of ACEs and to increase BCEs in early childhood.</p
Metal-Level Thermally Conductive yet Soft Graphene Thermal Interface Materials
Along
with the technology evolution for dense integration of high-power,
high-frequency devices in electronics, the accompanying interfacial
heat transfer problem leads to urgent demands for advanced thermal
interface materials (TIMs) with both high through-plane thermal conductivity
and good compressibility. Most metals have satisfactory thermal conductivity
but relatively high compressive modulus, and soft silicones are typically
thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material
with the thermal conductivity up to metal level for TIM application.
This study solves this problem by constructing a graphene-based microstructure
composed of mainly vertical graphene and a thin cap of horizontal
graphene layers on both the top and bottom sides through a mechanical
machining process to manipulate the stacked architecture of conventional
graphene paper. The resultant graphene monolith has an ultrahigh through-plane
thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of
0.87 MPa, comparable to that of silicones. In the actual TIM performance
measurement, the system cooling efficiency with our graphene monolith
as TIM is 3 times as high as that of the state-of-the-art commercial
TIM, demonstrating the superior ability to solve the interfacial heat
transfer issues in electronic systems
Metal-Level Thermally Conductive yet Soft Graphene Thermal Interface Materials
Along
with the technology evolution for dense integration of high-power,
high-frequency devices in electronics, the accompanying interfacial
heat transfer problem leads to urgent demands for advanced thermal
interface materials (TIMs) with both high through-plane thermal conductivity
and good compressibility. Most metals have satisfactory thermal conductivity
but relatively high compressive modulus, and soft silicones are typically
thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material
with the thermal conductivity up to metal level for TIM application.
This study solves this problem by constructing a graphene-based microstructure
composed of mainly vertical graphene and a thin cap of horizontal
graphene layers on both the top and bottom sides through a mechanical
machining process to manipulate the stacked architecture of conventional
graphene paper. The resultant graphene monolith has an ultrahigh through-plane
thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of
0.87 MPa, comparable to that of silicones. In the actual TIM performance
measurement, the system cooling efficiency with our graphene monolith
as TIM is 3 times as high as that of the state-of-the-art commercial
TIM, demonstrating the superior ability to solve the interfacial heat
transfer issues in electronic systems
Metal-Level Thermally Conductive yet Soft Graphene Thermal Interface Materials
Along
with the technology evolution for dense integration of high-power,
high-frequency devices in electronics, the accompanying interfacial
heat transfer problem leads to urgent demands for advanced thermal
interface materials (TIMs) with both high through-plane thermal conductivity
and good compressibility. Most metals have satisfactory thermal conductivity
but relatively high compressive modulus, and soft silicones are typically
thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material
with the thermal conductivity up to metal level for TIM application.
This study solves this problem by constructing a graphene-based microstructure
composed of mainly vertical graphene and a thin cap of horizontal
graphene layers on both the top and bottom sides through a mechanical
machining process to manipulate the stacked architecture of conventional
graphene paper. The resultant graphene monolith has an ultrahigh through-plane
thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of
0.87 MPa, comparable to that of silicones. In the actual TIM performance
measurement, the system cooling efficiency with our graphene monolith
as TIM is 3 times as high as that of the state-of-the-art commercial
TIM, demonstrating the superior ability to solve the interfacial heat
transfer issues in electronic systems
Metal-Level Thermally Conductive yet Soft Graphene Thermal Interface Materials
Along
with the technology evolution for dense integration of high-power,
high-frequency devices in electronics, the accompanying interfacial
heat transfer problem leads to urgent demands for advanced thermal
interface materials (TIMs) with both high through-plane thermal conductivity
and good compressibility. Most metals have satisfactory thermal conductivity
but relatively high compressive modulus, and soft silicones are typically
thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material
with the thermal conductivity up to metal level for TIM application.
This study solves this problem by constructing a graphene-based microstructure
composed of mainly vertical graphene and a thin cap of horizontal
graphene layers on both the top and bottom sides through a mechanical
machining process to manipulate the stacked architecture of conventional
graphene paper. The resultant graphene monolith has an ultrahigh through-plane
thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of
0.87 MPa, comparable to that of silicones. In the actual TIM performance
measurement, the system cooling efficiency with our graphene monolith
as TIM is 3 times as high as that of the state-of-the-art commercial
TIM, demonstrating the superior ability to solve the interfacial heat
transfer issues in electronic systems
