Recently, mechanical milling using a mixer mill or planetary mill has been fruitfully utilized in organic synthesis under solvent-free conditions. This review article provides a comprehensive ...overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels-Alder reactions, oxidations, reductions, halogenation/aminohalogenation,
etc.
The ball milling technique has also been applied to the synthesis of calixarenes, rotaxanes and cage compounds, asymmetric synthesis as well as the transformation of biologically active compounds.
Various solvent-free mechanochemical organic reactions can be realized by ball milling techniques.
Two‐dimensional (2D) black phosphorus (BP) has a unique band structure, but it suffers from low ambient stability owing to its high reactivity to oxygen. Covalent functionalization has been ...demonstrated to passivate the reactive BP effectively, however the reported covalent functionalization methods are quite limited to aryl diazonium and nucleophilic additions affording P−C and P−O−C single bonds, for which the retaining of one unpaired electron in the Group 15 phosphorus atom hampers the passivation effect. Now, covalent azide functionalization of BP nanosheets (BPNSs) is reported, leading to significant enhancement of the ambient stability of BP as confirmed by UV/Vis spectroscopic studies. The most stable configuration of the azide functionalized BPNSs (f‐BPNSs) is predicted by theoretical calculations, featuring the grafting of benzoic acid moiety onto BPNSs via the unprecedented P=N double bonds formed through in situ nitrene as a reactive intermediate.
Stabilizing black phosphorus (BP) via azide passivation: Azide functionalization is developed as a new covalent functionalization approach of BP nanosheets (BPNSs), leading to the formation of unprecedented P=N double bonds. These passivate the reactive BPNSs effectively and contribute to a dramatic enhancement of the ambient stability of BPNSs, with the degradation ratio inhibited by about 12 times relative to the pristine BPNSs.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Manipulating the backbone of small molecule acceptors (SMAs) is of particular importance in developing efficient organic solar cells (OSCs). The common design is constructing 2‐arm SMAs with linear ...or curved backbones. Herein, we report an acceptor 4A‐DFIC with a 4‐arm backbone unexpectedly generated in the reaction of an electron‐rich aromatic diamine and hexaketocyclohexane. Single‐crystal X‐ray diffraction analysis indicates the rigid and twisted molecular plane and the effective molecular stacking of 4A‐DFIC in solid state. 4A‐DFIC shows a low band gap of 1.40 eV and excellent light‐harvesting capability from visible to near‐infrared region. Binary and ternary OSCs based on 4A‐DFIC gave power conversion efficiencies (PCEs) of 15.76 % and 18.60 % (certified 18.1 %), respectively, which are the highest PCEs for multi‐arm SMA‐based OSCs to date.
A 4‐arm small molecule acceptor (SMA) 4A‐DFIC was serendipitously made. Power conversion efficiencies of 15.76 % and 18.60 % were achieved in 4A‐DFIC‐based binary and ternary organic solar cells, respectively, setting new records for multi‐arm SMA‐based solar cells.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The serendipitous discovery of dumb‐bell‐shaped C120 under high‐speed vibration milling conditions is described. The mechanochemical protocol has been employed to synthesize the He‐, H2‐ or ...H2O‐encapsualted C120, the cross‐dimer C130, trimer C180, bridged C60 dimers as well as products from many other reactions of fullerenes, carbon nanotubes and graphenes. Mechanochemistry extended to various reactions of non‐fullerene molecules is briefly discussed.
What is the most favorite and original chemistry developed in your research group?
Mechanochemistry and fullerene chemistry.
How do you get into this specific field? Could you please share some experiences with our readers?
The poor solubility of fullerenes in common organic solvents prompts scientists to seek alternative protocol for fullerene chemistry. An idea of performing chemical reactions of fullerenes in the absence of any organic solvent was conceived when I was a guest research fellow in Kyoto University. That was how I first got into the mechanochemical reactions of fullerenes, and made the serendipitous discovery of fullerene dimer C120.
How do you supervise your students?
I encourage my graduate students to do scientific research of their own
ideas within the scope of my group's research interests. I usually emphasize scientific rigor and intolerance of research misconduct to the graduate students when they first join my group. I provide them my guidance on how to do each piece of scientific work including detailed discussion of encountered problems, even spectral analysis and ChemDraw drawing, manuscript writing, etc.
What is the most important personality for scientific research?
Curiosity, creativity, and persistence.
What are your hobbies?
Sports, mainly jogging and running nowadays.
How do you keep balance between research and family?
My balance has heavily leaned toward work thanks to the understanding and support from my family.
The serendipitous discovery of dumb‐bell‐shaped C120 under high‐speed vibration milling conditions is described. The mechanochemical synthesis of encapsualted C120, the cross‐dimer C130, trimer C180, bridged C60 dimers and other molecules is presented.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Variant belief propagation (BP) algorithms are applied to low-density parity-check (LDPC) codes. However, conventional decoders suffer from a large resource consumption due to gathering messages from ...all the neighbour variable-nodes and/or check-nodes through cumulative calculations. In this paper, a check-belief propagation (CBP) decoding algorithm is proposed. Check-belief is used as the probability that the corresponding parity-check is satisfied. All check-beliefs are iteratively enlarged in a sequential recursive order, and successful decoding will be achieved after the check-beliefs are all big enough. Compared to previous algorithms employing a large number of cumulative calculations to gather all the neighbor messages, CBP decoding can renew each check-belief by propagating it from one check-node to another through only one variable-node, resulting in a low complexity decoding with no cumulative calculations. The simulation results and analyses show that the CBP algorithm provides little error-rate performance loss in contrast with the previous BP algorithms, but consumes much fewer calculations and memories than them. It earns a big benefit in terms of complexity.
Abstract
The serendipitous discovery of dumb‐bell‐shaped C
120
under high‐speed vibration milling conditions is described. The mechanochemical protocol has been employed to synthesize the He‐, H
2
‐ ...or H
2
O‐encapsualted C
120
, the cross‐dimer C
130
, trimer C
180
, bridged C
60
dimers as well as products from many other reactions of fullerenes, carbon nanotubes and graphenes. Mechanochemistry extended to various reactions of non‐fullerene molecules is briefly discussed.
What is the most favorite and original chemistry developed in your research group?
Mechanochemistry and fullerene chemistry.
How do you get into this specific field? Could you please share some experiences with our readers?
The poor solubility of fullerenes in common organic solvents prompts scientists to seek alternative protocol for fullerene chemistry. An idea of performing chemical reactions of fullerenes in the absence of any organic solvent was conceived when I was a guest research fellow in Kyoto University. That was how I first got into the mechanochemical reactions of fullerenes, and made the serendipitous discovery of fullerene dimer C
120
.
How do you supervise your students?
I encourage my graduate students to do scientific research of their own
ideas within the scope of my group's research interests. I usually emphasize scientific rigor and intolerance of research misconduct to the graduate students when they first join my group. I provide them my guidance on how to do each piece of scientific work including detailed discussion of encountered problems, even spectral analysis and ChemDraw drawing, manuscript writing,
etc
.
What is the most important personality for scientific research?
Curiosity, creativity, and persistence.
What are your hobbies?
Sports, mainly jogging and running nowadays.
How do you keep balance between research and family?
My balance has heavily leaned toward work thanks to the understanding and support from my family.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Two cycles in one pot! The synthesis of biologically important phenanthridinones has been achieved by the one‐pot formation of CC and CN bonds through a palladium‐catalyzed dual CH activation, ...which involves four bond ruptures and two bond formations (see scheme). The conversion of phenanthridinones into natural product like derivatives further demonstrates the utility of this synthetic achievement.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A highly efficient, air‐ and moisture‐stable and easily recoverable magnetic nanoparticle‐supported palladium catalyst has been developed for the Suzuki, Sonogashira and Heck reactions. A wide range ...of substrates was coupled successfully under aerobic conditions. In particular, the performance of the magnetic separation of the catalyst was very efficient, and it is possible to recover and reuse it at least eight times without significant loss of its catalytic activity.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Energy captured directly from sunlight provides an attractive approach towards fulfilling the need for green energy resources on the terawatt scale with minimal environmental impact. Collecting and ...storing solar energy into fuel through photocatalyzed water splitting to generate hydrogen in a cost-effective way is desirable. To achieve this goal, low cost and environmentally benign urea was used to synthesize the metal-free photocatalyst graphitic carbon nitride (g-C₃N₄). A porous structure is achieved via one-step polymerization of the single precursor. The porous structure with increased BET surface area and pore volume shows a much higher hydrogen production rate under simulated sunlight irradiation than thiourea-derived and dicyanamide-derived g-C₃N₄. The presence of an oxygen atom is presumed to play a key role in adjusting the textural properties. Further improvement of the photocatalytic function can be expected with after-treatment due to its rich chemistry in functionalization.
The majority of the studies on credit risk assessment models for financial institutions during recent years focus on the improvement of imbalanced data or on the enhancement of classification ...accuracy with multistage modeling. Whilst multistage modeling and data pre-processing can boost accuracy somewhat, the heterogeneous nature of data may affects the classification accuracy of classifiers. This paper intends to use the classifier, eXtreme gradient boosting tree (XGBoost), to construct a credit risk assessment model for financial institutions. Cluster-based under-sampling is deployed to process imbalanced data. Finally, the area under the receiver operative curve and the accuracy of classifications are the assessment indicators, in the comparison with other frequently used single-stage classifiers such as logistic regression, self-organizing algorithms and support vector machine. The results indicate that the XGBoost classifier used by this paper achieve better results than the other three and can serve as a superior tool for the development of credit risk models for financial institutions.
•This paper construct a credit risk assessment model for financial institutions.•This paper constructs a credit risk assessment model with the XGBoost method.•The research results can improvement of the loan business efficiency.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
