Sodium‐ion batteries (SIBs) have attracted enormous attention in recent years due to the high abundance and low cost of sodium. However, in contrast to lithium‐ion batteries, conventional graphite is unsuitable for SIB anodes because it is much more difficult to intercolate the larger Na ions into graphite layers. Therefore, it is critical to develop new anode materials for SIBs for practical use. Here, heteroatom‐doped graphene with high doping levels and disordered structures is prepared using a simple and economical thermal process. The solvothermal‐derived graphene shows excellent performance as an anode material for SIBs. It exhibits a high reversible capacity of 380 mAh g−1 after 300 cycles at 100 mA g−1, excellent rate performance 217 mAh g−1 at 3200 mA g−1, and superior cycling performance at 2.0 A g−1 during 1000 cycles with negligible capacity fade.
Unlike the excellent (S)-enantioselective epoxidation of styrene performed by natural styrene monooxygenase (ee >99%), the (R)-enantioselective epoxidation of styrene has not yet achieved a comparable efficiency using natural or engineered...
Exploring
the catalytic promiscuity of enzymes is a longstanding
challenge and a current topic of interest. Our group previously modified
a cytochrome P450BM3 monooxygenase to perform peroxygenase activity
with assistance from a rationally designed dual-functional small molecule
(DFSM). However, the DFSM-facilitated P450-H2O2 system showed limited peroxidase activity. On the basis of a mechanistic
analysis of the possible competitive oxidation pathways, the present
work applies a protein engineering strategy of mutating redox-sensitive
residues that enables the peroxygenase system to achieve efficient
peroxidase activity. The engineered system exhibits efficient one-electron
oxidation activity toward various substrates, including guaiacol,
2,6-dimethoxyphenol, o-phenylenediamine, and p-phenylenediamine. This system attains the best peroxidase
activity of any P450 reported to date and rivals most natural peroxidases,
suggesting significant potential for practical applications. This
work provides insights and strategies relevant for expanding the catalytic
promiscuity of P450s through combining the effects of protein engineering
and exogenous molecules.
It is a great challenge to optionally access diverse hydroxylation products from a given substrate bearing multiple reaction sites of sp 3 and sp 2 CÀ H bonds. Herein, we report the highly selective divergent hydroxylation of alkylbenzenes by an engineered P450 peroxygenase driven by a dual-functional small molecule (DFSM). Using combinations of various P450BM3 variants with DFSMs enabled access to more than half of all possible hydroxylated products from each substrate with excellent regioselectivity (up to > 99 %), enantioselectivity (up to > 99 % ee), and high total turnover numbers (up to 80963). Crystal structure analysis, molecular dynamic simulations, and theoretical calculations revealed that synergistic effects between exogenous DFSMs and the protein environment controlled regio-and enantioselectivity. This work has implications for exogenous-molecule-modulated enzymatic regiodivergent and enantioselective hydroxylation with potential applications in synthetic chemistry.
Directly from terminal alkynes and with N-halosuccinimides (halo = Br and I) or N-cholorophthalimide as the halogen sources, DBU as the activator, 1-haloalkynes were prepared in good to excellent yields at room temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.