Advances in the field of phosphorus chemistry are documented, by revealing the synthetic utility of previously underutilized quaternary phosphiranium salts (QPrS) as three-chain-atom electrophilic building blocks. Notably, control of their challenging C-centered electrophilicity is disclosed with an expedient synthesis of tertiary β-anilino phosphines as a proof-of-concept. 相似文献
The combination of supramolecular chemistry and soft colloids as microgels represents an ambitious way to develop multi‐versatile colloidal assemblies. Hereafter, terpyridine‐functionalized poly(N‐isopropylacrylamide) (PNiPAM) microgel building blocks are shown to undergo an assemble–freeze–disassemble process. The microgel assemblies, which are controlled by monitoring the attractive and repulsive potentials between the soft colloidal particles, are then frozen by forming inter‐particle metal–terpyridine bis‐complexes upon addition of the metallic cation (such as FeII, CoII). By oxidation of the metal–terpyridine bis‐complex links, the aggregates open up, which is due to the complex dissociation releasing the connected particles in the form of single microgels. We extended our work to the development of 1D filaments and 2D membranes materials made of soft particles connected via supramolecular chemistry. 相似文献
Abundant phosphorylation events control the activity of nuclear proteins involved in gene regulation and DNA repair. These occur mostly on disordered regions of proteins, which often contain multiple phosphosites. Comprehensive and quantitative monitoring of phosphorylation reactions is theoretically achievable at a residue‐specific level using 1H‐15N NMR spectroscopy, but is often limited by low signal‐to‐noise at pH>7 and T>293 K. We have developed an improved 13Cα‐13CO correlation NMR experiment that works equally at any pH or temperature, that is, also under conditions at which kinases are active. This allows us to obtain atomic‐resolution information in physiological conditions down to 25 μm . We demonstrate the potential of this approach by monitoring phosphorylation reactions, in the presence of purified kinases or in cell extracts, on a range of previously problematic targets, namely Mdm2, BRCA2, and Oct4. 相似文献
From the understanding of biological processes and metalloenzymes to the development of inorganic catalysts, electro‐ and photocatalytic systems for fuel generation have evolved considerably during the last decades. Recently, organic and hybrid organic systems have emerged to challenge the classical inorganic structures through their enormous chemical diversity and modularity that led earlier to their success in organic (opto)electronics. This Minireview describes recent advances in the design of synthetic organic architectures and promising strategies toward (solar) fuel synthesis, highlighting progress on materials from organic ligands and chromophores to conjugated polymers and covalent organic frameworks. 相似文献
The release of molecules entrapped within biogels is dictated by diffusion laws. Innovative biogel architectures are conceived and tested to control small molecule delivery from gelatin gels. The ionic interactions modulate the release of small molecules. Alginate is then added to gelatin gels and further hydrolyzed; the influence of viscosity is discussed. Next, various mixed gels are compared, such as a gelatin‐alginate IPN and the original architecture of an alginate gel entrapped in a gelatin gel with or without a polysaccharidase. The relative influence of ionic interactions and diffusional constraints on the delivery of small charged molecules is explored, and a solution for controlling diffusion is proposed for any situation.
A molecular photocatalyst consisting of a RuII photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light‐driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy shows that the intramolecular photophysics are not affected by this change. Additionally, the general catalytic behavior, that is, instant hydrogen formation, a constant turnover frequency, and stability are maintained. Unlike as observed for the Pd analogue, the presence of excess halide does not affect the hydrogen generation capacity of the PMD. The highly improved catalytic efficiency is explained by an increased electron density at the Pt catalytic center, this is confirmed by DFT studies. 相似文献
The present paper deals with the modeling of a district boiler (city of La Rochelle, west coast of France), as part of the OptiEnR research project. This “multi-energy” boiler supplies domestic hot water and heats residential and public buildings, using mainly wood and sometimes fuel or gas if necessary. The OptiEnR research project focuses on optimizing the performance of the boiler. Its main objective is to minimize the use of fossil energy, stocking renewable energy during low-demand periods and using it when peak-demand is high. Because of both the complexity of the plant as a whole and the strong interactions between the sub-systems (the wood boiler, the gas-fuel oil boiler, the breaking pressure bottle, the cogeneration plant, the hot water distribution network), a modular approach has been proposed. According to what information is available, a combination of white, grey and black boxes (Hammerstein–Wiener models) has been used to carry out the modeling task. To answer for the lack of information, additional parameters were proposed and identified. The model has been first used in simulation during heating periods, with the aim of optimizing both the parameters of the boilers control systems and the use of wood, gas and fuel oil. Next, it will be used, when adding to the plant a thermal storage unit and implementing a model predictive controller, to improve its functioning, especially reducing the coverage rate of the fossil energy boiler. 相似文献
In order to understand how locally static configurations around gravitationally bound bodies can be embedded in an expanding
universe, we investigate the solutions of general relativity describing a space–time whose spatial sections have the topology
of a 3-sphere with two identical masses at the poles. We show that Israel junction conditions imply that two spherically symmetric
static regions around the masses cannot be glued together. If one is interested in an exterior solution, this prevents the
geometry around the masses to be of the Schwarzschild type and leads to the introduction of a cosmological constant. The study
of the extension of the Kottler space–time shows that there exists a non-static solution consisting of two static regions
surrounding the masses that match a Kantowski–Sachs expanding region on the cosmological horizon. The comparison with a Swiss-Cheese
construction is also discussed. 相似文献