A continuous/discrete fractional Noether’s theorem

We prove a fractional Noether’s theorem for fractional Lagrangian systems invariant under a symmetry group both in the continuous and discrete cases. This provides an explicit conservation law (first integral) given by a closed formula which can be algorithmically implemented. In the discrete case, the conservation law is moreover computable in a finite number of steps.     

Steric effects on reaction rates II: Rate and equilibrium constants for oxidation of bicyclic alcohols

Equilibrium constants for oxidation of a series of bicyclic alcohols with cyclohexanone have been determined under Meerwein-Ponndorf conditions. The data provide the thermodynamic background for interpretation of the mechanism of alcohol oxidation and ketone reductions. Free energies of the equilibrium (ΔG_ox) are compared with values calculated by molecular mechanics.     

Steric Effects on Reaction Rates. Rate and equilibrium constants for oxidation of cyclanols

Equilibrium constants for oxidations of cyclanols by cyclohexanone in benzene have been determined in the presence of aluminium isopropoxide. The free energies of the equilibrium (ΔG_ox) are correlated with equilibrium constants for dissociation of cyanohydrins, rate constants for cyclanol oxidation with chromic acid, ketone reduction with sodium borohydride and trifluoroethanolysis of tosylates.     

Synthèse d'hétérocycles en catalyse par transfert de phase

A general study of the chemical behavior of heterocyclic anions, dianions and dianionic reagents under phase transfer catalysis conditions allowed us to synthesize various heterocyclic compounds such as imidazo[2,1-b]thiazole and derivatives; imidazo[2,1-b]thiazine and imidazo[2,1-b]benzothiazepine. Reaction conditions e.g., catalyst, solvent, temperature, etc., are indicated.     

Improving the thermoelectric performance and thermal stability of Ca3Co4O9 + δ ceramics by sintering in oxygen atmosphere

Journal of Sol-Gel Science and Technology - We report on the influence of sintering gas atmosphere on the thermoelectric (TE) performance of Ca3Co4O9?+?δ ceramics made from...     

In Situ Monitoring of RAFT Polymerization by Tetraphenylethylene‐Containing Agents with Aggregation‐Induced Emission Characteristics

A facile and efficient approach is demonstrated to visualize the polymerization in situ. A group of tetraphenylethylene (TPE)‐containing dithiocarbamates were synthesized and screened as agents for reversible addition fragmentation chain transfer (RAFT) polymerizations. The spatial‐temporal control characteristics of photochemistry enabled the RAFT polymerizations to be ON and OFF on demand under alternating visible light irradiation. The emission of TPE is sensitive to the local viscosity change owing to its aggregation‐induced emission characteristic. Quantitative information could be easily acquired by the naked eye without destroying the reaction system. Furthermore, the versatility of such a technique was well demonstrated by 12 different polymerization systems. The present approach thus demonstrated a powerful platform for understanding the controlled living radical polymerization process.     

A Multiresponsive Functional AIEgen for Spatiotemporal Pattern Control and All-round Information Encryption

Functional materials with multi-responsive properties and good controllability are highly desired for developing bioinspired and intelligent multifunctional systems. Although some chromic molecules have been developed, it is still challenging to realize in situ multicolor fluorescence changes based on a single luminogen. Herein, we reported an aggregation-induced emission (AIE) luminogen called CPVCM, which can undergo a specific amination with primary amines to trigger luminescence change and photoarrangement under UV irradiation at the same active site. Detailed mechanistic insights were carried out to illustrate the reactivity and reaction pathways. Accordingly, multiple-colored images, a quick response code with dynamic colors, and an all-round information encryption system were demonstrated to show the properties of multiple controls and responses. It is believed that this work not only provides a strategy to develop multiresponsive luminogens but also develops an information encryption system based on luminescent materials.     

Synthesis, structure, redox properties and azide binding for a series of biphenyl-based Cu(II) complexes

A series of biphenyl-based N(3)O ligands, 2, 4, 6, and 8 were synthesized and their Cu(II) complexes prepared. These complexes were characterized by a combination of elemental analysis, FAB-MS, UV-vis spectroscopy and electrochemistry. The structure of [Cu(N(3)O-mpy-NO2)Cl2], 12 [N(3)O-mpy = 2-(3-pyridylmethylimino)-2'-(2-methylaminophenol)biphenyl], was solved and showed that the ligand coordinates through the three nitrogens with the phenol oxygen uncoordinated. Titration of azide anion into solutions of the complexes in methanol resulted in the appearance of a new band between 485-495 nm at the expense of the starting peak at 380 nm. Cyclic voltammetry studies indicated that the complexes undergo quasi-reversible one-electron reductions in acetonitrile at potentials between 0.13-0.58 V vs. Ag/AgCl. The complexes were found to be weakly active for the oxidation of di-tert-butyl catechol (DTBC).     

Switching the light emission of (4-biphenylyl)phenyldibenzofulvene by morphological modulation: crystallization-induced emission enhancement

(4-Biphenylyl)phenyldibenzofulvene is weakly luminescent in the amorphous phase but becomes highly emissive upon crystallization; this unusual crystallization-induced emission enhancement effect allows its emission to be repeatedly switched between dark and bright states by fuming-heating and heating-cooling processes.