Spectroscopic Properties,Conformation and Structure of Difluorothiophosphoryl Isocyanate in the Gaseous and Solid Phase

Difluorothiophosphoryl isocyanate, F₂P(S)NCO was characterized with UV/vis, NMR, IR (gas and Ar-matrix), and Raman (liquid) spectroscopy. Its molecular structure was also established by means of gas electron diffraction (GED) and single crystal X-ray diffraction (XRD) in the gas phase and solid state, respectively. The analysis of the spectroscopic data and molecular structures is complemented by extensive quantum-chemical calculations. Theoretically, the C_s symmetric syn-conformer is predicted to be the most stable conformation. Rotation about the P−N bond requires about 9 kJ mol⁻¹ and the predicted existence of an anti-conformer is dependent on the quantum-chemical method used. This syn-orientation of the isocyanate group is the only one found in the gas phase and contained likewise in the crystal. The overall molecular structure is very similar in gas and solid, despite in the solid state the molecules arrange through intramolecular O⋅⋅⋅F contacts into layers, which are further interconnected by S⋅⋅⋅N, S⋅⋅⋅C and C⋅⋅⋅F contacts. Additionally, the photodecomposition of F₂P(S)NCO to form CO, F₂P(S)N, and F₂PNCO is observed in the solid Ar-matrix.     

Visible‐Light‐Enabled Stereodivergent Synthesis of E‐ and Z‐Configured 1,4‐Dienes by Photoredox/Nickel Dual Catalysis

A stereodivergent reductive coupling reaction between allylic carbonates and vinyl triflates to furnish both E‐ and Z‐configured 1,4‐dienes has been achieved by visible‐light‐induced photoredox/nickel dual catalysis. The mild reaction conditions allow good compatibility of both vinyl triflates and allylic carbonates. Notably, the stereoselectivity of this synergistic cross‐electrophile coupling can be tuned by an appropriate photocatalyst with a suitable triplet‐state energy, providing a practical and stereodivergent means to alkene synthesis. Preliminary mechanistic studies shed some light on the coupling step as well as the control of the stereoselectivity step.     

Host–Guest Complexation of Amphiphilic Molecules at the Air–Water Interface Prevents Oxidation by Hydroxyl Radicals and Singlet Oxygen

The oxidation of antioxidants by oxidizers imposes great challenges to both living organisms and the food industry. Here we show that the host–guest complexation of the carefully designed, positively charged, amphiphilic guanidinocalix[5]arene pentadodecyl ether (GC5A‐12C) and negatively charged oleic acid (OA), a well‐known cell membrane antioxidant, prevents the oxidation of the complex monolayers at the air–water interface from two potent oxidizers hydroxyl radicals (OH) and singlet delta oxygen (SDO). OH is generated from the gas phase and attacks from the top of the monolayer, while SDO is generated inside the monolayer and attacks amphiphiles from a lateral direction. Field‐induced droplet ionization mass spectrometry results have demonstrated that the host–guest complexation achieves steric shielding and prevents both types of oxidation as a result of the tight and “sleeved in” physical arrangement, rather than the chemical reactivity, of the complexes.     

π‐Interactions between Cyclic Carbocations and Aromatics Cause Zeolite Deactivation in Methanol‐to‐Hydrocarbon Conversion

The understanding of catalyst deactivation represents one of the major challenges for the methanol‐to‐hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π‐interactions in catalyst deactivation in the MTH reaction on zeolites H‐SSZ‐13 and H‐ZSM‐5. π‐interaction‐induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two‐dimensional solid‐state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology.     

Adjusting the chromatographic properties of poly(ionic liquid)‐modified stationary phases by substitution on the imidazolium cation

Poly(ionic liquid)‐modified stationary phases can have multiple interactions with solutes. However, in most stationary phases, separation selectivity is adjusted by changing the poly(ionic liquid) anions. In this work, two poly(ionic liquid)‐modified silica stationary phases were prepared by introducing the cyano or tetrazolyl group on the pendant imidazolium cation on the polymer chains. Various analytes were selected to investigate their mechanism of retention in the stationary phases using different mobile phases. Two poly(ionic liquid)‐modified stationary phases can provide various interactions toward solutes. Compared to the cyano‐functionalized poly(ionic liquid) stationary phase, the tetrazolyl‐functionalized poly(ionic liquid) stationary phase provides additional cation‐exchange and π‐π interactions, resulting in different separation selectivity toward analytes. Finally, applicability of the developed stationary phases was demonstrated by the efficient separation of nonsteroidal anti‐inflammatory drugs.     

Purification and antioxidant capacity analysis of anthocyanin glucoside cinnamic ester isomers from Solanum nigrum fruits

In a recent study, anthocyanins, which have a strong free radical‐scavenging activity, were examined for their potential to effectively prevent cancer. However, clinical trials are limited by the purity of the anthocyanin. Multiple methods are used to extract and purify anthocyanins. Based on previous work on Solanum nigrum, which is a widely distributed plant, in this study, DM130 macroporous resin, Sephadex LH20, and a C18 column were used to separate cis–trans anthocyanin isomers. These anthocyanins constitute the majority of total S. nigrum anthocyanins. The results showed that this “DM130‐LH20‐C18 system” can be used to obtain a cinnamic acid‐derived cis–trans anthocyanin, petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside, with a purity of 98.5%, for effective quantitation. In order to determine the antioxidant ability of the petunidin‐3‐(p‐coumaroyl)‐rutinoside‐5‐glucoside cis–trans isomers, three ordinary methods were adopted. The maximum antioxidant ability of the cis–trans anthocyanin was dozens of times higher than that of vitamin C.     

Coupled Electrical Conduction in Coordination Polymers: From Electrons/Ions to Mixed Charge Carriers

The coupled transport of ions and electrons is of great potential for next‐generation sensors, energy storage and conversion devices, optoelectronics, etc. Coordination polymers (CPs) intrinsically have both transport pathways for electrons and ions, however, the practical conductivities are usually low. In recent years, significant advances have been made in electronic or ionic conductive coordination polymers, which also results in progress in mixed ionic‐electronic conductive coordination polymers. Here we start from electronic and ionic conductive CPs to mixed ionic‐electronic conductive CPs. Recent advances in the design of mixed ionic‐electronic conductive CPs are summarized. In addition, devices based on mixed conduction are selected.     

Hybrid-triggered control for fuzzy Markov jump systems under input saturation

Nonlinear Dynamics - This article investigates the issue of hybrid-triggered control for fuzzy Markov jump system under input saturation. First, a hybrid-triggered control scheme is presented,...     

On the position of the upper limit temperature of homogeneous nucleation of precipitates in low concentrated Al?Zn alloys

The upper limit temperature T_hn of the onset of homogeneous nucleation of Guinier-Preston (GP) zones was determined for three Al Zn alloys with xZn = 4.5, 6.0 and 8.0 at.% by SAXS investigations (cooling from the range of homogeneity to various temperatures T_a and ageing at T_a). The results are T_hn = (95 ± 3) °C for xZn = 4.5 at.%, (118 ± 3) °C (6.0 at.%) and (154 ± 3) °C (8.0 at.%), respectively. The obtained results fit well the data known for the alloys with higher contents of Zn. It is stressed that one has to distinguish between T_hn, determined by isothermal measurements after a direct quench or cooling to the respective T_a, and the upper limit temperature T_rhn of the onset of the rapid homogeneous nucleation of GP zones (continuous cooling).