Electrophilic Reaction of 2,2,2-Trifluoro­diazoethane with the in Situ Generated <i>N</i>‑Heterocyclic Carbenes: Access to <i>N</i>‑Aminoguanidines

A facile and efficient electrophilic reaction of 2,2,2-trifluorodiazoethane (CF₃CHN₂) with the in situ generated <i>N</i>-heterocyclic carbenes is reported. Under basic conditions, a series of trifluoromethylated <i>N</i>-aminoguanidines were obtained in good to high yields. Furthermore, this protocol was applied in the synthesis of the agrochemical Imidacloprid analogue

Electrophilic Reaction of 2,2,2-Trifluoro­diazoethane with the in Situ Generated <i>N</i>‑Heterocyclic Carbenes: Access to <i>N</i>‑Aminoguanidines

A facile and efficient electrophilic reaction of 2,2,2-trifluorodiazoethane (CF₃CHN₂) with the in situ generated <i>N</i>-heterocyclic carbenes is reported. Under basic conditions, a series of trifluoromethylated <i>N</i>-aminoguanidines were obtained in good to high yields. Furthermore, this protocol was applied in the synthesis of the agrochemical Imidacloprid analogue

Data_Sheet_1_Organic food consumption in China: food safety concerns, perceptions, and purchase behavior under the moderating role of trust.docx

IntroductionIn tandem with economic growth and enhanced individual income levels, the demand for superior food quality has seen a significant uptick, leading to increased consumer interest in organic food products. However, studies focused on organic food consumption reveal a strikingly low conversion rate of this interest into actual purchasing behavior, particularly in the context of China. It is, therefore, crucial to implement effective strategies to bridge this gap, thereby fostering the growth of China's organic food sector.MethodsThis research introduces the theory of perceived values and innovation resistance into the stimulus-organism-response (SOR) theoretical model, exploring the interrelationships among various facets of food safety concerns, perceived values, perceived risks, and organic purchasing behavior. Furthermore, the moderating influence of trust in these relationships is taken into account. Employing structural equation modeling, data from 352 organic food consumers in China's premier cities were analyzed.Results and discussionFindings substantiated the significant interplay between perceived values and risks with food safety concerns. It was also observed that perceived values had a positive and significant impact on purchasing behavior, while perceived risks exerted a negative and significant influence. Importantly, the relationship between nutritional value and risk barrier with purchase behavior was found to be moderated by the level of trust. This study may help organic food producers, retailers, and policymakers bridge the consumers' intention-behavior gap.</p

Field, Experimental, and Modeling Study of Arsenic Partitioning across a Redox Transition in a Bangladesh Aquifer

To understand redox-dependent arsenic partitioning, we performed batch sorption and desorption experiments using aquifer sands subjected to chemical and mineralogical characterization. Sands collected from the redox transition zone between reducing groundwater and oxic river water at the Meghna riverbank with HCl extractable Fe­(III)/Fe ratio ranging from 0.32 to 0.74 are representative of the redox conditions of aquifers common in nature. One brown suboxic sediment displayed a partitioning coefficient (<i>K</i>_d) of 7–8 L kg^–1 at equilibrium with 100 μg L^–1 As­(III), while two gray reducing sediments showed <i>K</i>_d of 1–2 L kg^–1. Lactate amendment to aquifer sands containing 91 mg kg^–1 P-extractable As resulted in the reduction of As and Fe with sediment Fe­(III)/Fe decreasing from 0.54 to 0.44, and mobilized an equivalent of 64 mg kg^–1 As over a month. Desorption of As from nonlactate-amended sediment was negligible with little change in sediment Fe­(III)/Fe. This release of As is consistent with microbial reduction of Fe­(III) oxyhydroxides and the resulting decrease in the number of surface sites on Fe­(III) oxyhydroxides. Arsenic partitioning (<i>K</i>_d) in iron-rich, sulfur-poor aquifers with circumneutral pH is redox-dependent and can be estimated by HCl leachable sediment Fe­(III)/Fe ratio with typical Fe concentrations

Thermal Response of DNA Supramolecular Polymers Assembled with Hydrophobic Sticky Ends

We report the self-assembly and thermal dissociation of DNA dumbbell conjugates having a perylenediimide (PDI) linker on each end separated by 6–16 A–T base pairs. In the presence of NaCl these dumbbells form one-dimensional supramolecular assemblies as a consequence of the hydrophobic association of their PDI sticky ends. The dependence of assembly formation on dumbbell concentration, salt concentration, and temperature can be conveniently monitored by UV–vis spectroscopy. The melting of these linear assemblies follows two limiting mechanisms, depending on the length of the dumbbells. Upon heating in the presence of salt, the assemblies formed by the longer dumbbells undergo a sequential transition from assembly to base-paired monomer to random coiled monomer, whereas the assemblies formed by the shorter dumbbells undergo disassembly and base-pair melting cooperatively. In all cases, the intramolecular hydrophobic association of the PDI chromophores is observed at elevated temperature. The thermal behavior of these one-dimensional assemblies is compared to that of other sticky-ended assemblies

One-Pot Cascade Transformations of Zinc Trifluorodiazoethylide and α,β-Unsaturated Enones: Access to Trifluoromethylated Polycyclic Pyrazolines

One-pot cascade transformations are developed that involve [3 + 2] cycloaddition/Michael/aldol and [3 + 2] cycloaddition/double 1,2-addition reactions of zinc trifluorodiazoethylide with various α,β-unsaturated enones. The protocol provides straightforward access to trifluoromethyl-substituted polycyclic pyrazolines with high chemo-, regio-, and diastereoselectivity

Thermal Response of DNA Supramolecular Polymers Assembled with Hydrophobic Sticky Ends

We report the self-assembly and thermal dissociation of DNA dumbbell conjugates having a perylenediimide (PDI) linker on each end separated by 6–16 A–T base pairs. In the presence of NaCl these dumbbells form one-dimensional supramolecular assemblies as a consequence of the hydrophobic association of their PDI sticky ends. The dependence of assembly formation on dumbbell concentration, salt concentration, and temperature can be conveniently monitored by UV–vis spectroscopy. The melting of these linear assemblies follows two limiting mechanisms, depending on the length of the dumbbells. Upon heating in the presence of salt, the assemblies formed by the longer dumbbells undergo a sequential transition from assembly to base-paired monomer to random coiled monomer, whereas the assemblies formed by the shorter dumbbells undergo disassembly and base-pair melting cooperatively. In all cases, the intramolecular hydrophobic association of the PDI chromophores is observed at elevated temperature. The thermal behavior of these one-dimensional assemblies is compared to that of other sticky-ended assemblies

One-Pot Cascade Transformations of Zinc Trifluorodiazoethylide and α,β-Unsaturated Enones: Access to Trifluoromethylated Polycyclic Pyrazolines

One-pot cascade transformations are developed that involve [3 + 2] cycloaddition/Michael/aldol and [3 + 2] cycloaddition/double 1,2-addition reactions of zinc trifluorodiazoethylide with various α,β-unsaturated enones. The protocol provides straightforward access to trifluoromethyl-substituted polycyclic pyrazolines with high chemo-, regio-, and diastereoselectivity

Ni-Catalyzed Highly Chemo‑, Regio‑, and Enantioselective Decarboxylative Aldol Reaction of β,γ-Unsaturated α‑Ketoesters with β‑Ketoacids

A novel Ni-catalyzed decarboxylative aldol reaction of β,γ-unsaturated α-ketoesters with β-ketoacids is reported. The reaction proceeds smoothly with high chemo-, regio-, and enantioselectivity. This protocol provides a convenient approach to access enantioenriched chiral tertiary alcohols

A Direct Copper-Promoted Three-Component Entry to Trifluoromethylketoximes

A new copper-promoted three-component method for constructing ketoximes has been developed. This transformation can be achieved using indoles/pyrroles with the in situ generated 2,2,2-trifluoro­diazo­ethane and nitrite species under mild conditions, thus offering a direct pathway to (<i>E</i>)-3-indolyl/2-pyrrolyl trifluoro­methyl­ketoximes