Copper-Mediated Di- and Monofluoromethanesulfonylation of Arenediazonium Tetrafluoroborates： Probing the Fluorine Effect

A copper-mediated di- and monoffuoromethanesulfonylation of arenediazonium tetrafluoroborates using di- and monofluoromethanesul- finate reagents provides aryl difluoromethyl （or monofluoromethyl） sulfones in 8ood yields. It was found that the relative reactivity of these sodium fluoroalkanesulfinates in the present reactions decreases in the followin8 order： CH2FSO2Na 〉 CF2HSO2Na 〉 CF3SO2Na.

Fluorine Effects for Tunable C-C and C-S Bond Cleavage in Fluoro-Julia-Kocienski Intermediates

Classical Julia-Kocienski fluoroolefination represents an indispensable platform for the construction of monofluoroalkenes.Nevertheless,its complex multistep mechanistic manifold along with the unrevealed intrinsic“fluorine effect”in nucleophilic reactions might be responsible for the difficult control of the original stereoselectivity and is thus often ambiguous to predict.Herein,a novel strategy involving the defined fluorine effect and new reaction mechanism was developed for tunable C-C and C-S bond cleavage,providing a versatile avenue for highly stereoselective and easily scalable construction of diverse monofluoroalkenes.Density functional theory(DFT)investigations indicate the fluorine substituents can activate the C-C and C-S bond leading toα-elimination by antiphase orbital interaction.The rate-limiting step were calculated via fourmembered transition states with ring strain.Both the sterically eclipsed repulsion and secondary orbital interaction affect the stereoselectivity.

Fluorine substitution position effects on spiro(fluorene-9,9’-xanthene) cored hole transporting materials for high-performance planar perovskite solar cells

Fluorine substitution in molecular design has become an effective strategy for improving the overall performance of organic photovoltaics.In this study,three low-cost small molecules of spiro-linked hole transporting materials(SFX-O-2 F,SFX-m-2 F,and SFX-p-2 F) endowed with two-armed t rip he ny la mine moieties were synthesized via tuning of the fluorine substitution position,and they were employed for use in highly efficient perovskite solar cells(PSCs).Despite the fluorine substitution position playing a negligible role in the optical and electrochemical properties of the resulting small molecules,the photovoltaic performance thereof was observed to vary significantly.The planar n-i-p PSCs based on SFX-m-2 F demonstrated superior performance(18.86%) when compared to that of the corresponding SFX-o-2 F(9.7%) and SFX-p-2 F(16.33%) under 100 mW cm^(-2) AM1.5 G solar illumination,which is competitive with the performance of the benchmark spiro-OMeTAD-based device(18.98%).Moreover,the SFX-m-2 Fbased PSCs were observed to be more stable than the spiro-OMeTAD-based devices under ambient conditions.The improved performance of SFX-m-2 F is primarily associated with improved morphology,more efficient hole transport,and extraction characteristics at the perovskite/HTM interface.This work demonstrated the application of fluorination engineering to the tuning of material film morphology and charge transfer properties,showing the promising potential of fluorinated SM-HTMs for the construction of low-cost,high-efficiency PSCs.

Fluoridation routes,function mechanism and application of fluorinated/fluorine-doped nanocarbon-based materials for various batteries:A review

With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.

Study of Direct Determination of Trace Lanthanum in Biological Samples by ICP－AES Combined with Fluo

A new method for direct determination of lanthanum in solid biological materials by fluorination electrothermal vaporization ICP-AES technique with polytetrafluoroethylene(PTFE) disperser as a fluorination agent has been described. The effect of particle size on the signal intensity of La has been investigated. The vaporization behaviour of lanthanum and the main factors affecting fluorinating vaporization have been observed.Under optimum experimental conditions,the detection limit of La to this method is 2.0 ng/ml,and the RSD is 4.5%.The proposed method has been applied to determining directly trace lanthanum in solid biological standard reference materials without any chemical pretreatment,and the determined values are in good agreement with the certified ones.

Theoretical studies on the substitution effect of fluorine on ethylene

The substitution effect of fluorine on ethylene is investigated by means of studying the properties of the charge distribution at the bond critical points with the theory of atoms in molecules.It is found that fluorine atom acts not only as a σ electron acceptor,but also as a π electron donor,and these double effects are reflected in the quantity of ellipticity,Lap- lacian and the charge density of charge distribution at the bond critical points.For C—C,C—F bonds,the major axis of elliptical contours is perpendicular to the molecular plane,but for C—H bond,it is parallel to the molecular plane.Other effects originating from the substi- tution have also been discussed.

Synergistic Effect and Fluorination Effect in Ethylene Polymerization by Nickel Phenoxyiminato Catalysts

A series of binuclear nickel phenoxyiminato catalysts with different linkers and fluorine substituents were efficiently synthesized. Binuclear nickel catalysts with rigid linkers showed higher catalytic activity and thermal stability in ethylene polymerization and produced polymers with higher molecular weight possibly due to the larger steric hindrance and metal-metal synergistic effect. The introduction of fluorine atoms on the N-terphenyl moity also enhanced polymerization activity and molecular weight of polymer due to the electronic effect of fluorine atoms.

Diastereoselective Construction of α-Fluoroalkyl Cycloalkanols via Radical Alkylation of α-Fluoroalkyl Ketones

α-Fluoroalkyl (Rf) alcohols are privileged motifs in drugs and pharmaceutically active compounds.As such,it is highly desirable to develop efficient methods for assembling these scaffolds.Herein,a visible-light-induced cascade radical cyclization of alkenyl fluoroalkyl ketones is developed,producing a variety of decorate α-Rf cycloalkanols in promising yields with up to >20 : 1 dr selectivity.A radical chain mechanism involving an intramolecular radical addition to the α-Rf carbonyl group and a subsequent intermolecular hydrogen atom transfer (HAT) has been proposed.Density functional theory (DFT) calculations indicate that a fluorine effect contributes to the radical addition to carbonyls by lowering the π* (C=O) orbital energy of CORf and energy barrier of the HAT between alkoxy radicals and THF,which may be valuable for controllable transformations of fluorinated molecules.

Enantioselectivity Tunable Gold-Catalyzed Intermolecular[3+2]Cycloaddition of N-Allenamides with Nitrones

A highly enantioselective gold-catalyzed intermolecular[3+2]cycloaddition of N-allenamides with nitrones was realized by the application of Ming-Phos M6 as a chiral ligand.Both enantiomers of the cycloadducts with opposite configuration could be obtained in high yields with high regio-and enantioselectivity by the employment of either diastereomer of the chiral ligand.The acidic N—H bond(hydrogen bonding)of sulfinamide moiety of Ming-Phos and pentaflurophenyl substituent(fluorine effect)may play important roles in enhancement of enantioselectivity,that is,Ming-Phos is a multifunctional ligand in this transformation.