CF3 Group Research Articles

Tuning Perovskite Surface Polarity via Dipole Moment Engineering for Efficient Hole-Transport-Layer-Free Sn-Pb Mixed-Perovskite Solar Cells.

Post-treatment has been recognized as one of the effective methods for passivating the underlying defects in perovskite solar cells (PSCs), but little attention has been paid to how to pick suitable passivation agents with diverse isomers for efficient PSCs, particularly for the tin-lead (Sn-Pb) mixed PSCs. Here, we introduce the dependence of the power conversion efficiency (PCE) on a dipole moment for surface passivator screening, in which we chose three trifluoromethyl-phenylethylamine hydroiodide (CF3-PEAI) isomers as surface-treatment materials for hole-transport-layer-free (HTL-free) Sn-Pb mixed PSCs. The different positions of the -CF3 group for the CF3-PEAI isomer result in different dipole moments, which influences the interaction between CF3-PEAI and lead iodide. The para position CF3 with the highest dipole moment exhibits a higher PCE than the ortho-position with a lower dipole moment, which is attributed to the large dipole moment on the surface that could tune the surface polarity from p-type to n-type, facilitating electron charge transport in the HTL-free Sn-Pb mixed PSCs. An ultrathin 2D layer is formed on the perovskite surface to passivate the surface defects, which is responsible for the enhancement of the PCE and stability of the PSCs. As a result, the open-circuit voltage (VOC) of the device is improved from 0.775 to 0.824 V, yielding a champion PCE of 20.17%, which is one of the highest PCEs among the reported HTL-free Sn-Pb mixed PSCs. The device also shows improved stability with remaining 75% of its initial PCEs after storage in N2 for 700 h.

Ab Initio Determination of Molecular Geometry and Vibrational Frequencies of Benzotrifluoride

Using Gaussian 05 Revision C.02 version of the quantum chemical program ab initio computations has been carried out to compute optimized geometry, harmonic vibrational frequencies along with intensities in IR and Raman spectra and atomic charges at rhf / 6–31+g*, b3lyp / 6–31++g** and b3lyp / 6–311++g** levels. The optimized molecular structure is found to possess Cs point group symmetry with the plane of symmetry passing through the C atom, to which the CF3 group is attached, the centrally opposite C atom and the C atom of the CF3 group and perpendicular to the phenyl ring plane. One of the three F atoms of the CF3 group is found to be on one side of the ring plane and is situated on the plane of the symmetry while the other two F atoms are found to be on the other side of the ring plane placed symmetrically on either side of the symmetry plane. Vibrational assignments for the normal modes have been reviewed. To make vibrational assignments for the normal modes of vibration the Gauss View software was used. The CF3 group has the characteristic frequencies in the 340, 768, 1072, 1152 and 1318 cm-1 which are due to the modes δs (CF3), Vs (CF3 ), Vas(CF3) (a’), Vas(CF3) (a”) and V(C–CF3 ) respectively. The torsional frequency of the CF3 group is found to be 16 cm-1 which would lead to barrier height of ~ 0.5 kJ / mol for the torsional motion of the CF3 group.

Tuning interchain cavity of fluorinated polyimide by DABA for improved gas separation performance

Fluorinated polyimides with biphenyl structure and –CF3 with rigid chain structure exhibit great potential in membrane-based gas separation. However, the comprehensive separation performance of this type polyimides is not competitive as a gas separation material. Structure regulation is of great significance to improve the separation performance of polymer membrane. Few studies systematically investigated structure-property relationships in fluorinated polyimide structure. In this study, carboxylic groups are introduced into a fluorinated polyimide(6FDA-TFMB) via copolymerization with DABA diamine monomer. The hydrogen bond between –CF3 group in TFMB and –COOH group in DABA is proposed to enhance chain segment rigidity and optimize polymer chain arrangement. WAXD results and FFV data indicate that inter-chain cavity of fluorinated polyimide could be finely tuned by adjusting molar ratio of TFMB and DABA in the copolyimide. The resulted copolyimide membranes thus demonstrate tunable gas permeation properties. Gas permeability of 6FDA-TFMB/DABA firstly increases and then decreases, and ideal gas selectivity continuously increases with increasing DABA molar ratio. Among the polyimides, 6FDA-TFMB/DABA(6:4) membrane demonstrated superior separation performance, e.g. CO2 permeability of 135.6 Barrer and CO2/CH4 ideal selectivity of 31.6, surpassing the commercial cellulose acetate and Matrimid membrane. Attributed to the optimized interchain interaction, the 6FDA-TFMB/DABA (6:4) membrane displays an optimized CO2 plasticization resistance and physical aging in comparison with 6FDA-TFMB membranes. This study provides a guideline for controlling and optimize the performance of biphenyl fluorinated polyimide gas separation membrane.

Insight into mechanochemical destruction of PFOA by BaTiO3: An electron-dominated reduction process

Perfluorooctanoic acid (PFOA) is a representative persistent organic pollutant and its disposal by mechanochemical (MC) technology emerges in recent years. However, degradation mechanism of PFOA especially rupture of C−F bonds during MC process is still unclear. Therefore, we innovatively employed barium titanate as co-milling reagent in MC system to disclose an electron-dominated reduction process. By stimulating piezoelectric effect of BaTiO3 under MC impact, free electrons were generated. The results implied more than 95.00% degradation and 60.00% defluorination efficiency were obtained after 6 h′ ball milling. DPPH• was used as probe to confirm the existence of piezo-excited electrons, which were further verified to be major reactive species by atmosphere experiments. Thus, PFOA destruction was dominated by reduction process, characterizing by breakage of C−F bonds induced by electrons. Accordingly, the fate of organic fluorides was explored and BaF2 was identified as final product. The cleavage of carboxyl group initiated PFOA decomposition, following by successive removal of CF2 groups and elimination of F−. Moreover, the practical experiments and reusable trials implied promising application of this method. Overall, this paper provides a novel perspective for reductive decomposition of PFOA by MC technology and reveals the major role of electrons during reaction process.

Engineering J-aggregates for NIR-induced meso-CF3-BODIPY nanoparticles by activated apoptosis mechanism in photothermal therapy

Forming J-aggregates by organic monomer is a fascinating strategy to urge spectroscopic redshift with respect to that of the monomer. Herein, we designed 1,7-diphenyl-substituted meso‑CF3-BDP monomer confirmed by X-ray crystallographic analysis. The low-barrier rotation of the –CF3 group in meso‑CF3-BDP 1 significantly enhances the non-radiative efficiency, and the photothermal conversion efficiency (PCE) of the self-assembled nanoparticles (1-NPs: λabs = 746 nm) by J-aggregates was 82%. 1-NPs could effectively block cell cycle progression, inhibit cancer cell proliferation and trigger cell apoptosis under low power laser irradiation (0.2 W/cm2). This study proposes an alternate molecular design platform by J-aggregates to promote PCE through the insertion of rotating segment and trigger the cancer cells apoptosis in photothermal therapy at low power laser density.

Carbotrifluoromethylations of C-C Multiple Bonds (Excluding Aryl- and Alkynyltrifluoromethylations).

Organofluorine chemistry has become an expanding area of research in organic chemistry and drug design. The synthesis of fluorine-containing molecules has received high significance in synthetic chemistry. Trifluoromethylative difunctionalizations of carbon-carbon multiple bonds with the simultaneous introduction of a CF3 group and another function have considerable relevance. Because of the high importance of carbon-carbon bond-forming reactions in organic synthesis, carbotrifluoromethylations are considered to be a field of synthetic chemistry of increasing importance. Our current goal in this review is to summarize recent developments of various trifluoromethylation reactions (excluding aryl- and alkynyl-trifluoromethylations) taking into consideration several main approaches, such as alkenyltrifluoromethylation, alkyltrifluoromethylation, carbonyltrifluoromethylation, and cyanotrifluoromethylation reactions.

In Situ Interfacial Passivation in Aqueous Electrolyte for Mg-Air Batteries with High Anode Utilization and Specific Capacity.

Mg-air batteries are a promising new generation of batteries because they can operate in neutral electrolytes that are safe and nontoxic. However, the high corrosion and low utilization of Mg anodes in Mg-air batteries result in low specific capacity and severe self-discharge. In this study, an Mg(OTf)2 -based aqueous electrolyte is developed, which addresses these issues by reducing the contact of the Mg anode with water molecules from the hydrophobic -CF3 groups and forming an MgF2 protective layer. The assembled Mg-air batteries exhibit specific capacities of up to 1920 mAh g-1 Mg (87.32 % utilization based on the Mg anode). In addition, the resting time of the corresponding Mg-air batteries was 123 times longer than that of Mg-air batteries with pure NaCl electrolytes under the same conditions.

Chalcogen-Bond Catalysis: Telluronium-Catalyzed [4+2]-Cyclocondensation of (in situ Generated) Aryl Imines with Alkenes.

In the chalcogen series, tellurium species exhibit the strongest chalcogen bonding (ChB) interaction with electron-rich atom. This property explains the renewed interested toward tellurium-based derivatives and their use in different applications, such as organocatalysis. In this context, the catalytic activity of telluronium salts in the Povarov reaction is presented herein. Different dienophiles, as well as imines of variable electronic nature, efficiently react in the presence of catalytic amount of either diarylmethyltelluronium or triaryltelluronium salts. Both catalysts could also readily perform the three-component Povarov reaction starting from aldehyde, aniline and dihydrofuran. The reactivity of telluroniums towards imines and aldehydes was confirmed in the solid state by the ability of Te atom to interact through ChB with the oxygen carbonyl of acetone, and in solution with significant shift variations of the imine proton and of the tellurium atom in 1 H and 125 Te NMR spectroscopy. For the most active telluronium catalysts bearing CF3 groups, association constants (K) with N-phenyl phenylmethanimine in the range 22-38 M-1 were measured in dichloromethane.

Reductive Cleavage of C(sp2)–CF3 Bonds in Trifluoromethylpyridines

A reductive detrifluoromethylation protocol has been developed making use of an earth-abundant alkoxide base and silicon hydride species. A variety of pyridine and quinoline substrates bearing alkyl, aryl, and amino functional groups are reduced in moderate to high yields. The reaction is chemoselective for C(sp2)-CF3 groups located at the 2-position on the pyridine ring, leaving trifluoromethyl groups located elsewhere on the molecule intact. Preliminary mechanistic studies demonstrate that the combination of silane and base generates a strongly reducing system that may transfer an electron to electron-deficient π systems.

INTERACTION OF IONIC LIQUIDS BASED ON BIS(TRIFLUOROMETHYLSULFONIL)IMIDE ANION WITH HALLOYSITE NANOTUBES ACCORDING TO FT-IR SPECTROSCOPY

In this work, FT-IR spectroscopy was used to study the interactions in ionogels of the composition х[X]+[TFSI]−/(100 - x)НNT, where [TFSI]– is the bis(trifluoromethylsulfonyl)imide anion, the cation [X]+ = [BMPip]+ (1-butyl-1-methylpiperidinium), [BMPyr]+ (1-butyl-1-methylpyrrolidinium), and [BMIm]+ (1-butyl-3-methylimidazolium), HNT are halloysite nanotubes, х = (55.2±0.5) wt.%. A comparison of the spectra of the starting compounds and the resulting ionogels showed that the characteristic frequency of the stretching vibrations of OH bonds of adsorbed water molecules, observed in the spectra of pure halloysite, practically vanishes in the spectra of ionogel sts. The stretching vibrations of the C-H bond atoms of the cation, ν(CH), and the stretching vibrations of the C-F bond atoms of the CF3 group of the anion, ν(CF3), in the spectra of limited ionic liquids are shifted to the high frequency region by 1-3 cm-1. The ratio of the intensities of the asymmetric bending vibrations of the S=O bond atoms of the SO2 group, I(δasopSO2)/I(δasipSO2), which correspond to two different conformational isomers of the anion, increases by (15-19)%. As a result, it was found that the H2O molecules of halloysite are replaced by molecules of the ionic liquid due to the electrostatic interaction of the cation with the negatively charged outer siloxane (–Si–O–Si–) surface of the nanotubes and hydrogen bonds (CH···OSi), and due to the electrostatic interaction of the anion with a positively charged internal aluminol (–Al–OH) surface and hydrogen bonds (CF···HO–Al, SO···HO–Al). The restriction of the ionic liquid in the internal cavity of the HNT causes a conformational rearrangement of the [TFSI]− anion. The results obtained are of fundamental importance, make a certain contribution to understanding the effects in ionogels based on ionic liquids and nanoporous natural minerals, and can be used to develop quasi-solid electrolytes in the production of various electrochemical devices. For citation: Ramenskaya L.M., Grishina E.P., Kudryakova N.O. Interaction of ionic liquids based on bis(trifluoromethylsulfonil)imide anion with halloysite nanotubes according to FT-IR spectroscopy. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 3. P. 36-44. DOI: 10.6060/ivkkt.20236603.6752.

Validation of valence bond and molecular orbital models in analyzing the anionic hyperconjugation effect on the stability of alkyl and fluorinated carbanions in gaseous phase

AbstractIn this paper, the anionic hyperconjugation occurring in alkyl and fluorinated carbanions in the gaseous phase is examined at density functional theory (DFT) at the level of theory B3LYP/6‐31++G (d,p) with empirical dispersion‐GD3 theory. First, a contribution of this study is to confirm that the C‐H bond in (CH3)3C‐H (isobutane) is more acidic than the C‐H bonds in CH3CH2‐H (ethane) and (CH3)2CH‐H (propane) based on a comparison of conjugate base stability. Also, the natural population analysis (NPA) and CHELPG methods are well‐performed for calculating charge distribution on carbon atoms, and in contrast, the Mulliken population is better for hydrogen atoms to describe the anionic hyperconjugation in the valence bond (VB) model. The molecular orbital model accounts for the stability order of alkyl and perfluorinated carbanions through the number, strength, and overlap geometry between the lone electron pair on carbon atom and the vicinal σ*C‐H/σ*C‐F orbitals. On the other hand, the utility of VB theory becomes invalid because of the strong inductive effect of the fluorine element and the steric repulsion among CF3 groups in perfluorinated carbanions. Also, the hybridization of the carbon atom holding the lone electron pair can become more s‐character or p‐character dependent on the size of surrounding groups.

Evolution and Future of Hetero‐ and Hydro‐Trifluoromethylations of Unsaturated C−C Bonds

AbstractThe difunctionalizative trifluoromethylation of unsaturated C−C bonds is a highly useful and efficient method for the synthesis of trifluoromethyl compounds with attractive architectures from simple feedstocks, allowing the introduction of the CF3 group along with a wide variety of substituents either inter‐ or intramolecularly. Given that trifluoromethyl molecules are increasingly used as promising bioactive species in the design of new drugs and agrochemicals, difunctionalizative trifluoromethylation has been extensively studied during the last decade. This review focuses on reactions proceeding via the simultaneous formation of C−heteroatom (O, N, S, Se, B) and C−H bonds, as these reactions provide useful CF3 group‐containing building blocks. To identify the trends and prospects of the evolution of this methodology, we systematically describe the variants of these types of reactions and provide a more general view of reaction conditions, modes, and mechanisms. The presented comprehensive survey enables the categorization of reactions into those that are synthetically mature and those with room for further development.magnified image

Mobile resistance determinants, plasmid replicon types and phylogeny among Escherichia coli strains isolated from cats and dogs

Abstract
 Multidrug resistance is a great challenge for the treatment of infectious diseases. We determined antibiotic resistance patterns, integrons, plasmid-mediated ESBL-, AmpC beta-lactamase-, carbapenemase-, colistin resistance genes, plasmid replicon types and phylogeny of fecal E. coli strains isolated from domestic cats and dogs in Turkey.
 A total of 104 fecal samples of healthy 49 cats and 55 dogs were examined. The integrons, plasmid-mediated resistance genes, plasmid replicon types and phylogroups were determined by PCR. Antimicrobial susceptibilities were performed by disc diffusion and microdilution methods.
 
 coli strains were mostly resistant to AMP (56.73%), SXT (39.42%), CTX (38.46%) and CIP (30.77%). Colistin resistance was not detected. ESBL and carbapenemase rates were 35.5 % and 7.69%, respectively. Eighty (76.9%) and 49 (47.1%) strains were harboring class I and class II integrons, respectively. Besides 12 strains were shown to possess class III integrons. The most frequently detected genes were blaCTX-M (48.08%), blaTEM (45.19%) and blaVIM (20.19%). In our study, none of strains were positive for mcr-1 and mcr-2 genes. Integrons were mostly found on plasmids of incompatibility groups IncF (71.25%) and strains bearing CTX-M and TEM carried a wide range of plasmid replicons of which IncF, IncFIB, IncK, and IncN. The majority of the strains were grouped in B2 (31.73%) and B1 (22.12%) and resistant bacteria mostly belonged to phylogroup B2.
 
 We showed an increasing trend in ESBL-producing E. coli among fecal microbiota members. E. coli strains with different plasmid replicon types and phylogroups isolated from cats and dogs can be resistant to various antibiotics which are used in human and veterinary medicine.

Rotation‐Inversion Isomerization of Tertiary Carbamates: Potential Energy Surface Analysis of Multi‐Paths Isomerization Using Boltzmann Statistics

The front cover artwork is provided by Prof. Rainer Glaser's group at the Missouri University of Science and Technology. The image shows one of four potential energy surfaces generated from our rotation-inversion study of tertiary carbamates and highlights two of the eight possible transition state pathways between two ensembles of E- and Z-minima. In the context of synthetic studies of fluorinated carbamates R1 O-CO-N(R2 )CH2 CF3 , we unexpectedly observedtwosets of13 C NMR quartets for the CF3 group and we needed to understand their origin. Read the full text of the Research Article at 10.1002/cphc.2022005442.

Effects of chronic stress on bladder morphology of rats and impact of comfort food diet as an ameliorating agent

Objectives To investigate the effects of chronic stress on bladder morphology and the impact of food preference (standard or comfort foods) on the bladder of stressed rats. Methods In total, 32 Wistar male rats (3 months old) were divided into four groups: control (C), stressed (S), control + comfort food (C + CF), and stressed + comfort food (S + CF). Groups C and C + CF were maintained under normal conditions, while groups S and S + CF were subjected to chronic stress by the restraint method. Groups C and S received standard rat chow, while groups C + CF and S + CF received comfort food (Froot Loops®) and standard chow. The stress stimuli were induced daily for 2 h over 8 weeks. After 8 weeks, all animals were killed, and the bladders were removed and used for histomorphometric analysis. Results Body mass was similar among the groups. Stress did not promote differences regarding food intake, but animals receiving comfort food showed higher calories intake (in kcal/Kg) than animals receiving only standard chow. The C + CF and S + CF groups preferred comfort food over the standard chow; this preference was higher in the S + CF than in the C + CF group. The surface density of smooth muscle was reduced in stressed animals, while connective tissue and elastic system fiber content were increased in stressed groups. Further, epithelial height was increased in rats submitted to chronic stress. The surface density of elastic system fibers was decreased by the consumption of comfort food. Conclusions Chronic stress induces morphological modifications on the bladder wall and epithelium. These modifications may be related to lower urinary tract symptoms. Additionally, chronic stress caused a higher preference for comfort food intake which did not ameliorate or aggravate the stress-induced bladder alterations.

A series of π-expanded coplanar BODIPY dyes with deep-red emission: Synthesis, optical properties, and application in amplified spontaneous emission

Aromatic rings and a –CF3 group were introduced into a π-expanded BODIPY structure. The formation of a π-expanded coplanar conjugation chain successfully shifted BODIPY emission to the deep-red region (626 nm) with a high quantum yield (0.99).

A family of edge-sharing bi-octahedral diruthenium(III,III) compounds containing Ru-Ru single bonds.

From paddlewheel starting reactants Ru2(R'CO2)4+, a family of edge-sharing bi-octahedral (ESBO) diruthenium(III,III) compounds has been prepared, formulated as Ru2(μ-O2CR')2(μ-OR)2(η-L)2 (1-10) [R' = CH3, R = CH3, L = acac (1), tfac (2); R' = CH3, R = CH2CH3, L = hfac (3); R' = CH2CH3, R = CH3, L = acac (4), tfac (5); R' = CH2CH3, R = CH2CH3, L = hfac (6); R' = CH2Cl, R = CH3, L = tfac (7); R' = CH2Cl, R = CH2CH3, L = hfac (8); R' = C6H5, R = CH3, L = tfac (9); and R' = H, R = CH3, L = acac (10); here, acac, tfac and hfac represent acetylacetone, trifluoroacetylacetone and hexafluoroacetylacetone, respectively]. Compounds 1-10 have a similar ESBO coordination geometry of the Ru(μ-O2CR')2(μ-OR)2Ru core with a Ru-Ru center chelated and bridged by two μ-O2CR' and two μ-OR in a trans manner, and each Ru center is also coordinated with a η2-L bidentate ligand. The Ru-Ru distances fall in the range of 2.4560(9)-2.4771(4) Å. The investigation of the electronic spectra and vibrational frequencies as well as theoretical studies with density functional theory (DFT) reveal that compounds 1-10 are ESBO bimetallic species of d5-d5 valence electron counts showing a σ2π2δ2δ*2π*2 electronic configuration. Varying -CH3 to -CF3 groups on the η2-L bidentate ligands coordinating to the Ru(μ-O2CR')2(μ-OR)2Ru core, and according to Raman spectrum measurements combined with theoretical calculations, the intense bands of compounds 1-10 appearing at ∼345 cm-1 in the small-wavenumber region can be assigned to the stretching of the Ru-Ru single bond.

Pushing capacities and energy densities beyond theoretical limits of lithium primary batteries using active CFx nanocapsules with x > 1

CFNCs with a high-curvature 3D hollow structure and rich interfaces enable activation of –CF and –CF2 groups, which results in cathode capacity of 1056 mAh g−1 and energy density up to 2487 Wh kg−1 beyond the theoretical limits of the Li-CFx system.

Evidence for and evaluation of fluorine-tellurium chalcogen bonding.

In the field of noncovalent interactions, chalcogen bonding (ChB) involving the tellurium atom is currently attracting much attention in supramolecular chemistry and in catalysis. However, as a prerequisite for its application, the ChB should be studied in solution to assess its formation and, if possible, to evaluate its strength. In this context, new tellurium derivatives bearing CH2F and CF3 groups were designed to exhibit Te⋯F ChB and were synthesized in good to high yields. In both types of compounds, Te⋯F interactions were characterized in solution by combining 19F, 125Te and HOESY NMR techniques. These Te⋯F ChBs were shown to contribute to the overall JTe-F coupling constants (94-170 Hz) measured in the CH2F- and CF3-based tellurium derivatives. Finally, a variable temperature NMR study allowed us to approximate the energy of the Te⋯F ChB, from 3 kJ mol-1 for the compounds with weak Te σ-holes to 11 kJ mol-1 for Te σ-holes activated by the presence of strong electron withdrawing substituents.

Radical selenylative cyclization of trifluoromethyl propargyl imines for the synthesis of trifluoromethyl- and seleno-azaspiro[4,5]-tetraenones and quinolines.

A radical selenylative cyclization of trifluoromethyl propargyl imines with diselenides for the regiodivergent construction of diversely functionalized azaspiro[4,5]-tetraenones and quinolines has been developed, which enables dual incorporation of CF3 and Se groups into heterocycles in a one-pot reaction. When using Oxone as a green oxidant, the reaction proceeds through oxidative dearomative ipso-annulation or intramolecular ortho-annulation exhibiting good regioselectivity. The synthetic utility of this method is demonstrated by a scale-up reaction and further modification of the obtained products.