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The effective charges on hydrogen and carbon atoms and the Fukui functions for the electrophilic and radical attacks for the hydrogen atoms of the chair and boat conformations of cyclohexanone were calculated using the density functional theory (DFT) with the hybrid functionals: B3LYP in the 6-311g++(d,p) basis set; X3LYP in the 6-311g++(d,p) and D95++(d,p) basis sets; and pbe1pbe in the D95++(d,p) basis set, and by the MP2 method in the 6-311g++(d,p) basis set. For these conformations, the transition states were localized; the length of the broken CH bond in the transition state was determined; and the activation energies, activation entropies, and enthalpies of the elementary reactions of the tert-butylperoxyl ((СН3)3СOO•) radical with all types of CH bonds of cyclohexanone were calculated. The relative reactivity of the CH bonds of cyclohexanone in reactions with ((СН3)3СOO•); the local electrophilicity indices of the carbon-centered radicals formed from cyclohexanone after elimination of the hydrogen atom; and the energy difference (ΔЕSOMO) between the single-occupied molecular orbitals of these carbon-centered radicals and the (СН3)3СOO• radical were calculated. The CH bond dissociation energies of cyclohexanone were calculated by the DFT B3LYP 6-311g++(d,p), CBS-QB3, and G3MP2B3 methods using the isodesmic reactions technique. The factors governing the CH bond reactivity of cyclohexanone in reactions with the (СН3)3СOO• radical were considered. The increased reactivity of CH bonds of cyclohexanone in the 2, 6 (α) positions was shown to be due to the low bond dissociation energy, high electron-donor capacity of hydrogen atoms, smaller length of the broken CH bond in the transition state, and small ΔЕSOMO value. The lower reactivity of CH bonds at positions 3, 5 (β), and 4 (γ) is determined by the higher bond dissociation energies, decreased electron density due to the inductive effect of the carbonyl group, nucleophilicity of the carbon-centered radicals, greater length of the broken CH bonds in the transition state, and larger ΔЕSOMO value. The difference in the reactivity of CH bonds at positions 3, 5 (β), and 4 (γ) is determined by these factors, but not by the difference in the dissociation energies of these bonds. The reactivity of CH bonds in the boat conformation is higher than that in the chair conformation in the reactions with the (СН3)3СOO• radical.

A series of nine RuII arene complexes bearing tridentate naphthoquinone-based N,O,O-ligands was synthesized and characterized. Aqueous stability and their hydrolysis mechanism were investigated via UV/vis photometry, HPLC-MS, and density functional theory calculations. Substituents with a positive inductive effect improved their stability at physiological pH (7.4) intensely, whereas substituents such as halogens accelerated hydrolysis and formation of dimeric pyrazolate and hydroxido bridged dimers. The observed cytotoxic profile is unusual, as complexes exhibited much higher cytotoxicity in SW480 colon cancer cells than in the broadly chemo- (incl. platinum-) sensitive CH1/PA-1 teratocarcinoma cells. This activity pattern as well as reduced or slightly enhanced ROS generation and the lack of DNA interactions indicate a mode of action different from established or previously investigated classes of metallodrugs., Tridentate 3-substituted naphthoquinone organometallics show strong cytotoxicity in chemo-resistant colon cancer cells. The aquation pathway, the behavior in aqueous solutions, and the preliminary mode of action studies are presented.

This study presents the benchmark calculations of proton affinities (PAs) and gas-phase basicities (GBs) of 8-para substituted benzaldehyde compounds using the multilevel model chemistries (G3B3 and G4), density-functional quantum model (B3LYP) and ab initio model (MP2). The results show that the computed properties are strongly correlated with the available experimental data. The PAs and the GBs of other eight para-substituted benzaldehyde compounds, for which the experimental data does not currently exist, have been calculated using G3B3 and B3LYP methods. The correlations between the experimental PAs and GBs with the computed properties such as PA, GB, chemical properties (bond lengths, electron density and δ1 H NMR chemical shift) of the investigated benzaldehydes have been studied and statistically analyzed. The influence of the substituted groups has been discussed in terms of inductive effect and electron donating and electron withdrawing effect. The results obtained show that the chemical properties of the benzaldehyde compounds are controlled by the strong coupling between the CHO group and the nature of the para-substituent groups through the benzene ring as a conducting linkage.

A series of new mesogenic ester compounds were successfully synthesized. Azo compounds were prepared by coupling diazonium salt (which prepared from phenyl diamine with 1:1HCl and NaNO2) with phenol, and the prepared compounds were reacted with substituted benzoic acid to give esterification. FT-IR and 1H NMR spectrometers were used to confirm the structures of the prepared compounds the optical microscope polarization and DSC have been studied in the liquid crystal phases. It was observed that the thermal stability of the nematic phase increased with an increase in the polarity of the substituted groups at the para and meta position, as following (Cl > OCH3 > NO2 > CH3) also, the thermal stability of nematic phase was highest at meta substituted compared with para substituted. In addition to, the kinetic behavior of the prepared compounds showed the effect para position through p-CH3 and p-OCH3 due to the presence of resonance effect in addition inductive effect, so (σ + ) was used instead of (σ px). The results of the kinetic study showed through a Rho (ρ) value a decrease in the electronic density and an increase in the growth of the positive charge in the reaction center, this means that the reaction is stabilized with the presence of donating groups.

Five proline-derived acetylene monomers, (S)-N-aromatic carbamoyl-2-ethynyl pyrrolidine, were efficiently synthesized from the commercially available biomass-based starting material (S)-N-(tert-butoxycarbonyl)-prolinal. They were converted to the corresponding optically active helical polymers under the catalysis of a Rh-diene complex. These polymers exhibited excellent optical resolving power as the chiral stationary phases (CSPs) of high-performance liquid chromatography for hydrogen bond donating racemates and an organometallic complex. The correlations among the nature, size, and position of the substituent on the phenyl ring with the polymer conformation as well as the enantioseparation performance were systematically explored through NMR, Raman and UV-absorption spectroscopy and polarimetry, circular dichroism, HPLC, and computational simulation. It was found that the strength of the hydrogen bond and π–π interactions between enantiomers and CSPs played a remarkable role in enantioseparation. The strong electron-withdrawing substituent disfavored chiral recognition because of the reduced electron density of the ureal carbonyl group via the inductive effect, while the weak electron-withdrawing and electron-donating substituents favored optical resolution. The meta-substitution on the phenyl ring weakened the chiral discrimination on the large racemate. Moreover, reducing the eluent polarity tended to improve enantioseparation. This work helps explore the full potential of polyacetylene-based CSPs.

Ionic liquids, which are widely known as room temperature molten salts, have been the subject of much scientific debate for more than a decade. These compounds can be used as green solvents or even as additives in many reactions. Due to their noticeable conductivity, which is a function of the interaction energies existing between the ion pairs in ionic liquids, the synthesis and introduction of new families of these chemicals are of importance. The target of this paper is to design new carboxylate-based ionic liquids containing OH and CF3 groups. Our results indicate that the properties of these ILs are highly affected by the presence of OH and CF3 groups, in which OH stabilizes the negative charge of the anion via intramolecular hydrogen bonds and CF3 stabilizes it through the electron withdrawing effect. These groups decrease the binding energy between the anion and cation of the carboxylate-based ionic liquids and thus affect their physical properties such as melting point and density as well as their chemical properties. All calculations in this study were performed in the gas phase at the B3LYP/6-311++G(d,p) level.

A potential method to tune reactivity In organic chemistry, reaction rates are often sensitive to substituents that either donate or withdraw electron density from a reactive carbon center. Heo et al. now report that when reactants are tethered to an electrode, the polarization effect of an applied potential can exert an analogous influence, essentially acting as a tunable functional group. The authors demonstrate rate modulations in ester hydrolysis and arene cross-coupling, as well as a two-step acid-to-amide conversion that benefits from inversion of the polarization midway through the reaction. Science , this issue p. 214

Numerous studies on nitro group properties are associated with its high electron-withdrawing ability, by means of both resonance and inductive effect. The substituent effect of the nitro group may be well described using either traditional substituent constants or characteristics based on quantum chemistry, i.e., cSAR, SESE, and pEDA/sEDA models. Interestingly, the cSAR descriptor allows to describe the electron-attracting properties of the nitro group regardless of the position and the type of system. Analysis of classical and reverse substituent effects of the nitro group in various systems indicates strong pi-electron interactions with electron-donating substituents due to the resonance effect. This significantly affects the pi-electron delocalization of the aromatic ring decreasing the aromatic character, evidenced clearly by HOMA values. Use of the pEDA/sEDA model allows to measure the population of electrons transferred from the ring to the nitro group.

Hartree Fock (HF) and density functional theory (DFT) methods based on a 3-21G set level were used to computationally assess the nonlinear optic (NLO) response of six ruthenium (Ru) arylalkynyl complexes. The low basis set of 3-21G was proved to provide adequate results with difference of only about 3% between calculation and experimental data. Substitution of Ru-phenyl with six simplified models of Ru-H and Ru-methyl complexes revealed that DFT-based calculations were more accurate than HF in estimating the NLO response. The calculated bond lengths and angles of Ru-methyl were in good agreement with Ru-phenyl. Given that the calculated C≡C stretching vibration and UV-vis maximum absorption for Ru-methyl was comparable to Ru-phenyl, with values corresponding to 2154.56 cm-1 and 460.93 nm, respectively. It was evident that Ru-H, Ru-methyl and Ru-phenyl complexes undergo intraligands π-π* and Laporte forbidden metal d-d transition. Henceforth, it is affirmed that calculations using simplified Ru-H complexes were as much as reliable as the full structure of Ru to assess the NLO response. Assessment of electron inductive effect on Ru-carbonyl (Ru-Co), Ru-cyclopentadienyl (Ru-Cp) and Ru- bipyridine (Ru-bpy) complexes revealed two absorption maxima that appeared in regions 320−375 nm and 382−460 nm, which represent an intraligand π-π* orbital and Laporte forbidden d-d-transition, respectively. Migration of electrons from Ru center to the bipyridine ligand suggests a greater electron acceptor effect than Ru center to the arylalkynyl group. However, Ru conjugated to an electron withdrawing group i.e. carbonyl tend to render lower NLO response while elevating HOMO - LUMO energy gap and Ru to Cα bond lengths.

Herein, we report the versatile synthetic strategy and opto-electronic properties for the phosphorylation of BODIPY derivatives 5aa-5ak by substituting with an electron-donating/withdrawing group at the ortho position. Nevertheless, this new methodology relatively promotes the tolerance of the aldehyde moiety and the high yield for the synthesis of BODIPY o-OPhos derivatives. The photophysical studies suggest improved optical properties due to the inductive effect of various electron-donating/withdrawing groups. The UV-visible and the emission data suggest that BODIPY o-OPhos derivatives emphasize the property of the excited states with an increase in fluorescence intensity and high quantum yields due to the presence of bulky phospsho-triester at the meso- position which hinders the free rotation around the C-Ar bond and facilitates the development of OLEDs and various organophosphorus warfare agents. Electrochemical studies reveal 5ak depicts the ease of redox activity amongst the 5aa-5ak derivatives. The density functional theory indicates the highest occupied molecular orbital on the BODIPY moiety whereas the lowest unoccupied molecular orbital delocalized on BODIPY and the phospho-triester moieties. Thus, the unique development of the novel BODIPY derivatives with improved optical and redox properties pave the way for fluorescent probes and bioimaging techniques.

The formation and decomposition kinetics of N-chloro-N-methyl amino acids were studied to predict the fate and impact of these compounds in water treatment technologies and biological systems. These compounds form in fast second-order reactions between N-methyl amino acids and hypochlorous acid. The comparison of the activation parameters for the reactions of N-methyl substituted and nonsubstituted branched-chain amino acids reveals the transition-state features less organized structure and stronger bonds between the reactants in the reactions with the N-methyl derivatives. This is due to a combined positive inductive effect of the N-methyl group and the alkyl side chain as well as to the steric effects of the substituents. N-Methyl-N-chloro amino acids decompose much faster than the nonsubstituted compounds. The reaction rates do not depend on the pH, and the same final product is formed in the entire pH range. N-Chlorosarcosine is an exception, as it decomposes via competing paths, kdobs = kd + kdOH[OH-], yielding different final products. This feature is most likely due to the lack of an alkyl substituent on the α-carbon atom. Under physiological pH, aldehydes and methylamine form in these reactions, which are not particularly toxic.

Polymeric frameworks composed of molecular complexes have been attractive for the outstanding activity, selectivity, and stability toward CO2-to-CO conversion. In this work, polymerized cobalt phthalocyanines (CoPPc) with different functionalities were investigated with a series of spectroscopy characterizations, controlled-potential electrolysis, Tafel analysis, cyclic voltammetry analysis, and isotope labeling studies. The electronic structure of the Co center was revealed to be directly affected by the peripheral substituents via an inductive effect. Besides, the relationship between electronic structure and activity of the CoPPc-based catalysts for CO2 electroreduction was successfully elucidated at the molecular level.

The C-X bonds of organic compounds between group X and a saturated or unsaturated carbon atom differ in bond energy. To identify the causes of variation is of great significance in terms of bond nature understanding and bond energy estimation. In this paper, the electronegativity χ[X] of group X was calculated by the "valence electron equalized electronegativity" method. Then, χ[X] and the electronic effect constant of the substituent were taken as variables to establish equations for quantitative correlation between C(sp3)-X and C(sp2)-X for the calculation of C-X bond energies. The aim is make comparison between substituted methane, Me-X, and substituted benzene, Ph-X, as well as that between Me-X and substituted ethylene, C2H3-X. We conducted calculation over 40 compounds that contain different X groups, and the results reveal that the C(sp3)-X and C(sp2)-X bond energies are under the influence of a number of factors. In addition to the covalent properties of C and X atoms and χ[X], the bond energies of C(sp2)-X (i.e., D[C(sp2)-X]) are under the influence of the field/inductive effect (σF[X]) and conjugated effect (σR[X]) of group X, with the former causing a decrease while the latter an increase of D[C(sp2)-X]. Using the acquired quantitative correlation equations and on the basis of a relatively rich set of measured D[Me-X] data, we estimated D[Ph-X] of Ph-X and D[C2H3-X] of C2H3-X, and the estimation accuracy is within experimental uncertainty. Employing the above method, the D[C(sp2)-X] of 33 substituted benzenes, 53 substituted ethenes, and 82 α-substituted naphthalenes was estimated with satisfactory outcomes.

This work presents a density functional theory (DFT) study on the mechanism and origins of enantio- and regioselectivities in dual photoredox/chiral Bronsted acid-catalyzed asymmetric Minisci-type addition of carbon-centered radicals to N-heteroarenes [Science, 2018, 360, 419-422]. The previously proposed mechanism has been partially revised. First, photoexcited *[IrIII] is reductively quenched by TRIP anion rather than the experimentally proposed neutral radical generated from the chiral Bronsted acid cycle. Second, final product formation involves a hydrogen-atom transfer (HAT) from a neutral radical intermediate to the TRIP radical, instead of single-electron transfer (SET) to *[IrIII]. The TRIP catalyst has been shown to play a triple role by reductively quenching *[IrIII] with its anion form, activating the substrate, and inducing asymmetry. The calculated results rationalize the experimentally observed enantio- and regioselectivities and reveal that the enantioselectivity of the reaction originates from the hydrogen-bond interaction between TRIP and the N-H group of the carbon-centered radical, and the regioselectivity arises from the electron-withdrawing inductive effect from the protonated N-atom and the intramolecular hydrogen-bond interaction between the acetylamino group and the protonated pyridine ring. We also provide explanations for the experimentally observed a dramatic decrease in enantioselectivity when changing substrate or radical precursor and rationalize the solvent-controlled switch of regioselectivity.

The substituent effect on the covalent character of C-H bonds in methane derivatives is evaluated by means of local descriptors based on the topology of the electron density. Halogens, -OH, -SH, =O, =S, -NO2, -NH2, and -OCH3 increase the covalent character of the remaining C-H bonds, while alkaline metals (-Li and -Na) result in the opposite trend. This study proposes that the inductive effect is due to polarization changes driven by substituent charges.

With two distinct active sites, 2-hydroxy-2′-amino-diphenylethyne derivatives can offer benzofuro­[3,2-c]­quinolinones via the O-attack/N-carbonylation cyclization or indolo­[3,2-c]­coumarins via the N-attack/O-carbonylation cyclization. This work presents a density functional theory-based computational study to understand the mechanism and origin of the palladium­(II)-catalyzed regiodivergent reactivity of diphenylethyne derivatives. It is indicated that the reaction features a palladium­(II)–counterion–ligand cooperative catalysis. The O-attack/N-carbonylation cyclization mainly benefits from the inductive effect of the rigid electron-withdrawing bidentate nitrogen ligand and the stabilization of the 3c-4e bond between the trifluoroacetate (TFA) anion and the hydroxyl group in the substrate for the precursor and transition state, while the viability of the N-attack/O-carbonylation cyclization stems intrinsically from the stronger nucleophilicity of the N atom as well as the important π–π interaction between the flexible electron-rich bidentate phosphine ligand and the substrate. Moreover, these calculations propose an unconventional reductive elimination mechanism for the transformation from Pd­(II) to Pd(0), where the intramolecular nucleophilic attack of the N/O atom on the carbonyl C atom results in the formal reductive elimination product. The calculated overall barriers of 14.8 kcal/mol for Pd­(TFA)2 with the bidentate nitrogen ligand and 23.9 kcal/mol for Pd­(OTf)2 with the bidentate phosphine ligand are qualitatively consistent with the mild experimental conditions.

In this study, we provide a theoretical evaluation of relative stabilities and electronic structure for [BnXn]2- clusters (n = 10, 12, 13, 14, 15, 16). Structural and electronic characteristics of [BnXn]2- clusters are examined by comparison with the [B12X12]2- counterparts with a focus on the substituent effects (X = H, F, Cl, Br, CN, BO, OH, NH2) on the electronic structure, electron detachment energies, formation enthalpies, and charge distributions. For the electronic structure and electron detachment energies, substituent effects on boron clusters are shown to follow a very similar trend to the mesomeric and inductive effects (± M and ± I) of π-conjugated systems, and the most stable derivatives in terms of HOMO/LUMO and electron detachment energies are calculated for CN and BO substituents due to strong -M effects. In the case of formation enthalpies for larger boron clusters (n ≥ 13), the icosahedral barrier is shown to increase with the halogen and CN substitution, whereas it is possible to reduce the icosahedral barrier for the cases of X = OH and NH2. It is shown that this reduction results from destabilizing the [B12X12]2- cluster with electronic (+ M) and symmetry effects induced by OH and NH2 ligands.

In this study, X-ray photoelectron spectroscopy is used to probe the impact of the N3-substituted alkyl group on the electronic environment of the cation and the anion by comparing two types of imidazolium cations, 1-alkyl-3-butylimidazolium and 1-alkyl-3-methylimidazolium. Due to the more intense inductive effect changing from methyl to butyl, the electronic environment of the cationic nitrogen can be significantly affected, which is reflected in a shift of N 1s binding energy. The magnitude of the binding energy shift is found to be more pronounced in the case of the less basic anion and inversely proportional to the basicity of the anion. The increase of the N3-substituted alkyl chain length can also influence the charge-transfer effect from the anion to the cation. This gives rise to a change in the electronic environment of the anion. Such an impact is found to be concentrated on the anion-based component bearing more negative point charges.

Identification of redox-active moieties other than well-known carbonyl is essential to design the best candidates for organic cathodes in lithium-ion batteries among a broad-array of organic materials. In this study, an advanced computational modeling approach is employed to comprehensively investigate the redox properties for two representative organic classes, namely carbonitriles and quinones. It is highlighted that organic molecules with conjugating (non-conjugating) backbones would show higher redox potential for longer (shorter) backbone, owing to the strengthened inductive effect. Further examination verifies the importance of the relative electron-withdrawing strength of functionality over hydrogen on the redox potential and battery performance, suggesting a molecular design direction toward a carbonitrile with a longer conjugating backbone functionalized by an acyl chloride for highly-durable, high-performance cathodes. All these findings are comprehensively understood by the established universal correlations on redox property-electron affinity-solvation energy, highlighting two-stage transition behaviors of carbonitriles during the discharging process.

The inductive effect of phosphorus (P) atoms on the formation of graphite-like clusters in silicon carbide (SiC) was investigated by using confocal micro-Raman spectroscopy. SiC samples containing P atoms at concentrations of 1.0 × 10 20 and 1.0 × 10 21 cm −3 were prepared by P ion implantation. The P-containing and P-free SiC samples were irradiated simultaneously with 1.25 MeV Si 5+ ions at a fluence of 1.0 × 10 16 cm −3 at room temperature, 300 °C, and 500 °C. Two prominent peaks at 1385 and 1562 cm −1 , which correspond to the breathing vibration of six-membered carbon (C) rings and stretching vibration of sp 2 C–C bonds, respectively, are observed in the Raman spectra of as-irradiated P-containing SiC. These results demonstrate that P atoms can effectively promote the aggregation of C atoms into graphite-like clusters during irradiation. The formation of graphite-like clusters follows an inductive aggregation mechanism. The graphite-like cluster nucleus is tentatively identified as a C Si (P C ) 2 complex. For comparison, argon (Ar)-ion irradiation of magnesium (Mg)-containing SiC was also performed, where graphite-like clusters were not formed.

The syntheses, structures, and catalytic properties for lactones polymerization of eight novel yttrium complexes containing an amine‐bis(benzotriazole phenolate) (C¹ᴺᴺBiBTP) ligand are reported. A series of nitrophenolate (NP)‐type of ligands possessing R substituents with variable electronic properties (R = NO₂, Cl, H, CH₃) on ortho and/or para position attached to the phenolate rings have been selected and further reacted with C¹ᴺᴺBiBTP‐H₂ proligand and YCl₃·6H₂O. Two series of complexes, [Y(C¹ᴺᴺBiBTP)(TNP)(MeOH)₂] (3), [Y(C¹ᴺᴺBiBTP)(2,4‐DNP)(MeOH)₂] (4) and [Y(C¹ᴺᴺBiBTP)(2,5‐DNP)(MeOH)₂] (5) with two MeOH molecules as initiators as well as [Y(C¹ᴺᴺBiBTP‐H)(CNP)₂] (6), [Y(C¹ᴺᴺBiBTP‐H)(2‐NP)₂] (7) and [Y(C¹ᴺᴺBiBTP‐H)(MNP)₂] (8) with two NP derivatives, were synthesized. Their ring‐opening polymerizations of L‐lactide (L‐LA) were investigated for all complexes in order to further understand the correlations between the inductive effect of substitutions and catalytic properties. Particularly, the activity and controllability of yttrium complexes 3 and 5 were improved dramatically comparing with the literature complex with the similar coordination environment, [Y(C¹ᴺᴺBiBTP)(NO₃)(MeOH)₂], which can be a successful example to enhance the catalytic properties by exchanging coordinate molecules. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2038–2047

Study of hydrolysis of cis-tetrachlorodi-m-carboxylates of dirhenium (III) was carried out due to the electronic adsorption and IR spectroscopy and pHmeter. As a result, itwas shown that the hydrolysis is a multistage process which can be attributed to the reactions of the pseudo-first order. It is also shown that the electronic absorption spectroscopy (EAS) is a reliable method of investigation to study the hydrolysis of rhenium (III) complex compounds. This conclusion is based on the fact that in the systems with halide and carboxylic ligands, each of the five structural types can be clearly identified by the EAS in the region of both d–d* electron transition and charge transfer transition of L*Hal ®Re type. It is shown that with the increase in the length of the alkyl group and in its branching, the hydrolysis rate decreases, as a result of a change in the positive inductive effect of these groups and, consequently, an increase in the strengthening of quadruple Re–Re bond. In addition, with the help of the EAS, a transition of the chloride ligands to OHgroups can be observed. As a result of the study, a hydrolysis route, which initially leds to the gradual replacement of the chloride ligands of a complex compound with OH groups, and subsequently to the conversion of Re(III) compounds into the derivative of Re(IV) was proposed. The dependence of resistance to hydrolysis on the structure of the complex compound, the temperature and pH was determined. It allowed to predict the stability of the investigated compounds while their usage as biologically active substances and reagents in the synthesis of new compounds. The obtained results allow us to presence of anticancer, cytostabilizing and other biological activities is the coordination of Re(III) complex compounds with the components of biomolecules (proteins, DNA).

Several push‐pull oligocarbazole dye‐sensitizers have been studied using theoretical methods in order to better understand the relationship between structural electronic or optical properties and intramolecular path of active electrons during the ionization and injection processes. DFT/TD‐DFT calculations were performed on a series of five dye sensitizers. They differ by the presence of electron donating group (EDG) by inductive effect (noted+I) or electron releasing group (ERG) by mesomeric effect (noted+M) or electron withdrawing group by inductive effect (noted‐I) on the pushed part of the dyes studied. Our work focused on the internal distribution of electrons in the different parts of dye that are the push/pull moieties and the π‐bridge. The study concerned the ground state, the electronic transition process and the excited state. In each situation, the fragment acting in the ionization or transition phenomena were identified. In the ground state, the electrons of the push part appear to be the least bound because they have the highest probabilities of ionization. In the excited state, the ionized atoms are essentially positioned in the pushing part and some neighboring atoms of the bridge. In the electronic transition, the active atoms are located in the π‐conjugated part but only on the side adjacent to the acceptor group. To arrive to this conclusion, we optimized the structures of the five dyes in their ground and excited states. We calculated the atomic charges, the wavelengths and intensities of electronic transitions in the visible domain, the reorganization energies as well as the oxidation potential. It appears that +M donor ligands improve the performance of a dye because the great distribution of atoms to be ionized in the push parts.

The properties of hybrid silica xerogels obtained by the sol-gel method are highly dependent on the precursor and the synthesis conditions. This study examines the influence of organic substituents of the precursor on the sol-gel process and determines the structure of the final materials in xerogels containing tetraethyl orthosilicate (TEOS) and alkyltriethoxysilane or chloroalkyltri-ethoxysilane at different molar percentages (RTEOS and ClRTEOS, R = methyl [M], ethyl [E], or propyl [P]). The intermolecular forces exerted by the organic moiety and the chlorine atom of the precursors were elucidated by comparing the sol-gel process between alkyl and chloroalkyl series. The microstructure of the resulting xerogels was explored in a structural theoretical study using Fourier transformed infrared spectroscopy and deconvolution methods, revealing the distribution of (SiO)4 and (SiO)6 rings in the silicon matrix of the hybrid xerogels. The results demonstrate that the alkyl chain and the chlorine atom of the precursor in these materials determines their inductive and steric effects on the sol-gel process and, therefore, their gelation times. Furthermore, the distribution of (SiO)4 and (SiO)6 rings was found to be consistent with the data from the X-ray diffraction spectra, which confirm that the local periodicity associated with four-fold rings increases with higher percentage of precursor. Both the sol-gel process and the ordered domains formed determine the final structure of these hybrid materials and, therefore, their properties and potential applications. The authors gratefully acknowledge the financial support received from the Ministerio de Economia y Competitividad of Spain (Project MAT2016-78155-C2-2-R). G.C. thanks MINECO and the 'Ministerio de Ciencia, Investigación y Universidades' of Spain for his 'FPU' grant (FPU18/03467). The authors also acknowledge the use of the 'Centro de Instrumentación Científico-Técnica' at the University of Jaén and UCTAI at the Public University of Navarre.

Dimer radical ions of aromatic molecules in which excess charge is localized in a pair of rings have been extensively investigated. While dimer radical cations of aromatics have been previously produced in the condensed phase, the number of molecules that form dimer anions is very limited. In this study, we report the formation of intramolecular dimer radical ions (cations and anions) of diphenyl sulfone derivatives (DPs) by electron beam pulse radiolysis in the liquid phase at room temperature. The density functional theory (DFT) calculations also showed the formation of the dimer radical ions. The torsion barrier of the phenyl ring of DPs was also calculated. It was found that the dimer radical ions show the larger barrier than the neutral state. Finally, stability of the dimer radical anion is dependent on not only the inductive effect of the sulfonyl group but the conjugation involving the d-orbital of the S atom and the phenyl rings.

In this study, we employed a quantum-mechanical computational method to investigate the hydrogen-atom abstraction reactions of two nitrogen heterocyclic carbene boranes (NHC-boranes), NHC-BH3 and NHC-BH2CN, by a series of carbon-centered radicals bearing various substituents. We explored the degree of correlation of the activation and free energy barriers to their components. Furthermore, we also investigated the effects of the radical and substituent sizes, nucleophilicity/electrophilicity indices, and the spin density distribution of the radical reactants on the three fundamental barriers and the thermal contribution of the reaction energy to the kinetic barrier. Using the generated data, we assessed the abilities of the various radical reactants to abstract the hydrogen atom from NHC-boranes. Further, we performed a similar analysis after dividing those radical reactants into four groups, which were classified based on the dominant factor affecting their electronic density distribution, which involves the inductive effect, conjugation, hyperconjugation, and the feedback of lone-pair electrons. The results and conclusions of this investigation not only provide insight into the relationships between some of the key kinetic and thermodynamic parameters, which is useful for understanding the dynamics of such hydrogen-abstraction reactions, but also provide information for selecting suitable radical reactants for further experimental investigations.

Widespread Fe(III)-humic acid (HA) coprecipitates (FHCs) have substantial impacts on the adsorption and reduction of Cr(VI) in soils and sediments, but whether this process is equal to the sum of their individual components remains unknown. In this study, ferrihydrite (Fh)- and HA-like FHCs (C/Fe 3, respectively) were synthesized by controlling the initial C/Fe ratios (0.5–18) to explore the potential synergistic/antagonistic effects during the adsorption and reduction of Cr(VI). According to the results, antagonistic effects on Cr(VI) adsorption (5%−80%) were observed on Fh- and HA-like FHCs, where the antagonistic intensity increased with increasing HA proportions, respectively caused by the more serious occupation of adsorption sites and the stronger electrostatic repulsion to Cr(VI). Notably, significant synergistic reduction effects (5%−650%) occurred on Fh-like FHCs were found to be achieved by the activation of low-molecular HA (0.1–0.3 kDa) with primary/secondary hydroxylic groups, which might be induced by the inductive effect of Fh on complexed HA molecules according to density-functional theory (DFT) calculation. While slight antagonistic reduction effects (2%−45%) by HA-like FHCs were attributed to the decreasing accessibility of Cr(VI) to reductive phenolic groups, which might be blocked within FHC particles or complexed with Fe(III) ions through cation bridges.

The interactions between aprotonic tetrabutylphosphonium carboxylate ionic liquids (ILs), [P4 4 4 4 ][Cn COO] (n=1, 2 and 7), and water were investigated. The cation-anion interactions occur via the α-1 H on [P4 4 4 4 ]+ and the carboxylate headgroup of the anion. Upon addition, H2 O localises around the carboxylate headgroups, inducing an electron inductive effect towards the oxygens, leading to ion-pair separation. Studies with D2 O and [P4 4 4 4 ][Cn COO] revealed protic behaviour of the systems, with proton/deuterium exchange occurring at the α-1 H of the cation, promoted by the basicity of the anion, forming an intermediate ylide. The greater influence of van der Waals forces of the [P4 4 4 4 ][C7 COO] system allows for re-orientation of the ions through larger interdigitation. The protic behaviour of the neat ILs allows for CO2 to be chemically absorbed on the ylide intermediate, forming a phosphonium-carboxylate zwitterion, signifying proton exchange occurs even in the absence of H2 O. The absorption of CO2 in equimolar IL-H2 O mixtures forms a hydrogen carbonate, through a proposed reaction of the CO2 with an intermediate hydroxide, and carboxylic acid.

An unprecedented Rh(III)-catalyzed C–H activation of N-(pivaloyloxy)benzamide was recently reported by Feng et al. In this transformation, the substituent on the alkyne controls the chemoselectivity (annulation or hydroarylation). Given the importance of this novel strategy, we performed a density functional theory study to clarify the origins of the experimentally observed chemoselectivity. The results of our calculations showed that the conventional annulation of N-(pivaloyloxy)benzamide with an alkynone was kinetically favored, whereas the hydroarylation of α,α-difluoromethylene alkynes was kinetically favored. We found that the inductive effect of a fluorine substituent on the alkyne polarizes the Rh–C bond, and this facilitates the protonation step. Our calculations also explain the experimentally observed regioselectivity, which mainly arises from the interaction energy.

A facile way to simultaneously induce the formation and enhance the stability of graphene oxide liquid crystals (GO LCs) is reported. Sodium alginate (SA) with both inductive effect and stabilization effect was added into GO suspensions to prepare LCs at low concentration that could survive harsh conditions. Most importantly, different concentration zones of SA brought significantly different LCs degree and stability, which possessed distinct charge properties, rheological behaviors and chain morphology. Adding 0.5% SA located in entangled semi-dilute regime could induce the isotropic-nematic transition of GO at low concentration (

Recognition of (thio)sulfate and phosphate in aqueous solutions has been demonstrated by using oligo-urea-based receptors functionalized with quaternary ammonium groups. The ammonium groups allow for increased aqueous solubility while simultaneously providing positive coulombic interactions and stronger hydrogen bonding through an inductive effect. This simple and generally applicable modification provides an effective way to bolster the anion binding and water solubility of oligo-urea-based receptors. With a water soluble receptor 2, selective binding of adenosine phosphates was achieved at physiological pH.

Neglected tropical diseases caused by parasitic pathogens have caused an increase in research interest in drug discovery. Chagas disease is caused by protozoan Trypanosoma cruzi. Benznidazole and nifurtimox are effective drugs in the acute phase; nevertheless, for long-time treatment, they are toxic and have side effects, because these molecules produce free radicals and suffer oxidation–reduction processes. Studies of the structure and mode of action of these drugs have been performed and, until today, no effective treatment for this disease has been established yet. DFT-M06-2X studies in solution allowed us to explore the substituent effects on stability energy, physicochemical properties and chemical reactivity of nitroimidazoles with potential antiparasitic effects, using quantum-chemical descriptors: proton affinities, substituent effect stabilization energy, ionization potential, electrophilicity, hardness, atomic charges, dipole moment and Fukui functions. The basicity of the N3 atom and dipole moment decrease while the ionization potential, electrophilicity, and hardness increase with the electron-withdrawing substituents. Atomic charges, Fukui functions, and electrostatic potential showed that the main reactivity was on the nitro group and N3 atom. The methyl group linked to C2, and the position and inductive effect caused by the nitro group provoked major changes in the physicochemical features, chemical reactivity, and geometrical and energetic stabilities. Quantum-chemical descriptors allowed us to analyze and design novel nitroimidazole derivatives.

Developing efficient red thermally activated delayed fluorescence (TADF) emitters is a real challenge due to the serious nonradiation of their low-band-gap singlet charge transfer state. Dipyridophenazine (DPPZ) (weak electron-withdrawing pyridines fused with strong electron-withdrawing phenazine) is used as an acceptor to overcome this issue. The gradient multi-inductive effect of different heterocyclic units simultaneously enhances the intramolecular charge transfer for red emission of the TADF molecule oTPA-DPPZ, and facilitates the radiative transition of its singlet charge transfer state by increasing frontier molecular orbital overlap on the electron-deficient pyrazine moiety. The 10-fold increased oscillator strength of its singlet transition results in its excellent photoluminescence and electroluminescence quantum efficiencies of ∼75% and ∼19%, accompanied by red emission peaked around 600 nm.

1,3-Dipolar cycloaddition of pyrido[2,1-a]isoindole with internal alkynes functionalized by a BMes2ph and an N-aromatic heterocycle leads to the formation of two types of regioisomers (major a and minor b) that have distinct physical and photophysical properties. Examination on 5 pairs of regioisomers unveils that the major isomers consistently have a smaller optical energy gap and emission energy than the corresponding minor isomers, which is greatly amplified by the formation of an internal B ← N bond. The regioisomers with a B ← N bond display contrasting temperature-dependent structural dynamics and response to fluoride ions, owing to an entropy-driven or fluoride initiated B ← N bond rupture/ring-opening process and the different B ← N bond strength. The opposite inductive effect and the Lewis pair properties of the dichotomic substituent units are responsible for the contrasting properties of the regioisomers in this system.

A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZC6H4COOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase &Delta, acidG&deg, values obtained were close to the experimental ones reported in the literature. The good relationship between the &Delta, values and the electronegativity of ZC6H4COOH and its fragments, suggested a better importance of the inductive than polarizability contributions. The balance of inductive and resonance contributions of the substituent in the acidity of substituted benzoic acids showed that the highest inductive and resonance effects were for the -SO2CF3 and -NH2 substituents in the para- and ortho-position, respectively. The Fukui function confirmed that the electron-releasing substituent attached to the phenyl ring of benzoic acid decreased the acidity in the trend ortho &gt, meta &gt, para, and the electron-withdrawing substituent increased the acidity in the trend ortho &lt, meta &lt, para.

The transmission of electronic substituent effects through a carbon-carbon triple bond has been investigated from the small changes induced by a variable substituent X on the geometry of the phenyl group in β-substituted phenylacetylenes, Ph−C≡C−X. The geometries of many such molecules were determined by quantum chemical calculations at the B3LYP/6-311++G** level of theory. The structural variation of the phenyl probe is best represented by a linear combination of the internal ring angles, termed SFPHA. Multiple regression analysis of SFPHA using appropriate explanatory variables reveals a composite polar effect. The main components are, in order of decreasing importance: (i) the field effect of the substituent, enhanced by field-induced π-polarization of the −C≡C− spacer, (ii) the resonance-induced field effect, and (iii) the electronegativity effect. These results are compared with those obtained for (E)-β-substituted styrenes, Ph−CH=CH−X, using the same statistical technique, applied to a structural parameter termed SFSTY. The comparison shows that in β-substituted phenylacetylenes, the field effect of the substituent plays a more important role, and the resonance effect a less important, than in (E)-β-substituted styrenes. This is a consequence of the greater polarizability of the C≡C bond as compared with the C=C bond. The role played by the electronegativity of the substituent is the same for the two sets of molecules. A peculiar feature of the −C≡C− spacer is that its π-system consists of two separate parts, corresponding to the two π-bonds that concur to the formation of the triple bond. Only the part orthogonal to the plane of the phenyl probe may interact with the probe π-system, making it possible to transfer π-electron density from substituent to probe, or vice versa. The part coplanar with the phenyl probe may exchange π-electron density with the substituent, but not with the probe. Thus, π-interactions between substituent, spacer, and probe depend critically on the electronic structure and conformation of the substituent. We have classified the substituents in three categories according to the different types of π-interactions that occur in β-substituted phenylacetylenes. First category substituents exchange π-electron density with the orthogonal part of the π-system of the spacer, and hence with the π-system of the probe. While the orthogonal part of the π-system of the spacer acts as a π-electron channel, the coplanar part cannot exchange electrons with the π-system of the phenyl probe. With second category substituents, the conformation of the molecule inhibits the exchange of π-electron density between substituent and probe. The substituent can only exchange π-electrons with the part of the π-system of the spacer that is coplanar with the phenyl probe. Third category substituents exchange π-electron density with both parts of the π-system of the spacer. While the π-charge transferred into the orthogonal part can be further delocalized into the π-system of the phenyl probe, the π-charge transferred into the coplanar part cannot and remains blocked in the spacer. From there, however, it gives rise to an inductive effect that polarizes the π-electron system of the phenyl probe. The π-charge distribution in 45 β-substituted phenylacetylenes and the corresponding (E)-β-substituted styrenes has been determined by Natural Atomic Orbital analysis at the B3LYP/6-311++G** level of theory. The results of the analysis support our classification of the substituents in three categories and reveal the existence of a number of important correlations involving charges as well as structural parameters.

A number of mononuclear triphenylantimony(V) 3,5-di-tert-butylcatecholates of the type (6-AlkOCH2-3,5-DBCat)SbPh3 functionalized with alkoxymethyl group in the 6th position of aromatic ring in catecholato ligand, where Alk = Me (1), Et (2), iPr (3), tBu (4), n-Hexyl (5), and binuclear bis-catecholate Ph3Sb(3,5-DBCat-CH2OCH2-3,5-DBCat)SbPh3 (6) have been synthesized and characterized in details. The molecular structures of 1·0.5 (n-hexane), 2, 3, 4, 5·2MeOH, 6·2 (n-hexane) and 6·acetone have been determined by means of single-crystal X-ray analysis. The presence of alkoxymethyl-group in catecholate ligand does not lead to its coordination to the central antimony atom. Complexes 1–4 and 6 possess pentacoordinated environment of the central antimony atoms varying from the trigonal bipyramidal to the distorted tetragonal pyramidal. In crystal, molecules of complexes 1–5 form pairs where the “CPh–H … π-system” interactions were found. The coordination environment of the central antimony atom in 5∙2MeOH is a distorted octahedral with coordinated methanol; the second methanol molecule is fixed between thehydroxyl group of coordinated methanol and the oxygen atom of hexyloxymethyl-group in the 6th position of catecholate ligand through the intramolecular hydrogen bonding. The electrochemical oxidations of complexes 1–4 proceed as two one-electron oxidations (the quasireversible oxidation “catecholate/o-semiquinolate” and the irreversible oxidation “o-semiquinolate/o-benzoquinone”). The first half-wave potential (E11/2) depends weakly on the alkyloxy substituent in AlkO-CH2 group due to a weak inductive effect of AlkO group to the catecholate aromatic ring through the methylene linker. For binuclear bis-catecholate 6, the first redox stage is two-electronic quasi-reversible peak without the separation of two stages into two one-electron processes, which indicates the absence of the electronic interaction between the two catecholate fragments.

The chiral-at-metal complexes (RFe,RC)/(SFe,RC)-[CpFe(Prophos)NCR]X (X = I, PF6; R = Et, Ph, p-substituted Ph) were prepared, and the diastereomers were separated by fractional crystallization. Eight diastereomerically pure complexes (SFe,RC)-[CpFe(Prophos)NCR]X could be characterized by X-ray crystallography. The kinetics of epimerization with respect to the labile Fe-configuration in CDCl3 at ambient temperatures was measured for the EtCN, PhCN, and (p-C6H4NMe2) complexes. The half-lives of 162 and 760 min of the first-order reactions of (SFe,RC)-[CpFe(Prophos)NCPh]PF6 and (SFe,RC)-[CpFe(Prophos)NC(p-C6H4NMe2)]PF6 at 293 K demonstrate the importance of the inductive effect in the rate-determining cleavage of the Fe–NCR bond. The diastereomer ratios of 5:95 to 10:90 at equilibrium under thermodynamic control were strongly in favor of the (SFe,RC)-[CpFe(Prophos)NCR]X diastereomers. In ligand exchange reaction reactions, (RFe,RC)/(SFe,RC) diastereomer ratios of up to 35:65 were observed under kinetic control.

The synthesis, solid state characterization, theoretical and experimental photoluminescence studies of two new important classes of binuclear lanthanide complexes: [Ln2(Ibf)6(4,4'-dmbpy)2] Eu = 1, Gd = 2 and Tb = 3) and [Ln2(Ibf)6(5,5'-dmbpy)2] Eu = 4, Gd = 5 and Tb = 6) (where: Ibf = non – steroidal anti – inflammatory drug (NSAID) Ibuprofen, 4,4'-dmbpy and 5,5'-dmbpy are 4,4'-dimethyl-2,2'-bipyridine and 5,5'-dimethyl-2,2'-bipyridine, respectively) are reported in this work. The analytical and spectroscopic data suggest the formation of binuclear compounds. The RM1 model was used to obtain the molecular structures of the EuIII complexes and its optimized ground state geometries were used to calculated all details involved in the energy transfer process and compared with experimental data, being in an optimal agreement. The lowest ligand triplet state (T1) in these systems were obtained through of the time – resolved phosphorescence spectra, proving that the intramolecular energy transfer is responsible by high photoluminescence in these compounds. Still, the values of energy of the centroid of the 5D0 → 7F0 transition for the EuIII complexes, indicate an increase in the covalence degree for the Eu – L bonds, which is due to inductive effect (+I) of the –CH3 groups in the ancillary ligands, when compared with those [Eu2(Ibf)6(bpy)2] recently published. The high values of quantum efficiency and solubility in common organic solvents can opens the possibility to test this binuclear compounds in the field of efficient luminescent devices and biomarkers.

In this work, a novel cathode material for Na-ion batteries, Na0.97KFe(SO4)2, was successfully prepared via slow evaporation and a low-temperature process, and its outstanding electrochemical performance was demonstrated. Based on the structural information of KFe(SO4)2 obtained from Rietveld refinement of X-ray diffraction data, the possible atomic sites for Na ions entering the structure were verified using bond-valence sum energy maps. Electrochemical measurements and X-ray absorption near-edge structure analyses revealed that ∼0.97 mol Na ions can be reversibly (de)intercalated into the structure via the Fe3+/Fe2+ redox reaction. The average redox potential of Na0.97KFe(SO4)2 was shown to be ∼3.27 V (vs. Na+/Na), which is higher than that of other Fe-based phosphates owing to the inductive effect of (SO4)2−. It was verified that the specific capacity of Na0.97KFe(SO4)2 at C/10 was ∼85 mA h g−1. At 10C (full charge/discharge in 12 min), ∼53% of its capacity measured at C/10 was retained. In addition, up to ∼99% of its initial capacity was retained over 200 cycles at 1C with a high coulombic efficiency of 99.3097%, which was attributed to the negligible volume change (∼1.8%) during charge/discharge.

An investigation of C–F⋯H–O hydrogen bonds in the complexes CHnXCHnF⋯H2O (n = 0, 1, 2; X = H, F, Cl, Br) was performed at the MP2/aug-cc-pVTZ level. We found that the electron-withdrawing halogen substituents on the vicinal carbon cause the fluorine atom, participating in the hydrogen bond formation, to be less negatively charged. Thus, the halogen groups weaken the strength of organofluorine hydrogen bond by inductive effect. The position of the substituents on the vicinal carbon affects the strength of the C–F⋯H–O interaction. Compared with that in other isomers, the electron withdrawing substituent in 1-fluoro-ethane with stagger conformation as well as in 1-fluoro-ethene with trans configuration much weakens the interaction of C–F⋯H–O due to the hyperconjugative interaction between σ(C–F) and . By analogy, the electron-donating ones could largely strengthen it. We found that there is a good linear relationship between electron density at the BCP of F⋯H and Wiberg bond indexes (WBI) as well as between natural bond-bond polarizability (NBBP) and WBI, which indicates that the magnitude of NBBP and WBI could be a good indicator of the hydrogen bond strength.

Zeolitic Imidazolate Frameworks (ZIFs), which is a sub-class of MOF has been evolving as a potential candidate in adsorption, storage and separation of environmental hazardous gases. In this work, ZIF-68 and ZIF-69 structures were analyzed using Grand Canonical Monte Carlo (GCMC) simulations for their selective gas uptake for the natural gas purification and industrial separation. A suitable force field is selected in order to predict the exact experimental outcomes. It is found that the single –Cl functionalization in the organic linker of ZIF-69 has greater inductive effect, which dictates the interactions of gas molecules at the confinement. The predicted interactions directly correlate with the heat of adsorption and selectivity. This study infers that ZIF-68 will work as a gas storage material whereas ZIF-69 works as an excellent candidate for selective capture of methane from natural gas and industrial pollutants.

A series of Eu2+-doped orthosilicate-orthophosphate solid-solution phosphors, KxBa1.97–x(Si1–xPx)O4:0.03Eu2+, have been synthesized via the conventional solid-state reaction. Using varying compositions, the lowest-energy excitation can be tuned from 470 to 405 nm, with an emission from 515 to 423 nm. We determined how chainlike cation polyhedra controlled excitation- and emission-band features by introducing in-chain characteristic length d22 and outside-chain characteristic length d12 and that there was a nearly linear relationship between the lowest-energy-excitation position and the ratio of d22 to d12. This influence of chainlike polyhedra on luminescence can be understood through the inductive effect. Luminescent thermal properties are improved remarkably by the cosubstitution of K+ and P5+ ions for Ba2+ and Si4+ ions with a T1/2 over 200 °C. We have established the host-referred-binding-energy (HRBE) and vacuum-referred-binding-energy (VRBE) schemes for the electronic structure of the series of lant...

A new mechanism of the dipole—induced dipole polarization interaction was considered to explain an anomalous increase in the +I effect in a 1-phenylsilatrane molecule with the pentacoordinated Si atom. The interaction through the space between the silatrane cage having a high dipole moment and easily polarizable aromatic phenyl substituent induces dipole that adds the influence of the inductive effect along the bonds, which is characteristic of usual silatranes. The high inductive constant σI calculated for 1-phenylsilatrane on the basis of chemical shifts δC of aromatic carbon atoms was interpreted as a superelectronodonor effect in silatranes. However, the polarization effect through the space leads to a substantial change in the chemical shifts δC for the phenyl group in the direction that formally corresponds to the enhancement of the +I effect transmitted via the bonds. It is shown for the first time that the inductive effect in silatranes is not constant and varies according to the polarizability of the substituent at the Si atom.

Triarylboranes incorporating meta-substituted 2-R-o-carboranes (R = H, Me, iBu, Ph, 4-CF3C6F4) were prepared to investigate the effects of the meta-2-R-o-carborane on Lewis acidity. X-ray crystal structures revealed that the carboranyl C C bond distances increased with increasing steric and electron-withdrawing effects of the 2-R group. UV/Vis absorption titrations with fluoride ions showed high binding constants (K > 107 M−1 in THF and K = 3.9–6.6 × 103 M−1 in THF/H2O (9:1 vol)). Fluoride ion affinity was greater for the 2-aryl (4-CF3C6F4)-substituted triarylborane than 2-H and -alkyl (Me)-substituted triarylboranes, which was supported by anodic shifts in the reduction potentials of 2-aryl-o-carborane-substituted triarylboranes. Comparison of fluoride binding constants and reduction potentials of meta- and para-substituted triarylboranes indicated slightly lower Lewis acidity of meta-substituted triarylboranes. In contrast to para-substituted triarylboranes, the Lewis acidity of meta-substituted triarylboranes is likely to be primarily enhanced by the inductive effect of the 2-R-o-carborane.

Regioselective elimination of a vicinal bis-triflate having an adjacent ether oxygen functional group has been developed. Considered in the context of our studies of the regioselective elimination of vicinal dibromide, the key to the mechanism involves the electron-withdrawing inductive effect of the neighboring oxygen functional group. Aliphatic vinyl triflate was shown to be effective in Suzuki–Miyaura cross coupling compared with corresponding aliphatic vinyl bromide.

A series of tetrabutylphosphonium ([Bu4P]+)-based ionic liquids (ILs) with multiple-site for CO2 capture and activation in their anions are reported, which could efficiently catalyze the cyclization reaction of propargylic alcohols with CO2 at ambient conditions. Especially, the IL, [Bu4P]3[2,4-OPym-5-Ac], which has three interaction sites for attracting CO2 together with a pKa1 value of 9.13, exhibited the best performance, affording a series of α-alkylidene cyclic carbonates in moderate to good yields. The mechanism exploration demonstrated that IL served as a bifunctional catalyst with anion simultaneously activat-ing CO2 via multiple-site cooperative interactions and the C≡C triple bond in propargylic alcohol via inductive effect, thus resulting in the production of α-alkylidene cyclic carbonates..