Positional Isomers Research Articles

Some isomers of boron-nitrogen doped phenanthrene – DFT treatment

Phenanthrene is an even alternant aromatic hydrocarbon. In adjacent positions simultaneously boron and nitrogen doped phenanthrene and some of their derivatives have found some technological applications. In the present study, isomers of phenanthrene perturbed as mentioned above have been considered within the restrictions of density functional theory at the level of B3LYP/6-311++G(d,p) level. All the isomeric structures presently considered are thermally favored and electronically stable at the standard states. Various structural and quantum chemical data have been collected and discussed, including UV-VIS spectra. Also the NICS (0) data have been obtained for the isomers.

Photochemical permutation of thiazoles, isothiazoles and other azoles.

Thiazoles and isothiazoles are privileged motifs in drug and agrochemical discovery.1,2 The synthesis of these derivatives is generally approached, designed and developed on a case-by-case basis. Sometimes, the lack of robust synthetic methods to a given target can pose significant difficulties or even thwart the preparation of specific derivatives for further study.3,4 Here, we report a conceptually different approach whereby photochemical irradiation can be used to alter the structure of thiazoles and isothiazoles in a selective and predictable manner. Upon photoexcitation, these derivatives populate their π,π* singlet states that undergo a series of structural rearrangements leading to an overall permutation of the cyclic system and its substituents. This means that once the initial heteroaromatic scaffold has been prepared, it can then function as an entry point to access other molecules by selective structural permutation. This approach operates under mild photochemical conditions which tolerate complex scaffolds and chemically distinct functionalities. Preliminary findings also indicate the potential for extending this method to other azole systems, including benzo[d]isothiazole, indazole, pyrazole and isoxazole. This strategy establishes photochemical permutation as a powerful and convenient method for the preparation of complex and difficult-to-access derivatives from more available structural isomers.

C3H8O2 Isomers: Insights into Potential Interstellar Species.

2-Methoxyethanol, with a formula C3H8O2, was recently identified in the massive protocluster NGC 6334I. However, its structural isomers, 1,2-propanediol and 1,3-propanediol, remain undetected despite extensive searches in the Sgr B2 region. In this study, we explored the potential energy surface of the C3H8O2 system using CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ calculations, identifying 11 species, with the geminal diols 2,2-propanediol and 1,1-propanediol as the most stable forms. We examined the gas-phase decomposition barrier of these geminal diols and found that 1,1-propanediol is thermodynamically stable at low temperatures (10-150 K). C3H8O2 isomers with energies below 30 kcal/mol are relevant to the ISM, as they have been identified or tentatively detected in irradiation experiments of ice analogs of CO, H2O, and CH3OH.

Side Chain Phenyl Isomerization-Induced Spatial Conjugation for Achieving Efficient NIR-II Phototheranostic Agents.

The contradiction of near-infrared II (NIR-II) emission and photothermal effects limits the development of phototheranostic agents (PTAs) in many emerging cutting-edge applications. Organic aggregates present a promising opportunity for the balance of competitive relaxation processes through the manipulation of molecular structure and packing. Herein, side chain phenyl isomerization-induced spatial conjugation was proposed for constructing A-D-A type NIR-II PTAs with simultaneous enhancement of fluorescence brightness and photothermal properties. Three pairs of mutually isomeric fluorophores, whose phenyls respectively located at the outside (o-series) and inside (i-series) of the side chain, were designed and synthesized. The positional isomerization of the phenyl endows the o-series crystals with strong spatial conjugation between the phenyl group on the side chain and the backbone, as well as interlocked planar network, which is different to that observed in the i-series. Thus, all o-series nanoparticles (NPs) exhibit red-shifted absorption, enhanced NIR-II emission, and superior photothermal properties than their i-series counterparts. A prominent member of the o-series, o-ITNP NPs, demonstrated efficacy in facilitating NIR-II angiography, tumor localization, and NIR-II imaging-guided tumor photothermal therapy. The success of this side chain phenyl isomerization strategy paves the way for precise control of the aggregation behavior and for further development of efficient NIR-II PTAs.

Side Chain Phenyl Isomerization‐Induced Spatial Conjugation for Achieving Efficient NIR‐II Phototheranostic Agents

The contradiction of near‐infrared II (NIR‐II) emission and photothermal effects limits the development of phototheranostic agents (PTAs) in many emerging cutting‐edge applications. Organic aggregates present a promising opportunity for the balance of competitive relaxation processes through the manipulation of molecular structure and packing. Herein, side chain phenyl isomerization‐induced spatial conjugation was proposed for constructing A‐D‐A type NIR‐II PTAs with simultaneous enhancement of fluorescence brightness and photothermal properties. Three pairs of mutually isomeric fluorophores, whose phenyls respectively located at the outside (o‐series) and inside (i‐series) of the side chain, were designed and synthesized. The positional isomerization of the phenyl endows the o‐series crystals with strong spatial conjugation between the phenyl group on the side chain and the backbone, as well as interlocked planar network, which is different to that observed in the i‐series. Thus, all o‐series nanoparticles (NPs) exhibit red‐shifted absorption, enhanced NIR‐II emission, and superior photothermal properties than their i‐series counterparts. A prominent member of the o‐series, o‐ITNP NPs, demonstrated efficacy in facilitating NIR‐II angiography, tumor localization, and NIR‐II imaging‐guided tumor photothermal therapy. The success of this side chain phenyl isomerization strategy paves the way for precise control of the aggregation behavior and for further development of efficient NIR‐II PTAs.

Steering diffusion selectivity of chemical isomers within aligned nanochannels of metal-organic framework thin film

The movement of molecules (i.e. diffusion) within angstrom-scale pores of porous materials such as metal-organic frameworks (MOFs) and zeolites is influenced by multiple complex factors that can be challenging to assess and manipulate. Nevertheless, understanding and controlling this diffusion phenomenon is crucial for advancing energy-economic membrane-based chemical separation technologies, as well as for heterogeneous catalysis and sensing applications. Through precise assessment of the factors influencing diffusion within a porous metal-organic framework (MOF) thin film, we have developed a chemical strategy to manipulate and reverse chemical isomer diffusion selectivity. In the process of cognizing the molecular diffusion within oriented, angstrom-scale channels of MOF thin film, we have unveiled a dynamic chemical interaction between the adsorbate (chemical isomers) and the MOF using a combination of kinetic mass uptake experiments and molecular simulation. Leveraging the dynamic chemical interactions, we have reversed the haloalkane (positional) isomer diffusion selectivity, forging a chemical pathway to elevate the overall efficacy of membrane-based chemical separation and selective catalytic reactions.

Positional Isomerism: A Novel Paradigm for Enhancing Iodine Adsorption in Functionalized Metal-Organic Frameworks.

Porous metal-organic frameworks (MOFs) have shown great potential as adsorbents for capturing radioiodine, a major fission product generated during the reprocessing of nuclear fuel. However, studies exploring the correlation between the structure of MOFs and iodine uptake capacity remain notably rare. In this study, we introduce a new strategy for enhancing the iodine adsorption efficiency of MOFs by strategically varying the position of functional groups on the organic linkers. Employing ligand-functionalized UiO-67 MOFs, our findings reveal that ortho-amino substitution of UiO-67-o-NH2, proximal to the node of the dicarboxylate linker, markedly accelerates adsorption kinetics of iodine vapor in comparison to meta-amino substitution of UiO-67-m-NH2, where the amino groups are oriented away from the node. In contrast, UiO-67-m-NH2 exhibits a higher adsorption capacity of 2.19 g/g, compared to 1.91 g/g for UiO-67-o-NH2, attributable to its higher porosity. Furthermore, a competitive I2/H2O vapor adsorption study demonstrated that UiO-67-o-NH2 exhibits faster adsorption kinetics and higher selectivity for iodine in the presence of water vapor compared to UiO-67-m-NH2. Additionally, the crucial influence of positional isomerism on enhancing iodine adsorption has been corroborated through Raman spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. These analyses reveal that the nitrogen atom positioned at the ortho site demonstrates a stronger affinity for iodine molecules compared to the nitrogen atom at the meta site, thereby improving adsorption kinetics.

Systematic Characterisation of the Fragmentation of Flavonoids Using High-Resolution Accurate Mass Electrospray Tandem Mass Spectrometry

Flavonoids are a class of polyphenolic secondary metabolites found in plants. Due to their ubiquity in our daily dietary intake and their major anti-oxidative, anti-inflammatory and anti-mutagenic activities, they have been a major focus of wide-ranging research for the past two decades. Mass spectrometry combined with liquid chromatography is one of the most popular techniques for the analysis of flavonoids. In this study, high-resolution accurate mass electrospray tandem mass spectrometry was used to study 30 flavonoids in both positive and negative ionisation modes. From the data obtained, common losses were summarised and compiled. Dominating neutral losses were tabulated. The radical loss of CH3· was observed in flavonoids containing methoxy groups and three key diagnostic product ions were identified. These were m/z 153 (indicative of two OH groups on ring A) m/z 167 (indicative of one OH and one methoxy group on ring A) and m/z 151 (a flavanol, with no ketone oxygen but two OH groups on ring A). These will be useful in structural elucidation of unknown flavonoids and flavonoid metabolites. Energy breakdown graphs were utilised to distinguish between three pairs of structural isomers, and to help rationalise proposed fragmentation pathways. Lastly, a competition of loss of CH3· and methane was reported for rhamnetin and isorhamnetin in the negative ion mode for the first time. Proposed fragmentation pathways were given to rationalise the differences in peak intensities for this competitive process.

From historical drugs to present perils: UHPLC-QqQ-MS/MS determination of methaqualone and its designer analogs (NPS) with comprehensive fragmentation pathways study (QTOF)

Methaqualone, introduced in the 1960s as a sedative-hypnotic alternative to barbiturates, was withdrawn from the market due to its side effects and growing recreational use. Despite this, interest in methaqualone and its analogs remains high, raising concerns about potential abuse in the future. An ultra-high-performance liquid chromatography method coupled with triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) was developed to determine nine methaqualone-related compounds simultaneously. Biological samples were prepared using liquid-liquid extraction with ethyl acetate at pH 9, quantification was performed in blood using multiple reaction monitoring (MRM) mode. Methaqualone-d7 served as an internal standard. The limit of quantification (LOQ) ranged from 0.1 to 0.2 ng/mL, with precision and accuracy within 20%. Recovery ranged from 84.2% to 113.7%. The developed method allowed chromatographic separation of all compounds tested, including two structural isomers: methtylmethaqualone and etaqualone. The mass spectra aquired from quadrupole time-of-flight mass spectrometer allowed for the elucidation of comprehensive fragmentation study of methaqualone derivatives. The described situation poses a significant problem from the analytical point of view, as well as interpretation and forensic toxicological expertise. The developed method will contribute to increased analytical capabilities and enhanced detection of compounds from the methaqualone group that may appear on the illicit market.

Conversion of CO2 into Synthetic Motor Fuels

The process of CO2 conversion into synthetic hydrocarbons including the stages of synthesis gas production on the catalyst NIAP 06-06 and hydrocarbon synthesis by the Fischer-Tropsch method on a bifunctional zeolite-containing catalyst has been investigated. Experimental studies of the process of catalytic conversion of CO2 into synthesis gas were carried out in order to obtain gas with the ratio of H2/CO close to the required ratio for Fischer-Tropsch synthesis. The possibility of obtaining gasoline and diesel fractions of hydrocarbons with a high content of isomeric structures that increase the performance characteristics of motor fuels has been shown. The yield of hydrocarbons C5+ with 1 m3 of initial CO2 and H2 at the synthesis temperature of 220 °C is found to be 44.5 g.

Comparative Ecotoxicity Assessment of highly bioactive Isomeric monoterpenes carvacrol and thymol on aquatic and edaphic indicators and communities

The growing demand for sustainable natural products to replace harmful synthetic ones requires comprehensive ecotoxicity assessments to ensure their eco-friendly nature. This study explored for the first time the changes in microbial community growth and metabolic profiles from river and natural soil samples exposed to the two structural isomers, thymol (THY) and carvacrol (CARV), utilizing Biolog EcoPlate™ assays and 16S rRNA gene sequencing for taxonomic analysis. In addition, we addressed existing ecotoxicity data gaps for these two compounds by using aquatic (Daphnia magna and Vibrio fischeri) and soil (Eisenia fetida and Allium cepa) indicators. Results show acute toxicity of both CARV and THY on all indicators. V. fischeri (LC50=0.59 mg/L) >D. magna (4.75 mg/L) >A. cepa (6.47 mg/L) for CARV, and V. fischeri (LC50=1.71 mg/L) >A. cepa (4.05 mg/L) >D. magna (8.13 mg/L) for THY. E. fetida showed LC50 = 7.68 mg/Kg for THY and 1.04 for CARV. River and soil microbial communities showed resilience, likely because they contain taxa capable of biodegrading these products. No significant growth inhibition effects were observed up to 100 mg/L, though substrate utilization decreased at higher concentrations, particularly for polymers and amines in soil microorganisms and polymers in aquatic communities. Soil microorganisms were more affected than aquatic ones, with CARV being more toxic than THY (EC50120h = THY 94.13 and CARV 29.79 mg/L in soil microorganisms). These findings suggest that an increase in the consumption of these products and their subsequent ecotoxicity effects from environmental discharge should still be monitored before being ruled out. However, long-term effects are unlikely due to microbial degradation of these natural products, potentially reducing risks to other target species and opening the way for their use as substitutes for commercial antibiotics.

Evaluation of the ionization efficiency in phosphatidylcholine positional isomers with docosahexaenoic acid bound to the sn-1 or sn-2 position

Phosphatidylcholine (PC), a key phospholipid, contains 2 fatty acids that can be bound at the sn-1 and sn-2 positions, resulting in positional isomers when different fatty acids are attached. Currently, there is no established method for identifying phospholipid molecular species and quantifying individual isomers using authentic standards of each PC isomer. In this study, we prepare authentic analytical standards for PC positional isomers through chemical synthesis and preparative purification. These isomers contain docosahexaenoic acid (DHA, 22:6) and palmitic acid (16:0) attached at the sn-1 and sn-2 positions and are denoted as PC(22:6/16:0) and PC(16:0/22:6), respectively. Standard solutions of PC(22:6/16:0) and PC(16:0/22:6) were analyzed using liquid chromatography-tandem mass spectrometry, and calibration curves of the PC positional isomers were generated to compare their ionization efficiencies. The ionization efficiency of PC(22:6/16:0) was 2.32 times higher than that of PC(16:0/22:6), indicating that the ionization efficiency depends on the binding position of the fatty acid. Elucidating and correcting the differences in the ionization efficiencies of the PC positional isomers will enable the accurate quantitative analysis of lipidomes in the future.

Determination of endogenous GHB in ante-mortem whole blood, urine, and oral fluid by LC–MS/MS: The effect of different additives and storage conditions on the stability of GHB in blood

Two challenges in detecting γ-hydroxybutyric acid (GHB) intake are its endogenous presence and in vitro production after sampling. This study developed an LC–MS/MS method for selective GHB determination in human antemortem blood, urine, and oral fluid at endogenous concentrations. Furthermore, the stability of GHB in blood samples and its endogenous concentrations in samples taken under controlled circumstances were investigated. Samples were extracted in methanol/acetonitrile and processed by anion exchange solid-phase extraction. GHB was separated from structural isomers using a reversed–phase LC column with anion properties. The validated limit of quantification was 0.005 µg/mL in blood and 0.010 µg/mL in urine and oral fluid, at which the relative reproducibility standard deviation and bias were <15 %. The mean extraction recovery was ≥90 %. The average GHB concentration increased by 1.2 µg/mL in fluoride/citrate- preserved blood after 28 days of storage at 4°C; however, in fluoride/oxalate (FX)-preserved blood, the mean concentration increased by only 0.055 µg/mL. No change was observed at −20°C. In 105 randomly selected samples of FX-preserved blood collected for forensic antemortem toxicological analysis, all concentrations were <0.066 µg/mL, even after long-term storage at −20°C. In blood, urine, and oral fluid samples from a clinical study of GHB intake, endogenous baseline levels from 30 participants ranged from 0.0069–0.050, 0.024–0.38, and 0.034–0.93 µg/mL, respectively. These results demonstrate that the current cut-off level of 5 µg/mL for discriminating between endogenous and exogenous GHB in antemortem blood could be considerably lower for FX-preserved blood stored at −20°C.

A common phthalate replacement disrupts ovarian function in young adult mice.

Di-2-ethylhexyl terephthalate (DEHTP) is a replacement for its structural isomer di-2-ethylhexyl phthalate (DEHP), a known endocrine disrupting chemical and ovarian toxicant. DEHTP is used as a plasticizer in polyvinyl chloride products and its metabolites are increasingly found in biomonitoring studies at levels similar to phthalates. However, little is known about the effects of DEHTP on the ovary. In this research, we tested the hypothesis that DEHTP is an ovarian toxicant and likely endocrine disrupting chemical like its isomer DEHP. The impact of environmentally relevant exposure to DEHTP and/or its metabolite mono-2-ethylhexyl terephthalate (MEHTP) on the mouse ovary was investigated in vivo and in vitro. For the in vivo studies, young adult CD-1 mice were orally dosed with vehicle, 10µg/kg, 100µg/kg, or 100mg/kg of DEHTP for 10 days. For the in vitro studies, isolated untreated ovarian follicles were exposed to vehicle, 0.1, 1, 10, or 100µg/mL of DEHTP or MEHTP. Follicle counts, hormone levels, and gene expression of steroidogenic enzymes, cell cycle regulators, and apoptosis factors were analyzed. In vivo, DEHTP exposure altered follicle counts compared to control. DEHTP exposure also decreased expression of cell cycle regulators and apoptotic factors compared to control. In vitro, follicle growth was reduced compared to controls, and expression of the cell cycle regulator Cdkn2b was increased. Overall, these results suggest that DEHTP and MEHTP may be ovarian toxicants at low doses and should be subjected to further scrutiny for reproductive toxicity due to their similar structures to phthalates.

Evidence for Abiotic Dimethyl Sulfide in Cometary Matter

Technological progress related to astronomical observatories such as the recently launched James Webb Space Telescope (JWST) allows searching for signs of life beyond our solar system, namely, in the form of unambiguous biosignature gases in exoplanetary atmospheres. The tentative assignment of a 1σ–2.4σ spectral feature observed with JWST in the atmosphere of exoplanet K2-18b to the biosignature gas dimethyl sulfide (DMS; sum formula C2H6S) raised hopes that, although controversial, a second genesis had been found. Terrestrial atmospheric DMS is exclusively stemming from marine biological activity, and no natural abiotic source has been identified—neither on Earth nor in space. Therefore, DMS is considered a robust biosignature. Since comets possess a pristine inventory of complex organic molecules of abiotic origin, we have searched high-resolution mass spectra collected at comet 67P/Churyumov–Gerasimenko, target of the European Space Agency’s Rosetta mission, for the signatures of DMS. Previous work reported the presence of a C2H6S signal when the comet was near its equinox, but distinction of DMS from its structural isomer ethanethiol remained elusive. Here we reassess these and evaluate additional data. Based on differences in the electron ionization-induced fragmentation pattern of the two isomers, we show that DMS is significantly better compatible with the observations. Deviations between expected and observed signal intensities for DMS are <1σ, while for ethanethiol they are 2σ–4σ. The local abundance of DMS relative to methanol deduced from these data is (0.13 ± 0.04)%. Our results provide the first evidence for the existence of an abiotic synthetic pathway to DMS in pristine cometary matter and hence motivate more detailed studies of the sulfur chemistry in such matter and its analogs. Future studies need to investigate whether or not the present inference of cometary DMS could provide an abiotic source of DMS in a planetary atmosphere.

Positional isomers and non-covalent interactions of acrylonitrile-methylpyridinium iodide salts: Combined experimental and quantum chemical calculations investigations

Quaternary salts d-π-A+X- having a large π-conjugated system (I) 2-((Z)-1-cyano-2-[4-(dimethylaminophenyl]ethenyl)-1-methylpyridin-1-ium iodide, (II) 3-((Z)-1-cyano-2-[4-(dimethylaminophenyl]ethenyl)-1-methylpyridin-1-ium iodide, and (III) 4-((Z)-1-cyano-2 iodide -[4-(dimethylaminophenyl]ethenyl)-1-methylpyridin-1-ium iodide, were synthesized straightforwardly and easily and characterized by single-crystal X-ray diffraction, IR, UV–Vis, 1HNMR spectroscopy, DSC, and TGA. Quantum chemical calculations were performed to obtain electronic structure by using DFT. The salts I-III exhibited a hyperchromic shift and a strong bathochromic effect of 100 nm compared to the precursors, which indicates charge transfer (CT) due to ionic interactions. The Hirshfeld, MEPS, QTAIM, and NCI-RDG analyses showed that the -CN group and the counterion I(-) atom play major roles in the intermolecular interaction for crystal packing. The significance of non-covalent interactions for the stability of the molecules in their solid state is also revealed by natural bond orbital analysis.

플라보노이드류의 하위 그룹을 구성하는 기본 분자들에 대한 양자 화학적 연구

A quantum study was carried out the structure and the characteristics of the basic molecules that constituting the subgroup of flavonoid i.e. flavan, flavanone, flavonol, anthocyanidine, flavone, isoflavone, and flavonol. We have reported and discussed the stable structure of isomers and physical quantities associated with the frontier energy, which are HOMO-LUMO energy difference, electronegativity, chemical potential, molecular hardness, softness, electrostatic potential, electrophilicity, electrodonating power and electro-accepting power. And we also have presented and discussed the physical quantities associated with the frontier orbital, such as frontier orbital figure, electrostatic potential diagram, polarizability, dipole moments etc., and also the values of free energy and entropy of each molecule obtained as a result of the vibration-rotation analysis The physical quantities reported and discussed are considered important data for understanding the reactivity, biological, pharmacological activity, and antioxidant properties of molecules belonging to flavonoid in the future

In-situ Forming Multipolymeric Glucose-Responsive Hydrogels.

Stimuli-responsive hydrogels (HGs) have shown promise for smart drug delivery applications. Specifically, glucose-responsive HGs having phenylboronic acid (PBA) functional groups are extensively pursued for insulin delivery in hyperglycemia. Current polymeric glucose-responsive HGs are cumbersome to fabricate and show a limited insulin release profile. Herein, we develop a straightforward fabrication of glucose-responsive multipolymer HGs (MPHGs) using a three-component in situ mixing. Molecular cargo, such as insulin, was loaded during the gelation. Heterobifunctional formylphenylboronic acid (FPBA) crosslinkers were used to interconnect polyvinyl alcohol (PVA) and branched polyethyleneimine (PEI) via boronate ester and imine bonds, respectively. Three positional isomers of FPBA (2FPBA, 3FPBA, and 4FPBA) resulted in HGs with distinct viscoelastic behaviors under the same conditions. HGs derived from 4FPBA exhibited more solid-like properties compared to 2FPBA and 3FPBA due to a higher crosslinking density. All the HGs exhibited glucose-responsive dissolution and release of embedded insulin cargo without disrupting the native structure. Insulin release profiles show a higher glucose-responsive release from 4FPBA-derived MPHGs. All the HGs were injectable, self-healing, and noncytotoxic below 10 μg/ml concentrations. The MPHGs developed in this study uncover new directions in creating glucose-responsive matrices for self-regulating drug delivery applications. In the future, detailed in vivo studies will be performed for clinical applications.

Theoretical investigation of isomeric structures of B2O3. Kinetic and thermodynamic study of the transformation of boric oxide to metaboric acid HBO2. Complexation of HBO2: from dimer to hexamer

In this study, Density Functional Theory was adopted. Isomeric structures of boric oxide B 2 O 3 were investigated at B3LYP/6-311G++(d,p), M052X, M062X, M08HX, M11/6-311G++(d,p) levels of theory. For validation of stable states, optimisation was performed using the correlated coupled cluster with single, double, and perturbative triple excitations (CCSD(T)) method in conjunction with the augmented correlation-consistent polarisation valence Double Zeta (aug-cc-pVDZ) (AVDZ) basis sets. Intrinsic Reaction Coordinates (IRCs) calculations were carried out to give kinetics of reactions B 2 O 3 +H 2 O ⇌ 2HBO 2 , B 2 O 3 +HCl ⇌ HBO 2 + OBCl. Complexation of HBO 2 was considered using B3LYP-D3, B97-D, MN15 and wB97X-D dispersion-corrected functionals. Counterpoise-corrected complexation energies as well as frontier orbital HOMO-LUMO energy gaps of (HBO 2 ) n (n = 2, 3, 4, 5, 6) clusters were derived in order to study their stability owed to hydrogen bonds.

Boosting spontaneous orientation polarization of polar molecules based on fluoroalkyl and phthalimide units

Polar organic molecules form spontaneous polarization in vacuum-deposited films by permanent dipole orientations in the films, originating from the molecule’s potential ability to align itself on the film surface during deposition. This study focuses on developing polar molecules that exhibit spontaneous orientation polarization (SOP) and possess a high surface potential. In the proposed molecular design, a hexafluoropropane (6F) unit facilitates spontaneous molecular orientation to align the permanent dipoles, and a phthalimide unit induces strong molecular polarization. Furthermore, the introduction of phthalimides into the molecular backbone raises the glass transition temperature of the molecules, leading to the suppression of molecular mobility on the film surface during film deposition and an improvement in the dipole orientation. The resulting surface potential slope is approximately 280 mV nm−1 without substrate temperature control. Furthermore, this work proposes a method using position isomers as a design strategy to tune the SOP polarity. The substitution position of the strong polar units influences the direction of the total molecular dipoles and affects the SOP polarity of the 6F-based molecules. The proposed molecular designs in this study provide wide tunability of the SOP intensity and polarity, which contributes to highly efficient organic optoelectronic and energy-harvesting devices.