Intramolecular Charge Transfer Interactions Research Articles

Dissolved organic matter isolates obtained by solid phase extraction exhibit higher absorption and lower photo-reactivity: Effect of components

Notable differences in photo-physical and chemical properties were found between bulk water and solid phase extraction (SPE) isolates for dissolved organic matter (DOM). The moieties extracted using modified styrene divinylbenzene cartridges, which predominantly consist of conjugated aromatic molecules like humic acids, contribute mainly to light absorption but exhibit lower quantum yields of fluorescence and photo-produced reactive intermediates (PPRIs). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed lignin as the moieties displaying most significant variance in abundance. In Van Krevelen-Spearman plot, we observed molecules positively or negatively correlated with DOM's optical and photochemical properties (including SUVA254, steady-state concentrations of ·OH, 1O2 quantum yield, etc.) were confined to specific regions, which can be delineated using a threshold modified aromaticity index (AImod) of 0.3. Based on the relationships between optical properties and PPRI production, it is suggested that the energy gap between ground state and excited singlet state (△ES1→S0), governing the inner conversion rate, serves as a determinant for apparent quantum yield of PPRIs in DOM, with intra-molecular charge transfer (CT) interactions potentially playing a pivotal role. Regarding DOM's photoreactivity with pollutants, this study has revealed, for the first time, that protein/amino sugars/amino acids could act as antioxidant groups in addition to phenols on the photolysis of sulfadiazine. These findings provide valuable insights into DOM photochemistry and are expected to stimulate further research in this area.

Appending Coronene Diimide with Carbon Nanohoops Allows for Rapid Intersystem Crossing in Neat Film.

The development of innovative triplet materials plays a significant role in various applications. Although effective tuning of triplet formation by intersystem crossing (ISC) has been well established in solution, the modulation of ISC processes in the solid state remains a challenge due to the presence of other exciton decay channels through intermolecular interactions. The cyclic structure of cycloparaphenylenes (CPPs) offers a unique platform to tune the intermolecular packing, which leads to controllable exciton dynamics in the solid state. Herein, by integrating an electron deficient coronene diimide (CDI) unit into the CPP framework, a donor-acceptor type of conjugated macrocycle (CDI-CPP) featuring intramolecular charge-transfer (CT) interaction was designed and synthesized. Effective intermolecular CT interaction resulting from a slipped herringbone packing was confirmed by X-ray crystallography. Transient spectroscopy studies showed that CDI-CPP undergoes ISC in both solution and the film state, with triplet generation time constants of 4.5 ns and 238 ps, respectively. The rapid triplet formation through ISC in the film state can be ascribed to the cooperation between intra- and intermolecular charge-transfer interactions. Our results highlight that intermolecular CT interaction has a pronounced effect on the ISC process in the solid state, and shed light on the use of the characteristic structure of CPPs to manipulate intermolecular CT interactions.

Manipulating Intramolecular Charge Transfer and Supramolecular Interaction in D-A-D Conjugated Systems by Regioisomerization.

Three new donor-acceptor-donor (D-A-D) architecture regioisomers comprising a large planar electron-withdrawing core tribenzo[a,c,i]phenazine and two identical electron-donating triphenylamines with different substitution patterns were designed and synthesized. Employing this regioisomerization strategy, the intramolecular charge-transfer interactions are effectively tuned and result in a significant bathochromic shift of photoluminescence maximum over 100 nm, which induces the corresponding emission band extending into the near-infrared region as well as giving a high solid-state quantum yield of 25%. Meanwhile, it is found that the supramolecular interactions of this series of regioisomers with planar electron-donor pyrene are greatly affected by the substitution pattern.

Substituent Position Dependent Photophysical Properties of Indole – Barbituric and Thiobarbituric Acid based Molecular Rotors

AbstractA series of 2‐ and 3‐methylindole (MI)‐based barbituric acid (BA) and thiobarbituric acid (TBA) derivatives (2MIBA, 2MITBA, 3MIBA and 3MITBA) in Donor (D)‐π‐Acceptor (A) configuration having strong intramolecular charge transfer (ICT) interactions were synthesized by the simple and efficient route. Methyl substituent at the 2‐ and 3‐ position alters the coplanarity of the DA systems leaving 2MI derivatives as nonplanar whilst 3MI derivatives as planar one and the latter forms an intramolecular hydrogen bond between indole N−H and −C=O of BA or TBA, which facilitates the excited state intramolecular proton transfer (ESIPT) emission in 3MIBA and 3MITBA. Comparing the UV‐visible absorption spectra in the solution phase reveals that the ICT band of 2MITBA and 3MITBA are red‐shifted from the 2MIBA and 3MIBA due to the stronger electron‐accepting nature of C=S than the C=O. Since these molecules exert photo‐induced intramolecular charge transfer followed by a rotation around the bridging methylene group, only weak fluorescence is noted. Nevertheless, in an aggregated state, both 3MIBA and 3MITBA exhibit significant aggregation‐induced enhanced emission (AIEE) characteristics in their THF/water mixture, but the effect is not promising for 2MIBA and 2MITBA. Further, melamine‐3MITBA co‐assembly aided through an intermolecular hydrogen bonding network can also be used as a solid‐state emitter.

Tuning sensing efficacy of anthraimidazoledione-based charge transfer dyes: nitro group positioning impact.

Anthraimidazoledione-based optical sensors have been designed by varying the position of the nitro functional group. All three positional isomers showed highly colored, photostable optical signals owing to intramolecular charge transfer interactions. Despite having the same anion-binding site (imidazole unit), the selectivity and sensitivity of the compounds depend on the positioning of the nitro group. The selectivity was fairly good for the meta isomer, followed by the ortho and para isomers, respectively. In contrast, the sensitivity towards anions followed a completely opposite trend, with the para isomer being the most sensitive one towards anions. Interestingly, the color changing response along the turn-on fluorescence signal was observed only with CN- ions in a semi-aqueous environment. Though the introduction of water as a co-solvent could improve the selectivity, the sensitivity was found to be slightly less than that observed in pure organic medium. Mechanistic studies indicated hydrogen bonding interactions between the imidazole -NH proton and cyanide, which further facilitated the extent of intramolecular charge transfer.

Low bandgap fused-ring electron acceptors based on π-expended asymmetric benzotrithiophene core: Regulating aggregation and photovoltaic performance by side chain isomerization

Asymmetric molecular design strategy has received increasing attention in the development of fused-ring electron acceptors (FREAs). Benzo [2,1-b: 3,4-b’: 5,6-b”] trithiophene (asym-BTT) with intrinsically asymmetric and electron-rich π-plane is an ideal unit to construct asymmetric FREAs, whereas asym-BTT-based FREAs are still very limited. Herein, two asymmetric FREAs based on the π-expended asym-BTT fused-core with para-hexylphenyl and meta-hexylphenyl side chains (p-FABTT and m-FABTT) have been developed. Owing to strong electron-donating ability and planar configuration of π-expended asym-BTT fused-core, two acceptors exhibit effective intramolecular charge transfer and intermolecular interaction, leading to near infrared absorption above 900 nm with narrow bandgaps of around 1.34 eV. Although the same π-conjugated backbones of two acceptors afford the nearly identical energy levels and solution absorptions, side chain isomerization leads to significant differences in film absorption, molecular stacking orientation and crystallinity. In neat film, the m-FABTT with meta-hexylphenyl side chains exhibits slightly redshifted absorption with stronger 0-0 absorption peak from J-aggregation compared to p-FABTT with para-hexylphenyl side chains. More orderly molecular stacking and stronger π-π interactions with shorter π-π stacking distance in both the neat film and active layer can be observed for m-FABTT. When blended with donor polymer D18, m-FABTT exhibits broadened spectral region and proper phase separation morphology for effective exciton dissociation and charge transport. Therefore, the OSCs device based on m-FABTT achieves an optimal PCE of 7.14 % with a higher JSC of 15.39 mA cm−2 and an improved FF of 57.96 % as comparing with p-FABTT-based device (a PCE of 4.81 % with a JSC of 11.67 mA cm−2 and a FF of 48.51 %).

Enhancing the photo-stability of narrow-bandgap acceptors via non-covalent interactions

It is widely acknowledged the significant impact of narrow-bandgap non-fullerene acceptors (NFAs) in the field of organic electronics. However, most NFAs suffer from stability issues, attributed to their strong intra-molecular charge transfer interaction (ICT) effect and large conjugated plane. The exo-cyclic double bond between the end group and donor core is particularly susceptible. Herein, 4-IF4F and 6-IF4F were designed and synthesized with diverse configurations of π-bridge units to study the effect of non-covalent interaction on the photo-stability. Although the device based on 4-IF4F shows a slight low photovoltaic performance compared with 6-IF4F, the photostability of 4-IF4F is much better, attributed to its non-covalent interaction between the fluorine atom of the π-bridge and the hydrogen atom of the exocyclic double bond. Briefly, this work systematically investigated the incorporation of FTT units in NFAs and their photovoltaic performance, further demonstrating that it is a promising strategy by using non-covalent interaction to improve the stablility of narrow-bandgap NFAs.

Eco-friendly synthesis, structural elucidation, computational investigation and in vitro antioxidant activity of a new N-tosylated benzimidazole derivative

Synthesis of 2-(diethoxymethyl)-1-tosyl-1H-benzo[d]imidazole 5 in excellent yield was achieved from 2-(1-ethoxypropyl)-1H-benzo[d]imidazole by ionic liquid supported eco-friendly green protocol. The precursor, 2-(diethoxymethyl)-1H-benzo[d]imidazole was prepared from o-phenylenediamine in good yield. The compound 5 was characterized by 1H, 13C and mass spectroscopic analyses. Also, its structure was further confirmed by X-ray single crystal analysis. From Hirshfeld calculations, it was clear that the H…H (51.1 %), H…C (21.6 %), O…H (18.9 %) and N…H (6.3 %) interactions were the most dominant in the solid-state structure of compound 5. The crystal stability was controlled by the short distance of O3…H7 (2.556 Å), N2…H6 (2.555 Å) and H11C…H11C (1.964 Å). Natural bond orbital (NBO) calculations were used to calculate the different intramolecular charge transfer interactions in the synthesized benzimidazole molecule 5. In addition, the DFT calculations were used to predict its electronic and reactivity descriptors. Furthermore, the synthesized compound was examined for its antioxidant properties and it was found that the compound 5 exhibited potent antioxidant activity (IC50 value of 42.32 µM) when compared to the standard drug butylated hydroxyanisole (BHA) (IC50 value of 58.6 µM). In addition, the compound 5 showed significant tuberculosis activity (3.12 µg/mL) against Mycobacterium tuberculosis H37Rv when compared to the standard drug, ethambutol (1.56 µg/mL). The docking simulation was also performed for compound 5 which correlated well with the in vitro findings.

Uncovering the substituted-position effect on excited-state evolution of benzophenone-phenothiazine dyads.

Photofunctional materials based on donor-acceptor molecules have drawn intense attention due to their unique optical properties. Importantly, Systematic investigation of substitution effects on excited-state charge transfer dynamics of donor-acceptor molecules is a powerful approach for identifying application-relevant design principles. Here, by coupling phenothiazine (PTZ) at the ortho-, meta-, and para-positions of the benzene ring of benzophenone (BP), three regioisomeric BP-PTZ dyads were designed to understand the relationship between substituted positions and excited-state evolution channels. Ultrafast transient absorption is used to detect and trace the transient species and related evolution channels of BP-PTZ dyads at excited state. In a non-polar solvent, BP-o-PTZ undergoes the through-space charge transfer process to produce a singlet charge-transfer (1CT) state, which subsequently proceeds the intersystem crossing process and transforms into a triplet charge-transfer (3CT) state; BP-m-PTZ experiences intramolecular charge transfer (ICT) process to generate the 1CT state, which subsequently transforms into the 3CT state by the intersystem crossing (ISC) and finally converts into the local-excited triplet (3LE) state; as for BP-p-PTZ, only 3LE states can be detected after the ISC process from the 1CT state. On the other hand, the twisted ICT states are generated via twisted motion between the donor and acceptor for all BP-PTZ dyads or planarization of the PTZ unit in high polar solvents. The excited-state theoretical calculations unveil that the features of ICT and intramolecular interaction between the three dyads play a decisive role in determining the through-bond charge transfer and through-space charge transfer processes. Also, these results demonstrate that the excited-state evolution channels of PTZ derivatives could be modified by tuning the substituted positions of the donor-acceptor dyads. This study provides a deep perspective for the substitute-position effect on donor-acceptor-type PTZ derivatives.

Theoretical investigations on structural, spectral, NBO, NLO and topology exploration (AIM, ELF, LOL, RDG) of piperazine-2,5-dione oxalic acid monohydrate

The present work investigates the structural stability and nonlinear optical (NLO) activity of piperazine-2,5‑dione oxalic acid monohydrate (PDOAH) using quantum chemical computational techniques. The optimized molecular structure and vibrational wavenumbers of the PDOAH molecule are determined by density functional theory (DFT) with B3LYP/6–311G(d,p) basis set. The vibrational wavenumbers, IR intensities, Raman activities and their corresponding PED values are obtained and analysed. Natural bond orbital (NBO) analysis is carried out to determine inter and intramolecular charge transfer interaction, intermolecular hydrogen bonding and hyperconjugative interactions that stabilize the structure. The charge transfer interaction, electrophilic, nucleophilic and chemical reactivity sites are identified with the aid of molecular electrostatic potential (MEP) and frontier molecular orbital (FMO) analysis. The TD-DFT method is utilized in UV–Vis spectral analysis for the molecule in the water solvent. RDG and IRI analysis is performed to spot the van der Waals interaction and steric effect within the molecule. The Hirshfeld surface analysis is carried out to scrutinize the intermolecular interactions. The nonlinear optical (NLO) parameters of PDOAH are evaluated through DFT calculation and compared with that of urea.

Experimental and Computational studies on Intramolecular charge transfer, Terahertz and Two photon absorption of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) from their Vibrational spectra for Optical limiting and NLO applications

Non-linear optical (NLO) features of 3-[(4-Nitrophenyl Azo)]-9H-Carbazole-9-Ethanol (NPACE) chromophore were investigated by FT-IR, FT-Raman, and UV–visible spectra aided by Density Functional Theory (DFT) using the B3LYP/6–311++G(d,p) basis set of Gaussian 16 W package. It is observed from the DFT calculation that the slight increase in the endocyclic angle of C13 -C14 -C15 and the reduction in exocyclic angle of N40 –N39 -C14 and C15 -C14 –N39 ascertained by experimental XRD values indicating the intramolecular charge-transfer interaction between the carbazole and nitrophenyl group through the diazo bridge. The vibrational contribution to the linear electro-optic effect is 15% of the total hyperpolarizability being calculated at B3LYP/6–311++G (d, p) for the NPACE molecule. It is also observed that the 8a, 19a, and 19b modes of the carbazole ring and the 8a, 8b, and 19b modes of the phenyl ring are found to be simultaneously and intensely active in IR and Raman spectra explaining the charge transfer interactions throughout the molecule. The low value of the HOMO- LUMO energy gap (2.5843 eV) and the deviation between the measured absorption wavelength (3.36 eV) from the computed (3.87 eV), both these facts substantiate the intramolecular charge transfer. The polarizability and first-order hyperpolarizability were calculated as 6.48 × 10-24 and 3.8 × 10-29 esu, respectively. The second harmonic generation (SHG) measurement experiment of NPACE was carried out using the powder method. The SHG efficiency is measured in comparison with the urea standard. The calculated torsional mode at 20 cm−1 is in excellent quantitative agreement with the experimentally determined terahertz absorption peak. The two-photon absorption coefficient of NPACE was estimated to be 0.9 × 10-11 mW−1, which is mainly due to the D-π-A type of molecular structure, and the optical limiting threshold for NPACE was estimated to be 1.52 × 1013 Wm−2 enabling this material as a potential candidate for optical limiting applications.

Synthesis and properties of D-π-A triphenylamine derivatives with solvatochromism and bioimaging application

D-π-A type molecular structures often exhibit excellent photophysical properties due to intramolecular charge-transfer interactions. Herein, two donor-π-acceptor (D-π-A) type triphenylamine derivatives were designed and synthesized. These two compounds exhibited bright solid-state emission with orange-red fluorescence (compound 1, 620 nm) and near-infrared (NIR) fluorescence (compound 2, 650 nm). Moreover, the photophysical properties studies showed that these two compounds exhibited significant solvatochromism with different solvent polarity, indicating their effective intramolecular charge transfer. Furthermore, the two compounds showed remarkable aggregation-induced emission (AIE) effect, and compound 2 was more likely to form the aggregation state in the presence of less water. In addition, compared to compound 1, compound 2 only had a more sensitive response to high viscosity environments. These results indicate that the additional phenyl ring could be an alternative way to tune the fluorescence behaviors and provide a new strategy to design AIE-active and solvatochromism dyes. Finally, cell imaging experiments showed that these two compounds had the ability to be applied for bioimaging in living cells.

Photochromic and Electrochromic Hydrogels based on Electron Donor and Acceptor Bridged Viologen Derivatives for Multifunctional Signage Applications

AbstractInserting a conjugated bridge between the two pyridinium units of the viologen is an effective approach to tuning the colorations of the viologen derivatives. However, the relationship between the charge density on the viologen bridge and the related photochromic (PC) and electrochromic (EC) properties has been rarely studied. Herein, three conjugated bridges with different charge densities, i.e., thienyl, phenyl, and quinoxalinyl groups, are incorporated between the two pyridinium units of ammonium‐functionalized viologens. The coloration scope of the viologens before and after chromism is expanded due to the adjusted intramolecular charge transfer interactions. Moreover, the introduction of an electron‐withdrawing bridge is greatly beneficial to the chromic properties of the conjugation‐extended viologens in polyacrylamide hydrogels. The EC device based on AQV hydrogel exhibits the highest optical contrast of 85% at 580 nm, the fastest switching time (1.0 and 0.9 s for coloration and bleaching processes, respectively), and no decay in optical contrast after 1000 EC cycles. Furthermore, multifunctional and multicolored signages as sports icons and traffic signs are fabricated and demonstrated. Variable traffic signs presenting “Permitted”, “Warning”, and “Prohibited” cautions for pedestrians and vehicles can be realized in a single device with only one piece of ITO glass.

The Effects of Conjugated Fused Ring System: An Investigation of Electronic, Nonlinear Optical, X-Ray Structural Properties and Computational Studies on Chalcone Derivatives

The conjugated fused ring system of chalcone with D-A-π-A and A-A-π-D framing has been the subject of a detailed study on intramolecular charge transfer (ICT). The strong donors (Anthracene and Pyrene), strong acceptors (cyano), and large extended conjugation are in charge for the higher third order susceptibility in order of (10−6 esu) and show good optical limiting behavior with a lower optical limiting threshold which is determined by Z-scan analysis. Computational studies reveal that the higher values of dipole moments, polarizability and second hyperpolarizability values provided evidence that the proposed compounds are suitable as an efficient NLO material. The band gap energy generated from the FMOs was shown to be decreasing while μ increased, which is an indication of ICT occurring within molecules. Natural bond orbital (NBO) studies the different ICT interactions occurring and demonstrated a significant push-pull action for both compounds, with donor (pyrene and anthracene) and negative values for acceptors. The study of single-crystal X-ray diffraction shows the packing arrangements positioned side by side enhance the intermolecular charge transfer between the donor and the acceptor group of the molecules. Based on our experimental and theoretical findings, we can conclude that the studied compounds exhibit potential in NLO applications such as optical limiting devices.

Exploration of spectroscopic, computational, fluorescence turn-off mechanism, molecular docking and in silico studies of pyridine derivative.

The present work reports pyridine-based chalones using spectroscopic techniques to use pyridine derivative analysis. The solvatochromic behavior of 3DPP in non-polar, polar protic and aprotic solvents has been investigated experimentally. The photophysical property of the compound in diverse solvents is attributed to the intra-molecular charge transfer interactions. The dipole moment of 3DPP is estimated theoretically and experimentally using various solvatochromic methods. It is observed that there is a bathochromic shift in the emission spectra of 3DPP, which confirms the π → π* transition. Fluorescence quenching of 3DPP is studied. The type of fluorescence quenching mechanism is found to be collisional quenching. A study of FRET theory on 3DPP was carried out with metal ions. There is a considerable energy transfer between 3DPP and metal ions. NLO behaviors of the compound have been revealed with the help of Kurtz-Perry powder technique. Additionally, the title molecule is docked, carried ADMET studies and drug-like activity using in silico tools. It is probed for antifungal activity through bioinformatics kit which showed potential information.

Photoinduced Radical Persistent Luminescence in Semialiphatic Polyimide System with Temperature and Humidity Resistance.

Organic persistent luminescence (pL) systems with photoresponsive dynamic features have valuable applications in the fields of data encryption, anticounterfeiting, and bioimaging. Photoinduced radical luminescent materials have a unique luminous mechanism with the potential to achieve dynamic pL. It is extremely challenging to obtain radical pL under ambient conditions; on account of it, it is unstable in air. Herein, a new semialiphatic polyimide-based polymer (A0) is developed, which can achieve dynamic pL through reversible conversion of radical under photoexcitation. A "joint-donor-spacer-acceptor" molecular design strategy is applied to effectively modulate the intramolecular charge-transfer and charge-transfer complex interactions, resulting in effective protection of the radical generated under photoirradiation. Meanwhile, polyimide-based polymers of A1-A4 are obtained by doping different amine-containing fluorescent dyes to modulate the dynamic afterglow color from green to red via the triplet to singlet Förster resonance energy-transfer pathway. Notably, benefiting from the structural characteristics of the polyimide-based polymer, A0-A4 have excellent processability, thermal stability, and mechanical properties and can be applied directly in extreme environments such as high temperatures and humidity.

Synthesis, photophysical, voltammetric, and DFT studies of 4-aminochalones

Aminochalcones, with a D-A-D architecture, were synthesized using Claisen-Schmidt condensation. The compounds were characterized by FTIR, melting point, HRMS, 1H, and 13C NMR spectroscopy and analyzed for UV–visible and fluorescence in different solvents (chloroform, acetonitrile, and methanol). All compounds showed absorption in the range of 330–420 nm and emission in the range of 400–550 nm. Both absorption and emission spectra exhibit bathochromic shifts from non-polar to polar solvents due to intramolecular charge transfer (ICT) interaction. Compounds 17 and 18 displayed mega Stokes shift (Δλ = 116–130 nm) in polar solvents giving these compounds a higher fluorescent character. Furthermore, HOMO-LUMO energy levels of compounds 17 and 18, evaluated through cyclic voltammetry, were found to be −5.10, −5.15, and −2.56, −2.99 respectively with band gap energy values 2.54–2.61 eV. The DFT and TD-DFT computations at the B3LYP functional along with a 6-31G(d,p) basis set for a comprehensive study of spectral data, molecular orbitals (HOMO, LUMO) analysis, and electrostatic potential (MEP) surfaces are also presented. The Computational studies support the experimental findings. The findings hint towards the optoelectronic efficiency of 17 and 18, and their potential for further optimization and use in optoelectronic devices.

Synthesis, structure determination, NBO analysis and vibrational/electronic spectroscopic study of Iron(II) Bis(diethyldithiocarbamate) [Fe(DDTC)2

This work deals with the synthesis, computational molecular modeling, and vibrational/electronic spectroscopic analysis of the coordination complex [Fe(DDTC)2]. The complex was synthesized according to the guidelines provided by the graphical method. The optimization of the molecular structure was performed using Density Functional Theory with the exchange functional B3LYP and basis set 6–311G(d,p). The experimental FT-IR and Raman spectra of the complex were recorded in the range of 4000–0 cm−1 to correlate them with the calculated spectra. Most of the DFT calculated frequencies agreed with the experimental results, and complete vibrational assignments (including metal-ligand) were made. To investigate the internal electronic mobility of the complex, we performed natural bond orbital analysis (NBO), which provided information regarding intramolecular charge transfer interactions resulting from the overlapping of bonding and antibonding orbitals. The NBO analysis also provided information about the electronic distribution between the HOMO and LUMO orbitals due to charge transfers. We found that the NBO analysis provided the main charge transfers between donor and acceptor atoms, and the HOMO-LUMO energy gap revealed that the complex has high kinetic stability. We also correlated the calculated and experimental UV–Vis spectra to investigate the configurations of several excited states of the complex that involve intra-ligand transitions. The charge transfer and d-d (Laporte Forbidden) bands were assigned. The results also corroborate the existence of several Ligand to Metal Charge Transfer (LMCT) and Metal to Ligand Charge Transfer (MLCT) transitions, as well as d-d transitions. We found that the experimental vibrational spectra agreed with the theoretical ones.

Virtual screening, molecular docking, molecular dynamics and quantum chemical studies on (2-methoxy-4-prop-2-enylphenyl) N-(2-methoxy-4-nitrophenyl) carbamate: a novel inhibitor of hepatocellular carcinoma

HDAC protein is associated with hepatocellular carcinoma. Different medicinal plants were selected for this study to analyze the inhibitory efficacy against the target protein, HDAC. Using virtual screening, we filtered out the best compounds, and molecular docking (XP) was carried out for the top compounds which filtered out. The molecular docking results showed that the title compound (2-methoxy-4-prop-2-enylphenyl) N-(2-methoxy-4-nitrophenyl) carbamate (MEMNC) has the highest docking score of about −7.7 kcal/mol against the targeted protein histone deacetylase (HDAC) compared with the other selected phytocompounds. From the molecular dynamics analysis, the RMSD and RMSF plots depicted the overall stability of the protein–ligand complex. Toxicity properties show the acceptable range of various kinds of toxicity that were predicted using the ProTox-II server. In addition, DFT quantum chemical and physicochemical properties of the MEMNC molecule were reported. Initially, the molecular structure of the MEMNC molecule was optimized and harmonic vibrational frequencies were calculated using DFT/B3LYP method with a cc-pVTZ basis set using Gaussian 09 program. The calculated vibrational wavenumber values were assigned based on Potential Energy Distribution calculations using the VEDA 4.0 program and correlated well with the previous literature values. The molecule has bioactivity as a result of intramolecular charge transfer interactions, as demonstrated by frontier molecular orbital analysis. Molecular electrostatic potential surface and Mulliken atomic charge distribution analyses validate the reactive sites of the molecule. Thus, the title compound can be used as a potential inhibitor of HDAC protein, which paves the way for designing novel drugs to treat Hepatocellular carcinoma.Communicated by Ramaswamy H. Sarma

Stable Organic Radicals Participation in Charge Transfer: A New Strategy toward Molecular Functional Materials.

Charge-transfer (CT) engineering with inter-/intramolecular CT interactions by simple compositions has emerged as a universal and efficient way to construct organic functional materials. Stable organic radicals with unique physicochemical properties that cannot be realized in closed-shell molecules, have been widely demonstrated to be ideal building blocks to construct versatile organic CT materials. This concept article provides a brief overview of the advances in the design, structure and property of stable organic radicals-based CT molecular functional materials, and the strategy for the generation of these materials is also highlighted. First, radicals are introduced as open-shell donors or acceptors, with a focus on their importance and uniqueness in improving electrical, magnetic and optical properties of CT functional materials. Additionally, CT interactions in stable radical dimers and trimers are further discussed systematically. Finally, the challenges are summarized and perspectives for future development of stable organic radicals-based CT functional materials are provided.