Synthesis and Computational Exploration of Morpholine Bearing Halogenated Sulfonamides as Potential Tyrosinase Inhibitors.

In the presented work, a new series of three different 4-((3,5-dichloro-2-[(2/4-halobenzyl)oxy]phenyl)sulfonyl)morpholines was synthesized and the structure of these compounds were corroborated by 1 H-NMR & 13 C-NMR studies. The in vitro results established all the three compounds as potent tyrosinase inhibitors relative to the standard. The Kinetics mechanism plots established that compound 8 inhibited the enzyme non-competitively. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0025 µM. Additionally, computational techniques were used to explore electronic structures of synthesized compounds. Fully optimized geometries were further docked with tyrosinase enzyme for inhibition studies. Reasonably good binding/interaction energies and intermolecular interactions were obtained. Finally, drug likeness was also predicted using the rule of five (RO5) and Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. It is anticipated that current experimental and computational investigations will evoke the scientific interest of the research community for the above-entitled compounds.

Exploring the inhibitory potential of novel piperidine-derivatives against main protease (Mpro) of SARS-CoV-2: A hybrid approach consisting of molecular docking, MD simulations and MMPBSA analysis.

In the current study, a hybrid computational approach consisting of different computational methods to explore the molecular electronic structures, bioactivity and therapeutic potential of piperidine compounds against SARS-CoV-2. The quantum chemical methods are used to study electronic structures of designed derivatives, molecular docking methods are used to see the most potential docking interactions for main protease (MPro) of SARS-CoV-2 while molecular dynamic and MMPBSA analyses are performed in bulk water solvation process to mimic real protein like aqueous environment and effectiveness of docked complexes. We designed and optimized piperidine derivatives from experimentally known precursor using quantum chemical methods. The UV-Visible, IR, molecular orbitals, molecular electrostatic plots, and global chemical reactivity descriptors are carried out which illustrate that the designed compounds are kinetically stable and reactive. The results of MD simulations and binding free energy revealed that all the complex systems possess adequate dynamic stability, and flexibility based on their RMSD, RMSF, radius of gyration, and hydrogen bond analysis. The computed net binding free energy ( Δ G b i n d ) as calculated by MMPBSA method for the complexes showed the values of -4.29 kcal.mol-1 for P1, -5.52 kcal.mol-1 for P2, -6.12 kcal.mol-1 for P3, -6.35 kcal.mol-1 for P4, -5.19 kcal.mol-1 for P5, 3.09 kcal.mol-1 for P6, -6.78 kcal.mol-1 for P7, and -6.29 kcal.mol-1 for P8.The ADMET analysis further confirmed that none of among the designed ligands violates the Lipinski rule of five (RO5). The current comprehensive investigation predicts that all our designed compounds are recommended as prospective therapeutic drugs against Mpro of SARS-CoV-2 and it provokes the scientific community to further perform their in-vitro analysis.

Clinical tests accuracy in diagnosing subacromial impingement syndrome: A systematic review.

OBJECTIVE: To determine the sensitivity and specificity of the clinical diagnostic tests of subacromial impingement syndrome. METHODS: The systematic review comprised search on PubMed, PEDro, Cochrane Library and Google Scholar databases. For prospective cohort studies published in peer-reviewed English-language journals without any time limit, at least fully describing one clinical test. Only studies with free full text available were included. Data extracted included sensitivity and specificity for each clinical test, and variations were sorted out by the 3 reviewers by discussion. RESULTS: Of the 4137 studies identified, 2951(71.3%) were on PubMed, 119(2.9%) PEDro, 5(0.1%) Cochrane Library and 1062(25.7%) Google Scholar. After screening out all the studies that did not match the detailed inclusion criterion, 3(0.07%) studies were selected for review; 1(33.3%) each done in Spain, Turkey and France. Overall, there were 181 aged 15-82 years; 85(47%) males and 96(53%) females. Supraspinatus palpation test had a sensitivity of 92%, while the modified Neer test had specificity of 95.56% in terms of ruling out subacromial impingement syndrome. CONCLUSIONS: Supraspinatus palpation and modified Neer tests were found to be the most effective in the diagnosis of subacromial impingement syndrome.

Isolation of Thioinosine and Butenolides from a Terrestrial Actinomycetes sp. GSCW-51 and Their in Silico Studies for Potential against SARS-CoV-2.

In our continuous screening for bioactive microbial natural products, the culture extracts of a terrestrial Actinomycetes sp. GSCW-51 yielded two new metabolites, i. e., 5-hydroxymethyl-3-(1-hydroxy-6-methyl-7-oxooctyl)dihydrofuran-2(3H)-one (1), 5-hydroxymethyl-3-(1,7-dihydroxy-6-methyloctyl)dihydrofuran-2(3H)-one (2), and two known compounds; 5'-methylthioinosine (3), and 5'-methylthioinosine sulfoxide (4), which are isolated first time from any natural source, along with four known compounds (5-8). The structures of the new compounds were deduced by HR-ESI-MS, 1D and 2D NMR data, and in comparison with related compounds from the literature. Additionally, owing to the current COVID-19 pandemic situation, we also computationally explored the therapeutic potential of our isolated compounds against SARS-CoV-2. Compound 4 showed the best binding energies of -6.2 and -6.6 kcal/mol for Mpro and spike proteins, respectively. The intermolecular interactions were also studied using 2-D and 3-D imagery, which also supported the binding energies as well as put several insights under the spotlight. Furthermore, Lipinski's rule of 5 was used to predict the drug likeness of compounds 1-4, which indicated all compounds obey Lipinski's rule of 5. The study of bioavailability radars of the compounds 1-4 also confirmed their drug likeness properties where all the five crucial drug likeness parameters are in color area, which is safe to be used as drugs. Our isolation and computational findings highly encourage the scientific community to do further in vitro and in vivo studies of compounds 1-4.

Synthesis, spectral characterization, crystal structure and computational investigation of 2-formyl-6-methoxy-3-carbethoxy quinoline as potential SARS-CoV inhibitor.

The recent COVID-19 outbreak caused by the novel coronavirus SARS-CoV-2 has an immense impact on global health and economy. Although vaccines are being used, urgent need of drugs based on natural products with high efficacy and safety is a pressing priority. Quinoline alkaloids are well known for their therapeutic action against malaria; initially, it was tried against Coronaviruses. It is a basic vital scaffold to design drugs with required biological and pharmacological activities. In this present study, a new quinoline compound was synthesized and characterized by spectroscopy techniques. Crystal structure was established by SCXRD analysis and data is used as an input to perform various computations. Additionally, using state-of-the-art quantum computational techniques, the geometry optimization and calculation of UV-Vis spectrum of 2F6M3CQ were performed at B3LYP/6-311G* level of theory. The optimized molecular geometric parameters as well as UV-Vis spectrum values are found to be in good agreement with their respective experimental results. The visualization of 3-D plots of FMO and MEP indicated the structure and reactivity trends of 2F6M3CQ molecule. Molecular docking methods were utilized to find the drug ability of 2F6M3CQ with Mproprotein of SARS-CoV-2. There were many intermolecular interactions between Mpro protein and 2F6M3CQ molecule which lead to good binding energy (-5.5 kcal/mol) between them which was found to be better than the binding energy of chloroquinine molecule (-4.5 kcal/mol) as studied under same docking protocols. Finally, drug likeness and ADME properties of 2F6M3CQ were also analyzed. There is no violation found for RO5 in our 2F6M3CQ compound. ADME analysis shows drug like properties of compound 2F6M3CQ which predicts that it might be a potential candidate for inhibition of SARS-CoV-2.

A First-Principles Investigation on the Structural, Optoelectronic, and Thermoelectric Properties of Pyrochlore Oxides (La2Tm2O7 (Tm = Hf, Zr)) for Energy Applications.

A first-principles calculation based on DFT investigations on the structural, optoelectronic, and thermoelectric characteristics of the newly designed pyrochlore oxides La2Tm2O7 (Tm = Hf, Zr) is presented in this study. The main quest of the researchers working in the field of renewable energy is to manufacture suitable materials for commercial applications such as thermoelectric and optoelectronic devices. From the calculated structural properties, it is evident that La2Hf2O7 is more stable compared to La2Zr2O7. La2Hf2O7 and La2Zr2O7 are direct bandgap materials having energy bandgaps of 4.45 and 4.40 eV, respectively. No evidence regarding magnetic moment is obtained from the spectra of TDOS, as a similar overall profile for both spin channels can be noted. In the spectra of ε2(ω), it is evident that these materials absorb maximum photons in the UV region and are potential candidates for photovoltaic device applications. La2Tm2O7 (Tm = Hf, Zr) are also promising candidates for thermoelectric device applications, as these p-type materials possess ZT values of approximately 1, which is the primary criterion for efficient thermoelectric materials.

Chalcone Scaffolds Exhibiting Acetylcholinesterase Enzyme Inhibition: Mechanistic and Computational Investigations.

This study was aimed to perform the mechanistic investigations of chalcone scaffold as inhibitors of acetylcholinesterase (AChE) enzyme using molecular docking and molecular dynamics simulation tools. Basic chalcones (C1-C5) were synthesized and their in vitro AChE inhibition was tested. Binding interactions were studied using AutoDock and Surflex-Dock programs, whereas the molecular dynamics simulation studies were performed to check the stability of the ligand-protein complex. Good AChE inhibition (IC50 = 22 ± 2.8 to 37.6 ± 0.75 µM) in correlation with the in silico results (binding energies = -8.55 to -8.14 Kcal/mol) were obtained. The mechanistic studies showed that all of the functionalities present in the chalcone scaffold were involved in binding with the amino acid residues at the binding site through hydrogen bonding, π-π, π-cation, π-sigma, and hydrophobic interactions. Molecular dynamics simulation studies showed the formation of stable complex between the AChE enzyme and C4 ligand.

A Novel Method of Magnetic Nanoparticles Functionalized with Anti-Folate Receptor Antibody and Methotrexate for Antibody Mediated Targeted Drug Delivery.

Therapeutic effects of anticancer medicines can be improved by targeting the specific receptors on cancer cells. Folate receptor (FR) targeting with antibody (Ab) is an effective tool to deliver anticancer drugs to the cancer cell. In this research project, a novel formulation of targeting drug delivery was designed, and its anticancer effects were analyzed. Folic acid-conjugated magnetic nanoparticles (MNPs) were used for the purification of folate receptors through a novel magnetic affinity purification method. Antibodies against the folate receptors and methotrexate (MTX) were developed and characterized with enzyme-linked immunosorbent assay and Western blot. Targeting nanomedicines (MNP-MTX-FR Ab) were synthesized by engineering the MNP with methotrexate and anti-folate receptor antibody (anti-FR Ab). The cytotoxicity of nanomedicines on HeLa cells was analyzed by calculating the % age cell viability. A fluorescent study was performed with HeLa cells and tumor tissue sections to analyze the binding efficacy and intracellular tracking of synthesized nanomedicines. MNP-MTX-FR Ab demonstrated good cytotoxicity along all the nanocomposites, which confirms that the antibody-coated medicine possesses the potential affinity to destroy cancer cells in the targeted drug delivery process. Immunohistochemical approaches and fluorescent study further confirmed their uptake by FRs on the tumor cells' surface in antibody-mediated endocytosis. The current approach is a useful addition to targeted drug delivery for better management of cancer therapy along with immunotherapy in the future.

PMMA/ABS/CoCl2 Composites for Pharmaceutical Applications: Thermal, Antimicrobial, Antibiofilm, and Antioxidant Studies.

In this study, PMMA/ABS/CoCl2 ternary composite films were fabricated by the solution casting technique. The different weight ratios of cobalt chloride (≤10 wt) were incorporated into the PMMA/ABS blend (80:20). The chemical structure and thermal properties of the synthesized composites were assessed by FT-IR, TGA, and XRD. The biological properties of ternary composites, such as in vitro antibacterial activity and antioxidant capacity, were investigated. The enhanced thermal stability and promising antibacterial, selective antibiofilm, and potential antioxidant properties of PMMA/ABS/cobalt chloride composites demonstrated that they can be used for high-quality plastics and in many pharmaceutical applications.

Insighting isatin derivatives as potential antiviral agents against NSP3 of COVID-19.

The world is now facing intolerable damage in all sectors of life because of the deadly COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2. The discovery and development of anti-SARS-CoV-2 drugs have become pragmatic in the time needed to fight against this pandemic. The non-structural protein 3 is essential for the replication of transcriptase complex (RTC) and may be regarded as a possible target against SARS-CoV-2. Here, we have used a comprehensive in silico technique to find potent drug molecules against the NSP3 receptor of SARS-CoV-2. Virtual screening of 150 Isatin derivatives taken from PubChem was performed based on their binding affinity estimated by docking simulations, resulting in the selection of 46 ligands having binding energy greater than -7.1 kcal/mol. Moreover, the molecular interactions of the nine best-docked ligands having a binding energy of ≥ -8.5 kcal/mol were analyzed. The molecular interactions showed that the three ligands (S5, S16, and S42) were stabilized by forming hydrogen bonds and other significant interactions. Molecular dynamic simulations were performed to mimic an in vitro protein-like aqueous environment and to check the stability of the best three ligands and NSP3 complexes in an aqueous environment. The binding energy of the S5, S16, and S42 systems obtained from the molecular mechanics Poisson-Boltzmann surface area also favor the system's stability. The MD and MM/PBSA results explore that S5, S16, and S42 are more stable and can be considered more potent drug candidates against COVID-19 disease. Supplementary Information: The online version contains supplementary material available at 10.1007/s11696-022-02298-7.

Exploring the inhibitory potential of novel bioactive compounds from mangrove actinomycetes against nsp10 the major activator of SARS-CoV-2 replication.

The current study reveals the inhibitory potential of novel bioactive compounds of mangrove actinomycetes against nsp10 of SARS-CoV-2. A total of fifty (50) novel bioactive (antibacterial, antitumor, antiviral, antioxidant, and anti-inflammatory) compounds of mangrove actinomycetes from different chemical classes such as alkaloids, dilactones, sesquiterpenes, macrolides, and benzene derivatives are used for interaction analysis against nsp10 of SARS-CoV-2. The six antiviral agents sespenine, xiamycin c, xiamycin d, xiamycin e, xiamycin methyl ester, and xiamycin A (obeyed RO5 rule) are selected based on higher binding energy, low inhibition constant values, and better-docked positions. The effective hydrogen and hydrophobic (alkyl, π -sigma, π - π T shaped and π -alkyl) interaction analysis reveals the four antivirals sespenine, xiamycin C, xiamycin methyl ester, and xiamycin A are supposed to be the most auspicious inhibitors against nsp10 of SARS-CoV-2. Quantum chemistry methods such as frontier molecular orbitals and molecular electrostatic potential are used to explain the thermal stability and chemical reactivity of ligands. The toxicity profile shows that selected ligands are safe by absorption, distribution, metabolism, excretion, and toxicity profiling and also effective for inhibition of nsp10 protein of SARS-CoV-2. The molecular dynamic simulation investigation of apo and halo forms of nsp10 done by RMSD of C α atoms of nsp10, all amino acid residues RMSF, count total number of hydrogen bonds and radius of gyration (R g). MD simulations reveal the complexes are stable and increase the structural compactness of nsp10 in the binding pocket. The lead antiviral compounds sespenine, xiamycin C, xiamycin methyl ester, and xiamycin A are recommended as the most promising inhibitors against nsp10 of SARS-CoV-2 pathogenicity. Supplementary Information: The online version contains supplementary material available at 10.1007/s11696-021-01997-x.

Exploring the potential of novel phenolic compounds as potential therapeutic candidates against SARS-CoV-2, using quantum chemistry, molecular docking and dynamic studies.

In the current study, the interaction of SARS-CoV-2 protein (A and B chains of nsp13) with different recently synthesized phenolic compounds (Sreenivasulu et al., Synthetic Communications, 2020, 112-122) has been studied. The interactions have been investigated by using molecular docking, quantum chemical and molecular dynamics simulations methods. The molecular structures of all the ligands are studied quantum chemically in terms of their optimized structures, 3-D orbital distributions, global chemical descriptors, molecular electrostatic potential plots and HOMO-LUMO orbital energies. All the ligands show reasonably good binding affinities with nsp-13 protein. The ligand L2 shows to have better binding affinities to Chain A and Chain B of nsp13 protein, which are -6.7 and -6.4 kcal/mol. The study of intermolecular interactions indicates that L2 shows different hydrophobic and hydrogen bond interactions with both chains. Furthermore, molecular dynamic simulations of the nsp13-L2 complex are obtained over a time scale of 60 ns, which indicates its stability and flexibility behavior as assessed in terms of its RMSD and RMSF graphs. The ADMET analysis also shows no violation of Lipinski rule (RO5) by studied phenolic compounds. We believe that the current findings will be further confirmed by in vitro and in vivo studies of these recent phenolic compounds for their potential as inhibitors for SARS-Co-V-2 virus.

Exploring the new potential antiviral constituents of Moringa oliefera for SARS-COV-2 pathogenesis: An in silico molecular docking and dynamic studies.

The interactions of two crucial proteins of COVID-19 have been investigated with potential antiviral compounds from Moringa oliefera using quantum chemical, molecular docking and dynamic methods. The results of the present investigation show that ellagic acid and apigenin possess the highest binding affinities of -7.1 and -6.5 Kcal.mol-1against nsp9 and -6.9 and -7.1 Kcal.mol-1 against nsp10, respectively. The dynamic behavior of individual proteins and their respective best docked ligand-protein complexes are also studied at 30 ns timescale. Both of these compounds also show the highest intestinal absorption and total clearance rate as compared to the other compounds under present investigation without any toxicity.

Experimental and computational study of naphthalimide derivatives: Synthesis, optical, nonlinear optical and antiviral properties.

The nonlinear optical (NLO) and antiviral properties of naphthalimide Schiff base compounds (5a-c) were experimentally and computationally investigated. The synthesized compounds (5a-c) were successfully characterized via UV-Vis, FTIR, 1H NMR, fluorescence spectroscopy, and elemental analysis. The calculated average third-order NLO polarizabilities (˂γ˃) of 5a, 5b, and 5c were found to be 5, 9, and 21 times greater than the ˂γ˃ amplitude of p-NA, respectively. The computed results revealed the potential of the synthesized compounds for NLO applications. Additionally, molecular docking studies of the synthesized compounds with two crucial SARS-CoV-2 proteins were performed to examine their biochemical properties. Compound 5c exhibited a higher binding affinity with the spike protein compared to that with Mᴾᴿᴼ. The results obtained herein indicate the potential of the synthesized naphthalimide derivatives for optoelectronic and drug design applications.

i-Propylammonium Lead Chloride Based Perovskite Photocatalysts for Depolymerization of Lignin Under UV Light.

Lignin depolymerization for the purpose of synthesizing aromatic molecules is a growing focus of research to find alternative energy sources. In current studies, the photocatalytic depolymerization of lignin has been investigated by two new iso-propylamine-based lead chloride perovskite nanomaterials (SK9 and SK10), synthesized by the facile hydrothermal method. Characterization was done by Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), UV-Visible (UV-Vis), Photoluminescence (PL), and Fourier-Transform Infrared (FTIR) Spectroscopy and was used for the photocatalytic depolymerization of lignin under UV light. Lignin depolymerization was monitored by taking absorption spectra and catalytic paths studied by applying kinetic models. The %depolymerization was calculated for factors such as catalyst dose variation, initial concentration of lignin, and varying temperatures. Pseudo-second order was the best suited kinetic model, exhibiting a mechanism for lignin depolymerization that was chemically rate controlled. The activation energy (Ea) for the depolymerization reaction was found to be 15 kJ/mol, which is remarkably less than conventional depolymerization of the lignin, i.e., 59.75 kJ/mol, exhibiting significant catalytic efficiencies of synthesized perovskites. Products of lignin depolymerization obtained after photocatalytic activity at room temperature (20 °C) and at 90 °C were characterized by GC-MS analysis, indicating an increase in catalytic lignin depolymerization structural subunits into small monomeric functionalities at higher temperatures. Specifically, 2-methoxy-4-methylphenol (39%), benzene (17%), phenol (10%) and catechol (7%) were detected by GC-MS analysis of lignin depolymerization products.

Theoretical Study on Open-Shell Singlet Character and Second Hyperpolarizabilities in Cofacial π-Stacked Dimers Composed of Weak Open-Shell Antiaromatic Porphyrins.

From the analysis based on the broken-symmetry density functional theory (DFT) calculations, we in this study propose a strategy to enhance the open-shell characters and third-order nonlinear optical (NLO) properties of π-stacked dimers composed of antiaromatic molecules with weak open-shell characters. For this purpose, we here constructed cofacial π-stacked dimer models composed of aromatic and antiaromatic NiII porphyrins in order to examine the π-π stacking distance (R) dependence of the diradical characters (y) and static second hyperpolarizabilities (γ). The antiaromatic porphyrin dimers are found to have intermediate y around R∼3.3 Å, the result of which originates in the unique intermolecular interactions between the antiaromatic monomers. Static γ along the stacking direction of such antiaromatic porphyrin dimers with intermediate diradical characters are shown to be enhanced significantly as compared to those of the isolated monomers and the aromatic porphyrin dimers.

Stimulating intra- and intermolecular charge transfer and nonlinear optical response for biphenalenyl biradicaloid dimer under an external electric field.

An interesting biphenalenyl biradicaloid (IDPL) dimer consisting of both-middle superimposed phenalenyls and both-end nonsuperimposed phenalenyls has been synthesized, and has attracted intensive research interest due to its intra- and intermolecular interactions and semiconductive characteristics. It is significant that under regulation of the external electric field the directional charge transfer (CT) can produce attractive properties. In the present work, the structure and electronic properties of the IDPL dimer under an external electric field (along the horizontal Fx or the vertical Fz directions) are explored, and the following properties determined: (i) as the horizontal Fx increases, the intramolecular CT becomes larger, which induces the intermolecular CT of the IDPL dimer. (ii) In contrast, as the vertical Fz increases, the large intermolecular CT gives rise to the intramolecular CT of the IDPL dimer. (iii) More importantly, the external electric field effectively regulates and controls the first hyperpolarizability (ßtot) of the IDPL dimer. Compared with the vertical Fz, the horizontal Fx induces a larger first hyperpolarizability (ßtot = 5.48 × 105 a.u.). Furthermore, the application of a uniform external electric field (Fx,y,z) to the IDPL dimer was investigated to define the external electric field direction of the material application. The ßtot values were increased with increasing of the uniform Fx,y,z. Our study provides an effective strategy for developing high-performance NLO materials by tuning the external electric field, and could be of significance for application in switch devices.

How does hybrid bridging core modification enhance the nonlinear optical properties in donor-π-acceptor configuration? A case study of dinitrophenol derivatives.

This study spotlights the fundamental insights about the structure and static first hyperpolarizability (ß) of a series of 2,4-dinitrophenol derivatives (1-5), which are designed by novel bridging core modifications. The central bridging core modifications show noteworthy effects to modulate the optical and nonlinear optical properties in these derivatives. The derivative systems show significantly large amplitudes of first hyperpolarizability as compared to parent system 1, which are 4, 46, 66, and 90% larger for systems 2, 3, 4, and 5, respectively, at Moller-Plesset (MP2)/6-31G* level of theory. The static first hyperpolarizability and frequency dependent coupled-perturbed Kohn-Sham first hyperpolarizability are calculated by means of MP2 and density functional theory methods and compared with respective experimental values wherever possible. Using two-level model with full-set of parameters dependence of transition energy (ΔΕ), transition dipole moment (µ(0)) as well as change in dipole moment from ground to excited state (Δµ), the origin of increase in ß amplitudes is traced from the change in dipole moment from ground to excited state. The causes of change in dipole moments are further discovered through sum of Mulliken atomic charges and intermolecular charge transfer spotted in frontier molecular orbitals analysis. Additionally, analysis of conformational isomers and UV-Visible spectra has been also performed for all designed derivatives. Thus, our present investigation provides novel and explanatory insights on the chemical nature and origin of intrinsic nonlinear optical (NLO) properties of 2,4-dinitrophenol derivatives.

Diradical character and nonlinear optical properties of buckyferrocenes: focusing on the use of suitably modified fullerene fragments.

The buckyferrocenes, synthesized through face-to-face fusion of ferrocene and fullerene fragments (C60Me10), are expected to enjoy the rich scientific heritage of ferrocene and fullerene with an extensively large π-conjugation network between the two Fe atoms [Y. Matsuo, K. Tahara and E. Nakamura, J. Am. Chem. Soc., 2006, 128, 7154]. However, the addition of pentamethyl groups at each end of the fullerene fragment breaks the π-conjugation path as well as metal-metal spin correlation between the two-ferrocene faces in a buckyferrocene. We found that the unblocking of π-conjugation from different positions in fullerene fragments have substantial effects on their topologies, spin densities, diradical characters as well as nonlinear optical (NLO) properties of these buckyferrocenes. We study the topological dependence of open-shell diradical character and second hyperpolarizability (γ), the third-order NLO properties at the molecular scale, in several buckyferrocenes. On the basis of their different diradical characters (yi), which are defined by the occupation number of the lowest unoccupied natural orbital (LUNO) + i (i = 0, 1,…), these buckyferrocenes are categorized into three groups, i.e., closed-shell (yi = 0), intermediate open-shell singlet (0 < yi < 1), and almost pure open-shell singlet (yi = 1) compounds. For example, we found that buckyferrocenes including (CpFe)2η(5)C60Me10 and (CpFe)2η(5)C70Me10 have closed-shell configurations. The buckyferrocenes (CpFe)2η(5)C60, (CpFe)2η(5)C70, (CpFe)2η(5)C70Me8, (CpFe)2η(5)C70Me4 and (CpFe)2η(5)C30 are intermediate open-shell singlet, while (CpFe)2η(5)C60Me4 and (CpFe)2η(5)C60Me8 are pure open-shell singlet complexes. Interestingly, the γzzzz amplitude of (CpFe)2η(5)C60, an open-shell intermediate diradical complex, is about 41 times and 13 times as large as those of its closed-shell ((CpFe)2η(5)C60Me10) and pure diradical ((CpFe)2η(5)C60Me8) counterparts, respectively. Similarly, the γzzzz amplitudes of (CpFe)2η(5)C70, (CpFe)2η(5)C70Me4, and (CpFe)2η(5)C70Me8 with intermediate diradical character are about 36, 17, and 9 times as large as that of their closed-shell (CpFe)2η(5)C70Me10 counterpart. The fact that larger γzzzz values are obtained for buckyferrocenes with intermediate diradical characters is in line with the "y-γ correlation" obtained from the valence configuration interaction (VCI) results for a two-site diradical model [M. Nakano, et al., Phys. Rev. Lett., 2007, 99, 033001] as well as for fullerene and graphene systems. The γzzzz density analysis shows that the large positive contributions originate from the large γzzzz density distributions on the upper- and lower-extended edges of the buckyferrocenes, between which significant spin polarizations appear within the spin-unrestricted DFT level of theory. These results demonstrate that such buckyferrocenes are potential candidates for a novel class of open-shell singlet NLO systems, where γzzzz values are modulated by tuning their diradical character through the use of suitably modified fullerene fragments.

Computational prediction for designing novel ketonic derivatives as potential inhibitors for breast cancer: A trade-off between drug likeness and inhibition potency.

Unlike simple molecular screening, a combined hybrid computational methodology has been applied which includes quantum chemical methods, molecular docking, and molecular dynamics simulations to design some novel ketonic derivatives. The current study contains the derivatives of an experimental ligand which are designed as a trade-off between drug likeness and inhibition strength. We investigate the interaction of various newly designed ketonic compounds with the breast cancer receptor known as the Estrogen Receptor Alpha (ERα). The molecular structures of all newly designed ligands were studied quantum chemically in terms of their fully optimized structures, 3-D molecular orbital distributions, global chemical descriptors, molecular electrostatic potentials and energies of frontier molecular orbitals (FMOs). All ligands under study show good binding affinities with the ERα protein. The ligands CMR2 and CMR4 exhibit improved molecular docking interactions. The intermolecular interactions indicate that CMR4 demonstrates better hydrophobic and hydrogen bonding interactions with protein (ERα). Furthermore, molecular dynamics simulations were conducted on ligands and reference drugs interacting with the ERα protein over a time span of 120 nanoseconds. The molecular dynamics results are interpreted in terms of ligand-protein stability and flexible behaviour based on their respective values of RMSD, RMSF, H-bonds, the radius of gyration, and SASA graphs. To analyse ligand-protein interactions throughout the entire 120 ns trajectory, a more advanced MM/PBSA method is utilized, where six selected ligands (CMR1, CMR2, CMR3, CMR4, CMR5 and CMR9) illustrate promising results for inhibition of the ERα receptor as assessed through MM/BBSA analysis. The CMR9 has the highest MM/BBSA binding free energy (-14.46 kcal/mol). The ADMET analysis reveals that CMR4 has maximum intestinal absorption (6.68) and clearance rate (0.1). All the compounds are non-toxic and safe to use. These findings indicate the potential of involving different computational techniques to design the ligand structures and to study the ligand-protein interactions for better understanding and achieving more potent synthetic inhibitors for breast cancer.