Interactions In Complexes Research Articles

Synthesis of 3-Methoxy-6- [(2, 4, 6-trimethyl-phenylamino)-methyl]-phenol Schiff base characterized by spectral, in-silco and in-vitro studies

The structure of the title compound (I) (C17H19NO2)2 the Schiff base, {3-Methoxy-6-[(2,4,6-trimethyl-phenylamino)-methyl]-phenol} was characterized by 1H, 13C NMR, UV–VIS and IR spectroscopic techniques. The crystal structure was determined by X-ray analysis. The compound (I) was crystallized in the Monoclinic space group P21/c, with a = 25.9845 (12), b = 7.3318 (4), c = 16.3543 (8) Å, β = 100.713(°) (4), and Z = 8. The intermolecular interactions of the compound (I) was analyzed using Hirshfeld surface and Fingerprint analysis. Based on the crystal-void calculation, the volume of the void and surface area of the Schiff base compound (I) was described. The frontier molecular orbital energy gap reveals charge transfer interactions involving donors and acceptors. The invitro studies on antibacterial property of the title compound shows best MIC value for Staphylococcus aureus and the compound effect on MTT assay on A549 lung cancer cell line. The molecular docking result shows that the compound has good molecular-level interaction with anticancer drug target having good interactions with active site residues. The non-covalent interactions in the protein-ligand complex were well established from NCI analysis.

Inclusion Complexes Between β‐cyclodextrin and the Anticancer Drug 5‐Fluorouracil for its Solubilization: a Molecular Dynamics Study at Different Stoichiometries

AbstractCyclodextrins (CDs) are natural macrocyclic oligosaccharides able to solubilize hydrophobic drugs in water improving their bioavailability, thanks to favorable noncovalent interactions particularly in their hydrophobic cavity. Using a simulation protocol proposed in previous work, in this theoretical study based on Molecular Mechanics (MM) and Molecular Dynamics (MD) methods, inclusion complexes between β‐cyclodextrin and 5‐Fluorouracil (5‐FU) are investigated. 5‐FU is an anticancer drug hardly soluble in water used for more than 50 years. This drug is mainly administered by intravenous injection for the treatment of inner cancers or as a cream in the case of skin‐related cancers. For drug delivery applications, it is important to characterize stable inclusion complexes at different drug concentrations in order to enhance the anticancer activity by maintaining lower dose, thus reducing cytotoxic effects on the normal cells, causing several negative impacts in the course of treatment. In this work, the structure and stability of the host–guest complexes β‐CD:5‐FU in a 1:1 and 1:2 stoichiometries are investigated because this drug is relatively small compared to the size of the hydrophobic β‐CD cavity. The 5‐FU complexes with CDs allow its solubilization, thanks to favorable van der Waals interactions. Interestingly, these intermolecular interactions in inclusion complexes may also affect the release profile. MD simulations are a powerful tool to evaluate interactions between hydrophobic anticancer drugs and hydrophilic carriers with an inner hydrophobic cavity such as CDs and oligosaccharides in general.

Hydroxyl group interactions in metal dithiocarbamate complexes containing 2-hydroxyethyl substituents. Crystal structure determination, theoretical and Hirshfeld surface study of tris(2-hydroxyethyl(ethyl)amino-dithiocarbamato)indium(III). Survey of hydroxyl group interactions in metal tris(dithiocarbamato) complexes containing 2-hydroxyethyl substituents

X-ray crystal structure, theoretical and Hirshfeld surface study of tris(2-hydroxyethyl(ethyl)aminodi-thiocarbamato)indium(III) is reported. The arrangement of the sulfur atoms around the indium centre forms a trigonal prism with bond lengths and angles in close agreement with those reported for indium-dithiocarbarmate [In-dtc] complexes. There are two significant features of the structure: (i) the hydroxyl groups link to form quasi-chair shaped regular hexameric hydrogen bonded arrays, [···HO]6, R66(12), and (ii) C—-H···π interactions, involving [In-S-C-S] rings. While a few examples of cyclic hexameric hydrogen bonded arrays have been reported for dithiocarbamate complexes containing CH2CH2OH groups, this is the first report of a chair shaped arrangement, involving all the hydroxyl units.A survey has been carried out on the hydrogen bond arrangements made by the hydroxyl groups in reported dtc complexes of the type, [M{S2CNR(CH2CH2OH)}3], where M is a transition or main-group metal and R is an alkyl group or CH2CH2OH. Both long chain and ring arrangements of the hydroxyl groups are found, occupying spaces made available by the complexed-metal units. As compound 1 and related compounds are alcohols, albeit complex tris(primary alcohols), comparisons of the findings for these complexes are made with the structural findings for organic alcohols.

High-Frequency EPR Studies of New 2p-3d Complexes Based on a Triazolyl-Substituted Nitronyl Nitroxide Radical: The Role of Exchange Anisotropy in a Cu-Radical System.

Using the 1-(m-tolyl)-1H-1,2,3-triazole-4-(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) (TlTrzNIT) radical and metal β-diketonate complexes [M(hfac)2(H2O)2], where hfac is hexafluoroacetylacetonato, three new 2p-3d heterospin complexes were synthesized. Their structures were solved using single crystal X-ray diffraction data, and magnetic investigation was performed by DC and AC measurements and multifrequency EPR spectroscopy. Compounds 1 and 2 are isostructural complexes with molecular formula [M3(TlTrzNIT)2(hfac)6] (MII = Mn or Cu) while compound 3 is the mononuclear [Co(TlTrzNIT)(hfac)2] complex. In all complexes, the radical acts as a bidentate ligand through the oxygen atom of the nitroxide moiety and the nitrogen atom from the triazole group. Furthermore, in compounds 1 and 2, the TlTrzNIT is bridge-coordinated between two metal centers, leading to the formation of trinuclear complexes. The fitting of the static magnetic behavior reveals antiferromagnetic and ferromagnetic intramolecular interactions for complexes 1 and 2, respectively. The EPR spectra of 1 are well described by an isolated ferrimagnetic S = 13/2 (= 5/2 - 1/2 + 5/2 - 1/2 + 5/2) ground state with a biaxial zero-field splitting (ZFS) interaction characterized, respectively, by 2nd order axial and rhombic parameters, D and E, such that E/D is close to the maximum of 0.33. Meanwhile, EPR spectra for 2 are explained in terms of a ferromagnetic model with weakly anisotropic Cu-radical exchange interactions, giving rise to an isolated S = 5/2 (= 5 × 1/2) ground state with both an anisotropic g tensor and a weak ZFS interaction. Complex 2 represents one of only a few examples of Cu-radical moieties with measurable exchange anisotropy.

A zinc(II) metal–organic complex based on 2-(2-aminophenyl)-1H-benzimidazole ligand: Exhibiting high adsorption capacity for aromatic hazardous dyes and catecholase mimicking activity

A dual functional metal–organic complex (MOC) {[Zn(L1)(Cl)2]·DMF} (1), ( L1 = 2-(2-aminophenylbenzimidazole) was synthesized by a solvothermal method and characterized by various analytical techniques. Crystals of 1 were harvested by a solvent evaporation method, and single-crystal X-ray diffraction (SCXRD) analysis revealed that 1 adopted a distorted tetrahedral geometry around the central metal ion. The topological simplification of 1 ascertained the simple hcb net. The bulk-phase purity of as-synthesized 1 was confirmed by the decent match of powder X-ray diffraction (PXRD) patterns with the simulated patterns. The band gap and chemical reactivity potential of 1 were confirmed by HOMO-LUMO analysis. Complex 1 showed the efficient adsorption of cationic methylene blue (MB) and anionic methyl orange (MO) dyes from wastewater with good uptake. At room temperature and at neutral pH, complex 1 exhibited the highest removal efficiencies (90% and 80%) and adsorption capacities (qe = 116.22 mg/g and 102.62 mg/g) for MB and MO dyes, respectively. The plausible mechanism of cationic and anionic dyes removal is based on insight from structural information and existance of array of non-covalent interactions in complex 1. Additionally, complex 1 was also evaluated for catecholase-like activity in ethanol for the oxidation of 3,5-DTBC to 3,5-DTBQ. Complex 1 showed good catecholase-like activity with potential catechol conversion results, kcat = 0.98⨯102 h−1, KM = 0.0506 M, and Vmax = 0.0485⨯10-3 M min−1.

Constructing "Closed" and "Open" {Mn8} Clusters.

Use of the 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane ligand, LH3, in manganese chemistry affords access to two structurally related {Mn8} clusters: a “closed” {MnIII6MnII2} puckered square wheel of formula [Mn8L2(LH)O3(OH)2(MeO)2Br(imH)(H2O)3](Br)3 (1; imH = imidazole) and an “open” {MnIII8} rod of formula [MnΙΙΙ8L2O4(aibH)2(aib)2(MeO)6(MeOH)2](NO3)2 (2, aibH = 2-amino-isobutyric acid). In each case the triaza ligands, L/LH, direct the formation of {Mn3} triangles with their N atoms preferentially bonding to the Jahn–Teller axes of the MnIII ions. Subsequent self-assembly is dependent on the anion of the Mn salt and the identity of the organic coligand employed—the terminally bonded imidazole and the chelating/bridging amino acid. The {Mn3} triangles fold up on themselves in 1, forming a wheel. However, the syn, syn-bridging carboxylates in 2 prevent this from happening, instead directing the formation of a linear rod. Magnetic susceptibility and magnetization measurements reveal competing ferro- and antiferromagnetic interactions in both complexes, the exchange being somewhat weaker in 1 due to the presence of MnII ions.

Coupled Cluster Benchmarking of Large Noncovalent Complexes in L7 and S12L as Well as the C60 Dimer, DNA-Ellipticine, and HIV-Indinavir.

In this work, we report the benchmark binding energies of the seven complexes within the L7 data set, six host-guest complexes from the S12L data set, a C60 dimer, the DNA-ellipticine intercalation complex, and the largest system of the study, the HIV-indinavir system, which contained 343 atoms or 139 heavy atoms. The high-quality values reported were obtained via a focal point method that relies on the canonical form of second-order Møller-Plesset theory and the domain-based local pair natural orbital scheme for the coupled cluster with single double and perturbative triple excitations [DLPNO-CCSD(T)] extrapolated to the complete basis set (CBS) limit. The results in this work not only corroborate but also improve upon some previous benchmark values for large noncovalent complexes albeit at a relatively steep cost. Although local CCSD(T) and the largely successful fixed-node diffusion Monte Carlo (FN-DMC) have been shown to generally agree for small- to medium-size systems, a discrepancy in their reported binding energy values arises for large complexes, where the magnitude of the disagreement is a definite cause for concern. For example, the largest deviation in the L7 data set was 2.8 kcal/mol (∼10%) on the low end in C3GC. Such a deviation only grows worse in the S12L set, which showed a difference of up to 10.4 kcal/mol (∼25%) by a conservative estimation in buckycatcher-C60. The DNA-ellipticine complex also generated a disagreement of 4.4 kcal/mol (∼10%) between both state-of-the-art methods. The disagreement between local CCSD(T) and FN-DMC in large noncovalent complexes shows that it is urgently needed to have the canonical CCSD(T), the Monte Carlo CCSD(T), or the full configuration interaction quantum Monte Carlo approaches available to large systems on the hundred-atom scale to solve this dilemma. In addition, the performances of cheaper popular computational methods were assessed for the studied complexes with respect to DLPNO-CCSD(T)/CBS. r2SCAN-3c, B97M-V, and PBE0+D4 work well in large noncovalent complexes in this work, and GFN2-xTB performs well in π-π stacking complexes. B97M-V is the most reliable computationally efficient approach to predicting noncovalent interactions for large complexes, being the only one to have binding errors within the so-called 1 kcal/mol "chemical accuracy". The benchmark interaction energies of these host-guest complexes, molecular materials, and biological systems with electronic and medicinal implications provide crucial reference data for the improvement of current and future lower-cost methods.

The Fng3 ING protein regulates H3 acetylation and H4 deacetylation by interacting with two distinct histone-modifying complexes.

The steady-state level of histone acetylation is maintained by histone acetyltransferase (HAT) and histone deacetylase (HDAC) complexes. INhibitor of Growth (ING) proteins are key components of the HAT or HDAC complexes but their relationship with other components and roles in phytopathogenic fungi are not well-characterized. Here, the FNG3 ING gene was functionally characterized in the wheat head blight fungus Fusarium graminearum. Deletion of FNG3 results in defects in fungal development and pathogenesis. Unlike other ING proteins that are specifically associated with distinct complexes, Fng3 was associated with both NuA3 HAT and FgRpd3 HDAC complexes to regulate H3 acetylation and H4 deacetylation. Whereas FgNto1 mediates the FgSas3-Fng3 interaction in the NuA3 complex, Fng3 interacted with the C-terminal region of FgRpd3 that is present in Rpd3 orthologs from filamentous fungi but absent in yeast Rpd3. The intrinsically disordered regions in the C-terminal tail of FgRpd3 underwent phase separation, which was important for its interaction with Fng3. Furthermore, the ING domain of Fng3 is responsible for its specificities in protein-protein interactions and functions. Taken together, Fng3 is involved in the dynamic regulation of histone acetylation by interacting with two histone modification complexes, and is important for fungal development and pathogenicity.

Determining Repulsion in Cyclophane Cages.

Superphane, i.e., [2.2.2.2.2.2](1,2,3,4,5,6)cyclophane, is a very convenient molecule in studying the nature of guest⋯host interactions in endohedral complexes. Nevertheless, the presence of as many as six ethylene bridges in the superphane molecule makes it practically impossible for the trapped entity to escape out of the superphane cage. Thus, in this article, I have implemented the idea of using the superphane derivatives with a reduced number of ethylene linkers, which leads to the [2] cyclophanes where . Seven such cyclophanes are then allowed to form endohedral complexes with noble gas (Ng) atoms (He, Ne, Ar, Kr). It is shown that in the vast majority of cases, the initially trapped Ng atom spontaneously escapes from the cyclophane cage, creating an exohedral complex. This is the best proof that the Ng⋯cyclophane interaction in endohedral complexes is indeed highly repulsive, i.e., destabilizing. Apart from the ‘sealed’ superphane molecule, endohedral complexes are only formed in the case of the smallest He atom. However, it has been shown that in these cases, the Ng⋯cyclophane interaction inside the cyclophane cage is nonbonding, i.e., repulsive. This highly energetically unfavorable effect causes the cyclophane molecule to ‘swell’.

Ab-initio simulation of the interaction of gold nanoclusters with glycine

Nanomaterial-Biomolecules complexes have several important applications in biological processes and bionanoscience. In this regard, the adsorption of the simplest amino acid (glycine) on the gold nanocluster has been studied to understand the interaction of amino acid with Au nanocluster. Small nanoclusters (neutral and cationic) of five, eight, thirteen, fifteen, and eighteen atoms have been utilized for this study. UV-Vis spectroscopy, Reduced Density Gradient (RDG), HOMO-LUMO analysis has been performed for nanoclusters and their glycine adsorbed complexes which provides information about the charge transfer binding mechanism, and establish the nature of interaction in glycine-gold nanocluster complexes. It is observed that the neutral and cationic Au nanoclusters show the highest adsorption energy for clusters of five, thirteen, and fifteen atoms. When the HOMO-LUMO energy gap of the cationic form of Au nanoclusters and glycine adsorbed Au nanoclusters are studied, it is observed that the HOMO-LUMO energy gap is decreased monotonically as cluster size increases in all cases (namely the lowest energy structure, first higher energy structure, and second higher energy structure). The results from the current work will be applicable as nanocluster sensors for glycine detection.

A Piroxicam Inclusion Complexation for Solubility Enhancement: Design and Development

Published on:June 2022 Journal of Young Pharmacists, 2022; 14(2):192-197 Original Article | doi:10.5530/jyp.2022.14.36 Authors: Saravanakumar Kasimbedu1,*, Shilpaja Chella1, Bharathi T1, Nagaveni Pommala2, Durga Srinivasa Rao Mannepalli3 1Department of Pharmaceutics, Sree Vidyanikethan College of Pharmacy, Sree Sainath Nagar, Tirupati, Andhra Pradesh, INDIA. 2Department of Pharmaceutics, S.V.U. College of Pharmaceutical Sciences, S.V. University, Tirupati, Andhra Pradesh, INDIA.3Department of Pharmaceutics, Jagan’s Institute of Pharmaceutical Sciences, Muthukur, SPSR Nellore, Andhra Pradesh, INDIA. Abstract: Background: Over last few years, the physical and chemical characteristics of inclusion complexes have generated a lot of attention. One of the most important reasons for this is the significance of enzyme-substrate and drug-receptor interactions in inclusion complexes. Materials and Methods:The aim of the study was to design Piroxicam’s inclusion complexation, to improve its solubility by the reduction of particle size which leads to improve the particle surface area thereby increases the wettability of the mixture. Physical mixture, co-grinded mixture, kneading and solvent evaporation method were used to prepare the inclusion complexation of Piroxicam with β-cyclodextrin at 1:0.5, 1:1, and 1:2 w/w (Piroxicam/β-cyclodextrin) ratios. Results: Differential scanning calorimetry, Fourier-transform infrared and X-ray diffraction and scanning electron microscopy studies were used to investigate the interaction of Piroxicam with β-cyclodextrin. From scanning electron microscopic studies, it was observed that crystalline were formed as spherical in shape with rough surface, small piece and Pure Piroxicam in crystalline form with rough surfaces. From Scanning electron microscopic studies, it was observed that amorphous were formed as spherical in shape with smooth surface, wide piece and β-Cyclodextrine in amorphous form with rough surfaces. Conclusion: The inclusion complexations of Piroxicam with β-cyclodextrin exhibited higher saturation solubility and dissolution rate than that of the pure drug of Piroxicam. Formulation K2 showed more drug release rate by reducing the particle size with complexation technique like kneading technique.Keywords: Co-grinded mixture, Inclusion Complexation, Kneading, Wetting Property, Particle Shap

Structural and theoretical exploring of noncovalent interactions in Chlorido- and Nitrito-rhenium(I) tricarbonyl complexes bearing 2,3-Butadiene-bis(2-nitrobenzylidene)hydrazine Ligand: Intramolecular Re–κ1-endo-ONO(lone pair)…π*(C[tbnd]O) interaction

Herein, we report the synthesis, characterization and combined structural and full computational analysis of noncovalent interactions in a new hydrazine ligand and its two chlorido- and endo-nitrito-rhenium(I) tricarbonyl complexes. The analysis of crystal structures has been accompanied by comprehensive computational studies of the noncovalent interactions utilizing the quantum theory of atoms in molecules (QTAIM), natural bond orbitals (NBO), independent gradient model (IGM), and electron localization function (ELF) to shed light on the nature of the interactions. On the other hand, comprehensive energy decomposition analysis (EDA) by extended transition state coupled with natural orbitals for chemical valence (ETS-NOCV) scheme in a series of crystallographically retrieved dimers of the complexes was done to unveil the physical origin of these interactions and the factors affecting the interaction strength. In case of the Re- κ1-nitrito complex, the Interacting Quantum Atoms (IQA) scheme was used for detailed analysis of the interesting intramolecular Re–κ1-endo-ONO(lone pair)…π* (CO) interaction in the nitrito complex.

Composition-selective full inclusion host-guest interaction of azobenzene-containing photoresponsive nanoring with fullerene C60.

By means of density functional theory calculations, the encapsulation capabilities of a series of azobenzen-containing photoresponsive nanoring hosts (labeled as host 1, 2, 3, 4, 5 and 6 according to the number of the azo unit, respectively) for fullerene C60 were surveyed. Interestingly and abnormally, it is found that the host 5, of which the diameter is only 1.218 nm, can form stable full inclusion complex with C60 . However, irrespective of their cavity sizes (11.98 ~ 12.94 Å) of the hosts, the structures 1~ 4 and 6 were all disable to form inclusion complex with C60 . In this paper, the group-number-composition-selective full inclusion host-guest interaction of the azobenzene-containing nanorings with fullerene C60 is firstly presented. The calculated interaction energies, together with the detection and visualization of the weak interaction regions, provided evidences for the host-guest binding based on relative strong repulsion interaction in the full inclusion complex. Analysis on the frontier orbital feature of the host-guest systems suggests that under the electron excited condition, the chemical activity may be transferred from host 5 to guest C60 by formation of the floating host-guest complex, and the chemical reactivity of the host 5 can be passivated via formation of the full inclusion host-guest complex. Additionally, UV-vis-NIR and 1 H NMR spectra of the hosts before and after the formations of the complexes have been simulated and discussed qualitatively, which may be helpful for further experimental investigations in future.

Mingling with minimal mixing: Mafic-silicic magma interactions in the Oamikaub ring complex, Namibia

The ca. 560 Ma Oamikaub ring complex (ORC) is a member of the Goas Intrusive Suite in the Damara Belt of Namibia. The volumetrically dominant granitic rocks contain a variety of microgranular magmatic enclaves (MEs), commonly with lobate and cuspate borders against their enclosing host rocks. Some also have mafic selvages and evidence for internal melt segregation. These features indicate magma mingling and deformation during host-magma flow and emplacement, and a small degree of chemical mixing with the host magmas. The spatial diversity and mineralogical characteristics of the MEs show that mechanical hybridism occurred prior to mingling at emplacement level. Despite one group of MEs forming near-linear arrays in chemical plots, the mineralogical and isotopic data show that these do not form a mixing series. A second group represents samples of chilled mafic magmas that chemically resemble the mafic rocks that form the earliest-emplaced components of the ORC. However, their fine-grained textures and isotopic characteristics show that these were a separate, later pulse of mafic magmas. There were multiple episodes of mingling and the younger pulses of mafic ORC magmas were generally more hybridised with evolved crust. Magma mingling and limited marginal hybridisation of MEs produced impressive outcrop features. However, apart from initial, source-level hybrid formation, magma mixing had little or no role in producing compositional variations in either the MEs or their host rocks. Globally, such relationships are common in enclave suites from granitic rocks, and their study can provide insights into processes and materials in magma source regions. In the present case, enriched mantle melting, crustal melting (of mafic to silicic rocks) and fractionation of tholeiitic parental magmas may all have played their parts in forming the ME suite of the ORC.

The effect of dicarboxylic acid isomer on the photochromism of naphthalenediimide-based metal-organic frameworks

As a class of special type materials, photochromic metal-organic frameworks (MOFs) have attracted extensive attention because their usually show interesting color changes and coupled with the variation of some chemical and physical properties under light irradiation. In order to study the effect of secondary building on the photochromism of MOFs, two isomeric naphthalenediimide-based MOFs with different secondary building linkers, namely [Zn2(DPNDI)(2,6-NDC)2] (1) and [Zn2(DPNDI)(1,4-NDC)2] (2) (DPNDI = N, N’-di(3-pyridyl)-1,4,5,8-naphthalenediimide, 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid, 2,6-H2NDC = 2,6-naphthalenedicarboxylic acid), were synthesized via solvothermal reaction and the structure were characterized by single-crystal X-ray diffraction, IR and TGA. Owing to the different CH···π interactions between the naphthalene moieties of dicarboxylic acid and electron-deficient DPNDI ligand, they showed different photochromic behaviors and photocontrolled luminescence upon ultraviolet-visible irradiation. Specifically, complex 2 was photochromic but complex 1 was not. The difference can be ascribed to the larger CH···π interaction in complex 1 than in complex 2. This work is expected to provide a new perspective for designing novel photochromic MOF materials

MAPIYA contact map server for identification and visualization of molecular interactions in proteins and biological complexes.

Correct identification and effective visualization of interactions in biomolecular structures facilitate understanding of their functions and molecular design. In response to the practical needs of structure-based analysis, we have created a Mapiya web server. The Mapiya integrates four main functionalities: (i) generation of contact maps – intramolecular and intermolecular—for proteins, nucleic acids, and their complexes; (ii) characterization of the interactions physicochemical nature, (iii) interactive visualization of biomolecular conformations with automatic zoom on selected contacts using Molstar and (iv) additional sequence- and structure-based analyses performed with third-party software and in-house algorithms combined into an easy-to-use interface. Thus, Mapiya offers a highly customized analysis of the molecular interactions' in various biological systems. The web server is available at: http://mapiya.lcbio.pl/

Azo-based multifunctional molecules and their copper(II) complexes as potential inhibitors against Alzheimer’s disease: XRD/Hirshfeld analysis/DFT/molecular docking/cytotoxicity

In this article, new azo multifunctional ligands (E)-1-hexyl-4-methyl-6-(λ1-oxidaneyl)-2-oxo-5-(p-tolyldiazenyl)-1,2-dihydropyridine-3-carbonitrile(L1H), (E)-1-hexyl-4-methyl-5-((4-nitrophenyl)diazenyl)-6-(λ1-oxidaneyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile) (L2H) and their copper(II) complexes were prepared and identified using various analytical and spectroscopic techniques such as CHN analysis, IR, mass spectra, UV–Vis, XRD and EPR methods. The spectroscopic data agree with the suggested molecular structures of the Cu(II) complexes. Single-crystal structure demonstrated elongated octahedral for both the copper complexes. In support, EPR exhibits a typical four-line spectral pattern assigned to monomeric copper (II) complexes. Interestingly upon docking with 1EVE, the copper complexes unveiled varying degrees of adjustment upon binding to fit and well-interact with the protease's active site. The hydrogen bonding and hydrophobic interactions entropy directly affect the structural reorganization. Donepezil and our compounds were assessed together for their potential inhibitory against Alzheimer’s disease. The binding affinity of the ligand and copper complexes in this research paper with 1EVE ranges from −9.6 to −8.3 kcal/mol. In comparison, the Donepezil drug is −10.9 kcal/mol, suggesting possible successful drugs for Alzheimer’s disease. Druglike nature, medicinal chemistry friendliness, andmultiple toxicological were predicted using free SwissADME software and the ProTox-II platform for this study.

UPF1 promotes rapid degradation of m6A-containing RNAs

N6-methyladenosine (m6A) is the most prevalent internal modification in eukaryotic mRNAs and affects RNA processing and metabolism. When YTHDF2, an m6A-recognizing protein, binds to m6A, it facilitates the destabilization of m6A-containing RNAs (m6A RNAs). Here, we demonstrate that upstream frameshift 1 (UPF1), a key factor for nonsense-mediated mRNA decay, interacts with YTHDF2, thereby triggering rapid degradation of m6A RNAs. The UPF1-mediated m6A RNA degradation depends on a specific interaction between UPF1 and N-terminal residues 101-168 of YTHDF2, UPF1 ATPase/helicase activities, and UPF1 interaction with proline-rich nuclear receptor coactivator 2 (PNRC2), a decapping-promoting factor preferentially involved in nonsense-mediated mRNA decay. Furthermore, transcriptome-wide analyses show that YTHDF2-bound mRNAs that are not substrates for HRSP12-RNase P/MRP-mediated endoribonucleolytic cleavage are destabilized with a higher dependency on UPF1. Collectively, our data indicate dynamic and multilayered regulation of the stability of m6A RNAs and highlight the multifaceted role of UPF1 in mRNA decay.

Insight into Spodium-π Bonding Characteristics of the MX2⋯π (M = Zn, Cd and Hg; X = Cl, Br and I) Complexes-A Theoretical Study.

The spodium–π bonding between MX2 (M = Zn, Cd, and Hg; X = Cl, Br, and I) acting as a Lewis acid, and C2H2/C2H4 acting as a Lewis base was studied by ab initio calculations. Two types of structures of cross (T) and parallel (P) forms are obtained. For the T form, the X–M–X axis adopts a cross configuration with the molecular axis of C≡C or C=C, but both of them are parallel in the P form. NCI, AIM, and electron density shifts analyses further, indicating that the spodium–π bonding exists in the binary complexes. Spodium–π bonding exhibits a partially covalent nature characterized with a negative energy density and large interaction energy. With the increase of electronegativity of the substituents on the Lewis acid or its decrease in the Lewis base, the interaction energies increase and vice versa. The spodium–π interaction is dominated by electrostatic interaction in most complexes, whereas dispersion and electrostatic energies are responsible for the stability of the MX2⋯C2F2 complexes. The spodium–π bonding further complements the concept of the spodium bond and provides a wider range of research on the adjustment of the strength of spodium bond.

Unveiling the nature of interactions in the supramolecular complex of Cucurbit [7-8] uril with ascorbic acid, dopamine and uric acid for biosensing applications: a computational study

Unveiling the nature of interactions in the supramolecular complex of Cucurbit [7-8] uril with ascorbic acid, dopamine and uric acid for biosensing applications: a computational study