Electro-synthesis approach for some metal ion complexes derived from thiosemicarbazide; characterization,conformational, inhibitory simulation and Hirshfeld surface properties

Series of Co (II), Cu (II), Zn (II) and Sn (II) complexes derived from thiosemicarbazide ligand (HTSC), was synthesized by environmentally favorable method (electrochemical). All isolated complexes, were deliberately characterized by available analytical and spectral tools. The proposed molar ratio was 1:2 (M:L) as the only isolated one, beside the significant contribution for solvent molecules. The octahedral configuration was proposed for all complexes. Conformational analysis was implemented using advanced program to determine the best structural forms for complexes. Moreover, essential parameters were calculated to export important features for studied complexes. Meanwhile, Hirshfeld crystal surface properties, were interested to illustrate strength of packing interaction forces. Furthermore, distinction of site types inside the molecule and their H-donor or H-acceptor ability. Antimicrobial study was conducted against different microorganisms, to assert on the importance of new complexes in therapeutic field. Furthermore and to strengthen the study, the inhibition simulation was performed with respect to all complexes against selected pathogen proteins. Essential interaction data, were exported for each docking process, to classify inhibition efficiency. Co (II) and Cu (II) complexes were the complexes that played well in therapeutic simulation treatments against Bacillus subtilis (1bn8) and Candida albicans kinase (4c0t) proteins.     

Optical biopsy of breast cancer tissue

In this paper, we report results of Fluorescence Emission Spectra (FES) and Stokes Shift Spectra (SSS) of 19 cancer tissue of invasive ductal carcinoma of different grades in comparison with normal breast tissues (obtained away from tumor regions). We were able to get distinct differences in the spectral features of normal and malignant tissues in terms of the ratios of concentrations of biomolecules like tryptophan, collagen and NADH. The sensitivity and specificity were in the range of 75%. What was all the more important was the parallelism in the spectral features of normal and malignant breast tissue pieces of above set of subjects. The objective of our research is to evolve one such protocol and the first step is the spectral characterization of in vitro optical analyses of excised tumor tissues.     

Factors affecting improvement of fluorescence intensity of quartet and doublet state of NO diatomic molecule excited by glow discharge

We report on the observation of new fluorescence emission spectral transitions obtained from NO diatomic molecule in the region from ultraviolet(UV) to near infrared(NIR) in a low power glow discharge system. This glow discharge electronic excitation populates different quartet and doublet states of NO in its proximity such as the A~2-Σ(υ = 2), b~4Σ(υ = 3), B~2Π(υ = 4), and X~2Π(υ = 33–32) states. Due to inter-system crossing, emission lines originating from these levels to lower lying states are recorded and spectral line assignments are performed. The observed systems include b~4-Σ–a~4Π, B~2Π–a~4Π, a~4Π–X~2Π, A~2Σ–X~2Π, X~2Π–X~2Π(33–15), X~2Π–X~2Π(33–17), X~2Π–X~2Π(33–20), and X~2Π–X~2Π(33–18). This new information will conduce to the better understanding of the interesting features of NO molecule. Such parameters that affect the recording of low density of NO molecules are also discussed In addition to the factors such as the time evolution, argon gas concentration relative to NO mixture, the percentage of NO molecular gas concentration,discharge electric current signals and discharge applied voltage are studied. Those factors would enhance the fluorescence signal intensity of NO molecules. The recent results might be significant as reference data for optimizing the glow discharge spectrometer and diagnostics of NO gas.     

Topological rigidity of linear cellular automaton shifts

We prove that topologically isomorphic linear cellular automaton shifts are algebraically isomorphic. Using this, we show that two distinct such shifts cannot be isomorphic. We conclude that the automorphism group of a linear cellular automaton shift is a finitely generated abelian group.     

Spatial determination of magnetic avalanche ignition points

Using time-resolved measurements of local magnetization in the molecular magnet _Mn12${\mathrm{Mn}}_{12}$-ac, we report studies of magnetic avalanches (fast magnetization reversals) with non-planar propagating fronts, where the curved nature of the magnetic fronts is reflected in the time-of-arrival at micro-Hall sensors placed at the surface of the sample. Assuming that the avalanche interface is a spherical bubble that grows with a radius proportional to time, we are able to locate the approximate ignition point of each avalanche in a two-dimensional cross-section of the crystal. We find that although in most samples the avalanches ignite at the long ends, as found in earlier studies, there are crystals in which ignition points are distributed throughout an entire weak region near the center, with a few avalanches still originating at the ends.     

Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production

Biodiesel is a promising candidate for sustainable and renewable energy and extensive research is being conducted worldwide to optimize its production process. The employed catalyst is an important parameter in biodiesel production. Metal–organic frameworks (MOFs), which are a set of highly porous materials comprising coordinated bonds between metals and organic ligands, have recently been proposed as catalysts. MOFs exhibit high tunability, possess high crystallinity and surface area, and their order can vary from the atomic to the microscale level. However, their catalytic sites are confined inside their porous structure, limiting their accessibility for biodiesel production. Modification of MOF structure by immobilizing enzymes or ionic liquids (ILs) could be a solution to this challenge and can lead to better performance and provide catalytic systems with higher activities. This review compiles the recent advances in catalytic transesterification for biodiesel production using enzymes or ILs. The available literature clearly indicates that MOFs are the most suitable immobilization supports, leading to higher biodiesel production without affecting the catalytic activity while increasing the catalyst stability and reusability in several cycles.     

Induced fit conformational changes of a "reversed amidine" heterocycle: optimized interactions in a DNA minor groove complex

To better understand the molecular basis for recognition of the DNA minor groove by heterocyclic cations, a series of "reversed amidine" substituted heterocycles has been prepared. Amidine derivatives for targeting the minor groove have the amidine carbon linked to a central heterocyclic system, whereas in the reverse orientation, an amidine nitrogen provides the link. The reverse system has a larger dihedral angle as well as a modified spatial relationship with the groove relative to amidines. Because of the large dihedral, the reversed amidines should have reduced binding to DNA relative to similar amidines. Such a reduction is observed in footprinting, circular dichroism (CD), biosensor-surface plasmon resonance (SPR), and isothermal titration calorimetric (ITC) experiments with DB613, which has a central phenyl-furan-phenyl heterocyclic system. The reduction is not seen when a pyrrole (DB884) is substituted for the furan. Analysis of a number of derivatives defines the pyrrole and a terminal phenyl substituent on the reversed amidine groups as critical components in the strong binding of DB884. ITC and SPR comparisons showed that the better binding of DB884 was due to a more favorable binding enthalpy and that it had exceptionally slow dissociation from DNA. Crystallographic analysis of DB884 bound to an AATT site shows that the compound was bound in the minor groove in a 1:1 complex as suggested by CD solution studies. Surprisingly, unlike the amidine derivative, the pyrrole -NH of DB884 formed an H-bond with a central T of the AATT site and this accounts for the enthalpy-driven strong binding. The structural results and molecular modeling studies provide an explanation for the differences in binding affinities for related amidine and reversed amidine analogues.     

Solid-phase synthesis and CD spectroscopic investigations of novel beta-peptides from L-aspartic acid and beta-amino-L-alanine

[structure: see text] A solid-phase synthesis method for the preparation of novel beta3- and beta2-peptides derived from l-aspartic acid and beta-amino-l-alanine, respectively, is described. The methodology allows independent buildup of the beta-peptide backbone and the introduction of sequential side chain substitutions. Representative peptides from the two classes, an amino-substituted beta3-hexapeptide and an acyl-substituted beta2-hexapeptide, have been prepared, and their solution conformation is studied by circular dichroism (CD) spectroscopy.     

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies

UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K⁺-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (K_CT), molar extinction coefficients (ε_CT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl₃. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.     

Characterization of new Co(II) complexes and photographic monitoring for their toxic impact on breast cancer cells according to simulation study

Five new nitrogen-rich ligands (thioanhydrides) were synthesized and fully characterized. Then, their corresponding Co(II) complexes were prepared and also elucidated by analytical and spectral conformational techniques. First of all, the mono-negative tri-dentate mode was proposed with all derivatives towards mono-nuclear central atom. According to ligand field transitions and magnetic susceptibility values, the square-planar as well as octahedral geometries were the forms suggested. The presence of water molecules was investigated thermally. For conformational implementation under optimal conditions, energy minimization was carried out and fundamental data were obtained and studied. In silico investigation was carried out using the MOE docking approach to predict the inhibition activity for the new compounds. The Co(II)– 3e complex played an excellent inhibitory role. After that and based on preliminary results, in vitro antitumor screening against MCF-7 cell line was conducted for all Co(II) complexes. The results were consistent with that for standard drug (doxorubicin), and the inhibition feature for the complexes was ranked. Through photographic monitoring, outstanding inhibition activity towards breast cancer spreading was recorded for the Co(II)– 3e complex, which coincides well with MOE docking data.