Synthesis, characterization and antimicrobial activity of m-toluenesulfonamide, N,N′-1,2-ethanediylbis (mtsen) and [Cu(II)(phenanthroline)2]mtsen complex

Binding Investigation of Some Important Metal Ions Copper (I), Nickel (II), and Aluminium (III) with Bovine Serum Albumin Using Valid Spectroscopic Techniques

Studies based on the interaction of metals with proteins resulted in the development of promising metal-based compounds with encouraging medicinal potential. This study was aimed to utilize FT-IR and UV-Vis spectroscopic techniques to analyze the interactions of biologically significant metal ions, such as Al3+, Ni+2, and Cu+, with bovine serum albumin (BSA). Different concentrations of metal ions were interacted with BSA, and the complexes were analyzed using the two techniques. The change in the BSA secondary structure components such as β-sheet, β-antiparallel, α-helix, β-turn, and random coil were analyzed using second derivative resolution enhancement. The FT-IR spectroscopy suggested a marked decrease in the C=O stretching (corresponding to amide I) and C=N stretching (corresponding to amide II) intensities. Interestingly, upon complexation, a marked reduction (22.58–29.03%) in the α-helical component was observed with a considerable increase in the random coil component. The intensity of the absorption peak of BSA obtained using UV was observed to increase consecutively as the concentration of Cu+, Al3+, and Ni2+ ions increased. The binding constants for the BSA-Cu+, BSA-Ni+2, and BSA-Al+3 complexes were calculated to be 3.46 × 104 M−1, 1.28 × 104 M−1, and 2.08 × 104 M−1, respectively. It was concluded that the binding interaction decreased in the order Cu+ > Al3+ > Ni2+. These findings were similar to our previous findings using affinity capillary electrophoresis (ACE). Therefore, it can be inferred that the FT-IR and UV techniques might be utilised effectively to assess the metal-protein interaction and can have wide application in routine analysis. These techniques have several advantages in being simple, easy-to-perform, rapid, and affordable over other high-end techniques.

Interaction of Conazole Pesticides Epoxiconazole and Prothioconazole with Human and Bovine Serum Albumin Studied Using Spectroscopic Methods and Molecular Modeling

The interactions of epoxiconazole and prothioconazole with human serum albumin and bovine serum albumin were investigated using spectroscopic methods complemented with molecular modeling. Spectroscopic techniques showed the formation of pesticide/serum albumin complexes with the static type as the dominant mechanism. The association constants ranged from 3.80 × 104-6.45 × 105 L/mol depending on the pesticide molecule (epoxiconazole, prothioconazole) and albumin type (human or bovine serum albumin). The calculated thermodynamic parameters revealed that the binding of pesticides into serum albumin macromolecules mainly depended on hydrogen bonds and van der Waals interactions. Synchronous fluorescence spectroscopy and the competitive experiments method showed that pesticides bind to subdomain IIA, near tryptophan; in the case of bovine serum albumin also on the macromolecule surface. Concerning prothioconazole, we observed the existence of an additional binding site at the junction of domains I and III of serum albumin macromolecules. These observations were corroborated well by molecular modeling predictions. The conformation changes in secondary structure were characterized by circular dichroism, three-dimensional fluorescence, and UV/VIS absorption methods.

Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies

Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, (1)H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

Synthesis of novel Schiff's bases of highly potential biological activities and their structure investigation

Novel bisaldehyde-hydrazide Schiff's bases AS1 (2,2'-(ethane-1,2-diylbis(oxy))dibenzaldehyde terephthalohydrazide) and AS2 (N',N'″-(((ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))di(benzohydrazide)) were prepared as new macrocyclic compounds via condensation reactions. AS1 had been prepared by condensation between (2,2'-(ethane-1,2-diylbis(oxy))dibenzaldehyde) bisaldehyde and terephthalohydrazide in a ratio1:1. AS2 had been obtained by condensation between (2,2'-(ethane-1,2-diylbis(oxy))dibenzaldehyde) bisaldehyde and benzohydrazide in ratio 1:2. The structures of AS1 and AS2 were characterized by elemental analysis (EA), mass (MS), FT-IR and (1)H-NMR spectra, and thermal analyses (TG, DTG). The activation thermodynamic parameters such as ΔE(∗), ΔH(∗), ΔS(∗) and ΔG(∗) were calculated from the TG curves using Coats-Redfern method. It is important to investigate their molecular structures to know the active groups and weak bonds responsible for their biological activities. Consequently in the present work, the obtained thermal (TA) and mass (MS) practical results are confirmed by semi-empirical MO-calculations (MOCS) using PM3 procedure. Their biological activities had been tested in vitro against Escherichia coli, Proteus vulgaris, Bacillus subtilis and Staphylococcus aurous bacteria in order to assess their anti-microbial potential.

New aromatic/heteroaromatic propanesulfonylhydrazone compounds: synthesis, physical properties and inhibition studies against carbonic anhydrase II (CAII) enzyme

Some new aromatic/heteroaromatic propanesulfonylhydrazone derivatives (1-8) were synthesized and characterized by elemental analyses, FT-IR, (1)H NMR, (13)C NMR, LC/MS techniques. The geometry optimizations and spectral calculations were performed by using DFT/B3LYP/6-311G(d,p) basis set in Gaussian 09 program. The inhibition activities of the synthesized compounds on carbonic anhydrase II (CAII) isoenzyme have been investigated by comparing IC50 values. Acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) AAZ, a clinically used in CAII inhibition has also been investigated as standard inhibitor. The best aromatic/heteroaromatic propanesulfonylhydrazone inhibitors of this isoform were o-aminobenzaldehydepropanesulfonylhydrazone (1) and thiophenecarboxyaldehyde propanesulfonylhydrazone (5) having the same IC50 (0.55 mM) value. The molecular descriptors for propanesulfonylhydrazones were obtained to develop structure activity relationship (SAR) model between experimental IC50 values and the molecular descriptors calculated by PM3-based SAR models in Hyperchem 8, respectively. The obtained models confirm the good carbonic anhydrase II (CAII) inhibition activity of the propanesulfonylhydrazone derivatives. The selected descriptors are sensitive both to the imine (CH=N) and NH2 groups that are responsible from higher activities of (1) and (5) in their series.

FT-IR, dispersive Raman, NMR, DFT and antimicrobial activity studies on 2-(Thiophen-2-yl)-1H-benzo[d]imidazole

2-(Thiophen-2-yl)-1H-benzo[d]imidazole (TBI) was synthesized under microwave conditions and was characterized by FT-IR, dispersive Raman, (1)H-, (13)C-, DEPT-, HETCOR-NMR spectroscopies and density functional theory (DFT) computations. The FT-IR and dispersive Raman spectra of TBI were recorded in the regions 4000-400 cm(-1) and 4000-100 cm(-1). The experimental vibrational spectra were interpreted with the help of normal coordinate analysis based on DFT/B3LYP/6-311++G(d,p) theory level for the more stable tautomeric form (Tautomer 1). The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. A satisfactory consistency between the experimental and theoretical findings was obtained. The frontier molecular orbitals (FMOs), atomic charges and NMR shifts of the two stable tautomeric forms were also obtained at the same theory level without any symmetry restrictions. In addition, the title compound was screened for its antimicrobial activity and was found to be exhibit antifungal and antibacterial effects.

Molecular structure and spectroscopic analysis of 1,4-Bis(1-methyl-2-benzimidazolyl)benzene; XRD, FT-IR, dispersive-Raman, NMR and DFT studies

This study reports the structural characterization of a bis-benzimidazole derivative, 1,4-Bis(1-methyl-2-benzimidazolyl)benzene (BMBB), by using spectroscopic and quantum chemical methods. The BMBB molecule was synthesized under microwave conditions and was characterized by using single-crystal X-ray diffraction, FT-IR, dispersive Raman and NMR spectroscopies. The potential energy surface scan study was carried out for the conformation of the theoretical structure. Quantum chemical calculations of relative energies, molecular geometry, vibrational wavenumbers, frontier molecular orbitals, atomic charges and gauge including atomic orbital (GIAO) (1)H and (13)C-NMR chemical shifts of the compound were carried out by using density functional method (DFT) at B3LYP/6-311++G(d,p) theory level. The complete assignments of the vibrational modes were performed with DFT calculations combined with scaled quantum mechanics force field (SQMFF) methodology. A satisfactory consistency between the experimental and theoretical findings was obtained. On account of the relative energies, population analysis and XRD results, the most stable conformational form of the molecule was also determined.