Synthesis,spectroscopic, thermal properties,Calf thymus DNA binding and quantum chemical studies of M(II) complexes

A new series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) were prepared from the ligand of 5‐(4‐benzenesulfonic acid azo)‐2‐thioxo‐4‐thiazolidinone (H₂L). The M(II) complexes were structurally elucidated by elemental analysis, infrared spectra, spectral studies, thermal analysis, magnetic measurements and X‐ray diffraction analysis. Elemental analysis and IR result suggested the ligand was bonded to the metal ions in monobasic/neutral bidentate through the nitrogen atom of the hydrazone group and oxygen atom of carbonyl group. The bond length, bond angle, HOMO, LUMO and quantum chemical parameters were calculated to confirm the geometry of the ligand and the M(II) complexes. In vitro antimicrobial behavior of ligand (H₂L) and its M(II) complexes (1‐5) was screened with targeted bacterial and fungal strains. Spectroscopic (UV‐vis) technique was employed in order to study the binding mode and binding strength of the ligand (H₂L) and its M(II) complexes to Calf thymus DNA (CT‐DNA). Intercalation is the most possible mode of interaction of the ligand (H₂L) and its M(II) complexes with CT‐DNA and the determined binding constants. Molecular docking was used to predict the binding between the starts (4‐aminobenzenesulfonic acid (start 1) and 2‐thioxo‐4‐thiazolidinone (start 2)) and tautomers (A‐C) of ligand (H₂L) with the receptors of prostate cancer mutant (PDB code: 2Q7K) and breast cancer mutant (PDB code: 3HB5).     

Polymer complexes. LXIX. Some divalent metal(II) polymer complexes of potentially bidentate monomer N‐[4‐(5‐methyl‐isoxazol‐3‐ylsulfamoyl)‐phenyl]‐acrylamide: Synthesis,spectroscopic characterization,thermal properties,antimicrobial agents and DNA studies

Monomer of N‐[4‐(5‐methyl‐isoxazol‐3‐ylsulfamoyl)‐phenyl]‐acrylamide (HL) and some transition metal polymeric complexes of the general formula {[M(HL)(OH₂)₂(OCOCH₃)₂] xH₂O}_n (M = Co(II), x = 2; Ni(II), x = 3; Mn(II), x = 2) and [Cd(HL)₂(OCOCH₃)₂] were synthesized and characterized by elemental analysis, IR, UV spectroscopy, conductance measurements, magnetic susceptibility, thermogravimetric analyses and X‐ray diffraction analysis. In all polymer complexes, the spectral data revealed that the ligand act as bidentate neutral molecule and coordinate to metal ion through enolic sulphonamide OH and isoxazol‐N. In all polymer complexes, the spectral data revealed that the ligand act as bidentate neutral molecule and coordinate to metal ion through enolic sulphonamide OH and isoxazol‐N. The molar conductance data revealed that the polymer complexes are non‐electrolytes while UV‐vis and magnetic measurements data have been shown that the polymer complexes have octahedral geometry. All the studies revealed coordination six for the metals in all the polymer complexes and octahedral structures were suggested. The inhibitive effect of HL against C38 steel was investigated in 2 M HCl solution (tafel polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) methods). The type of HL is mixed inhibitor whose adsorption habit onto C38 steel.     

The Reaction of Ketenylidenetriphenylphosphorane (Ph3P˭C˭C˭O) with Acidic H‒E (E˭O,N) Bonds

Abstract

The reactivity of ketenylidenetriphenylphosphorane (1) with the protic reagents 2,4,6-trimethylphenol (7), 2,6-di-tert-butyl-4-methylphenol (8), and diphenylamine (9) has been explored. Three novel carbonyl-stabilized ylides have been synthesized and characterized. Crystal structures were obtained for Ph₃PCHC(O)O(C₆H₂Me₃) (11), Ph₃PCHC(O)O(C₆H₂t-Bu₂Me) (12), and Ph₃PCHC(O)NPh₂ (13), respectively. These products were then methylated in an attempt to develop a new route to low-valent carbon compounds. Crystals of [Ph₃PCH(CH₃)C(O)O(C₆H₂Me₃)]I (14) were isolated and characterized but this route did not prove to be synthetically useful, at least toward the goal of preparing low-valent carbon-centered materials. Finally, 1 was also reacted with the bulky tin reagent, bis[bis(trimethylsilyl)amido]tin(II), in the presence of 2,4,6-trimethylphenol. A complex mixture of products was obtained, from which crystals of an unusual chelated tin compound (15) were isolated and characterized using X-ray crystallography.     

Synthesis of the [11]Cyclacene Framework by Repetitive Diels–Alder Cycloadditions

The Diels–Alder cycloaddition between bisdienes and bisdienophile incorporating the 7-oxa-bicyclo[2.2.1]heptane unit are well known to show high diastereoselectivity that can be exploited for the synthesis of molecular belts. The related bisdiene 5,6,7,8-tetramethylidene-2-bicyclo[2.2.2]octene is a valuable building block for the synthesis of photoprecursors for acenes, but it has not been employed for the synthesis of molecular belts. The present work investigates by computational means the Diels–Alder reaction between these bisdiene building blocks with syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene, which shows that the diastereoselectivity of the Diels–Alder reaction of the etheno-bridged bisdiene is lower than that of the epoxy-bridged bisdiene. The reaction of the etheno-bridged bisdiene and syn-1,4,5,8-tetrahydro-1,4:5,8-diepoxyanthracene in 2:1 ratio yields two diastereomers that differ in the orientation of the oxa and etheno bridges based on NMR and X-ray crystallography. The all-syn diastereomer can be transformed into a molecular belt by inter- and intramolecular Diels–Alder reactions with a bifunctional building block. The molecular belt could function as a synthetic intermediate en route to a [11]cyclacene photoprecursor.     

Structural and characterization of novel copper(II) azodye complexes

The synthetic methods of novel Cu(II) and adduct complexes, with selective azodyes containing nitrogen and oxygen donor ligands have been developed, characterized and presented. The prepared complexes fall into the stoichiometric formulae of [Cu(L(n))(2)](A) and [Cu(L(n))(2)(Py)(2)](B), where two types of complexes were expected and described. In type [(A) (1:2)] the chelate rings are six-membered/four coordinate, whereas in type [(B) (1:2:2)] they are six-membered/six coordinate. The important bands in the IR spectra and main (1)H NMR signals are tentatively assigned and discussed in relation to the predicted assembly of the molecular structure. The IR data of the azodye ligands suggested the existing of a bidentate binding involving azodye nitrogen and C-O oxygen atom of enolic group. They also showed the presence of Py coordinating with the metal ion. The coordination geometries and electronic structures are determined from the framework of the proposed modeling of the formed novel complexes. The complexes (1-5) exist in trans-isomeric [N,O] solid form, while adduct complexes (6-10) exist in trans isomeric (Py) form. The square planar/octahedral coordination geometry of Cu(II)/adduct is made up of an N-atom of azodye, the deprotonated enolic O-atom and two Py. The azo group was involved in chelation for all the prepared complexes. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(L(n))(2)]. The ligands in the dimmer are stacked over one another. In the solid state of azo-rhodanine, the dimmers have inter- and intramolecular hydrogen bonds. Interactions between the ligands and Cu(II) are also discussed.     

Thermal stability and degradation of chitosan modified by benzophenone

N-(biphenylmethylidenyl) chitosan polymer was prepared, characterized and thermal stability was compared with chitosan. Thermal degradation products of the modified polymer were identified by GC-MS technique. It seems that the mechanism of degradation of the prepared polymer is characterized by formation of low molecular weight radicals, followed by random scission mechanism along the backbond chain.     

Improving dosimetric properties of tellurite glasses

Thermoluminscence (TL) properties of quaternary tellurite glass in the form 80(TeO₂)–5(TiO₂)–(15−x)(WO₃)–(x)A_nO_m where A_nO_m=Nb₂O₅, Nd₂O₃, Er₂O₃ and x mol% have been measured. TL main dosimetry peak for each produced glass sample were investigated for ⁶⁰Co gamma rays. Dosimetric properties of the quaternary tellurite glasses have been measured as a function of different compositions of the glass system in different rare earth oxides concentration by using thermoluminescence (TL) detection technique.     

An approach to evaluate the efficiency of γ-ray detectors to determine the radioactivity in environmental samples

This work provides an approach to determine the efficiency of γ-ray detectors with a good accuracy in order to determine the concentrations of either naturally occurring or artificially prepared radionuclides. This approach is based on the efficiency transfer formula (ET), the effective solid angles, the self- absorptions of the source matrix, the attenuation by the source container and the detector housing materials on the detector efficiency. The experimental calibration process was done using radioactive (Cylindrical & Marinelli) sources, in different dimensions, that contain aqueous ¹⁵²Eu radionuclide. The comparison point to a fine agreement between the experimental measured and calculated efficiencies for the (NaI & HPGe) detectors using volumetric radioactive sources.     

Hamiltonian formulation of classical fields with fractional derivatives: revisited

An investigation of classical fields with fractional derivatives is presented using the fractional Hamiltonian formulation. The fractional Hamilton’s equations are obtained for two classical field examples. The formulation presented and the resulting equations are very similar to those appearing in classical field theory.