Discrimination of isomeric structures using information theoretic topological indices

Three newly defined information theoretic topological indices, namely “degree complexity (I^d),” “graph vertex complexity (H^V),” and “graph distance complexity (H^D)” along with three other information indices have been used to study their discriminating power of 45 trees and 19 monocyclic graphs. It is found that the newly defined indices have satisfactory discriminating power while H^D has been found to be the only index to discriminate all the graphs studied.     

Almost periodic solutions to SO(2,1)σ-model field theory

We construct almost periodic conoidal wave solutions toSO(2,1)-model field theory with the help of a periodic inverse problem suggested by Dote. The solutions can be explicitly constructed in terms of Riemann functions.     

Ion impact stopping cross sections for various media (Z = 3–100)

ABSTRACT

Stopping cross sections (SCS) for protons, alphas and Li ions are calculated with a modified form of our earlier work by incorporating a different electron density distribution of target materials; this involves four parameters – two projectile dependent and the rest two remain fixed. The prosed model has been tested for three stripped ion (H⁺, He^{2 +} and Li^{3 +}) projectiles and found that it describes quite satisfactorily the experimental SCS data from low energies with projectile velocities nearing v = Z₁v₀ (with Z₁ as the atomic number and v₀ the Bohr velocity) up to 100.0 MeV over a wide range of stopping media with atomic numbers Z₂ =3–100.     

Interrupting the Nazarov cyclization with indoles

A carbon-terminated interrupted Nazarov reaction is described. The trimethylsilyl enol ethers derived from propargyl vinyl ketones undergo selective proton transfer at the distal acetylenic carbon atom to provide allenyl vinyl ketones as transient intermediates. In the presence of indoles, a cascade of reactions is initiated that converts the initially formed pentadienyl cations to cyclopentenones bearing a quaternary alpha carbon atom.     

Square planar complexes of Cu(II) and Ni(II) with N<Subscript>2</Subscript>O donor set of two Schiff base ligands: synthesis and structural aspects

Abstract Two new square planar Cu(II) and Ni(II) complexes, [CuL¹(NCO)] (1) and [NiL²(N₃)] (2) have been synthesized with two different tridentate N₂O donor Schiff base ligands L ¹ H (1:1 condensation product of benzoylacetone and 2-diethylaminoethylamine) and L ² H (1:1 condensation product of benzoylacetone and 2-dimethylaminoethylamine), respectively. Both the complexes 1 and 2 have been characterized by elemental analysis, IR, UV-Vis spectroscopy, room temperature magnetic susceptibility measurement, electrochemical, thermal, and single crystal X-ray diffraction studies. Structural studies reveal that in both the complexes metal centers have square planar environment with N₂O donor set of Schiff base ligands and terminal pseudohalide anions (isocyanate for 1 and azide for 2) at four coordination sites of square plane. Graphical abstract Square planar complexes of Cu(II) and Ni(II) with N ₂ O donor set of two Schiff base ligands: synthesis and structural aspects Subhra Basak, Soma Sen, Samiran Mitra, C. Marschner, W. S. Sheldrick Two new square planar Cu(II) and Ni(II) complexes, [CuL¹(NCO)] (1) and [NiL²(N₃)] (2) have been synthesized with two different tridentate N₂O donor Schiff base ligands L ¹ H and L ² H respectively. Both the complexes 1 and 2 have been characterized by elemental analysis, IR, UV-Vis spectroscopy, room temperature magnetic susceptibility measurement, electrochemical, thermal and single crystal X-ray diffraction studies.      

A novel azetidinyl gamma-lactam based peptide with a preference for beta-turn conformation

Novel azetidinyl gamma-lactam based peptides have been synthesized with only compound showing a preference for the beta-turn conformation.     

Role of sulfur compounds in the detection of amino acids by ninhydrin on TLC plate

Three new sulfur reagents for specific identification of amino acids on thin-layer chromatography plates have been introduced. These three sulfur containing reagents are capable of developing various distinguishable colors with many of them. A probable mechanism for such color formation is proposed.     

Studies on the kinetics and mechanism of redox decomposition of 1,2,6-trinitrotriamminecobalt(III) and 1,2,6-trinitrodiethylenetriaminecobalt(III) complexes in aqueous acid

Summary In aqueous acid media the title complexes undergo decomposition ultimately forming cobalt(II). Detailed analysis of the kinetic data reveals that the reactions proceed in two consecutive stages, the initial step being the faster one. Evidence has been presented that the initial faster step involves aquation releasing one NO ₂ ^– ligand and forming an aquodinitro complex, which subsequently undergoes a slower intramolecular redox decomposition into Co²⁺. Each step, on the other hand, has been found to consist of two concurrent paths,viz. spontaneous and acid catalysed, respectively. Activation parameters corresponding to all these specific rate constants have been evaluated and a plausible mechanism for the overall reaction has been proposed.On leave from Agra College, Agra, India.     

Crystal and molecular structure of 4-aminoacetyl-N-p-nitrophenylsulfanilamide

The crystal and molecular structure of 4-aminoacetyl-N-p-nitrophenylsulfanilamide (C₁₄H₁₃N₃O₅S), a derivative of sulfonamide, has been determined from X-ray diffraction data using Cu-K radiation. The compound crystallised in the monoclinic space groupP2₁/c, witha=12.258(9),b=7.339(5),c=16.359(9) Å,=98.84(4)°. The structure was solved by direct methods and refined by full-matrix least-squares to a finalR value of 0.047 with 2487 unique reflections. In packing, the molecules are found to be stabilised by N-H O hydrogen bonds.