Some Invariants of Equitorsion Third Type Almost Geodesic Mappings

Mediterranean Journal of Mathematics - In this paper, we consider equitorsion third type almost geodesic mappings of non-symmetric affine connection spaces. Applying different computational...     

A novel fragmentation-cyclization reaction of steroidal α-hydroxy oximes

By a novel “one pot” fragmentation-cyclization reaction 17β-hydroxy-17α-substituted-16-oximino derivatives in the androstane and estrane series were converted to a new type of D-homo derivative.     

Isomerism and fluxional behaviour in η2 -vinyl complexes resulting in inversion of configuration at an asymmetric carbon atom. The crystal and molecular structures of two isomeric forms of [MoCl{η2 -C(CF3)C(CF3)(PEt3)} (CF3CCCF3)(η5 -C5H5)]

η² -Vinyl complexes [MCl{η² -C(CF₃)C(CF₃)L} (CF₃CCCF₃)(η⁵ -C₅H₅)] (M = Mo, W: L = tertiary phosphine or phosphite or pyridine) have been shown by NMR and X-ray diffraction studies to exist in two distinct isomeric forms which exhibit (a) different orientations of the η² -vinyl ligand (b) different configurations at the asymmetric carbon atom of the η² -vinyl ligand: variable temperature NMR studies reveal fluxional behaviour thought to involve reversible inversion of configuration at this carbon atom.     

Magnetic criteria of aromaticity in a benzene cation and anion: how does the Jahn–Teller effect influence the aromaticity?

The aromatic/antiaromatic behavior of the Jahn–Teller (JT) active benzene cation and anion has been investigated using Density Functional Theory (DFT) calculations of Nuclear Independent Chemical Shifts (NICS) and magnetic susceptibility. NICS parameters have been scanned along the Intrinsic Distortion Path (IDP) for the benzene cation showing antiaromaticity which decreases with increasing deviation from D_6h to D_2h symmetry. Changes in NICS values along the IDP from D_6h to C_2v in the benzene anion revealed non-aromatic character.     

Sequence and Hot Transitions in the Co2 Molecule; Interference of Adjacent Lines Belonging to Different Transitions as a Function of Temperature

Carbon-dioxide spectra of some higher transitions in the 9-11μm region were studied. Spectra of the sequence ([10°1,02°1]_I,II - 00°2) and hot (01¹1 - 11¹0) bands were calculated as a function of temperature. the positions of the ro-vibrational transitions and their intensities were determined as a function of temperature. for lines in hot and sequence transitions whose positions are close to some of the regular lines ([l0⁰0,02⁰0]_I,II - 00°1)¹ absorption coefficients of adjacent lines were calculated as functions of line center distances and temperature. the resulting values of the absorption coefficient for conditions of constant pressure or constant volume were determined.     

On the metalation of 4-substituted pyridazines

A series of new pyridazines bearing ortho-directing groups at C-4 (protected/activated amino or carboxylic acid functionalities) was prepared and their metalation with lithium 2,2,6,6-tetramethylpiperidide was studied. Reactions of the ortho-lithiated species thus obtained with aldehydes as electrophiles opens an access to 4,5-disubstituted pyridazines 3, 4, 14 , and 15 .