Racemic threo and erythro 4-methyl-3-heptanol, obtained from the commercial alcohol by fractional distillation using a spinning band column, were resolved by high-pressure liquid chromatographic separation of their (−)-MTPA diastereoesters. The biological activity of the four stereoisomers towar...

A simple and efficient synthesis of optically active insect pheromones, such as (R)- and (S)-3-octanol, (R)-2-dodecanol, (R)-2-methyl-4-heptanol and (R)-2-methyl-4-octanol starting from non-racemic β-hydroxy sulfides has been established.

Ultrafine chromium (III) oxide powders have been produced by laser-induced pyrolysis of chromyl chloride vapour. The crystalline particles are characterized by their mean diameter, which is found to be between 10 and 300 nm. This is determined as a function of the parameters of the reaction. The...

The dynamics of the 1B1 state of chromyl chloride, CrO2Cl2, are investigated via picosecond time-resolved measurements on a jet-cooled sample. Quasi-biexponential time evolution of fluorescence is observed for each of the nine single vibronic levels studied. A rapid, mode-dependent acceleration ...

Infrared multiphoton absorption (MPA) of chromyl chloride (CrO2Cl2) and luminescence, due to inverse electronic relaxation (IER), were studied in the gas phase at pressures of 6.7 to 133 Pa (0.050 to 1.00 Torr) with CO2 laser pulses of 10 and 60 ns duration. A dependence of MPA measured photoaco...

In this work we report a detailed structural study of the K2-xNaxMg2(SO4)3 series in order to evaluate the effect of Na incorporation on the structure. The results show that the cubic langbeinite structure is observed at room temperature for high Na levels; K2-xNaxMg2(SO4)3 (0 ≤ x ≤ 1.8). Incr...

Analytical probe for determination of Chromium (II) ions is almost rare in contrary to tremendous probes for chromium (III) and chromium (VI). Here, highly fluorescent carbon quantum dots (CQDs) doped with nitrogen and phosphorous were prepared solvothermally. Size, morphology, surface structure...

SummaryBackgroundMultiple sclerosis is a degenerative inflammatory disease of the CNS characterised by immune-mediated destruction of myelin and progressive neuroaxonal loss. Myelin in the CNS is a specialised extension of the oligodendrocyte plasma membrane and clemastine fumarate can stimulate...

A new versatile method for the synthesis of supported mono and diphosphines on polypyrrole matrix is described, based on the protective borane complexation of the phosphorus atom. For the first time, the unknown alkylation of a diphosphine ethano bridge, was obtained with near yield close to 70%...

The diastereoselective synthesis of a P-chirogenic β-aminophosphine ligand with carbon–carbon bond formation of the ethano bridge in a 3:1 ratio via reaction of an α-metallated P-chirogenic phosphine borane with a benzaldimine is described. The diastereoselectivity is attributed to a transiti...

Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1)...

Improved methods for the preparation of methylene-bridged diphosphine ligands are described. Both enantiomers of the key intermediate tert-butylmethylphosphine–borane were prepared via resolution or by the conversion of one enantiomer into the opposite enantiomer. The precursor borane complexes...

Primary P-phenyl and P-methyl phosphine-boranes 1 and 2 are prepared by complexation of the free phosphines with BH3 · SMe2. They are stable and can be purified by distillation. Under basic conditions, they lead selectively to secondary alkylphosphine-boranes and under neutral conditions to the...

The preparation and reactivity of novel (R1O)(R2O)P(BH3)H [R1, R2=Et, TIPS] synthons is investigated. The direct alkylation of these compounds with lithium hexamethyldisilazide (LiHMDS) and various electrophiles, provided new series of phosphonite-borane complexes, which can be converted into H-...

Both enantiomers of tert-butylmethylphosphine–borane have been used for the synthesis of P-chiral diphosphines and/or their borane complexes. The enantiopure borane complex of 1,2-bis(tert-butylmethylphosphino)ethane (t-Bu-BisP∗) was prepared in high yield from the secondary phosphine–borane a...

Eight hairdressers and four clients were found to be allergic to glyceryl monthioglycolate (GMTG) contained m “acid” permanent waves used in American beauty salons only since 1973 Previous studies in Germany showed that compounds closely related to GMTG were strong sensitizers In contrast, amm...

Glyceryl monothioglycolate, a reducing agent used in permanent waving solutions, is a recognized cause of allergic contact dermatitis. Because of an unexplained persistence of dermatitis in beauty shop clients after exposure to permanent wave solutions containing glyceryl monothioglycolate, we l...

Aqueous Li ion batteries offer a safe and low cost alternative to their organic electrolyte counterparts; however, they usually suffer from poor cyclability due to the structural instability of electrode-active materials in the aqueous electrolytes. In the light of excellent electrochemical reve...

Reductive leaching of vanadium from spent vanadium catalysts for sulfuric acid production by sulfur dioxide, with the use of weakly acidic aqueous solutions of sulfurous acid, is studied. It is shown that the rate and completeness of vanadium leaching is related to the presence of admixtures of ...

A new comprehensive utilization of vanadium slag (VS) method focusing on inhibiting leaching of iron (Fe) during the leaching of vanadium (V) using sulfuric acid (SA) was proposed. In this process, Cr2O3 was added to VS to conjugate with Fe in the VS to form (Fex,Cr1-x)2O3 which is insoluble in ...