Zur Konstitution der Trimethylsilylderivate von Imidodiphosphorylverbindungen

On the Constitution of the Trimethylsilyl Derivatives of Imidodiphosphoryl Compounds Esters and dialkylamides of the imidodiphosphoric acid react with hexamethyl-disilazane to form trimethylsilyl derivatives. ¹H-, ²⁹Si-, and ³¹P-NMR data show the trimethylsilyl group to be bond to oxygen with rapid reversible exchange between both phosphoryloxygen atoms.     

Ester der Imidodiphosphorsäure

Imidodiphosphoric Acid Esters Imidodiphosphoryl tetrachloride reacts with aliphatic alcohols (C₁–C₃) as well as with sodium phenolate to form tetraalkylesters or tetraphenylesters of the imidodiphosphoric acid, resp. The tetraalkylesters (alkyl = methyl, ethyl, n-propyl) are also formed by reaction of trichlorphosphazene phosphoryldichloride, Cl₃P?N? POCl₂, with the corresponding alcohols. The purification of the esters can be reached by destillation of their silyl derivatives followed by desilylation. The esters are associated by intermolecular O…?H…?O hydrogen bonds.     

Influence of chromatographic conditions on separation in comprehensive gas chromatography

Comprehensive gas chromatography (GC x GC) is now established as a powerful technique, which offers unprecedented separation power. For complex samples, the distribution of peaks in the two-dimensional (2D) space still may need to be optimised. Since temperature (T) is a critical variable, and compounds can be shifted in relative positions on column 1 arising from temperature program rate (rT) changes, and since retention in the second dimension, D2 (2tR) is likewise affected by the prevailing T (elution temperature; Te), then any factors which alter Te will affect the extent of separation in D2. Since temperature program and carrier gas velocity rate will affect the Te of the solutes, these two factors are considered in this paper. Apart from these two parameters, results of different stationary phase choice for the second dimension column as well as the second dimension column length are reported. rT is found to have the most profound impact on the Te of solutes and will be more likely to cause an inversion of elution order if such behaviour can occur. Peak widths and 2tR increase with a decrease in Te. On the other hand, flow-rate has less impact on peak widths and 2tR although Te is affected by a change in flow-rate. Specific solute-stationary phase interactions will cause the elution order of certain solutes to be altered, and may be observed when a different stationary phase is employed as the second column, depending on the solute-stationary phase separation mechanism. Experiments conducted on different second dimension column length showed that although a longer column will lead to better separations, wrap-around may confound the separation process and may cause the solutes from sequential modulation events to co-elute. Thus a suitable second dimension column phase and length must be employed in order to obtain good separation. The factors investigated in this study will cause different extents of changes in the solute elution order and solute separations, and will affect the 2D contour presentation.     

Surface Modification and Characterization of Dichloromethane Plasma Treated Polypropylene Film

Surface of polypropylene (PP) film was modified in plasma of dichloromethane (CH₂Cl₂). The nature of surface modifications and formation of cross-linked layer due to plasma polymerization was studied by surface energy measurements and solubility test. Surface modification achieved by CH₂Cl₂ plasma was compared with the reported work on chloroform (CHCl₃) and carbontetrachloride (CCl₄) plasma modifications. Modified surface characterized by ATR-FTIR technique indicated formation of saturated and unsaturated cross-linked product. On the basis of relative intensity change of the specific bands, the site of attachment of chlorine on PP surface was investigated. Adhesive strength of modified film was measured by T-peel test method. Stability of modified surface was studied by measuring surface energy and peel strength after two months.     

Green chemical multi-component one-pot synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones under solvent-free conditions and their anti-fungal activity

A rapid one-pot solvent-free procedure has been developed for the synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones by neat three-component cyclocondensation of anthranilic acid, phenyl acetyl chloride and substituted anilines under microwave irradiation. The experimental methodology and microwave conditions described here are well established, allowing significant rate enhancement and good yields compared to conventional reaction conditions. The reaction is generalized for O, M & P substituted anilines to give quinazolin-4(3H)-ones. Synthesized compounds have been screened for their antifungal activity.     

Thin-layer chroamtography of pt-metals complexes with ketoanils: Analysis and effect of chelate ring contraction on RF values

Summary Thin-Layer chromatogrtaphy on silica gel was used for the separation of platinum group metal complexes using one-, two-, and three-component solvent systems. In octahedral and square planar, cationic complexes, containing two identical five-membered chelate rings formed by three different ketoanils, a linear dependence on chelate ring contraction (and also metal-ligand bond frequencies and ligand field parameters) of their R_F values has been established in one-component solvent systems.     

A binuclear manganese complex of a pyridoxal derivative and its use as an oxidation catalyst

Summary A new binuclear complex of manganese, [Mn₂L(OAc)₂], where H₃L = N,N-[4(3-hydroxy-5-hydroxymethyl-2-methyl)pyridylmethylene]-1,3-diamionopropane-2-ol, was prepared and characterized by analysis and various spectral methods. The studies reveal that it is a mixed valence manganese(II)/manganese(III) complex with endogenous -oxo and exogenous -carboxylato bridges.The complex can be used as a catalyst for the selective oxidation of hydrocarbons (cyclohexene, cis-cyclooctene, styrene, norbornene and trans-4-octene) using terminal oxidant at ambient temperatures. The yields calculated on the basis of the oxidant concentrations indicate that the complex works as an efficient catalyst for the oxidation of hydrocarbons. A probable mechanism for the reaction is proposed.     

Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II)

The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.     

Colored electrically conducting polymers from furan,pyrrole, and thiophene

Furan, pyrrole, and thiophene were polymerized under catalysis by trichloro- and trifluoroacetic acid to produce colored polymers which were characterized by various methods, including electronic and proton magnetic resonance spectra and electrical conductances of deeply colored trichloroacetic acid adducts. The predominant repeat units of these polymers are of the same type as those of deeply colored cyclopentadiene polymers, except that a CH₂ group is replaced by O, NH, or S.