Separazione, caratterizzazione e proprietà di alcuni idrosso- ed acquo-derivati di complessi del tipo Coen2X+Coen_2X^+ (X=base coniugata di un acido diprotico)

The intermediates of the hydrolysis reaction in basic medium for $Coen_2CO_3^+$ and $Coen_2mal^+$ (en = ethvlenediamine and mal = malonate) were separated by ion-exchange chromatography. They are $Coen_2CO_3OH$ and $Coen_2malOH$, respectively; foe each of them the $cis$ and $trans$ isomers were identified and characterized bv spectrophotometric and chromatographic measurements. The kinetics of isomerization from the $trans$ to the $cis$ form has been studied for the diprotonated malonate complex and compared with the results previously obtained for similar species

PREPARATIVE AND ANALYTICAL STUDIES OF SOME DICARBOXYLATO-α-DIIMINECOBALT(III) COMPLEXES

Abstract Two series of [Co(III)(AA)2(OCOR)2]NO3 complexes (where AA = 1.10-phennanthroline or 2,2′-bipyri-dine and R = H.CH3, C2H5 or C3H7) were prepared by the reaction of [Co(III)(AA)2Co3]No3 with the appropriate carboxylic acid in aqueousn solution at 50–60°C. A convenient high-yield route to [Co(phen)2Co3]No3 is proposed. The complexes were characterized spectroscopic and by chromatographic(TLC) techniques. A linear relationship is found between the number of carbon atoms in the carboxylic ligand and the chromatographic RM values of the two homologgous series of complexes

Effect of the mobile phase composition on the retention behaviour of diphenylsilica pre-coated plates"

The retention of some rifamycins and steroids on diphenyl bonded pre-coated silica gel plates, in relation to the mobile phase used, was examined by thin-layer chromatography. Neat organic solvents, non-aqueous and aqueous binary mixtures were tested as eluents. By comparison of retention data for rifamycins and steroids, respectively, under non-aqueous and aqueous conditions, a dual retention mechanism on this diphenyl phase was found. Interactions with the residual silanol groups seemed to prevail when employing as mobile phase the more lipophilic solvents tested, such as chloroform or dichloromethane, whereas interactions with the aryl groups of the bonded phase prevailed when using high polarity alcohols or aqueous mixtures. As a consequence, by changing the mobile phase, a large variation in selectivity with a concomitant change in retention order of the test compounds was observe