No abstract

Four new complexes [V(NTA)(H2O)2]⋅H2O (1), H[Sn(NTA)] (2), H[Sm(NTA)]⋅H2O (3), and [Sm(NTA)(H2O)2]⋅H2O (4) were obtained during the reactions of metal salts (VCl3, SnCl2⋅2H2O, SnCl4, Sm(NO3)2⋅6H2O and SmCl3⋅6H2O) with nitrilotriacetic acid, H3NTA. The infrared and 1 H-NMR spectra of the solid complexes have been obtained and assigned. Thermogravimetric analyses were also carried out. The data obtained agree with the proposed structures and show that the complexes decomposed to the corresponding metal oxide. The ligand and their metal complexes were screened for their antimicrobial activities by the agar-well diffusion technique using DMSO as a solvent against the following bacterial species: Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and antifungal activity against Aspergillus niger, Aspergillus flavus, Saccharomyces cerevisiae and Candida albicans. The obtained results were compared with some types of known antibiotics. The minimum inhibitory concentration (MIC) values were calculated at 30 °C for 24−48 h. The activity data show that the complexes are more potent antimicrobials than the parent ligand.

No abstract

No abstract

The interaction of the cyclic base 1,4,10,13-tetraoxa-7,16-diazacyclooctadecae (TODACOD) w i t h different x-electron acceptors have been studied spectrophotometrically in CHCl3. These m k z t r o n acceptors are 1 -chloro-2,4,6-trinitrobenzene (picryl chloride), 7,7', 8,8'-tetracyanoquinone (TCNQ) and tetrachloro-p-benzoquinone (chloranil). The results indicate the formation of 1 :4 charge transfer complexes with the general structures [(TODACOD)(Accept)s]. The charge transfer absorptions as well as the infixed spectra of these complexes are obtained.115

No abstract

There are various classes of dyestuffs, one of which is the azodye. Azo groups have received much attention because of their use as models of biological systems. Azo compounds are involved in many important biological reactions such as protein synthesis inhibition, carcinogenesis, nitrogen fixation and antibacterial effects. Azodyes with the water solubilizing substituent --SO3Na are susceptible to azo reduction as the principal metabolic step [1].Azodyes are a simple type of organic semiconductors [2][3][4]. The formation of metal complexes between azodyes and transition metal cations leads to an increase in the charge carrier density and a reduction in the value of activation energy required for the conduction process. Chrysophenine is an important azo dyeing agent [5]. Its complexes with some lanthanides were studied [6]. The complexes obtained were intrinsic semiconductors.In continuation of our electrical studies of organic complexes as new types of conducting materials [7], the work reported here aimed to investigate the effect of complexation with Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) on the electrical behaviour of chrysophenine: SO3Na H5 C20-@N~N~~-CH= SO3Na HC-~N~N~OC2H5 (4, 4'-bis((p-ethoxyphenyl)azo) 2, 2'-stilbenedisulphonic acid, disodium salt)Mononuclear and polynuclear solid complexes of stoichiometric ratios M:L and 2M:L, where M is a transition metal and L is chrysophenine, were prepared by mixing an appropriate aqueous solution of transition metal chloride with a hot aqueous solution of chrysophenine. The mixture was stirred for 3 h at 70~ then allowed to cool at room temperature. The separated solid was filtered off, washed with ethanol then dried. Binuclear complexes of type MI:M2:L, in which Ms is Fe(II) and M 2 is various transition metal cations, were also prepared, as described previously [2].To determine the number of water crystallization molecules in the solid complexes, thermal treatment was done by heating a weighed sample in an oven at 120 ~ for 5 h, then weighing after heating. The results indicated that chrysophenine and its complexes have two molecules of water crystallization, except the Cr complex, which has three, and the Fe complex, which has only one.Conductometric titration is a useful analytical tool for determining the stoichiometry of the complexes depending upon the change in conductance of the solution at equivalent points. It was carried out using 30 ml of metal cation solution (10 -3 M) which was titrated with chrysophenine solution (10 -2 M). A digital conductivity meter 5800-05 solution analyser (Cole Parmer Instrument Co.) was used. Fig. 1 shows the relation between the conductance of the different cations and the volume of dye added. For each addition of chrysophenine, the conductance value was raised. The conductograms exhibit two apparent breaks after addition of 1.5 and 3.0 ml of dye, suggesting that the probable stoichiometries of the complexes are 2M:L and M:L, respectively.