Akmal S. Gaballa

Synthesis, spectroscopic properties, and antimicrobial activity of some new 5-phenylazo-6-aminouracil-vanadyl complexes

Six complexes, [VO(L1-H)2] · 5H2O (1), [VO(OH)(L2,3−H)(H2O)] · H2O (2,3), [VO(OH)(L4,5−H)(H2O)] · H2O (4,5), [VO(OH)(L6−H)(H2O)] · H2O (6), were prepared by reacting different derivatives of 5-phenylazo-6-aminouracil ligands with VOSO4 · 5H2O. The infrared and 1H NMR spectra of the complexes have been assigned. Thermogravimetric analyses (TG, DTG) were also carried out. The data agree quite well with the proposed structures and show that the complexes were finally decomposed to the corresponding divanadium pentoxide. The ligands and their vanadyl complexes were screened for antimicrobial activities by the agar-well diffusion technique using DMSO as solvent. The minimum inhibitory concentration (MIC) values for 1–4 and 6 were calculated at 30°C for 24–48 h. The activity data show that the complexes are more potent antimicrobials than the parent ligands.

Synthesis, characterization and antimicrobial studies on cis-platinum(II) complexes of 5-nitrosouracil derivatives.

Two complexes were obtained during the reactions of 6-amino-1-methyl-5-nitrosouracil (AMNU) and 6-methylamino-1-benzyl-5-nitrosouracil (MABNU) with cis-diaquadiamineplatinum(II) nitrate complex, cis-[Pt(NH(3))(2)(H(2)O)(2)](NO(3))(2). The complexes were isolated in good yields as powdery precipitates. They were characterized through their elemental analysis, infrared, UV-vis, and (1)H NMR spectroscopies as well as thermal analyses. The obtained results indicated that, pyrimidine bases substitute easily aqua ligands and interact with Pt(II) ions as a monodentate ligand in the neutral and ionic form for the ligands AMNU and MABNU, respectively. The exocyclic oxygen atoms are the most probable binding site. Square planar structures, cis-form, were proposed in both cases. The free ligands, and their Pt(II) complexes were screened for their antimicrobial activities.

Spectroscopic and thermal investigations of charge-transfer complexes formed between cefotaxime sodium drug and various acceptors

Charge-transfer complexes formed between cefotaxime sodium (CFX) as electron donor with different electron acceptors as iodine (I2), picric acid (HPA), chloranilic acid (H2CA), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 7,7′,8,8′-tetracyanoquinodimethane (TCNQ) have been studied in the liquid and solid states. The stoichiometries of all complexes were found to be 1: 1 molar ratio between the donor (CFX) and acceptors (I2, HPA, H2CA, DDQ, and TCNQ). Characterizations of the formed CT-complexes were based on elemental analyses, photometric titration measurements, IR, and 1H NMR spectra as well as thermal analyses. The characteristic physical constants (KCT, ɛCT, μ, ΔG, ID, f, ECT) of the formed CT-complexes are shown to be strongly dependent on the type and structure of the electron acceptors. Finally, the biological activities of the obtained CT complexes were tested for their antibacterial activities.

Synthesis, spectroscopic and thermal studies on platinum(II) complexes of 5-nitrosouracil derivatives

Three complexes were obtained during reactions of 6-amino-1-methyl-5-nitrosouracil, 6-methylamino-1-methyl-5-nitrosouracil and 6-methylamino-1-benzyl-5-nitrosouracil with K2PtCl4. The complexes were isolated in good yields as powdery precipitates and characterized through elemental analysis, infrared and 1H NMR spectroscopies, and thermal analysis. The pyrimidine bases easily substitute chloro ligands as a neutral monodentate ligand form. The exocyclic oxygen atoms are the probable binding sites rather than ring or exocyclic nitrogen atoms. trans Square planar structures were proposed in all cases.

Preparation and Spectroscopic Studies of Charge-Transfer Complexes of Thiamine Hydrochloride with Different Electron Acceptor

Abstract—Electronic interactions associated with charge transfer complexes formation of iodine, chloranilic acid (H2CA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with vitamin B1 have been studied spectrophotometrically. The accumulated data indicated formation of CT-complexes of the general formula [(VB1)(acceptor)n], (n = 1 or 2). The 1 : 2 and 1 : 1 donor: acceptor molar ratios were calculated on the basis of elemental analysis and photometric titrations. The solid complexes were prepared and characterized by their conductivity, UV-Vis, IR, and 1H NMR spectra, and thermogravimetric analyses (TGA, DTG). The characteristic physical constants (KCT, εCT, μ, ΔG, Ip, f, ECT) of the formed CT-complexes were determined to be strongly dependent on nature of the electron acceptors.