A computational study at the density functional theory (DFT) as well as electrochemical methods, was carried out on the structural and physico-chemical properties of a series of sulfonamide derivatives (SAs) as WHO essential medications in the treatment of basic health system. The B3LYP/6-311++G(d,p) level of theory carried out on sulfadiazine (SDZ), sulfathiazole (STZ), sulfaquinoxaline (SQX), sulfacetamide (SAA), and the reference unsubstituted sulfonamide (SA) was discussed and rationalized in term of the N 1 -sulfonamide substituent. The geometric structures and the electronic properties related to the bacteriostatic reactivity were revealed to be affected by the steric and "push-pull" characteristics of the substituents. Electrochemical experiments on oxidation of SAs, using cyclic voltammetry are presented. The results obtained showed that the calculated ionization potentials (IPs) could be correlated linearly with the electro-oxidation potentials. From the molecules studied it is evident that SDZ act as the most electro-active agent, possessing the highest biological activity. DFT computations carried out using the standard molar enthalpies of formation in the gas phase predicted improvements in the thermodynamic stabilization of the SDZ, SQX, and SAA molecules and an unstabilization of STZ with respect to the parent molecule SA.
We have demonstrated electronic structure and magnetic properties of Cu3, Ag3 and Au3 trimers using a full potential local orbital method in the framework of relativistic density functional theory. We have also shown that the non-relativistic generalized gradient approximation for the exchange-correlation energy functional gives reliable magnetic properties in coinage metal trimers compared to experiment. In addition we have indicated that the spin-orbit coupling changes the structure and magnetic properties of gold trimer while the structure and magnetic properties of copper and silver trimers are marginally affected. A significant orbital moment of 0.21μB was found for most stable geometry of the gold trimer whereas orbital magnetism is almost quenched in the copper and silver trimers.
The metal(II) ion complexes of a pentadentate macrocycle 1, namely 3,12-dioxa-6,9,18-triazabicyclo[12.3.1]octadeca-1(18),14,16-triene-2,13-dione are synthesized. This macrocycle is prepared from the reaction of dipotassium salt of 2,6-pyridinedicarboxylic acid with ethylenediamine and 1,2-dibromoethane. The reaction of 1 (L) in methanol with MCl 2 .xH 2 O gave complexes with the general formula [M(L)Cl 2 ] (where M= Ni(II) 2, Cu(II) 3 and Zn(II) 4, respectively). The analysis of IR, 1 Hand 13 C-NMR spectral data of all complexes propose that 1 is bonded to metal(II) ions through a nitrogen atom of pyridine ring, two nitrogen atoms of amine groups and two oxygen atoms of ester moieties. The thermal analysis indicated that there are no water molecules of hydration or coordinated in the structure of the complexes. Among these complexes, the Cu(II) 3 complex demonstrated good antibacterial and antifungal activities. The molecular geometry, AIM atomic charge and frontier molecular orbitals of the compounds are investigated theoretically using DFT method. Based on the theoretical data of these complexes represented, a bipyramidal pentagonal arrangement can be envisaged in such a way that the N 3 O 2 pentadentate donor sites form the planar pentagonal base of the bipyramid and the two Cl atoms occupy the vertexes.
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