Coordination behaviour of sulfanilamide derivatives

A thermodynamic relationship and phase transition study involving two polymorphs of sulfamethoxazole: form I vs. form II

Two sulfamethoxazole polymorphs (form I and II) have been studied. The form II → form I transformation is observed via milling and dissolution in acetonitrile. A phase transition mechanism is proposed based on their supramolecular geometries.

New Heteroleptic Ruthenium(II) Complexes with Sulfamethoxypyridazine and Diimines as Potential Antitumor Agents

Two new complexes of Ru(II) with mixed ligands were prepared: [Ru(bpy)₂smp](PF₆) (1) and [Ru(phen)₂smp](PF₆) (2), in which smp = sulfamethoxypyridazine; bpy = 2,2′-bipyridine; phen = 1,10-phenanthroline. The complexes have been characterized by elemental and conductivity analyses; infrared, NMR, and electrospray ionization mass spectroscopies; and X-ray diffraction of single crystal. Structural analyses reveal a distorted octahedral geometry around Ru(II) that is bound to two bpy (in 1) or two phen (in 2) via their two heterocyclic nitrogens and to two nitrogen atoms from sulfamethoxypyridazine—one of the methoxypyridazine ring and the sulfonamidic nitrogen, which is deprotonated. Both complexes inhibit the growth of chronic myelogenous leukemia cells. The interaction of the complexes with bovine serum albumin and DNA is described. DNA footprinting using an oligonucleotide as substrate showed the complexes’ preference for thymine base rich sites. It is worth notifying that the complexes interact with the Src homology SH3 domain of the Abl tyrosine kinase protein. Abl protein is involved in signal transduction and implicated in the development of chronic myelogenous leukemia. Nuclear magnetic resonance (NMR) studies of the interaction of complex 2 with the Abl-SH3 domain showed that the most affected residues were T79, G97, W99, and Y115.

Crystal structure, Hirshfeld surface analysis, spectroscopic and biological studies on sulfamethazine and sulfaquinoxaline ternary complexes with 2,2′-biquinoline

Three ternary complexes with sulfaquinoxaline or sulfamethazine have been synthesized and their structural, spectroscopic and biological properties have been studied.

Sulfamethazine copper(ii) complexes as antimicrobial thermal stabilizers and co-stabilizers for rigid PVC: spectroscopic, thermal, and DFT studies

Binary and ternary Cu(ii) complexes of the sulfamethazine antibacterial drug have been prepared, characterized, and tested for their antibacterial thermal stabilizer efficiency for PVC.

Bis[4-amino-N-(4-methylpyrimidin-2-yl-κN3)benzenesulfonamidato-κN](2,2′-bipyridine-κ2N,N′)mercury(II)

The complete mol­ecule of the title complex, [Hg(C₁₁H₁₁N₄O₂S)₂(C₁₀H₈N₂)], is generated by crystallographic twofold symmetry, with the mercury cation lying on the rotation axis. The mercury coordination polyhedron can be described as tetra­hedral (from the N,N′-bidenate bi­pyridine mol­ecule and the sulfonamide N atoms of the sulfamerazine anions) or as squashed trigonal-prismatic, if two long (> 2.80 Å) Hg—N bonds to pyrimidine N atoms are included. The dihedral angle between the aromatic rings in the anion is 73.3 (2)°. In the crystal, N—H⋯(N,O) and N—H⋯N hydrogen bonds link the mol­ecules into a three-dimensional network.

Synthesis and biological activities on metal complexes of 2,5-diamino-1,3,4-thiadiazole derived from semicarbazide hydrochloride

A bioactive ligand, 2,5-diamino-1,3,4-thiadiazole (L), derived from semicarbazide hydrochloride, and its metal complexes were prepared and characterized. The complexes were characterized using elemental, infra-red, ultraviolet/visible, magnetic moment, atomic absorption, thin layer chromatography and molar conductance measurements. The IR data revealed that the ligand (L) behaved as a tridentate neutral ligand. It coordinated to the metal ion via sulphur and nitrogen of the amines. The molar conductance data reveal that the chelates are non-electrolytes. From the Ultraviolet/Visible spectra and magnetic moment data, the complexes were found to have octahedral geometrical structure. In vivo evaluation of the antimicrobial activities of the metal complexes and the ligands showed greater activity against some micro-organisms when compared to the parent compounds. The chelates do not show toxicity against the activities of enzymes from homogenates of liver, kidney and serum in experimental rats.

Polymer complexes. LIII. Supramolecular coordination modes and structural of novel sulphadrug complexes

Novel polymer complexes of copper(II), palladium(II), platinum(II) and cadmium(II) containing homopolymer [4-acrylamido benzene sulphonyl guanidine; (HL)] and various anions (SO₄²⁻, CH₃COO⁻, NO₃⁻, Br⁻ or Cl⁻) have been designed and carried out. Their structures were investigated by elemental analyses, spectral (IR, UV-vis, ¹H NMR and ESR) and magnetic moments. The modes of interactions between the ligand and the metals were discussed, where oxygen (of O=S=O group) and nitrogen atom [of imino nitrogen (NH/N) of the guanidine group] are involved in chelation. The homopolymer shows two types of coordination behaviour. In mononuclear polymer complexes 4 and 6-10, it acts as a neutral bidentate ligand chelated through the NH and O atoms, whereas in the polymer complexes 1-3, 5 and 11, monobasic bidentate ligand is coordinated through the -N and -O atoms. The poly-chelates are of 1:1/1:2 (metal-homopolymer) stoichiometry and exhibit four coordination. On the basis of electronic spectral data and magnetic susceptibility measurement square planar geometry has been proposed. The ESR spectral data provided information about their structure on the basis Hamiltonian parameters and degree of covalency. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated.

Synthesis, characterization and antimicrobial properties of a Co(II)-phthalylsulfathiazolate complex

The reaction between phthalylsulfathiazole (H(2)PST), in alkaline aqueous solution, and cobalt(II) nitrate led to a pink solid, [Co(PST)(H(2)O)(4)] (1), which was characterized by elemental and thermogravimetric analysis; FT-IR, Raman and diffuse reflectance spectra. Spectroscopic data reveal that the ligand would be doubly deprotonated and that the Co(II) ion environment is a distorted octahedral one. (1) showed antibacterial activity similar to the ligand.

Synthesis, characterization and thermal studies on metal complexes of new azo compounds derived from sulfa drugs

Four new azo ligands, L1 and HL2-4, of sulfa drugs have been prepared and characterized. [MX(2)(L1)(H(2)O)(m)].nH(2)O; [(MX(2))(2)(HL2 or HL3)(H(2)O)(m)].nH(2)O and [M(2)X(3)(L4)(H(2)O)].nH(2)O; M=Co(II), Ni(II) and Cu(II) (X=Cl) and Zn(II) (X=AcO); m=0-4 and n=0-3, complexes were prepared. Elemental and thermal analyses (TGA and DTA), IR, solid reflectance spectra, magnetic moment and molar conductance measurements have accomplished characterization of the complexes. The IR data reveal that HL1 and HL2-3 ligands behave as a bidentate neutral ligands while HL4 ligand behaves as a bidentate monoionic ligand. They coordinated to the metal ions via the carbonyl O, enolic sulfonamide S(O)OH, pyrazole or thiazole N and azo N groups. The molar conductance data reveal that the chelates are non-electrolytes. From the solid reflectance spectra and magnetic moment data, the complexes were found to have octahedral, tetrahedral and square planar geometrical structures. The thermal behaviour of these chelates shows that the water molecules (hydrated and coordinated) and the anions are removed in a successive two steps followed immediately by decomposition of the ligand in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the TG curves applying Coats-Redfern method.

Vibrational spectroscopic studies and ab initio calculations of sulfanilamide

FT-Raman and FT-IR spectra of sulfanilamide were recorded and analyzed. The vibrational frequencies of the compound have been computed using the Hartree-Fock/6-21G(*) basis and compared with the experimental values. The assignments of the observed bands were made on the basis of available literature.

Nanomolar cationic dendrimeric sulfadiazine as potential antitoxoplasmic agent

The high doses of sulfadiazine (SDZ), used in synergistic combination with pyrimethamine, are mainly responsible for severe side effects and discontinuation of toxoplasmosis treatments. In the search for new strategies that improve the efficacy of treatments with reduced doses of SDZ, we have determined the performance of cationic G4 (DG4) and anionic G4.5 (DG4.5) poly(amidoamine) (PAMAM) dendrimers to act as SDZ nanocarriers. Both dendrimers could efficiently load SDZ (SDZ-DG4 and SDZ-DG4.5) up to a ratio of 30 molecules SDZ per dendrimer molecule. The MTT assay on Vero and J774 cells showed no cytotoxicity for DG4.5 and its SDZ complex incubated between 0.03 and 33 microM of dendrimer concentration. On the other hand, DG4 and its SDZ complex resulted cytotoxic when incubated at dendrimer concentrations higher than 3.3 microM. Finally, complexes and empty dendrimers were in vitro tested against Vero cells infected with RH strain of Toxoplasma gondii along 4h of treatment. For SDZ-DG4.5 and DG4.5 to cause an infection decrease between 25 and 40%, respectively, a dendrimer concentration of 33 microM was required; however, SDZ-DG4 produced the highest infection decrease of 60% at 0.03 microM. These preliminary results, achieved with nanomolar doses of SDZ-DG4 as unique active principle, point to this complex as a suitable potential candidate for antitoxoplasmic therapy.

Application of nuclear magnetic resonance spectroscopy for quantitative analysis of miconazole, metronidazole and sulfamethoxazole in pharmaceutical and urine samples

Specific, accurate and precise NMR methods were developed for determining miconazole, metronidazole and sulfamethoxazole antibiotic drugs in authentic, pharmaceutical and urine samples. Proton nuclear magnetic resonance spectroscopy (1H NMR) with maleic acid as an internal standard and DMSO-d6 as NMR solvent were used. 1H NMR signals at 9.0, 8.06, 7.50 and 6.26 ppm corresponding to miconazole, metronidazole, sulfamethoxazole and maleic acid were respectively used for calculating the concentrations of drugs per unit dose. Average percent recoveries of (97.54-101.10), (98.06-100.46) and (97.83-102.83) with average uncertainties of 1.02, 0.45 and 0.86 were respectively obtained for determining authentic samples of miconazole, metronidazole and sulfamethoxazole in the concentration range of 0.92-170 mg/0.6 ml DMSO-d6. In pharmaceutical formulations and urine samples, average percent recoveries in the ranges of 97.50-101.33 and 94.46-100.86 were respectively obtained. Relative standard deviations (R.S.D.)<or=2.68 were obtained for analyzing the three drugs in authentic, pharmaceutical and urine samples. Admixtures of the three drugs in authentic, pharmaceutical and urine samples were analyzed. Good precisions (0.79-2.99%) and recoveries (93.40-104.97%) were obtained indicating the high selectivity and resolving power of the developed NMR methods and no needs for separation steps. Applying statistical Student t-test revealed insignificant difference between the real and measured contents at the 95% confidence level. F-test revealed insignificant difference in precisions between the developed NMR methods and HPLC methods reported for analyzing miconazole, metronidazole and sulfamethoxazole.

Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (Mössbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.