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A new complex of Bi(III) and sulfapyridine was synthesized and characterized by elemental analysis, atomic absorption spectrometry, conductivity analysis, electrospray ionization mass spectrometry (ESI-MS), infrared spectroscopy, and single crystal X-ray diffraction methods. The antimicrobial and the cytotoxic activities of the compound were investigated. Elemental and conductivity analyses are in accordance to the formulation [BiCl3(C11H11N3O2S)3]. The structure of the complex reveals a distorted octahedral geometry around the bismuth atom, which is bound to three sulfonamidic nitrogens from sulfapyridine, acting as a monodentate ligand, and to three chloride ions. The presence of the compound in solution was confirmed by ESI-MS studies. The complex is 3 times more potent than the ligand against Salmonella typhimurium, 4 times against Staphylococcus aureus, Shigella dysenteriae, and Shigella sonnei and 8 times more potent against Pseudomonas aeruginosa and Escherichia coli. The compound inhibits the growth of chronic myelogenous leukemia cells with an IC50 value of 44 μM whereas the free ligand has no effect up to 100 μM. [ABSTRACT FROM AUTHOR]

Two novel trivalent antimony(III) and bismuth(III) complexes with the nitrogen-donor heterocyclic ligand dipyrido[3,2-a:2',3'-c]phenazine (dppz) were synthesized and characterized as [Sb(dppz)Cl3].H2O.CH3OH and [Bi(dppz)Cl3]. The crystal structure of Sb(III) complex was determined by X-ray crystallography. These complexes were evaluated for their activity against the promastigote form of Sb(III)-sensitive and -resistant Leishmania infantum chagasi and Leishmania amazonensis strains. Both complexes were more effective than dppz alone in inhibiting the growth of Leishmania promastigotes and were at least 77 and 2,400 times more active than potassium antimonyl tartrate in Sb(III)-sensitive and -resistant Leishmania, respectively. The cytotoxicity of dppz and its complexes against mouse peritoneal macrophages occurred at dppz concentrations at least 6-fold greater than those found to be active against Leishmania promastigotes.To investigate the role of the metal in the improved antileishmanial activity of dppz, the activity of the Sb(III) complex was compared between the Sb-resistant mutants and their respective parental sensitive strains. The lack of cross-resistance to the Sb(III)-dppz complex together with the much lower activity of antimonyl tartrate, SbCl3 and BiCl3 strongly support the model that the metal is not active by itself but improves the activity of dppz through complexation [ABSTRACT FROM AUTHOR]

The cation distribution in a natural magnesium aluminium chromite spinel (cubic, space group Fd&3macr;m), Al0.41Cr1.42Fe0.65-Mg0.4O4, was determined by electron-microprobe analysis, Mössbauer spectroscopy and single-crystal X-ray analysis. Several structural models of the octahedral and tetrahedral cation, distributions were tested; the most probable is (Mg0.40(11)2+,Al0.28(5)3+,Fe0.39(4)2+)[Al0.13(5)3+,Cr1.42(6)3+,Fe0.26(4)3+,Φ0.19]O42-, where (…) and […] represent the tetrahedral and octahedral sites, respectively, and Φ represents a vacancy. [ABSTRACT FROM AUTHOR]

Abstract: Cobalt and zinc salts of 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), [C6H2(COO)4H4], have been synthesized and investigate by polarized Raman spectroscopy. These compounds present short intramolecular hydrogen bonds (SHB) between adjacent carboxyl groups. Raman spectra indicate the presence of this interaction in both salts. Three specific vibrational of SHB modes have been investigated: O–H–O symmetric [ν sym(OHO)] and asymmetric [ν asym(OHO)] stretching modes and O–H stretching mode [ν(O–H)], which they were observed around 300, 850 and 2500cm−1, respectively. In crystallographic point of view, the cobalt salt presents a symmetric SHB while the zinc salt presents an asymmetric SHB. In cobalt salt all three vibrational modes of O–H–O groups in polarized Raman spectra occur in Ag orientation although in zinc salts two of them are observed in Ag orientation and one in Bg. Spectra analysis indicate that ν sym(OHO) mode is observed as Ag to cobalt salt and Bg to zinc salt. This mode occurs in a crowed spectral region and its identification was made by deconvolution techniques. Comparing spectra of the two salts, it is observed a small difference in relative intensity and wavenumber shift of ν sym(OHO) (deviance of 43cm−1) and ν(OH) (deviance of 21cm−1) modes due probably to differences in O⋯O distance between salts and in orientation of pyromellitate anion in unit cell. The ν asym(OHO) mode does not present significant wavenumber shift due difference in SHB. The ν(OH) band presents a great potential for hydrogen bond studies due to the fact that in its vibrational region (around 2500cm−1) it is not observed other vibrational modes of these compounds. [Copyright &y& Elsevier]

The chemical composition, [Mg0.015 (2),Al1.20 (2),Si2.99 (1),Ca3.00 (2),Ti0.027 (3),Mn0.017 (3), Fe0.75 (3)]O12 (magnesium alumin­ium silicon calcium titanium manganese iron dodeca­oxide), of a natural garnet collected at Diamantina, Minas Gerais, Brazil was determined by electron microprobe analysis. The structure refinement from X-ray powder data is insensitive to the small amounts of Ti, Mn and Mg. The determined cation distribution using the Rietveld method is {Ca32+}[Al1.338 (8)3+,Fe0.662 (8)3+](Si34+)O122−, which is in agreement with a solid solution of the grossular-andradite series. The arrangement of the cations around the O atom is best described as a highly distorted tetrahedral. [ABSTRACT FROM AUTHOR]

Abstract: Five salts of 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), [C6H2(COO)4H4], have been synthesized and investigated by infrared and Raman spectroscopy and by single crystal X-ray diffraction methods: sodium salt [Na2(H2O)2][C6H2(COO)4H2], potassium salt [K(H2O)3][C6H2(COO)4H3] and transition metal salts [M(H2O)6][C6H2(COO)4H2], which M = Mn, Ni and Zn. Crystal structures of all five compounds show short intramolecular asymmetric hydrogen bonds (SHB) between adjacent carboxyl groups with O···O distance average of 2.40Å. The Raman and infrared spectra reported indicate the presence of short hydrogen bonds in all salts, in agreement with the X-ray data. The O–H stretching mode [ν(Oeen observed at about 2500cm−1. Deuterated analogues were synthesized and their Raman spectra show that ν OH/ν OD ratio average is about unit. The symmetric [ν sym(O··H··O)] and asymmetric [ν asym(O··H··O)] stretching modes have been attributed about 300 and 870cm−1, respectively, in all salts, and for deuterated analogues, the ratio ν OH/ν OD to ν sym(O··H··O, O··D··O) is close to unit like it occurs in ν(Oibrational modes, mainly SHB modes, are tentatively assigned by molecular orbital ab initio calculations of pyromellitic acid and anions [C6H2(COO)4H3]− and [C6H2(COO)4H2]2−. Geometry optimizations showed a good agreement with experimental data. Frequency calculation confirms the assignment of specific vibrational modes. Ab initio calculations show that ν(C=O) and ν sym(COO) are strongly coupled with in plane OH bending [δ(OH)]. In Raman spectra of deuterated analogues is observed a frequency shift of these bands. [Copyright &y& Elsevier]

The title compound, C32H48O5, isolated from the leaves of Miconia macrothyrsa, is a penta­cyclic triterpene, in which rings A, B, D and E take a chair conformation, while ring C has a half-chair conformation. Rings A and B and rings B and C are trans-fused, while rings D and E are cis-fused. In the crystal structure, there are inter­molecular O—H⋯O hydrogen bonds and intra­molecular C—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

A natural sample of perovskite (calcium caesium sodium iron titanium oxide) from the Tapira Alkaline Complex in southeastern Brazil was found by electron microprobe analysis to have the chemical formula (Ca(2+) (0.95 (1))Ce(3+) (0.011 (2))Na(+) (0.010 (4)))(Fe(3+) (0.022 (2))Ti(4+) (0.98 (1)))O(2-) (3) and by IR spectroscopy to be an anhydrous mineral. Oxygen anions are arranged around Ti(4+) in an almost perfect octa-hedron and around Ca(2+) in a distorted 12-fold polyhedron.