Rosica P. Nikolova

Crystal structure and properties of the copper(II) complex of sodium monensin A

The preparation and structural characterization of a new copper(II) complex of the polyether ionophorous antibiotic sodium monensin A (MonNa) are described. Sodium monensin A binds Cu(II) to produce a heterometallic complex of composition [Cu(MonNa)(2)Cl(2)].H(2)O, 1. The crystallographic data of 1 show that the complex crystallizes in monoclinic space group C2 with Cu(II) ion adopting a distorted square-planar geometry. Copper(II) coordinates two anionic sodium monensin ligands and two chloride anions producing a neutral compound. The sodium ion remains in the inner cavity of the ligand retaining its sixfold coordination with oxygen atoms. Replacement of crystallization water by acetonitrile is observed in the crystal structure of the complex 1. Copper(I) salt of the methyl ester of MonNa, 2, was identified by X-ray crystallography as a side product of the reaction of MonNa with Cu(II). Compound 2, [Me-MonNa][H-MonNa][CuCl(2)]Cl, crystallizes in monoclinic space group C2 with the same coordination pattern of the sodium cation but contains a chlorocuprate(I) counter [CuCl(2)](-), which is linear and not coordinated by sodium monensin A. The antibacterial and antioxidant properties as two independent activities of 1 were studied. Compound 1 is effective against aerobic Gram(+)-microorganisms Bacillus subtilis, Bacillus mycoides and Sarcina lutea. Complex 1 shows SOD-like activity comparable with that of the copper(II) ion.

Growth, composition and dielectric properties of Pb3Ni1.5Mn5.5O15 single crystal

Single crystals of Pb3Ni1.5Mn5.5O15 were successfully grown by the high temperature solution growth method. Their composition was determined by energy dispersive X-ray analysis. The phase homogeneity of the grown crystals was examined and confirmed by powder X-ray phase analysis. The structure was characterized by X-ray single crystal diffractometry and was indexed in the trigonal space group P-3c1 (No. 165) with lattice parameters a = 9.9142(2) A and c = 13.4923(18) A. The dielectric properties of Pb3Ni1.4Mn5.6O15 were investigated in the temperature range 150 – 500 K. The AC -measurements were carried out for 3 different frequencies: 10 kHz, 100 kHz and 1 MHz. From the DC measurements thermal activation energy was estimated.

Synthesis of ferrocenylmethylidene and arylidene substituted camphane based compounds as potential anticancer agents

Herein is described the synthesis of (+)-camphor derivatives containing sulfonamide groups, ferrocenylmethylidene or arylidene moieties. The obtained derivatives were tested against seven human cancer cells lines, namely BV-173, K-256a, NB-4, A549, H1299, MCF-7, and MDA-MB231, and two normal human cell lines, HEK293 and HUVEC, in order to determine their activity against malignant cells. Some of them exhibit IC50 values below 10 μM in at least one of the cancer cell lines. Ferrocenylmethylidene ketone 16 can be outlined as the most potent and selective in the current study (IC50 for cancer cells – up to 4.0 μM; IC50 for HEK293 and HUVEC – 68 and 69 μM, respectively). There is a clear trend showing that the presence of a conjugated ferrocenylmethylidene group is essential for the cytotoxicity, however different sulfonamide substituents and derivatization of the carbonyl group can modify the activity. Thus, this class of compounds could have good prospects for further structural optimisation.

Synthesis and anti-enterovirus activity of new analogues of MDL-860

A series of twelve novel compounds, analogues of antiviral agent MDL-860 were synthesized and their antiviral activity was evaluated in vitro against enteroviruses poliovirus 1 (PV1), Coxsackieviruses B1 (CVB1) and Coxsackieviruses B3 (CVB3). Compounds 14, 24 and 25 manifested strong antiviral effects against CVB1 and PV1 (SI values of 405 and 118 for CVB1 and PV1 respectively). In contrast to the wide anti-enteroviral activity of MDL-860, these three compounds were inactive against CVB3. Compounds 14, 24 and 25 along with MDL-860 were tested in vivo in mice infected with CVB1. Marked protective effects of compounds 14 and 24 were established, PI values of 50% and 33.3%, respectively. In addition, almost all of the tested compounds manifested very low toxicity.

Synthesis and structural transformations of the “glaserite” type zirconosilicate Na{sub 3−x}H{sub 1+x}ZrSi{sub 2}O{sub 8}·yH{sub 2}O

Abstract A hydrous sodium zirconosilicate material with “glaserite” type structure and generalized formula Na3−xH1+xZrSi2O8·yH2O, 0

(R)-Methyl {[(2-carb-oxy-bicyclo-[2.2.2]octan-1-yl)-ammonio]-methyl}-phos-phon-ate dichloro-methane 0.25-solvate.

The carboxylic acid molecule of the title compound, C11H20NO5P·0.25CH2Cl2, exists as a zwitterion with the H atom of the phosphonate group being transferred to the imine N atom. In the asymmetric unit, there are two crystallographically independent acid molecules adopting the same absolute configuration and differing slightly in their geometrical parameters. In each molecule, the imino and carboxyl groups are connected via an intramolecular N—H⋯O hydrogen bond. Intermolecular O—H⋯O and N—H⋯O hydrogen bonds induce the formation of layers parallel to the ab plane. The dichloromethane solvent molecule, with a site occupancy of 0.5, is located between the layers.

A new monoclinic polymorph of dichlorido-tetra-kis(dimethyl sulfoxide)-ruthenium(II).

The title compound, cis,fac-dichloridotetrakis(dimethyl sulfoxide)-κ3 S,κO-ruthenium(II), [RuCl2(C2H6OS)4], was obtained from newly synthesized ruthenium complexes of 3-amino-2-chloropyridine. The Ru atom has a distorted octahedral coordination with two cis-oriented chloride ligands and four dimethyl sulfoxide ligands. Three of the sulfoxide ligands are S-bonded in a fac configuration, while the fourth is O-bonded. The title compound represents a new, and fourth, polymorph of the complex. Two other monoclinic forms and an orthorhombic modification have been reported previously.

(±)-Ethyl 6,7-dimeth-oxy-1-(1H-pyrrol-2-yl)-1,2,3,4-tetra-hydroisoquinoline-2-car-boxyl-ate.

In the title compound, C18H22N2O4, the dihedral angle between the pyrrolyl and quinolinyl fragments is 68.97 (2)°. Two non-classical intramolecular C—H⋯O hydrogen bonds stabilize the molecular geometry. In the crystal structure, molecules form infinite chains via moderate intermolecular N—H⋯O(CH3) hydrogen bonds.