Complexes ofN Research Articles

Variable disruption of epithelial monolayers by Neisseria meningitidis carriage isolates of the hypervirulent MenW cc11 and MenY cc23 lineages.

Colonization of mucosal tissues by Neisseria meningitidis requires adhesion mediated by the type IV pilus and multiple outer-membrane proteins. Penetration of the mucosa and invasion of epithelial cells are thought to contribute to host persistence and invasive disease. Using Calu-3 cell monolayers grown at an air-liquid interface, we examined adhesion, invasion and monolayer disruption by carriage isolates of two clonal complexes of N. meningitidis. Carriage isolates of both the serogroup Y cc23 and the hypervirulent serogroup W cc11 lineages exhibited high levels of cellular adhesion, and a variable disruption phenotype across independent isolates. Inactivation of the gene encoding the main pilus sub-unit in multiple cc11 isolates abrogated both adhesive capacity and ability to disrupt epithelial monolayers. Contrastingly, inactivation of the phase-variable opa or nadA genes reduced adhesion and invasion, but not disruption of monolayer integrity. Adherence of tissue-disruptive meningococci correlated with loss of staining for the tight junction protein, occludin. Intriguingly, in a pilus-negative strain background, we observed compensatory ON switching of opa genes, which facilitated continued adhesion. We conclude that disruption of epithelial monolayers occurs in multiple meningococcal lineages but can vary during carriage and is intimately linked to pilus-mediated adhesion.

A ruthenium(iii) complex derived from N,N′-bis(salicylidene)ethylenediamine as a chemosensor for the selective recognition of acetate and its interaction with cells for bio-imaging: experimental and theoretical studies

A ruthenium(iii) complex ofN,N′-bis(salicylidene)ethylenediamine (L1) was used as chemosensor for the recognition of acetate in cells for bio-imaging.

Synthesis, structural characterization and cytotoxic activity of diorganotin(IV) complexes ofN-(5-halosalicylidene)-α-amino acid

Four new diorganotin(IV) complexes of N-(5-halosalicylidene)tryptophane, R2Sn[5-X-2-OC6H3CHNCH(CH2Ind)COO] [Ind = 3-indolyl; R, X = Et, Cl (1); Et, Br(2); n-Bu, Cl (3); n-Bu, Br (4)], were synthesized and characterized by elemental analysis, IR and NMR (1H, 13C and 119Sn) spectra. The crystal structures of complexes 1–3 were determined by X-ray single crystal diffraction and showed that the tin atoms are in a distorted trigonal bipyramidal geometry and form five- and six-membered chelate rings with the tridentate ligand. Intermolecular weak interactions in 1–3 link molecules, respectively, into a two-dimensional array, a one-dimensional infinite chain and a one-dimensional double-chain supramolecular structure. Bioassay results of the compounds indicated that the dibutyltin complexes 3 and 4 have potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complexes 1 and 2 display weak cytotoxic activity. Copyright © 2008 John Wiley & Sons, Ltd.

Synthesis and crystal structure of N,N′‐dimethyldithio‐arbamato‐copper(I) polymer {[Cu(Me2dtc)]2}n

AbstractReactions of CuSCN with tetramethylthiuram disulfide in CH3CN in the presence of styrene and N,N,N′,N″,N″‐pentamethyldiethylenetriamine gave rise to a new copper(I) complex ofN,N′‐dimethyldithiocabamate ([CU(S2CNMe2)]2)n. The title compound crystallized in the triclinic P‐1 space group with lattice parameters a=0.7610(4) nm, b=0.8911(4) nm, c=0.9268(5) nm, α=68.66(1)°, β=83.88(2)°, γ=79.31(2)°, V=0.5748(5) nm3, Z=2. The compound has a unique 1D chain structure composed of CuSCSCuSCS eight‐membered rings and a pair of CUS bonds, the structure of which has been determined by singlecrystal X‐ray crystallography. The isolation of this compound may provide some helpful information for the cause of the induction periods of the reverse atom transfer radical polymerization.

Synthesis and structures of complexes ofN-(2-aminoethyl)diaziridines with transition metal salts

A series of complexes ofN-(2-aminoethyl)diaziridines with transition metal salts (Zn2+, Cd2+, Ni2+, Co2+, Mn2+, or Fe2+) were synthesized. Their structures were established by IR and NMR spectroscopy. The structure of bis[1,2-bis(2-aminoethyl)diaziridine]cadmium(II) diperehlorate was confirmed by X-ray diffraction analysis.

Technetium-99m complex of N-(2-pyridylmethyl)iminodiacetic acid as a new renal radiopharmaceutical.

A tetradentate chelating agent constituting of an iminodiacetic acid group and a nitrogen atom of pyridine, N-(2-pyridylmethyl)iminodiacetic acid (PMIDA), was coordinated with 99mTc and evaluated as a renal functional agent. The complex of PMIDA with 99mTc was prepared by using a stannous chloride solution as a reducing agent. The chelating efficiency was analyzed by thin layer chromatography and electrophoresis. Chelation with 99mTc resulted in a single radiochemical product. Biological studies were performed in mice and rats. 99mTc-PMIDA was removed from the circulation solely by the kidneys. Clearance of 99mTc-PMIDA from the blood and the kidneys was as rapid as that of 99mTc-diethylenetriaminepentaacetic acid. The rate of blood clearance was unaffected by the administration of probenecid (a test for tubular secretion by the weak-acid mechanism), so that the glomerular filtration rate could be estimated by measuring its clearance from the blood. The results in animals with myohemoglobinuric acute renal failure suggested that 99mTc-PMIDA might be a useful renal function radiopharmaceutical.

Synthesis and characterization of diorganotin(IV) complexes ofN-(2-pyridylmethylene)arylamines and mutagenicity testingin vivo of Et2SnCl2�[L4=N-(2-pyridylmethylene)-4-toluidine

Diorganotin(IV) dichloride complexes of the type R2SnCl2·L (R = methyl, ethyl, vinyl, t-butyl, n-butyl or phenyl; L = N-(2-pyridylmethylene)arylamine) have been synthesized and characterized on the basis of IR, NMR and 119Sn Mössbauer studies. Investigation of the complexes indicated that N-(2-pyridylmethylene)arylamines form distorted trans-octahedral complexes with R2SnCl2 similar to the well-known R2SnCl2·L. Cytogenetic toxicology testing has been performed for Et2SnCl2·L4 [L4 = N-(2-pyridylmethylene)-4-toluidine] in mouse bone-marrow cells in vivo since such testing is a regulatory requirement before new drugs are released. This tin compound induced delay in cell-cycle kinetics and sister chromatid exchanges (SCEs) significantly. The effect of Et2SnCl2·L4 was greater when endogenous glutathione (GSH) was depleted by buthionine sulphoximine (BSO). It seems that Et2SnCl2·L4 induces SCEs due to formation of adduct by binding on DNA which could interfere in DNA synthesis and cause delay in cell proliferation. Depletion of GSH could reduce the shielding effect of GSH on chromatin and allows more Et2SnCl2·L4 to bind on DNA. © 1998 John Wiley & Sons, Ltd.

Carbon dioxide activation: synthesis and characterization of a cadmium(ii) dinuclear complex with a novel μ-carbonato bridge

The cadmium(II) complex of N′-isopropyl-2-methylpropane-1,2-diamine (npda), [Cd(npda) 3 ][ClO 4 ] 2 1 in aqueous methanol absorbs CO 2 from air to form a cadmium(II) dinuclear complex, [Cd(npda) 4 (CO 3 )(H 2 O)][ClO 4 ] 2 ·H 2 O 2, the first ever example of a µ-carbonato cadmium(II) diamine complex which is characterized by elemental analysis, IR and crystal structure determination.

Cobalt(II) and copper(II) complexes ofN,N?,N?,N?-tetra(2-cyanoethyl)-1,4,8,11-tetraazacyclotetradecane

Cobalt(II) and copper(II) complexes of the title ligand, TCEC, as well as a cobalt(II) complex ofN,N′,N",N'''-tetra (1-methyl-2-cyanoethyl)-1,4,8,11-tetraazacyclotetradecane, TMCEC, have been isolated and spectrally characterized.

Synthesis and characterisation of cobalt(II), cobalt(III) and rhodium(III) complexes ofN, N?, N?, N?-tetra(2-cyanoethyl) cyclam [TCEC] andN, N?, N?, N?-tetra)3-aminopropyl) cyclam [TAPC

Complexes of cobalt(II), cobalt(III) and rhodium(III) with TCEC and TAPC have been synthesised. TCEC with cobalt(II) gave [Co(TCEC)Br]Br and [Co(TCEC)Cl]Cl, five coordinate high spin square pyramid complexes, but the corresponding cobalt(III) complex could not be characterised. Rhodium(III) gave a six coordinate [Rh(TCEC)Cl2]Cl complex, in which the two coordinated chlorides have acis-geometry and the four pendant arms lie on one side of the N4 plane with none of the —C≡N groups coordinated TAPC on the other hand gives the cobalt(III) complex, [Co(TAPC)Br]Br2, in which one of the amino groups of the four pendant arms is coordinated to cobalt. Rhodium(III) with TAPC gave [Rh(TAPC)Cl]Cl2 in which one axial site is occupied by the amino group of one of the pendant arms and the other by Cl−.

Crystal structures of the nickel(II) and copper(II) complexes ofN,N?-bis(dehydroaceto)ethylenediimine

The nickel(II) and copper(II) complexes ofN,N′-bis(dehydroaceto) ethylenediimine are monomeric and hydrated. In both compounds, coordination occurs at the C(4) carbonyl of the dehydroacetic acid moiety. The Ni atom has square-planar geometry with a water molecule at a substantial distance away. Both structurally distinct Cu atoms have square-pyramidal geometry, the apical position of one being occupied by an oxygen atom of the C(2) carbonyl group in a neighbouring molecule, and that of the other by a water molecule which participates in hydrogen-bond formation.

Synthesis and spectroscopic properties of some thermochromic copper(II) complexes ofN(2-aminoethyl) heterocyclic derivatives

Compounds of the type CuL2X2, where L =N(2-aminoethyl)piperazine [N(2-amet)pipz],N(2-aminoethyl)-pyrrolidine [N(2-amet)pyrr] andN(2-aminoethyl)morpholine [N(2-amet)morph] and X = BF 4 − , ClO 4 − and NO 3 − , have been prepared and characterized by means of magnetic moments, e.s.r., electronic and i.r. spectra. Only forN(2-amet)pyrr and Cu[N(2-amet)morph]2(NO3)2 complexes, do the electronic and i.r. spectra suggest polyanion coordination. In particular, as their electronic and i.r. spectra in the 293–393K range are temperature-dependent, it may be ascribed to the presence of a reversible continuous thermochromism arising from a temperature-dependent axial interaction between the anion and the CuN4 plane, which diminishes as the temperature increases. In all the other complexes, the thermochromism may be associated with a geometry which is more planar forN(2-amet)morph than forN(2-amet)pipz derivatives.