Novel Pentacyano Complexes of Tri- and Tetravalent Platinum.

New pentacyano complexes of tri- and tetravalent platinum were obtained in aqueous solution and characterized by multinuclear NMR ((195)Pt, (13)C) supported by Raman spectroscopy. The complexes form as products of redox decomposition of metal-metal bonded platinum-thallium compounds. The trimetallic [(NC)(5)Pt-Tl-Pt(CN)(5)](3)(-) yields a new dimeric compound of Pt(III), [(NC)(5)Pt-Pt(CN)(5)](4)(-).

The Early Phase of the Iron(III)-Sulfite Ion Reaction. Formation of a Novel Iron(III)-Sulfito Complex.

The kinetics and mechanism of the iron(III)-sulfite ion reaction were studied by using the stopped-flow method at 10.0 degrees C in 1.0 M NaClO(4).

Synthesis, Potentiometry, and NMR Studies of Two New 1,7-Disubstituted Tetraazacyclododecanes and Their Complexes Formed with Lanthanide, Alkaline Earth Metal, Mn(2+), and Zn(2+) Ions.

Two new 1,7-disubstituted-1,4,7,10-tetraazacyclododecane ligands, DO2P and DO2PME, and their complexes with Mg(2+), Ca(2+), Sr(2+), Mn(2+), Zn(2+) and Ln(3+) were prepared and characterized by pH potentiometry. The pH titration data showed that DO2P and DO2PME both form 1:1 M:L complexes with all divalent and trivalent metal ions. Protonated complexes did not appear to form with the bis(phosphonate ester) ligand, DO2PME, but were evident for all of the metal ion-DO2P complexes.

Equilibrium Dynamics in the Thallium(III)-Cyanide System in Aqueous Solution.

Ligand exchange reactions of thallium(III) cyano complexes, Tl(CN)(n)()(3)(-)(n)(), have been systematically studied in aqueous solution containing 4 M ionic medium {[ClO(4)(-)](tot) = 4 M, [Na(+)](tot) = 1 M, [Li(+)](tot) + [H(+)](tot) = 3 M}, at 25 degrees C, using (205)Tl and (13)C NMR one-dimensional inversion transfer techniques. Rate constants for all dominating exchange pathways were determined and compared to the previously studied thallium(III) halide complexes. Also in the case of cyanide ligands the ligand exchange is dominated by the rare type of reactions occurring via a direct encounter of two complexes (self-exchange reactions), e.

Reactions of morphine derivatives with phenyliodo(III)diacetate (PIDA): synthesis of new morphine analogues.

The reactions of morphine and its derivatives with phenyliodo(III)diacetate (PIDA) have been studied. This methodology has not been introduced to morphine alkaloids, despite the fact that such a strategy would ensure dearomatization of the electrophilic aromatic ring of morphine derivatives leading to nucleophilic ortho-quinoidal structures with potential pharmacological interest. The products, formed in regio- and diastereoselective or diastereospecific reactions, carry mixed-acetal or 1,3-dioxolane moieties.

19F NMR study of the equilibria and dynamics of the Al3+/F- system.

A careful reinvestigation by high-field 19F NMR (470 MHz) spectroscopy has been made of the Al3+/F- system in aqueous solution under carefully controlled conditions of pH, concentration, ionic strength (I), and temperature. The 19F NMR spectra show five distinct signals at 278 K and I = 0.6 M (TMACl) which have been attributed to the complexes AlFi(3-i)+(aq) with i < or = 5.

Simple synthesis of benzofuranoid neolignans from Myristica fragrans.

The total synthesis of four neolignans-fragnasols A (1), B (2), and C (3) and dehydrodiisoeugenol (4)-starting from the readily available phenol derivative isoeugenol (5) was accomplished. The key step of the synthesis of these natural products is a novel type of dimerization of 5 into 4 with iodobenzene diacetate.

Some factors affecting metal ion-monohydroxamate interactions in aqueous solution.

The chelating properties exhibited by a series of monohydroxamic acids (propanohydroxamic acid (Pha), hexanohydroxamic acid (Hha), benzohydroxamic acid (Bha), N-methyl-acetohydroxamic acid (MAha), N-phenyl-acetohydroxamic acid (PhAha) and 2-hydroxypyridine-N-oxide (PYRha)) towards copper(II), nickel(II), zinc(II), calcium(II), magnesium(II) and aluminium(III) ions were studied by pH-metric, spectrophotometric and, in one case, by 27Al NMR methods. The results were compared with the corresponding data for metal ion-acetohydroxamate (Aha) and metal ion-desferrioxamine B (DFB) complexes. Changes of the substituents either on the carbon or on the nitrogen of the hydroxamate moiety caused a measurable effect on the chelate stability only in the case of aluminium(III) complexes.

Thermodynamic, kinetic and structural studies on the ternary palladium(II) complexes of thioether ligands.

Potentiometric, calorimetric, NMR and stopped-flow kinetic studies were performed on the palladium(II) complexes of thioether and/or nitrogen donor ligands. The ternary systems always contained a tridentate ligand (dien, terpy and dianions of dipeptides, GlyGly, GlyAla and GlyMet) and a monodentate thioether (AcMet). The stability constants of thioether complexes were obtained by indirect potentiometric measurements using uridine as a competitive ligand.

The rates of the exchange reactions between [Gd(DTPA)]2- and the endogenous ions Cu2+ and Zn2+: a kinetic model for the prediction of the in vivo stability of [Gd(DTPA)]2-, used as a contrast agent in magnetic resonance imaging.

The kinetic stability of the complex [Gd(DTPA)]2- (H5DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid), used as a contrast-enhancing agent in magnetic resonance imaging (MRI), is characterised by the rates of the exchange reactions that take place with the endogenous ions Cu2+ and Zn2+. The reactions predominantly occur through the direct attack of Cu2+ and Zn2+ on the complex (rate constants are 0.93+/-0.

Synthesis of the repeating unit of the O-specific polysaccharide of Shigella sonnei and quantitation of its serologic activity.

The chemical synthesis of the zwitterionic disaccharide 2 is described that corresponds to the repeating unit of the O-specific polysaccharide (1) of the gram-negative human pathogen Shigella sonnei. Passive hemolysis inhibition tests using a hyperimmune rabbit serum raised against S. sonnei showed that the serologic activity of the disaccharide 2 is nearly 2- to 3-fold higher than those of its component monosaccharides.

Antiulcer effect of the N- and O-beta-D-glucopyranosides of 5-aminosalicylic acid.

Starting from methyl 5-nitrosalicylate (20) the N- and O-beta-glucopyranosyl derivatives (24, 28) of 5-aminosalicylic acid were prepared. The LD50 values of these compounds were determined on mice, and the inhibitory effect of 24 (0.83 mmol/kg) and 28 (1.

Hyers-Ulam stability of monomial functional equations on a general domain.

In the present paper the Hyers-Ulam stability of monomial functional equations for functions defined on a power-associative, power-symmetric groupoid is proved.

Application of the fundamental parameter method to the in vivo x-ray fluorescence analysis of Pt.

The application of the fundamental parameter method (FPM) to the in vivo x-ray fluorescence (XRF) analysis of Pt has been investigated. The FPM is conventionally used to carry out elemental analysis of samples in vitro without the need to use standard samples of accurately known composition for system calibration. The present work has involved the use of the FPM to calculate the concentration of Pt solutions in phantoms, with concentrations ranging from 25-1000 ppm.

Efficient inhibition of muscle and liver glycogen phosphorylases by a new glucopyranosylidene-spiro-thiohydantoin.

Reaction of C-(1-bromo-1-deoxy-beta-glucopyranosyl)formamide 2 with thiocyanate ions was the key step of a short synthesis of D-glucopyanosylidene-spiro-thiohydantoin 7 which proved to be a potent inhibitor of muscle and liver glycogen phosphorylases.

Effect of the different factors on the iontophoretic delivery of calcium ions from bentonite.

The calcium content of mud patches used for therapy is very small. Several mineral clays originating from Hungary served as a base material for experiments in order to find a suitable drug for transdermal introduction of calcium ions into the body. The Ca++ transport through the pig skin has been investigated in vitro in diffusion cells applying iontophoresis.

Hyers-ulam stability of functional equations with a square-symmetric operation.

The stability of the functional equation f(x composite function y) = H(f(x), f(y)) (x, y in S) is investigated, where H is a homogeneous function and composite function is a square-symmetric operation on the set S. The results presented include and generalize the classical theorem of Hyers obtained in 1941 on the stability of the Cauchy functional equation.

NADPH-diaphorase activity in the nervous system of the embryonic and juvenile pond snail, Lymnaea stagnalis.

Nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry has been applied in the present study to determine the distribution of putative nitric oxide (nitric oxide synthase)-producing cells during embryonic and early postembryonic development in the pond snail, Lymnaea stagnalis L., with special reference to the nervous system. The first NADPH-d-positive structures appear as early as 18% of development (E18, trochophore stage) and correspond to the pair of protonephridia.

Solution pH: A Selectivity Switch in Aqueous Organometallic Catalysis-Hydrogenation of Unsaturated Aldehydes Catalyzed by Sulfonatophenylphosphane-Ru Complexes.

The equilibribrium distribution of water-soluble ruthenium hydrides [HRuCl(tppms) ] and [H Ru(tppms) ] (tppms = (3-sulfonatophenyl)diphenylphosphane) in the reaction with H is governed by the pH value. As a consequence, the selectivity in the hydrogenation of cinnamaldehyde for reaction at C=C or C=O can be completely inverted by changing the pH value (see drawing below).

The determination of benzalkonium chloride in eye-drops by difference spectrophotometry.

A direct, extraction-free spectrophotometric method was developed for the determination of benzalkonium chloride (BAC) in various eye-drops. The procedure is based on ion-pair formation between BAC and 2',4',5',7'-tetrabromofluorescein (eosin-Y) which decreases the absorbance and induces a bathochromic shift of the maximum in the eosin-Y spectrum. The effects of pH, excess of reagent and ionic strength on the ion-pair formation have been studied in detail.

Synthesis of chromogenic substrates of alpha-amylases on a cyclodextrin basis.

One-pot acetylation and subsequent partial acetolysis of alpha-, beta- and gamma-cyclodextrins resulted in crystalline peracetylated malto-hexaose, -heptaose, and -octaose, respectively. Prolonged acetolysis of beta-cyclodextrin gave a mixture of acetylated maltooligosaccharides, from which peracetylated malto-triose, -tetraose, and -pentaose were isolated. The acetylated oligosaccharides were converted into alpha-acetobromo derivatives, and then transformed into 4-nitrophenyl and 2-chloro-4-nitrophenyl beta-glycosides.