Electrospray Ionization Mass Spectrometry Fingerprinting Of Propolis.

Crude ethanolic extracts of propolis, a natural resin, have been directly analysed using electrospray ionization mass (ESI-MS) and tandem mass spectrometry (ESI-MS/MS) in the negative ion mode. European, North American and African samples have been analyzed, but emphasis has been given to Brazilian propolis which displays diverse and region-dependent chemical composition. ESI-MS provides characteristic fingerprint mass spectra, with propolis samples being divided into well-defined groups directly related to their geographical origins. Chemometric multivariate analysis statistically demonstrates the reliability of the ESI-MS fingerprinting method for propolis. On-line ESI-MS/MS tandem mass spectrometry of characteristic [M - H](-) ion markers provides an additional dimension of fingerprinting selectivity, while structurally characterizing the ESI-MS marker components of propolis. By comparison with standards, eight such markers have been identified: para-coumaric acid, 3-methoxy-4-hydroxycinnamaldehyde, 2,2-dimethyl-6-carboxyethenyl-2H-1-benzopyran, 3-prenyl-4-hydroxycinnamic acid, chrysin, pinocembrin, 3,5-diprenyl-4-hydroxycinnamic acid and dicaffeoylquinic acid. The negative mode ESI-MS fingerprinting method is capable of discerning distinct composition patterns to typify, to screen the sample origin and to reveal characteristic details of the more polar and acidic chemical components of propolis samples from different regions of the world.129739-4

Enzymatic inhibition studies of selected flavonoids and chemosystematic significance of polymethoxylated flavonoids and quinoline alkaloids in Neoraputia (Rutaceae)

Our taxonomic interest in the Neoraputia stimulated an investigation of N. paraensis searching for alkaloids. Fractions were monitored by ¹H NMR and ESI-MS/MS and only those which showed features of anthranilate alkaloids and flavonoids absent in the previous investigations were examined. Stems afforded the alkaloids flindersine, skimmianine, 8-methoxyflindersine and dictamnine; leaves yielded 3',4',7,8-tetramethoxy-5,6-(2,2-dimethylpyrano)-flavone, 3',4',5,7,8-pentamethoxyflavone, 5-hydroxy-3',4',6,7-tetramethoxyflavone, 3',4'-methylenedioxy-5,6,7-trimethoxyflavone and 5-hydroxy-3',4'-methylenedioxy-6,7-dimethoxyflavone. The alkaloids have remained undiscovered for 10 years. A number of flavonoids isolated from N. paraensis, N. magnifica, Murraya paniculata, Citrus sinensis graft (Rutaceae), Lonchocarpus montanus (Leguminosae) were evaluated for their ability to inhibit the enzymatic activity of the protein glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi. Highly oxygenated flavones and isoflavone were the most actives.Nosso interesse quimiotaxonômico sobre Neoraputia nos estimulou a examinar N. paraensis, visando a busca de alcalóides. As frações foram monitoradas via RMN ¹H e ESI-EM/EM e foram analisadas somente aquelas cujos espectros apresentavam características de alcalóides do ácido antranílico e flavonóides não isolados anteriormente. Foram isolados do caule os alcalóides flindersina, skimmianina, 8-metoxiflindersina e dictamnina; das folhas os flavonóides 3',4',7,8-tetrametoxi-5,6-(2,2-dimetilpirano)-flavona, 3',4',5,7,8-pentametoxiflavona, 5-hidroxi-3',4',6,7-tetrametoxiflavona, 3',4'-metilenodioxi-5,6,7-trimetoxiflavona e 5-hidroxi-3',4'-metilenodioxi-6,7-dimetoxiflavona,. Os alcalóides do ácido antranílico não foram encontrados em dez anos. Vários flavonóides isolados de N. paraensis, N. magnifica, Murraya paniculata, enxerto de Citrus sinensis (Rutaceae) e Lonchocarpus montanus (Leguminosae) foram testados frente a gliceraldeído-3-fosfato desidrogenase de Trypanosoma cruzi, visando verificar seus potenciais em inibir a atividade da enzima. Os flavonóides polimetoxilados e um isoflavonóide foram os mais ativos.380387Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Synthesis and characterization of the [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl](PF(6))(2) dimer

The polymetallic [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru( bpy)(2)Cl](PF(6))(2) complex (bpy = 2,2`-bipyridine, BPE = trans- 1,2-bis(4-pyridil) ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru(3)O] moiety with a [ Ru( bpy) 2( BPE) Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS) spectrometry. The [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl] (2+) doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)(2)(BPE)] charge-transfer bands and to the [Ru(3)O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at - 1.07 V, 0.13 V, 1.17 V, 2.91 V and - 1.29 V (vs SHE) assigned to the [Ru(3)O](-1/0/+ 1/+ 2/+3) and to the bpy (0/-1) redox processes; also a wave is observed at 0.96 V, assigned to the Ru (+2/+ 3) pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling through the pi-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation.Brazilian agenciesCouncil of National ResearchCNPq, Institute of Millennium of Complex MaterialsResearch Foundation of Sao Paulo State (FAPESP

Supramolecular conformational effects in the electrocatalytic properties of electrostatic assembled films of meso(3- and 4-pyridyl) isomers of tetraruthenated porphyrins

Meso(3- and 4-pyridyl)porphyrins coordinated to four [Ru(bipy)2Cl]+ complexes, M(3-TRPyP) or M(4-TRPyP), where M=2H+ and Zn2+, have been obtained and characterized by electrochemistry, spectroscopy and mass spectrometry. Layer-by-layer electrostatic assembled films with tetrasulfonated phthalocyaninatecuprate(II) anion, CuTSPc, displayed distinct electrocatalytic activity towards sulfite and nitrite oxidation. In general, the films derived from the M(4-TRPyP) isomers are more effective for the oxidation of nitrite, whereas those containing the M(3-TRPyP) isomers are more efficient for the oxidation of sulfite. The results demonstrated the influence of molecular geometry on the active sites of porphyrinic nanomaterials, enhancing the electron-transfer process in the M(3-TRPyP) derivative. This effect results from changes in the chemical environment around the active sites, induced by the contrasting molecular packing interactions with CuTSPc.Meso (3- e 4-piridil)porfirinas coordenadas a quatro complexos [Ru(bipy)2Cl]+, M(3-TRPyP) e M(4-TRPyP), onde M = 2H+ e Zn2+, foram obtidas e caracterizadas por métodos eletroquímicos, espectroscopia e espectrometria de massas. Os filmes eletrostaticamente montados camada por camada com ftalocianina de cobre tetrassulfonada, CuTSPc, apresentaram atividade eletrocatalítica diferenciada para a oxidação de sulfito e nitrito. Em geral, os filmes derivados dos isômeros M(4-TRPyP) são mais ativos para a oxidação de nitrito, enquanto aqueles contendo os isômeros M(3-TRPyP) são mais eficientes para a oxidação de sulfito. Os resultados revelaram uma influência significativa da geometria molecular no sítio ativo dos nanomateriais porfirínicos, que favorece os processos de transferência eletrônica nos derivados de M(3-TRPyP), através de mudanças no empacotamento molecular com a CuTSPc.418425Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Cyclization Reactions Of Acylium And Thioacylium Ions With Isocyanates And Isothiocyanates: Gas Phase Synthesis Of 3,4-dihydro-2,4-dioxo-2h-1,3,5-oxadiazinium Ions.

Gas-phase reactions of several acylium and thioacylium ions, that is H2C=N-C+=O, H2C=N-C+=S, O=C=N-C+=O, S=C=N-C+=O, H3C-C+=O, and (CH3)2N-C+=O, with both a model isocyanate and isothiocyanate, that is, C2H5-N=C=O and C2H5-N=C=S, were investigated using tandem-in-space pentaquadrupole mass spectrometry. In these reactions, the formation of mono- and double-addition products is observed concurrently with proton transfer products. The double-addition products are far more favored in reactions with ethyl isocyanate, whereas the reactions with ethyl isothiocyanate form, preferentially, either the mono-addition product or proton transfer products, or both. Retro-addition dominates the low-energy collision-induced dissociation of the mono- and double-addition products with reformation of the corresponding reactant ions. Ab initio calculations at Becke3LYP//6-311 + G(d,p) level indicate that cyclization is favored for the double-addition products and that products equivalent to those synthesized in solution, that is, of 3,4-dihydro-2,4-dioxo-2H-1,3,5-oxadiazinium ions and sulfur analogs, are formed.161602-

Electrospray Mass And Tandem Mass Spectrometry Of Homologous And Isomeric Singly, Doubly, Triply And Quadruply Charged Cationic Ruthenated Meso-(phenyl)m-(meta- And Para-pyridyl)n (m + N = 4) Macrocyclic Porphyrin Complexes.

Ten homologous or isomeric singly, doubly, triply and quadruply charged cationic macrocyclic complexes I-Va, bn+ (n = 1-4) formed by the coordination of [Ru(bipy)2Cl]+ to the pyridyl N-atoms of a series of meso-(phenyl)m-(meta or para-pyridyl)n-porphyrins (m + n = 4) were transferred to the gas phase and structurally characterized by electrospray ionization (ESI) mass (MS) and tandem mass (MS/MS) spectrometry. Previously known to be stable in solution and in the solid state, I-Va, bn+ are found to constitute also a new class of stable, long-lived multiply charged gas-phase ions with spatially separated charge sites. Increasing intramolecular electrostatic repulsion from Ia, b+ to IVa, b3+ facilitates in-source and tandem collision-induced dissociation (CID). However, for the quadruply charged ions Va, b4+, electrostatic repulsion is alleviated mainly by ion pairing with the CF3SO3- counterion forming the salt clusters [Va,b/CF3SO3]3+ and [Va,b/(CF3SO3)2]2+ with reduced charge states. Ion-pairing that yields [IVa,b/CF3SO3]2+ is also observed as a minor ESI process for the triply charged ions IVa, b3+. The gaseous ions I-Va, bn+ (n = 2, 3 or 4) dissociate by sequential 'charge partitioning' with the formation of two cationic fragments by the release of [Ru(bipy)2Cl]+. The meta (a) and para (b) isomers and the positional isomers II2+ and III2+ display nearly identical ESI-MS and ESI-MS/MS spectra. ESI-MS/MS of I-Va, bn+ shows that the Ru-py(P) is, intrinsically, the weakest bond since this bond breaks preferentially upon CID.391161-