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A new, straightforward protocol is described for the selective synthesis of the simplest [60]fullerene hydride, which has used the hydrolysis of acylated fullerene compounds. The protocol is advantageous over other methods for preparing [C.sub.60][H.sub.2], which has allowed a rapid access to [C.sub.60][H.sub.2] in good yield and high purity without tedious separating processes.

A novel polycationic [60]fullerene hexakis-adduct has been synthesized and investigated by electrospray ionization and tandem mass spectrometry. The polycationic ligand system comprises 12 pre-formed positive charges, compensated in the neutral molecule by bromide anions. Stable quasi-molecular cations were obtained through the release of the anionic counter ions covering a charge-state envelope from 3+ to 12+. Collision-induced dissociation experiments revealed three fragmentation pathways. A dominant neutral loss channel leads to daughter ions of the same charge state as the highly charged precursor ion and singly charged daughter ions can be expelled from the polycations through two distinct dissociation channels involving both the neutral and the charge-carrying part of their ligands. [ABSTRACT FROM AUTHOR]

The ion formation of crown ether–[60]fullerene conjugates of the type (crown − H)–C60–H with crown = 12cr4, 15cr5 and 18cr6 has been studied with matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation mass spectrometry (ESI MS). In total five different ways of ion formation are presented, including metalation (MALDI, ESI), protonation and oxidation (both in MALDI) in the positive-ion mode and deprotonation (MALDI, ESI) and reduction (MALDI) in the negative-ion mode. In line with thermochemistry, the deprotonation and electron transfer processes involve the C60 moiety as the charge-carrying entity, while protonation and metalation occur at the crown ether. Particular emphasis has been placed on the study of metal cation attachment in MALDI varying the crown ether size in the conjugate and using different alkali metal chlorides in the target preparation. Dissociation reactions of the metalated conjugates are influenced by the interaction strength of the metal cation to the crown ether fullerene conjugate. The data confirm an increase in bond strength with smaller metal cations, supporting the notion of charge density-driven interactions. [ABSTRACT FROM AUTHOR]

Anionic metal oxide clusters, so-called polyoxometalates, can be developed as molecular model compounds to mimic the chemical and photochemical reactivity of solid-state metal oxides on the molecular level. Inspired by the well-known visible-light photocatalyst BiVO4, the first molecular bismuth vanadium oxide has been synthesized to investigate the chemical and photochemical similarities between the solid-state and molecular compounds. The cluster H3[(Bi(dmso)3)4V13O40] ⋅ca. 4 DMSO was obtained from simple precursors in almost quantitative yield. Structural analysis showed that the cluster shell is based on the unusual all-vanadium ε-Keggin framework [ε-V12O40]15−, which is stabilized by coordination of four BiIII centers. The acidic character of the three cluster protons was demonstrated by titration studies. The cluster shows promising photocatalytic properties in visible-light photooxidation reactions and has high activity (turnover number >1200), high quantum yield ( Φ=7.6 %), and good recyclability, which make it a promising first example of a new class of heterometallic polyoxometalates. [ABSTRACT FROM AUTHOR]

The intermolecular interactions between a ruthenium-based photosensitizer ([Ru(tbbpy)2(biH2)]2) and a molecular metal oxide ([β-Mo8O26]4−) are investigated in solution and in the solid state. The supramolecular interactions were studied using 1H-NMR, UV-Vis and emission spectroscopy, ESI mass spectrometry and single-crystal X-ray diffraction. The formation of supramolecular aggregates was observed both in the crystal lattice and in solution. In addition, it is shown that aggregation in solution can be controlled by the competitive formation of ion pairs. [ABSTRACT FROM AUTHOR]

A dynamic HPLC study of C70chlorination led to the discovery, isolation, characterization, and development of the efficient preparatory procedures for two previously unknown soluble chlorofullerenes C70Cl8and C70Cl6and for insoluble [C70Cl8]n. A novel synthesis of 99% pure C70Cl10with a nearly quantitative yield was also developed. The first stability study of C70Cl10,8,6in solution showed that these compounds are very light-sensitive. [ABSTRACT FROM AUTHOR]

A dynamic HPLC study of C70chlorination led to the discovery, isolation, characterization, and development of the efficient preparatory procedures for two previously unknown soluble chlorofullerenes C70Cl8and C70Cl6and for insoluble [C70Cl8]n. A novel synthesis of 99% pure C70Cl10with a nearly quantitative yield was also developed. The first stability study of C70Cl10,8,6in solution showed that these compounds are very light-sensitive. [ABSTRACT FROM AUTHOR]

The first molecular bismuth vanadium oxide cluster compound H3 [{Bi(dmso)3}4V13O40] ·≈4DMSO is synthesized by addition of an aqueous Bu4NOH solution to a hot solution of Bi(NO3)3 and (Bu4N)3[H3V10O28] in DMSO/2% H2O (80 °C, 1 h, 91% yield). [ABSTRACT FROM AUTHOR]

A targeted ultrahigh-performance liquid chromatography tandem mass spectrometry with electrospray ionization (UHPLC-ESI-MS/MS) method has been developed for the quantification of tryptophan and its downstream metabolites from the kynurenine and serotonin pathways. The assay coverage also includes markers of gut health and inflammation, including citrulline and neopterin. The method was designed in 96-well plate format for application in multiday, multiplate clinical and epidemiology population studies. A chromatographic cycle time of 7 min enables the analysis of two 96-well plates in 24 h. To protect chromatographic column lifespan, samples underwent a two-step extraction, using solvent protein precipitation followed by delipidation via solid-phase extraction (SPE). Analytical validation reported accuracy of each analyte <20% for the lowest limit of quantification and <15% for all other quality control (QC) levels. The analytical precision for each analyte was 2.1-12.9%. To test the applicability of the method to multiplate and multiday preparations, a serum pool underwent periodic repeat analysis during a run consisting of 18 plates. The % CV (coefficient of variation) values obtained for each analyte were <15%. Additional biological testing applied the assay to samples collected from healthy control participants and two groups diagnosed with inflammatory bowel disease (IBD) (one group treated with the anti-inflammatory 5-aminosalicylic acid (5-ASA) and one group untreated), with results showing significant differences in the concentrations of picolinic acid, kynurenine, and xanthurenic acid. The short analysis time and 96-well plate format of the assay makes it suitable for high-throughput targeted UHPLC-ESI-MS/MS metabolomic analysis in large-scale clinical and epidemiological population studies.

Inspired by reports on the use of pencil lead as a matrix-assisted laser desorption/ionization matrix, paving the way towards matrix-free matrix-assisted laser desorption/ionization, the present investigation evaluates its usage with organic fullerene derivatives. Currently, this class of compounds is best analysed using the electron transfer matrix trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene] malononitrile (DCTB), which was employed as the standard here. The suitability of pencil lead was additionally compared to direct (i.e. no matrix) laser desorption/ionization-mass spectrometry. The use of (DCTB) was identified as the by far gentler method, producing spectra with abundant molecular ion signals and much reduced fragmentation. Analytically, pencil lead was found to be ineffective as a matrix, however, appears to be an extremely easy and inexpensive method for producing sodium and potassium adducts.

The photochemical properties of homo- and heterometallic molybdate-based Lindqvist polyoxometalate clusters are investigated in a comparative study and it is shown that vanadium substitution can be used as a facile synthetic tool to optimize the visible light absorption and photocatalytic activity of the cluster. The mono-vanadium substituted unit, [VMo(5)O(19)](3-) shows light absorption up to 480 nm whereas the light absorption of the molybdate analogue [Mo(6)O(19)](2-) is mainly in the UV region below 400 nm. The electronic absorption properties of both clusters are further investigated using TD-DFT calculations which show that vanadium incorporation leads to the formation of low-energy O → V LMCT transitions. In comparative photochemical dye decomposition test reactions under UV and Vis irradiation, a higher reactivity is observed for [VMo(5)O(19)](3-) together with turnover numbers of more than 1600. In addition it is shown that under anaerobic conditions, the photoreaction proceeds faster than in the presence of oxygen, suggesting that oxygen acts as a quencher in one of the photoredox steps.

New Brønsted acidic ionic liquids (BAILs) are prepared by treating zwitterions, which are composed of an imidazolium cation and a sulfonate anion, with an alkanedisulfonic acid. Acidification of the zwitterions produces the cation and deprotonation of the alkanedisulfonic acid forms the anion of the new BAILs. Direct laser desorption/ionisation (LDI), matrix-assisted LDI (MALDI) and electrospray ionisation (ESI) are employed to transfer ions into the gas-phase for detection by mass spectrometry and for dissociation studies by tandem mass spectrometry. The components of the BAILs are confirmed by LDI and MALDI by the detection of the respective cation and anion and by ESI by the observation of the cation and the dianion. A prominent feature of ESI is the formation of aggregates (cluster ions). Positively charged cluster ions are formally composed of multiple zwitterions plus one additional proton. In the negative-ion mode the clusters also incorporate the zwitterions which are, however, linked with the alkanedisulfonate dianion. In collision-induced dissociations (CID), the cationic aggregates show the evaporation of zwitterions until the protonated zwitterion is reached. Similarly, the cluster dianions release zwitterions until the free alkane disulfonate dianion is reached. However, the 1:1 adduct of dianion and zwitterion also displays proton transfer and Coulomb explosion into the mono-protonated disulfonic mono-anion and an imidazole-based carbene with sulfonate mono-anion., (This journal is © the Owner Societies 2012)