Biomedical subjects

Olga Bortolini

Publications and source records attributed to Olga Bortolini.

6 recordsLinked to original sources

PubMed2007

Development of cation/anion "interaction" scales for ionic liquids through ESI-MS measurements.

Electrospray ionization mass spectrometry applied to ionic liquids allowed the study of loosely bonded supramolecules, originating from these organic salts. Based on the observation that ionic liquids formed cationic [C(q+1)X(q)](+) and anionic [C(q)X(q+1)](-) supramolecular aggregates, we have investigated mixed networks, formed by different cations coordinated to a selected anion or by different anions bonded to a given cation, i.e., [C1...X...C2](+) and [X1...C...X2](-), with the aim to build a scale of the cation-anion interaction strength. The qualitative order of intrinsic bond strength to Br- was found to be the following: [emim](+) > [bmim](+) > [mor1,2](+) > [hmim]+ > [omim](+) > [mor1,4](+) > [bupy](+) > [bpyrr](+) > [picol](+) > [bm(2)im](+) > [TBA](+). Similarly, the interaction energies to 1-butyl-3-methylimidazolium (bmim) species envisaged two classes of anions: species tightly coordinated to the cationic moiety that include CF3COO(-), Br(-), N(CN)2(-), and BF4(-) and anions loosely interacting with the alkylimidazolium species such as OTf(-), PF6(-), and Tf2N(-).

Anions↗

PubMed2005

Hydrogen-bonded aggregations of oxo-cholic acids.

The crystal structures of six new crystals of oxo-cholic acids (oxo-CA) are reported: (I) 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholan-24-oic acid; (II) 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholan-24-oic acid; (III) 7alpha-hydroxy-3,12-dioxo-5beta-cholan-24-oic acid; (IV-alpha) and (IV-beta) 12alpha-hydroxy-3,7-dioxo-5beta-cholan-24-oic acid; (V) 3,7,12-trihydroxy-5beta-cholan-24-oic acid. (IV-beta) is a pseudopolymorphic solvated form of (IV-alpha) and contains small channels which can trap disordered water molecules. In all the structures the four saturated cycles, forming the common alicyclic skeleton, have the same conformation, while the carboxylic side chain adopts flexible conformations in order to produce the most efficient crystal aggregations. The structures display a variety of supramolecular architectures dominated by networks of cooperative O-H...O hydrogen bonds forming different packing motifs often supported by weaker C-H...O interactions.

Cholic Acids↗

PubMed2005

Bile acid derivatives as enantiodifferentiating host molecules in inclusion processes.

A review on the use of bile acids as hosts for molecular recognition and enantioresolution is presented. The optical resolution of different classes of organic derivatives, i.e., lactones, aliphatic alcohols, sulfoxides, epoxides, ketones, cyclic amides, cyclic carbonates, and sulfites, may be obtained by host-guest enantioselective inclusion complexation. The salient aspects of the enclathration process, including X-ray diffraction results, are discussed.

Animals↗

PubMed2005

Vanadium (V) peroxocomplexes: structure, chemistry and biological implications.

A short account on the identification in solution of diverse type of vanadium peroxocomplexes is offered. The methodology used is a combination of several techniques, i.e., multinuclear NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and theoretical calculation. The analysis has been carried out in aqueous alcoholic solutions, and in some case also in the presence of appropriate ligands, in order to model some of the natural conditions where vanadium-dependent haloperoxidase enzymes (VHPO) work. With the results obtained, it has been possible to shed light on important aspects of the catalytic cycle of VHPO. Furthermore, a number of synthetic aspects of the reactivity of the various vanadium peroxocomplexes is reviewed.

Histidine↗

PubMed2002

Improved enantioselectivity in the epoxidation of cinnamic acid derivatives with dioxiranes from keto bile acids.

The asymmetric epoxidation of substituted cinnamic acids has been obtained in the presence of different keto bile acid derivatives as optically active carbonyl inducers and Oxone as oxygen source. Predominant or almost exclusive formation of both enantiomeric epoxides is obtained (ee up to 95%) depending on the specific substitution at carbons C(7) and C(12) of the bile acid.

Bile Acids and Salts↗

PubMedDate not supplied

Mass spectrometric characterization of high-valent metal-oxo, -peroxo and -peroxy intermediates of relevance in oxidation processes.

The coupling of mass spectrometry with ionization techniques like electrospray ionization (ESI) or matrix-assisted matrix-assisted laser desorption-ionization (MALDI) offers many advantages over other well-established spectroscopic techniques employed for the investigation of intermediates or short-lived species in condensed-phase. In this review we describe some of the applications of mass spectrometry, in particular of ESI-MS to the detection and characterization of high-valent metal-oxo, -peroxo and -peroxy derivatives, crucial intermediates in the oxyfunctionalization of organic substrates. In addition, by utilizing gas-phase ion-molecule reactions and MS/MS experiments, information on the intrinsic reactivity of the short-lived intermediates may be obtained. The combined use of ESI-MS in association with other spectroscopic techniques and theoretical calculations is discussed as well.

Journal Article↗