Synthesis of a tricyclic tetraazatriacetic ligand for gadolinium(III) as potential contrast agent for MRI

A tricyclic tetraazatriacetic compound, which is a rigidified derivative of PCTA12 ligand with a cyclohexylene bridge replacing an ethylene one, was prepared. Two synthetic routes have been investigated, both of them implying a common functionalized triamine intermediate. Whatever the route, four synthetic steps were necessary to obtain the target tricyclic ligand. The more effective one (Route B) led to the desired compound in 19% overall yield from the triamine intermediate. The corresponding gadolinium complex of 1/1 stoichiometry was then prepared in order to evaluate it as potential contrast agent for MRI.     

Characterization of major and minor alk(en)ylresorcinols from mango (Mangifera indica L.) peels by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

5-Alkyl- and 5-alkenylresorcinols, as well as their hydroxylated derivatives, were extracted from mango (Mangifera indica L.) peels, purified on polyamide and characterized by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APcI-MS) for the first time. Among the 15 compounds analyzed, 3 major and 12 minor C(15)-, C(17)-, and C(19)-substituted resorcinols and related analogues, showing varying degrees of unsaturation, were characterized by their specific fragmentation patterns in collision-induced dissociation experiments. This marks the first report on the occurrence of mono-, di-, and triunsaturated C(15)-homologues, saturated and triunsaturated C(17)-homologues, and mono- and diunsaturated C(19)-homologues in mango peels. Additionally, several hydroxylated C(15)- and C(17)-homologues, also not yet described in mango, and a C(14)-monoene, unique because of its even-numbered side chain, were tentatively identified on the basis of their fragmentation patterns. The results obtained in the present study indicate that HPLC-DAD-APcI-MS(n), combined with the newly developed solid-phase extraction, is a powerful tool for the analysis of alk(en)ylresorcinols and could therefore be used for their determination in various matrices.     

Recent Applications of Molecular Spectroscopy in Bioorganometallic Chemistry–Part 2: Ferrocenes and Other Organometallic Complexes

Abstract: This is the second part of an overview of the applications of the various molecular spectroscopic methods that have been employed in bioorganometallic chemistry research since 2005 focusing on ferrocenes and other non-metal carbonyl organometallic complexes. These spectroscopic methods encompass infrared (IR), nuclear magnetic resonance (NMR), mass, Raman, ultraviolet-visible (UV-Vis), and several other less common spectroscopic techniques.     

Resolvent Estimates and Matrix-Valued Schrödinger Operator with Eigenvalue Crossings; Application to Strichartz Estimates

We consider a semi-classical Schrödinger operator with a matrix-valued potential presenting eigenvalue crossings on isolated points. We obtain estimates for the boundary values of the resolvent under a generalized non-trapping assumption. As a consequence, we prove the smoothing effect of this operator, derive Strichartz type estimate for the propagator and get an existence theorem for a system of non-linear Schrödinger equations.     

Optical Properties of Lanthanide Doped Hybrid Organic-Inorganic Materials

Sol-gel matrices have been investigated for some years as potential matrices for rare earth luminescence. Sm³⁺, Eu³⁺, Dy³⁺, Er³⁺ and Tm³⁺ optical properties in siloxane-zirconium hybrid matrices prepared at room temperature have been investigated. Even if luminescence efficiency is governed by non-radiative relaxation linked to hydroxyl groups, in these matrices, rare earth fluorescence is always observed but lifetimes and quantum yields are dependent on the elaboration procedure. Eu³⁺ is used as a probe of the local surrounding around the dopant and the emission and decay profiles measurements in rare earth doped and undoped matrices are presented.     

4f-surface binding energy shift for Eu and Gd metals

Synchrotron radiation excited photoemission spectra of Eu and Gd are presented. For Eu a 4f-surface component is resolved with 0.63 eV binding energy shift. For Gd the comparison with XPS data gives strong evidence for a surface shifted 4f-component (ΔE=0.48 eV). The mean free path of photoelectrons is determined.     

Metabolic signature of breast cancer cell line MCF-7: profiling of modified nucleosides via LC-IT MS coupling

Background  

Cancer, like other diseases accompanied by strong metabolic disorders, shows characteristic effects on cell turnover rate, activity of modifying enzymes and DNA/RNA modifications, resulting also in elevated amounts of excreted modified nucleosides. For a better understanding of the impaired RNA metabolism in breast cancer cells, we screened these metabolites in the cell culture supernatants of the breast cancer cell line MCF-7 and compared it to the human mammary epithelial cells MCF-10A. The nucleosides were isolated and analyzed via 2D-chromatographic techniques: In the first dimension by cis-diol specific boronate affinity extraction and subsequently by reversed phase chromatography coupled to an ion trap mass spectrometer.