Long-Lived Two-Photon Excited Luminescence of Water-Soluble Europium Complex: Applications in Biological Imaging Using Two-Photon Scanning Microscopy.

International audienceA new europium complex presenting good solubility and stability in water, intense emission in the red (616 nm), long luminescence lifetime, and significant two-photon absorption cross-section in the biological window has been designed and successfully used for two-photon scanning microscopy bioimaging experiments on fixed cancer cells

Meso-Ester Corroles

International audienceDedicated to Professor Mieczysław Józef Mąkosza on the occasion of his 80th birthday. Abstract: The introduction of ester groups on the 5 and 15 meso positions of corroles stabilizes them against oxidation and induces a red-shift of their absorption and emission spectra. These effects are studied through the photophysical and electrochemical characterization of up to sixteen different 5,15-diester corroles where the third meso position is free or occupied by an aryl group, a long alkyl chains or an ester moiety. The single crystal X-ray structure analysis of five 5,15-diestercorroles and Density Functional Theory (DFT) and Time Dependant Density Functional Theory (TD-DFT) calculations, show that the strong electron withdrawing character of the 5,15 ester substituents is reinforced by their π-overlapping with the macrocycle aromatic system. The crystal packings of corroles 2, 4, 6, 9 and 15 feature short distances between chromophores that are stacked into columns thanks to the low steric hindrance of meso ester groups. This close packing is partially due to intermolecular interactions involving inner hydrogen and nitrogen atoms and thereby stabilizing a single and identical corrole tautomeric form

Tricaesium tris­(pyridine-2,6-dicarboxyl­ato-κ3 O 2,N,O 6)lutetium(III) octa­hydrate

Colourless block crystals of the title compound, Cs3[Lu(dipic)3]·8H2O [dipic is dipicolinate or pyridine-2,6-dicarboxyl­ate, C7H3NO4] were synthesized by slow evaporation of the solvent. The crystal structure of this LuIII-complex, isostructural with the DyIII and EuIII complexes, was determined from a crystal twinned by inversion and consists of discrete [Lu(dipic)3]3− anions, Cs+ cations and water mol­ecules involving hydrogen bonding. The Lu atom lies on a twofold rotation axis and is coordinated by six O atoms and three N atoms of three dipicolinate ligands. One Cs atom is also on a twofold axis. The unit cell can be regarded as successive layers along the crystallographic c-axis formed by [Lu(dipic)3]3− anionic planes and [Cs+, H2O] cationic planes. In the crystal structure, although the H atoms attached to water mol­ecules could not be located, short O—O contacts clearly indicate the occurrence of an intricate hydrogen-bonded network through contacts with other water mol­ecules, Cs cations or with the O atoms of the dipicolinate ligands

Multi-pyridine decorated Fe(ii) and Ru(ii) complexes by Pd(0)-catalysed cross couplings: new building blocks for metallosupramolecular assemblies

Eight metal complexes of the type [M(tpy)2]2+ (tpy = 2,2′:6′,2′′-terpyridine) featuring four pendant pyridine rings are reported and characterised by NMR, MS, absorption spectroscopy and electrochemical methods. Palladium-mediated Suzuki and Sonogashira cross-coupling reactions were performed on both free 4′-(3,5- dibromophenyl)-tpy and its Ru(ii) complex in good yields. The ready N-alkylation of the pendant pyridyl units has significant influence on the absorption and electrochemical reduction of the complexes, processes which are localised on the periphery and leaves the [Ru(tpy)2]2+ core essentially unaffected. The binding of metal ions by the free pyridines is also demonstrated as means of assembling larger ordered non-covalent structures. This journal i