João Pedro Martins

4,7-Diphenyl-1,10-phenanthroline methanol hemisolvate.

The asymmetric unit of the title compound, C24H16N2·0.5CH3OH, is comprised of two independent bathophenanthroline molecules (systematic name: 4,7-diphenyl-1,10-phenanthroline) and one methanol molecule. The bathophenanthroline molecules are not planar as there is a considerable rotation of all terminal phenyl rings with respect to the central phenanthroline units [dihedral angles in the range 52.21 (12)–62.14 (10)°]. In addition, a non-negligible torsion is apparent in one of the phenanthroline units: the angle between the mean planes of the two pyridine rings is 14.84 (13)°. The methanol solvent molecule is linked to both N atoms of a bathophenanthroline molecule through a bifurcated O—H⋯(N,N) hydrogen bond.

Experimental and Theoretical Studies on the Structure and Photoluminescent Properties of New Mononuclear and Homodinuclear Europium(III) β-Diketonate Complexes

Two novel europium(III) complexes, a monomer and a homodimer, with 1-(4-chlorophenyl)-4,4,4-trifluoro-1,3-butanedione (Hcbtfa) and 5-chloro-1,10-phenanthroline (cphen) ligands, formulated as [Eu(cbtfa)3(cphen)] and [Eu2(cbtfa)4(cphen)2(CH3O)2], have been synthesized. Their structures have been elucidated by X-ray diffraction and their absorption and emission properties have been studied in the solid state. The experimental data has then been used to test the recently released LUMPAC software, a promising tool which can facilitate the design of more efficient lanthanide light-conversion molecular devices by combining ground state geometry, excited state energy, and luminescent properties calculations.

Synthesis, structural modelling and photoluminescence of Tb(III) polymeric complexes for solution-processed OLEDs

Current manufacturing technologies for OLEDs involve the use of expensive high vacuum techniques and call for thermal stability requirements which are not fulfilled by many materials. These problems disappear when the OLED films are deposited directly from solution. In this study, we have synthesized, modelled by semi-empirical quantum chemistry methods and characterized the optical properties of two novel Tb(III) complexes with carboxylic acids, which can be readily used as “complex-only” emissive layers in wet-processed OLEDs. Upon excitation in the UV region, very efficient energy transfer from the ligands to Tb3+ takes place, giving rise to intense green emission, both in powder and as a thin film. The good quantum efficiencies (31.3% and 24.7%, respectively) and adequate thin film forming properties make these materials promising chromophores for cost-effective OLEDs.

Poly[μ2-aqua-μ4-[1-(4-chloro-phen-yl)-4,4,4-tri-fluoro-butane-1,3-dionato]-potassium].

In the title compound, [K(C10H5ClO2F3)(H2O)]n, the two independent K+ ions are located on a twofold rotation axis. For each of the cations, the distorted cubic coordination environment is defined by two F and four O atoms of symmetry-related 1,4-chlorophenyl-4,4,4-trifluorobutane-1,3-dionate anions and by two O atoms of water molecules. The μ4-bridging character of the anion and the μ2-bridging of the water molecule lead to the formation of layers parallel to (100). The coordinating water molecules are also involved in O—H⋯O hydrogen bonds that reinforce the molecular cohesion within the layers, which are stacked along [100]. The β-diketonate anion is not planar, with an angle of 31.78 (10)° between the mean planes of the diketonate group and the chlorophenyl ring.