RESUMO
The new bis(bidentate) tetraphosphane cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphanyl)buta-1,3-diene (dppbd) (7) was obtained by applying a photochemical synthetic protocol. The key step of the photochemical reaction consisted of an intramolecular [2+2] cycloaddition involving a C-C double and triple bond of the Pt-dimer species of the formula [Pt2Cl4(dppa)(trans-dppen)] (2) {dppa = 1,2-bis(diphenylphosphanyl)acetylene and dppen = 1,2-bis(diphenylphosphanyl)ethene} leading to [Pt2Cl4(dppbd)] (5). The asymmetrically bridged precursor complex 2 was obtained by combinatorial chemistry. Single crystal X-ray structure analyses of 2 and 5 proved that the intramolecular photochemical reaction occurred. Cyanolysis of 5 gave 7, which was oxidized to dppbdO4 (8). Compounds 7, 8, and the PdII dimer complex [Pd2Cl4(dppbd)] (9) were characterized in the solid state by a single-crystal X-ray structure analysis. Interesting photophysial properties emerged from the UV/Vis spectra acquired for 7 and the dimer Os complexes meso-Δ,Λ/Λ,Δ-[Os2(bpy)4(dppbd)](PF6)4 (10) and rac-Δ,Δ/Λ,Λ-[Os2(bpy)4(dppbd)](PF6)4 (11).
RESUMO
The trigonal indium borate In19B34O74(OH)11 was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 13 GPa and 1150 °C. The crystal structure could be determined by single-crystal X-ray diffraction data collected at room temperature. In19B34O74(OH)11 crystallizes in the trigonal space group R3Ì (Z = 3) with the lattice parameters a = 1802.49(6) pm, c = 1340.46(5) pm, and V = 3.7716(3) nm3. The structure of In19B34O74(OH)11 contains alternating B-O T2 supertetrahedra units. The presence of hydroxyl groups was confirmed with vibrational spectroscopic methods such as Raman and IR. Besides H2InB5O10, In19B34O74(OH)11 is now the second known compound in the system In-B-O-H.
RESUMO
The synthesis and the photophysics of three dinuclear copper(I) complexes containing bis(bidentate)phosphine ligands are described. The steric constraint imposed by tetrakis(di(2-methoxyphenyl)phosphanyl)cyclobutane) (o-MeO-dppcb) in combination with 2,9-dimethyl-1,10-phenanthroline in one of the complexes leads to interesting photophysical properties. The compound shows an intense emission at room temperature in deoxygenated acetonitrile solution (Φ = 49%) and a long excited-state lifetime (13.8 µs). Interestingly, at low temperature, 77 K, the emission maximum shifts to lower energy, and the excited-state lifetime increases. This observation leads to the conclusion that a mixing between the excited triplet and singlet states is possible and that the degree of mixing and population of state strongly depends on temperature, as the energy difference is quite small. The electroluminescent properties of this compound were therefore tested in light-emitting electrochemical cells (LEECs), proving that the bright emission can also be obtained by electrically driven population of the singlet state.
