Publications by authors named "Rosenildo C da Costa"

Article Synopsis
  • The new ligand, 6-diisopropylphosphino-2-pyridone, reacts with a ruthenium complex to produce two different products, and their formation ratios can be influenced by the solvent used.
  • When combined with specific additives like AgOTf and Na[BArF], it leads to the creation of additional ruthenium complexes that have distinct properties.
  • The study reveals a novel orange-colored complex formed through deprotonation of a hydroxyl group, highlighting potential for new chemical interactions and reactions, including the catalytic conversion of CO into formate salts.
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A portfolio of value-added chemicals, fuels and building block compounds can be envisioned from CO on an industrial scale. The high kinetic and thermodynamic stabilities of CO, however, present a significant barrier to its utilisation as a C1 source. In this context, metal-ligand cooperation methodologies have emerged as one of the most dominant strategies for the transformation of the CO molecule over the last decade or so.

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The selectivities of ionophore-doped ion-selective electrode (ISE) membranes are controlled by the stability and stoichiometry of the complexes between the ionophore, L, and the target and interfering ions (I and J , respectively). Well-accepted models predict how these selectivities can be optimized by selection of ideal ionophore-to-ionic site ratios, considering complex stoichiometries and ion charges. These models were developed for systems in which the target and interfering ions each form complexes of only one stoichiometry.

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Article Synopsis
  • - The study successfully synthesizes and characterizes new group 10 metal complexes using flexible scorpionate ligands derived from 7-azaindole heterocycles.
  • - These complexes are formed by adding specific compounds to metal precursors, resulting in stable structures with unique geometric configurations.
  • - Notably, unlike other similar complexes, these do not exhibit hydrogen migration from the boron atom, allowing for better analysis of the boron-hydrogen interactions in the complex through B NMR spectroscopy.
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The synthesis and characterisation of a new anionic flexible scorpionate ligand, methyl(bis-7-azaindolyl)borohydride [MeBai]- is reported herein. The ligand was coordinated to a series of group nine transition metal centres forming the complexes, [Ir(MeBai)(COD)] (1), [Rh(MeBai)(COD)] (2), [Rh(MeBai)(CODMe)] (2-Me) and [Rh(MeBai)(NBD)] (3), where COD = 1,5-cyclooctadiene, CODMe = 3-methyl-1,5-cyclooctadiene and NBD = 2,5-norbornadiene. In all cases, the boron based ligand was found to bind to the metal centres via a κ3-N,N,H coordination mode.

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Electrochemical reduction of an azoniahelicene affords a dimer, accompanied by a strong change in the electronic circular dichroism. The fast dimerisation event leads to a >500 mV shift of the oxidation potential, affording a large area of bistability, where the chiroptical signal only depends on the redox history.

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By simply doping the conventional light-emitting polymer F8BT with a helically chiral aromatic molecule, it is shown that substantial levels of CP-electroluminescence can be generated directly. Both photoluminescent and electroluminescent emission from the polymer are observed to become circularly polarized, with the sign of the CP emission directly determined by the handedness of the dopant.

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Three 3,6-difluoro-1,2,4,5-tetrakis(amino)benzene compounds, bearing dimethylamino (1), piperidin-1-yl (3), or morpholin-1-yl (5) substituents, have been synthesized and subsequently defluorinated to give the corresponding 1,2,4,5-tetrakis(amino)benzene compounds 2, 4, and 6; the crystal structures of compounds 1, 4, and 6 have been obtained. Cyclic voltammetry shows that all six compounds will lose two electrons to form dications, and the use of suitable oxidizing agents has allowed isolation and crystallographic characterization of the dications 2(2+) and 6(2+) (as [PF(6)](2) salts) and 4(2+) (as a [I(5)][I(3)] salt). The separation DeltaE between the loss of the first electron and the second varies between compounds, from 0.

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