168646-54-6Relevant articles and documents
Graphite Conjugation Eliminates Redox Intermediates in Molecular Electrocatalysis
Jackson, Megan N.,Kaminsky, Corey J.,Oh, Seokjoon,Melville, Jonathan F.,Surendranath, Yogesh
, p. 14160 - 14167 (2019)
The efficient interconversion of electrical and chemical energy requires the intimate coupling of electrons and small-molecule substrates at catalyst active sites. In molecular electrocatalysis, the molecule acts as a redox mediator which typically undergoes oxidation or reduction in a separate step from substrate activation. These mediated pathways introduce a high-energy intermediate, cap the driving force for substrate activation at the reduction potential of the molecule, and impede access to high rates at low overpotentials. Here we show that electronically coupling a molecular hydrogen evolution catalyst to a graphitic electrode eliminates stepwise pathways and forces concerted electron transfer and proton binding. Electrochemical and X-ray absorption spectroscopy data establish that hydrogen evolution catalysis at the graphite-conjugated Rh molecule proceeds without first reducing the metal center. These results have broad implications for the molecular-level design of energy conversion catalysts.
A rational synthesis of a novel imidazo[4,5-f][1,10]phenanthroline templated Schiff base: Characterization, photoluminescence and DFT/TD-DFT study
Karslio?lu,Demir,Yilmaz,G?rdük
, p. 137 - 147 (2017)
A new imidazo[4,5-f][1,10]phenanthroline (imp) derivative imidazo-N5,N6-bis((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenyl)methylene)-1,10-phenanthroline-5,6-diamine (impap) was synthesized in five steps starting from bare phenanthroline (phen) precursors. The novel compound was fully characterized by 1H-NMR, IR, elemental analysis and electrospray ionization mass spectroscopy (ESI-MS) techniques. Solid state emission spectrum of impap showed two distinct strong emission maxima with large Stokes shifts. The ground state gas phase geometry of impap was predicted by DFT calculations. Excited state properties of the molecule were examined through TD-DFT calculations conducted at the optimized geometry. Responsible transitions for the strong fluorescence of impap were assigned to single component charge transfer transitions with large oscillator strengths based on the ground state calculated molecular orbital contributions.
Synthesis of free and ruthenium coordinated 5,6-diamino-1,10- phenanthroline
Bodige, Swamy,MacDonnell, Frederick M.
, p. 8159 - 8160 (1997)
A new preparative route to 5,6-diamino-1,10-phenanthroline is described which triples the isolated yields found in existing syntheses (67% vs. 22% from 1,10-phenanthroline) and utilizes mild reaction conditions. The method is general and can even be used on chiral metal complexes containing the appropriate starting material/ligand, 1,10-phenanthroline-5,6-dione, with retention of stereochemistry.
Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ3- N, N′, C and κ3- N, N′, O Donor Platforms
Alrefai, Riyadh,H?rner, Gerald,Schubert, Hartmut,Berkefeld, Andreas
, p. 1163 - 1177 (2021)
This work reports on complex chromophores of planar nickel(II) of the general formula [(κ3-N,N′,C/O)Ni-ER], which combines a κ2-N,N′-coordinate aromatic N-heterocycle with a pendant phenyl/phenol donor and the variable coligands ER (= carboxylato, phenolato, amido, and arylthiolato). The absorption properties of the planar complex chromophores vary broadly depending on the interplay of the three constituting components. Increasing the manifold of π?-orbitals at the N-heterocyclic moiety through π-extension along 1,10-phenanthroline, tetrahydrodipyridophenazine, and dipyridophenazine has only a small impact on the energies of charge transfer type transitions across the visible (vis) to near-infrared (NIR) spectral region and is due to an inversion among spatially distinct but energetically close unoccupied molecular orbitals. Substantial absorptivity across the visible spectral region rather associates with the increasing capability among carboxylato, phenolato, amido, and arylthiolato coligands to engage in Ni-O/N/S π-bonding. This adds a mechanism for electronic coupling of coligand RE- and π?-orbitals at the N-heterocycle fragment through occupied d orbitals at nickel, enabling light-induced charge transfer. Aryl-S- performs best in this regard, but {Ni-O/N/S}-to-(N-heterocycle-π?) charge transfer efficacy depends on donor-acceptor orbital alignment and appears to be kinetically hindered except for amido coligands owing to polar effects. Irrespective of the nature of coligand RE-, the choice of the pendant phenyl/phenol side arm rules overall absorptivity by setting the energy of occupied frontier molecular orbitals.
Combining a Phenanthroline Moiety with Two Peralkylated Guanidine Residues: Janus Head Pro-Ligands
Ortmeyer, Jochen,Vukadinovic, Yannik,Neuba, Adam,Egold, Hans,Fl?rke, Ulrich,Henkel, Gerald
, p. 6085 - 6095 (2017)
A novel family of Janus head pro-ligands is described that combine a phenanthroline moiety with two peralkylated guanidine residues. The bis-bidentate molecules provide coordination sites with metal-differentiating properties and thus are especially well suited to form heterobinuclear complexes. Synthesized members of this family differ in their substitution patterns and comprise variants with tetramethyl-, tetraethyl-, dipentylene-, dimethylethylene-, and dimethylpropylene-guanidino functionalities. They were characterized by low-temperature X-ray crystallography and studied by means of temperature-dependent 1H NMR spectroscopy, which provided information on the dynamics of their guanidine moieties. Furthermore, the redox behavior was investigated by using cyclic voltammetric techniques.
New rhenium(I) complex with thiadiazole-annelated 1,10-phenanthroline for highly efficient phosphorescent OLEDs
Hu, Yong-Xu,Zhao, Guang-Wei,Dong, Yan,Lü, Yan-Li,Li, Xiao,Zhang, Dong-Yu
, p. 569 - 575 (2017)
A new neutral tricarbonyl rhenium(I) complex (Re-TDAP) was designed and synthesized by annelating a thiadiazole unit on the frame of 1,10-phenanthroline ligand. The optoelectronic properties of Re-TDAP were fully investigated. Compared to the 589 nm peak emission of a prototype Re-PHEN (PHEN = 1,10-phenanthroline) in CH2Cl2 solution, annelating thiadiazole group caused the peak emission of Re-TDAP to red-shift to 621 nm. The phosphorescent organic light-emitting diodes using Re-TDAP as dopant were fabricated with the structure of ITO/m-MTDATA (10 nm)/NPB (20 nm)/CBP: x wt% Re-TDAP nm)/TPBi (30 nm)/Alq3 (20 nm)/Liq (2 nm)/Al. The devices showed high performances with maximum efficiencies of 16.8 cd/A, 5.8 lm/W and 5.0%, which was better than that of a prototype Re-PHEN-doped device under the same conditions. These results suggest that rational molecular design is very beneficial to color tunability and photophysical regulation of the complex.
Flexible RuII Schiff Base Complexes: G-Quadruplex DNA Binding and Photo-Induced Cancer Cell Death
Gillard, Martin,Weynand, Justin,Bonnet, Hugues,Loiseau, Frédérique,Decottignies, Anabelle,Dejeu, Jér?me,Defrancq, Eric,Elias, Benjamin
, p. 13849 - 13860 (2020/10/02)
A series of new RuII Schiff base complexes built on the salphen moiety has been prepared. This includes four flexible monometallic RuII compounds and six rigid bimetallic analogues that contain NiII, PdII or PtII cations into the salphen complexation site. Steady state luminescence titrations illustrated the capacity of the compounds to photoprobe G-quadruplex (G4) DNA. Moreover, the vast array of the Schiff base structural changes allowed to extensively assess the influence of the ligand surface, flexibility and charge on the interaction of the compounds with G4 DNA. This was achieved thanks to circular dichroism melting assays and bio-layer interferometry studies that pointed up high affinities along with good selectivities of RuII Schiff base complexes for G4 DNA. In cellulo studies were carried out with the most promising compounds. Cellular uptake with location of the compounds in the nucleus as well as in the nucleolus was observed. Cell viability experiments were performed with U2OS osteosarcoma cells in the dark and under light irradiation which allowed the measurements of IC50 values and photoindexes. They showed the substantial role played by light irradiation in the activity of the drugs in addition to the low cytotoxicity of the molecules in the dark. Altogether, the reported results emphasize the promising properties of RuII Schiff base complexes as a new class of candidates for developing potential G4 DNA targeting diagnostic or therapeutic compounds.
