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Lalrempuia, Ralte
Preferred name
Lalrempuia, Ralte
Official Name
Lalrempuia, Ralte
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Now showing 1 - 6 of 6
- PublicationMethyltransferase Activity of an Iridium Center with Methylpyridinium as Methylene SourceAn iridium center transfers a methyl group from pyridinium to an aryl unit, using exclusively the pyridine-bound methyl group as a mild methylene source. The reaction also involves cleavage of an unactivated C(aryl)[BOND]H bond and nitrile solvent activation. The process is reminiscent of DNA methylation and entails the formation of two new C(sp2)[BOND]C(sp3) bonds within the metal coordination sphere (see scheme).
392Scopus© Citations 32 - PublicationRegioselective Electrophilic C-H Bond Activation in Triazolylidene Metal Complexes Containing a N-Bound Phenyl Substituent(American Chemical Society, 2012-11-29)
; ; ; Transmetalation of a 1,4-diphenyl-substituted 1,2,3-triazolylidene silver complex with an electrophilic metal center, e.g., RuII, IrIII, or RhIII, induces spontaneous and chemoselective cyclometalation involving C–H bond activation of the N-bound phenyl group exclusively. Less electrophilic metals such as IrI, RhI, and PtII yield a monodentate triazolylidene complex, while cyclometalation with borderline cases (PdII) or the activation of the C-bound phenyl ring requires acetate as a promoter.305Scopus© Citations 61 - PublicationSynthesis, Photo-, and Electrochemistry of Ruthenium Bis(bipyridine) Complexes Comprising a N-heterocyclic Carbene Ligand(American Chemical Society, 2013-05-06)
; ; ; ; ; Analogues of [Ru(bpy)3]2+ were prepared in which one pyridine ligand site is substituted by a N-heterocyclic carbene (NHC) ligand, that is, either by an imidazolylidene with a variable wingtip group R (R = Me, 3a; R = Et, 3b; R = iPr, 3c), or by a benzimidazolylidene (Me wingtip group, 3d), or by a 1,2,3-triazolylidene (Me wingtip group, 3e). All complexes were characterized spectroscopically, photophysically, and electrochemically. An increase of the size of the wingtip groups from Me to Et or iPr groups distorts the octahedral geometry (NMR spectroscopy) and curtails the reversibility of the ruthenium oxidation. NHC ligands with methyl wingtip groups display reversible ruthenium oxidation at a potential that reflects the donor properties of the NHC ligand (triazolylidene > imidazolylidene > benzimidazolylidene). The most attractive properties were measured for the triazolylidene ruthenium complex 3e, featuring the smallest gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the series (2.41 eV), a slightly red-shifted absorption profile, and reasonable excited-state lifetime (188 ns) when compared to [Ru(bpy)3]2+. These features demonstrate the potential utility of triazolylidene ruthenium complexes as photosensitizers for solar energy conversion.372Scopus© Citations 95 - PublicationCarbene Iridium Complexes for Efficient Water Oxidation: Scope and Mechanistic Insights(Royal Society of Chemistry, 2014-07-01)
; ; ; ; ; Iridium complexes of Cp* and mesoionic carbene ligands were synthesized and evaluated as potential water oxidation catalysts using cerium(IV) ammonium nitrate as a chemical oxidant. Performance was evaluated by turnover frequency at 50% conversion and by absolute turnover number, and the most promising precatalysts were studied further. Molecular turnover frequencies varied from 190 to 451 per hour with a maximum turnover number of 38 000. While the rate of oxygen evolution depends linearly on iridium concentration, concurrent spectroscopic and manometric observations following stoichiometric oxidant additions suggest oxygen evolution is limited by two sequential first-order reactions. Under the applied conditions, the oxygen evolving species appears to be a well-defined and molecular species based on kinetic analyses, effects of careful ligand design, reproducibility, and the absence of persistent dynamic light scattering signals. Outside of these conditions, the complex mechanism is highly dependent on reaction conditions. While confident characterization of the catalytically active species is difficult, especially under high-turnover conditions, this work strongly suggests the primary active species under these conditions is a molecular species.365Scopus© Citations 94 - Publication
898Scopus© Citations 330 - PublicationTunable single-site ruthenium catalysts for efficient water oxidation(RSC publicating, 2011-06-16)
; ; ; ; ; ; The catalytic water oxidation activity of mononuclear ruthenium complexes comprising a pyridine-functionalized abnormal triazolylidene ligand can be adjusted by modification of the triazolylidene substituents, which is readily achieved through click-type cycloaddition chemistry, affording some of the most active ruthenium catalysts known thus far for water oxidation(TONs > 400, TOFs close to 7000/h).689Scopus© Citations 130