128073-07-4Relevant articles and documents
Thermodynamic N-donor trans influence in labile pseudo-octahedral zinc complexes: A delusion?
Aboshyan-Sorgho, Lilit,Lathion, Timothe,Gune, Laure,Besnard, Cline,Piguet, Claude
, p. 13093 - 13104 (2014)
While the forces responsible for the chelate effect are well-established in coordination chemistry, the origin and implementation of the related thermodynamic trans influence remains debatable. This work illustrates a simple approach for quantifying this effect in labile pseudo-octahedral [Zn(Lk)3]2+ complexes lacking stereochemical preferences (Lk = L1-L4 are unsymmetrical didentate α,α′-diimine ligands). In line with statistics, the triply degenerated meridional isomers mer-[Zn(Lk)3]2+ are stabilized by 0.8 ≥ ΔGexch mer→fac ≥ 4.2 kJ/mol over their nondegenerated facial analogues fac-[Zn(Lk)3]2+ and therefore display no apparent trans influence at room temperature. However, the dissection of the free energy terms into opposite enthalpic (favoring the facial isomers) and entropic (favoring the meridional isomers) contributions reveals a trans influence assigned to solvation processes occurring in polar solvents. Altogether, the thermodynamic trans influence operating in [Zn(α,α′-diimine)3]2+ complexes is 1-2 orders of magnitude smaller than the chelate effect. A weak templating effect provided by a noncovalent lanthanide tripod is thus large enough to produce the wanted facial isomer at room temperature.
NOVEL NUCLEOSIDE OR NUCLEOTIDE DERIVATIVES, AND USES THEREOF
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Paragraph 0059; 0087, (2020/12/10)
The present disclosure relates to a novel nucleoside or nucleotide derivative, a racemate thereof, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof; and a pharmaceutical composition for preventing or treating viral infection-associated diseases, containing the same as an active ingredient.
Smaller than a nanoparticle with the design of discrete polynuclear molecular complexes displaying near-infrared to visible upconversion
Zare, Davood,Suffren, Yan,Gune, Laure,Eliseeva, Svetlana V.,Nozary, Homayoun,Aboshyan-Sorgho, Lilit,Petoud, Stphane,Hauser, Andreas,Piguet, Claude
, p. 2529 - 2540 (2015/02/19)
This work shows that the operation of near-infrared to visible light-upconversion in a discrete molecule is not limited to non-linear optical processes, but may result from superexcitation processes using linear optics. The design of nine-coordinate metallic sites made up of neutral N-heterocyclic donor atoms in kinetically inert dinuclear [GaEr(L1)3]6+ and trinuclear [GaErGa(L2)3]9+ helicates leads to [ErN9] chromophores displaying unprecedented dual visible nanosecond Er(4S3/2→4I15/2) and near-infrared microsecond Er(4I13/2→4I15/2) emissive components. Attempts to induce one ion excited-state absorption (ESA) upconversion upon near-infrared excitation of these complexes failed because of the too-faint Er-centred absorption cross sections. The replacement of the trivalent gallium cation with a photophysically-tailored pseudo-octahedral [CrN6] chromophore working as a sensitizer for trivalent erbium in [CrEr(L1)3]6+ improves the near-infrared excitation efficiency, leading to the observation of a weak energy transfer upconversion (ETU). The connection of a second sensitizer in [CrErCr(L2)3]9+ generates a novel mechanism for upconversion, in which the superexcitation process is based on the CrIII-sensitizers. Two successive Cr→Er energy transfer processes (concerted-ETU) compete with a standard Er-centred ETU, and a gain in upconverted luminescence by a factor larger than statistical values is predicted and observed.
