1115084-83-7Relevant articles and documents
Perylenetetracarboxy-3,4:9,10-diimide derivatives with large two-photon absorption activity
Garoni, Eleonora,Nisic, Filippo,Colombo, Alessia,Fantacci, Simona,Griffini, Gianmarco,Kamada, Kenji,Roberto, Dominique,Dragonetti, Claudia
, p. 1885 - 1893 (2019)
Three new perylenetetracarboxy-3,4:9,10-diimides, bearing 2,6-diisopropylphenyl groups at the imide positions and 4-(R-ethynyl)phenoxy moieties (R = 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole (P2), pyrene (P3) or pyrene-CH2OCH2 (P4)) at the four bay positions, were prepared, along with the known related derivative (R = phenyl (P1)), and well characterized. They have large two-photon absorption (TPA) cross-sections (σ2), as determined by the Z-scan technique, the highest values being reached with P2 which bears a planar π-delocalized donor moiety. P3 is characterized by higher σ2 values than both P1, as expected for the higher π-conjugation of the donor pyrene moiety with respect to phenyl, and P4, due to the presence of the flexible and non-conjugated CH2OCH2 bridge between the pyrene and the ethynyl fragment in the latter compound. The molecular geometry of P1-P4 has been optimized by DFT modeling, showing that in P2 and P3 the bay substituents are stacked due to the π-π interactions of both pyrene and thiophene groups. The LUMO of P1-P4 lies at the same energy and is essentially delocalized on the perylene core whereas the HOMO and HOMO?1 of both P2 and P3 are degenerate and do not show contribution from the perylene core contrarily to that of P1 and P4. The HOMO-LUMO gap is therefore essentially influenced by the HOMO which reflects the electronic charge delocalization on the bay substituents, the lower gaps being observed for P2 and P3, which are characterized by the best TPA properties.
Irreversible Cysteine-Selective Protein Labeling Employing Modular Electrophilic Tetrafluoroethylation Reagents
Václavík, Ji?í,Zschoche, Reinhard,Klimánková, Iveta,Matou?ek, Václav,Beier, Petr,Hilvert, Donald,Togni, Antonio
, p. 6490 - 6494 (2017)
Fluoroalkylation reagents based on hypervalent iodine are widely used to transfer fluoroalkyl moieties to various nucleophiles. However, the transferred groups have so far been limited to simple structural motifs. We herein report a reagent featuring a secondary amine that can be converted to amide, sulfonamide, and tertiary amine derivatives in one step. The resulting reagents bear manifold functional groups, many of which would not be compatible with the original synthetic pathway. Exploiting this structural versatility and the known high reactivity toward thiols, the new-generation reagents were used in bioconjugation with an artificial retro-aldolase, containing an exposed cysteine and a reactive catalytic lysine. Whereas commercial reagents based on maleimide and iodoacetamide labeled both sites, the iodanes exclusively modified the cysteine residue. The study thus demonstrates that modular fluoroalkylation reagents can be used as tools for cysteine-selective bioconjugation.
Chiral Chromium Salen@rGO as Multipurpose and Recyclable Heterogeneous Catalyst
Abd El Sater, Mariam,Mellah, Mohamed,Dragoe, Diana,Kolodziej, Emilie,Jaber, Nada,Schulz, Emmanuelle
supporting information, p. 9454 - 9460 (2021/05/26)
The first immobilization of a pyrene-tagged chromium salen complex through π-π noncovalent interactions on reduced graphene oxide (rGO) is described. A very robust supported catalytic system is obtained to promote asymmetric catalysis in repeated cycles, without loss of activity or enantioselectivity. This specific behavior was demonstrated in two different catalytic reactions (up to ten reuses) promoted by chromium salen complexes, the cyclohexene oxide ring-opening reaction and the hetero-Diels-Alder cycloaddition between various aldehydes and Danishefsky's diene. Furthermore, the chiral chromium salen@rGO has been found to be compatible with a multi-substrate type use, in which the structure of the substrate involved is modified each time the catalyst is reused.
