Surface-bound, perylenediimide (PDI)-based molecular assemblies have been synthesized on nanocrystalline TiO2 by reaction of a dianhydride with a surface-bound aniline and succinimide bonding. In a second step, the Fe(II) polypyridyl complex [Fe(II)(tpy-PhNH2)2](2+) was added to the outside of the film, also by succinimide bonding. Ultrafast transient absorption measurements in 0.1 M HClO4 reveal that electron injection into TiO2 by (1)PDI* does not occur, but rather leads to the ultrafast formation of the redox-separated pair PDI(•+),PDI(•-), which decays with complex kinetics (τ1 = 0.8 ps, τ2 = 15 ps, and τ3 = 1500 ps). With the added Fe(II) polypyridyl complex, rapid (<25 ps) oxidation of Fe(II) by the PDI(•+),PDI(•-) redox pair occurs to give Fe(III),PDI(•-) persisting for >400 μs in the film environment.
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http://dx.doi.org/10.1021/acs.jpclett.5b02194 | DOI Listing |
Org Lett
December 2024
School of Chemical Science and Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, Shanghai 200092, People's Republic of China.
Org Lett
December 2024
Soft Molecular Activation Research Center (SMARC), Chiba Iodine Resource Innovation Center (CIRIC), Synthetic Organic Chemistry, Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.
A newly developed -9-anthranylmethyl bis(imidazolidine)pyridine (-9-Anth-PyBidine)-Cu(OAc) complex catalyzed asymmetric haloimidation reactions of alkylidenemalononitriles with -bromosuccinimide and -chlorosuccinimide, employing the succinimide moiety directly as a copper-bound nucleophile. The anthranyl substituent showed a gearing effect that produced a well-organized asymmetric sphere involving the -H proton of the imidazolidine ring in the ligand. The gearing effect afforded hydrogen bonding-assisted copper-catalyzed haloimidation reactions with high enantioselectivity.
View Article and Find Full Text PDFBiofabrication
November 2024
Institute of Biomedical Engineering, Boğaziçi University, Rasathane Cd. Kandilli Campus, Kandilli Mah., 34684 Istanbul, Turkey.
In this research, carboxymethyl cellulose (CMC)/gelatin (Gel)/graphene oxide (GO)-based scaffolds were produced by using extrusion-based 3D printing for cardiac tissue regeneration. Rheological studies were conducted to evaluate the printability of CMC/Gel/GO inks, which revealed that CMC increased viscosity and enhanced printability. The 3D-printed cardiac patches were crosslinked with N-(3-dimethylaminopropyl)-n'-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) (100:20 mM, 50:10 mM, 25:5 mM) and then characterized by mechanical analysis, electrical conductivity testing, contact angle measurements and degradation studies.
View Article and Find Full Text PDFOrg Lett
October 2024
Department of Chemistry, Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Pashan, 411008 Pune, Maharashtra, India.
The traditional intermolecular O-H insertion strategy is typically associated with the reactivity exhibited by the singlet spin state, or it can alter the spin state from triplet to singlet by hydrogen bonding. Herein, we report diazoarylidene succinimide that generates a persistent ground-state triplet carbene under visible light (Blue LED, 456 nm) without a photosensitizer. This triplet carbene undergoes an intramolecular O-H insertion via hydrogen atom transfer, forming a persistent aryloxy radical without altering its spin state and leading to biologically relevant 2-chromenes.
View Article and Find Full Text PDFAdv Sci (Weinh)
July 2024
Department of Bioengineering, University of Oregon, 6231 University of Oregon, Eugene, OR, 97403, USA.
Michael addition between thiol- and maleimide-functionalized molecules is a long-standing approach used for bioconjugation, hydrogel crosslinking, and the functionalization of other advanced materials. While the simplicity of this chemistry enables facile synthesis of hydrogels, network degradation is also desirable in many instances. Here, the susceptibility of thiol-maleimide bonds to radical-mediated degradation is reported.
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