Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• the two metallic centers in the tweezers cavity in a bridging mode. For the heterometallic Zn/Au system, luminescence quenching was observed in the closed state. The pyridine-hydrazine-pyridine unit has been extensively studied by Lehn and co-workers in coordination-responsive supramolecular polymers

• reversibly reopened by the addition of TREN as a competitive ligand. The authors reported a slight luminescence quenching in the zinc-closed state with a decrease in the quantum yield from 0.27 to 0.21. However, Hg2+ presented a special behavior with the formation of a 2:1 complex, the closing of the

• tweezers by the first equivalent generating an allosteric binding site specific to a second Hg2+ ion. While the addition of one equivalent of Hg2+ decreased the quantum yield to 0.09, the formation of a bis-coordinated [tweezers-Hg2]4+ complex resulted in a total luminescence quenching (quantum yield <10−3

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• -coupled electron transfer (PCET), forming neutral radical species 33 and the corresponding phosphate conjugate base (Scheme 8B). The hypothesis is supported by an observed increase in the luminescence quenching of *Ir(p-CF3-ppy)3 by 32 in the presence of diphenyl phosphoric acid, as quantified by the

NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• indeed recognize the highly positively charged area on cytochrome c (Cyt c) that binds Cyt c peroxidase. The inhibition of this protein–protein interaction was demonstrated as well using a luminescence quenching assay. The protein surface recognition of two porphyrin ligands bearing carboxylate

Investigating radical cation chain processes in the electrocatalytic Diels–Alder reaction

• Yasushi Imada,
• Yohei Okada and
• Kazuhiro Chiba

Beilstein J. Org. Chem. 2018, 14, 642–647, doi:10.3762/bjoc.14.51

• luminescence quenching experiments [19]. With such an understanding in hand, radical ion chain processes could be further optimized to realize greener transformations. We have been developing anodic cycloadditions [20][21][22][23][24][25] enabled by lithium perchlorate/nitromethane electrolyte solution [26

Sexithiophenes as efficient luminescence quenchers of quantum dots

• Christopher R. Mason,
• Yang Li,
• Paul O’Brien,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2011, 7, 1722–1731, doi:10.3762/bjoc.7.202

• dot emission was studied by photoluminescence spectroscopy and compared with the performance of alkyl end-capped sexithiophenes 2a and 2b. Keywords: electrochemistry; luminescence quenching; quantum dots; sexithiophenes; synthesis; Introduction Structurally well-defined oligothiophenes as functional

• , while the high-energy absorption edge for the nanocrystals is 657 nm. Comparison with the absorption profiles for 1b and 2b confirms that no overlap occurs between the emission from the quantum dot and the absorption by the oligothiophene (Figure 5). As such, any luminescence quenching observed would