《Mechanical-Bond-Induced Exciplex Fluorescence in an Anthracene-Based Homo[2]catenane》 was written by Garci, Amine; Beldjoudi, Yassine; Kodaimati, Mohamad S.; Hornick, Jessica E.; Nguyen, Minh T.; Cetin, M. Mustafa; Stern, Charlotte L.; Roy, Indranil; Weiss, Emily A.; Stoddart, J. Fraser. Electric Literature of C8H8Br2 And the article was included in Journal of the American Chemical Society in 2020. The article conveys some information:
Collisional intermol. interactions between excited states form short-lived dimers and complexes that lead to the emergence of excimer/exciplex emission of lower energy, a phenomenon which must be differentiated from the photoluminescence (PL) arising from the monomeric mols. Although the utilization of noncovalent bonding interactions, leading to the generation of excimer/exciplex PL, was studied extensively, precise control of the aggregates and their persistence at low concentrations remains a rare phenomenon. In the search for a fresh approach, we sought to obtain exciplex PL from permanent structures by incorporating anthracene moieties into pyridinium-containing mech. interlocked mols. (MIMs). Beyond the optical properties of the anthracene moieties, their π-extended nature enforces [π···π] stacking that can overcome the Coulombic repulsion between the pyridinium units, affording an efficient synthesis of an octacationic homo[2]catenane. Notably, upon increasing the ionic strength by adding tetrabutylammonium hexafluorophosphate, the catenane yield increases significantly as a result of the decrease in Coulombic repulsions between the pyridinium units. Although the ground state photophys. properties of the free cyclophane and the catenane are similar and show a charge transfer band at ∼455 nm, their PL characters are distinct, denoting different excited states. The cyclophane emits at ∼562 nm (quantum yield (ΦF) = 3.6%, emission lifetime Γs = 3 ns in MeCN), which characteristic of a disubstituted anthracene-pyridinium linker. By contrast, the catenane displays an exciplex PL at low concentration (10-8 M) with an emission band centered on 650 nm (ΦF = 0.5%, Γs = 14 ns) in MeCN and at 675 nm in aqueous solution Live-cell imaging performed in MIAPaCa-2 prostate cancer cells confirmed that the catenane exciplex emission can be detected at micromolar concentrations1,4-Bis(bromomethyl)benzene(cas: 623-24-5Electric Literature of C8H8Br2) was used in this study.
1,4-Bis(bromomethyl)benzene(cas: 623-24-5) belongs to organobromine compounds.Most of the natural organobromine compounds are produced by marine organisms , and several brominated metabolites with antibacterial , antitumor , antiviral , and antifungal activity have been isolated from seaweed, sponges, corals, molluscs, and others. Electric Literature of C8H8Br2 Moreover, several studies demonstrate that the average proportion of bromine in drugs is significantly higher than that in natural products.
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary